Ray's 1987 944 LS1 Build & Swap

Turbobob924...Thank you!

I love doing the documentation because similar efforts by others on the Forum have helped me so much in my build!  Just my way of giving back.

I have more posts coming on my final vacuum lines arrangement for PCV and HVAC...and my fuel line, and my wiring harness connections.  Hopefully soon!!

If only the grass would grow a bit slower and the "honey-do" list would end...(never really happens!!)

I hope you and all Americans enjoyed our freedoms to the fullest yesterday in honor of those that paid the ultimate price for it!

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The rest of the story…

This has been a long time coming but as you all know, life happens!

Vacuum line routing is a particularly mundane and tedious effort so if you prefer to skip the narrative, below is a schematic of my final vacuum line set-up for PCV and HVAC.

If anyone that’s been down this path sees an error in my ways… please let me know.  TIA!!

<<<<HOLD THE PRESS>>>>

I got some critical input from Bob at Hotrodz of Dallas and learned that the rear FAST manifold port I selected for my vacuum source is too much vacuum for PCV use and will result in oil loss.  It is however, fine for HVAC use.
I'll be changing my diagram below to reflect use of the FAST vacuum port on the front PS just past the throttle body.  Stay tuned.

Thanks Bob for your input!!!!

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<Updated Schematic>

The following is the blow-by-blow narrative account with some photos:

PCV Valve Vacuum Line

I received some valuable input from the forum and learned that GM has moved away from using the old style PCV ball-valve that generates intermittent vacuum, and now uses orifice type units with steady vacuum, calibrated for specific engine applications.  Not knowing what orifice calibration is right for my engine, I elected to go old school and returned to my local AutoZone and pick up a factory PCV Valve replacement for a 93-97 GM 350 V8.  This PCV valve has about 3X the air flow as the Beck-Arnley unit, so I feel good about moving forward. Duralast PCV Valve P/N: PCV1107DL  $1.85

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<Replacement GM PCV Valve>                                              <GM-PCV Valve Hose Adapter>

The larger crankcase side of the PCV valve normally fits in a valve cover grommet provided for the PCV and has a 3/4 in. OD.  My challenge was to adapt this PCV valve to the 3/8 in. nipple on my Holley valve cover.  Fortunately, I had a multitude of hose types and sizes on hand to get started, not to mention a boatload of SS hose clamps in various sizes.  Nonetheless, I still made multiple runs to my local AutoZone.

As it turns out, the GM PCV valve fits tightly inside 3/4 in. ID heater hose.  Conveniently, the 10 mm - 3/8 in. ID Air Brake hose supplied with my TPC Hydro-boost kit also fit tightly inside the 3/4 in. hose and provided the connection I needed to valve cover nipple.

To complete the PCV vacuum line, the forum guys recommended a universal “see-through” in-line fuel filter to collect any excess oil evaporation.  This will be changed out periodically as needed. I picked up a Duralast unit for 5/16 in. line for $5 at AutoZone.

For ease of connection and a good seal, I used Syl-Glide on all the connections, and clamped everything tight with SS hose clamps.
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<FAST PCV Vacuum Port>                                     <Completed PCV Valve and Filter Installation>

For the PCV valve vacuum source, the 7/16 in. (11mm) OD nipple on the FRONT PS of my FAST 92mm intake manifold is the correct vacuum port to use. This port has a 3/16" orifice into the manifold. A standard 3/8 in. ID PCV line can be routed from this nipple to the PCV valve with an in-line fuel filter.  
For a tighter line between the fuel filter and the vacuum port, I opted to use a custom bent section of 10mm aluminum AC line with short sections of 3/8 in. ID PCV line as connectors.

The last step for the PCV system was to prepare a proper air intake.  This was simple and involved connecting a 17 in. piece of 3/8 in. PVC line on the DS valve cover nipple and then attaching a small universal air filter on the end.  I came up short on the 3/8 in. PVC hose and used the 3/8 in. TPC air brake hose I had left over.  For the air filter, I purchase a Spectre Performance 3991 Black 9mm Breather Filter ($12) from Amazon.  It came with a SS hose clamp and I used a short piece of 10mm aluminum AC line to make the connection to the 3/8 in hose. I mounted the filter on the firewall with a hose clamp where I could get at it easily in the future.  

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<Spectre Performance 9mm Air Filter>                         <PCV Air Filter Firewall Mount>

HVAC Vacuum Lines

For the HVAC vacuum source, I used the 1/2" OD nipple on the back of my FAST 92 intake manifold. On a whim, I grabbed a spare standard 90-degree spark plug boot and tried it on for size. I was pleased when the spark plug side fit perfectly on the FAST nipple and the cable side fits perfectly around 5/16 in. ID fuel line hose for the HVAC vacuum source.  

Although it was a tight fit, I used marine grade shrink wrap for an airtight connection. Apparently the 5/16 in. ID fuel line runs a bit small because it’s a perfect but tight fit for the 9/32 in. OD of 5/32 in. ID Porsche plastic vacuum line which will be the vacuum source that connects to both the vacuum reservoir canister and the HVAC unit.

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< Spark Plug Boot, 5/16” Fuel Line, Shrink Wrap >                 <Completed Assembly>

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<HVAC Vacuum Line on FAST Rear Port>          <Doorman ~4mm OD Emissions Hard Line (Top)                                                                                <Porsche Plastic 4mm OD HVAC Line (Bot.)>              

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<Final HVAC Vacuum Line Firewall Connections>           <Heater Valve Solenoid Connection>            

So, the 5/32” ID vacuum line with the Porsche check valve gets connected directly to the upper firewall HVAC nipple (#4).  The lower firewall HVAC nipple (#5) is connected via a Porsche hard HVAC 4mm OD line (orange) to a Porsche rubber Tee.  This is the vacuum source for both the vacuum reservoir canister and the heater valve solenoid.  I purchased a new 3 ft piece of 5/32” (3.9mm) OD “hard” emission tubing from AutoZone, DORMAN, PN 47418, $9.  A small piece of 5/32 in. ID vacuum line was needed to make the connection to the solenoid.

Now I can finally install the fuel rail cross-over line and reroute the fuel line.  That will be next along with extension of the driver’s side coil pack wiring.

After getting the HVAC and PCV vacuum lines sorted out, I could now install my FAST fuel rail cross-over line without concern that it was in the way of anything else.  It’s a 3/8” SS hose with -6 AN fittings.  I thought it would be simple to connect the AN fitting, but the SS line has enough “spring” when curved to make it difficult to properly align and start the AN threads.  One side goes on easy enough but the other side… not so much.  Aluminum AN fitting can easily cross-thread so it’s important to get them started by hand.  The solution was to loosen the AN connector on the fuel rail so I could get good alignment with the AN fitting from the cross-over. I then tightened all the fittings until “snug.”

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<FAST Fuel Rail Cross-over Line>

The next order of business was to reroute the 10mm factory fuel supply line.  First, I removed the fuel & brake line retaining brackets using a 4mm Allen wrench.  They’re nylon so don’t be too aggressive with these.

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<Removing the Fuel & Brake Line Bracket>                     <Mounting Stud and Rubber Cushions>

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<Cutting the Fuel Line>                                 <10mm Fuel Line ID Comparison with -6 AN Fitting>

My original plan was to introduce a second 90-degree bend in the fuel line redirecting it horizontally to the front of the wheel well. I quickly abandoned that idea as bending a 10mm steel line in place is not as easy as I thought… in other words, I don’t have enough arm/hand strength to pull it off with the tools available.  My next approach was to cut the line at the bottom where it was already horizontal.  

I used my Rigid mini tube cutter for the job, being careful to progress slowly by keeping the cutting wheel pressure low with multiple revolutions.  The cut was clean but still required some deburring which I did by hand with a rat tail file.  I then cleaned out the line with a Q-Tip doused in Amsoil MP (like WD-40).  After the cut, I noticed that the ID of my Summit -6 AN female hose end adapter was smaller than the ID of the 10mm fuel line.  After measuring these and some of my other hardware, below are my findings:

10mm Fuel Line ID = ~8.25mm (a 5/16” drill bit fits loosely)
Summit -6 AN Hose Adapter to -6 AN F
              At fitting end = ~6.75mm (0.266”) (a 17/64” drill bit fits)
              At taper end = ~6.70mm (0.264”) (a 17/64” drill bit won’t quite fit)
FAST -6 AN M ID = ~7.3mm (0.285”) (9/32” drill bit fits loosely)
Advertised Standard -6 AN ID = 8.6mm (0.34”) for flexible hose
The advertised standard ID for -6 AN is an equivalent for 3/8” (0.375” or 9.5mm) ID hose.  I’m a little concerned that the AN M fitting ID is only 0.285” or 7.3mm.  This is a 24% reduction in fuel line ID ((0.375-0.285)/0.375)100 compared to a 3/8” ID hose. I’m even more concerned that the tapered hose insert of the Summit -6 AN Hose Adapter is 0.264” or ~6.7mm. which represents nearly a 30% reduction in fuel line ID.   TO ME THIS IS A SIGNIFICANT RESTRICTION.

This prompted me to do some research and I discovered that there are two (2) AN standards, one for General applications, and one for Transportation and Refrigerant applications.  Below is a chart from Colliflower Hose and Fittings that shows the differences:

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REF: [You must be registered and logged in to see this link.]

Notice that the -6 AN hose size for Transportation applications is 5/16” ID vs 3/8” ID for General applications. If I use 5/16” (0.312”) as the -6 AN hose ID, the percent reduction in fuel line ID previously calculated for the -6 AN M and -6 AN hose end adapter become 8.7% and 15.4% respectively.  This is better but does it really matter when using EFI??

According to the Summit HELP Center:
REF:https://help.summitracing.com/app/answers/detail/a_id/4879/kw/Fuel%20line%20size
The recommended fuel line size from Tank to Pump for an engine producing 350-450 HP is 3/8” or -6AN. The Fuel Return Line should be at least the same size, or one size larger than the supply.  
So…my 3/8” line and -6AN fittings should be OK for this section of fuel line.

For the fuel line from pump to engine, according to the JEGS Help Center:
REF: [You must be registered and logged in to see this link.]
EFI system flow rate and fuel pressure are not particularly sensitive to fuel line size.  Rather, key factors are pump volume and pressure.  The OEM replacement Bosch pump for my ‘87 944S (PN05800464069) produces 39 GPH at 58 psi through a 5/16” line.  The Corvette fuel filter/pressure regulator also operates at 58 psi though a 5/16” line.

Using a B.S.F.C. (Brake Specific Fuel Consumption) of 0.50 lbs fuel per hour per HP, and a target 450 HP, my projected required fuel rate is 225 lbs/hr.  
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Since a gallon of gasoline weights ~6.1 lbs, the calculated fuel flow rate for optimum performance is 225/6.1 or 36.9 GPH.  This compares favorably with the Bosch pump output of 39 GPH.  I’m good to go!!  
Correction: Please see a subsequent post regarding the Bosch fuel pump I'm using. (link below)

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It’s as if someone already figured all this stuff out!

In conclusion, from what I can gather, the ID reduction present in the Summit -6 AN hose end adapter will not be an issue.  Forum feedback on this is welcome!

The next step was to install a -6 AN M Steel Compression Fitting on my 10mm feed hard line. This is Item “H” on the Component Diagram in my 1/31/22 Post entitled,  Fuel Line Modifications – Part 1 Planning.

The factory Porsche fuel line appears to have a PVF (Polyvinyl Fluoride) coating which I have on good authority does not need be removed.   The contents of the engine side supply line was unknown but the tank to fuel pump line was completely “gunked” up when I removed the old pump.  As a precaution, I mixed up a cup of SAE 30W motor oil in a quart of gasoline and gravity fed it through the fuel line from the engine side into a catch can at the rear.  It was a good decision as there was plenty of dirt/debris in the line.  When I did this a second time for good measure, the fuel did not flow through completely like the first time.  The line appeared to be clogged.  I applied some compressed air at the engine side and whatever was stuck in there is now gone and the line is fully open!  The oil/fuel mixture that came out was clear.  

After a good exterior tube cleaning with some BrakeKleen, it was time to install the compression fitting.
The fitting came from DiscountHydraulicHose with a washer and O-ring which are not used with a hard line and cutting ring.

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<Compression Fitting Component Orientation>

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<Compression Fitting Line-up>                                     <Compression Fitting Hand-Tight>
(2 is just a fitting number I used)                                  (I marked 12 o’clock for improved view)

Installing the Compression Fitting

Interestingly, virtually all major tube fitting brands use the same standard instructions for tube fitting installation.
1. Insert the tubing into the fitting until it bottoms out on the fitting shoulder.
2. The shoulder is a stopping point inside the fitting body. By bottoming the tubing out against the shoulder you’re making sure that the ferrule (cutting ring) has enough biting surface on the tubing for a strong connection.
3. Tighten the fitting nut by hand until hand-tight.
4. Using a marker, mark the fitting nut and body at the 6 o'clock position.
5. Using a wrench, tighten the nut 1-¼ turns from the hand-tight position ending with your mark at the 9 o'clock position.
6. Check the gap between the fitting body and the nut using a gap gauge

I’ve read that Step 6 is skipped by many people, and it's the reason that tube fittings have such a high average of failures.  
REF: [You must be registered and logged in to see this link.]

After forging ahead with the first 5 steps, I checked with the DiscountHydraulicHose support team but did not receive a gap recommendation, presumably because of the multitude of variables involved. The instruction I received for PVF coated tube was to tighten the tube nut 1 full turn after hand tight, and then check for tube deformation.  Of course, I was cautioned not to overtighten the fitting.

Having already turned the tube nut 1-1/4 turn, I was a bit concerned and compelled to check the internal diameter of the line for deformation.  Unfortunately, this really isn’t possible without taking the fitting apart and I’m not sure how that would affect the seal.  I could pass a 9/32 in. drill bit inside the fitting and down the tube, but the tube diameter is very close to 5/16” ID and there was no noticeable restriction.  If it leaks, I guess I’ll find out later.  At least it’s easily accessible.

Next, I did clean-up cuts on my Summit brand 3/8” (-6 AN) braided SS fuel line in preparation for 2-Summit -6 AN female adapter ends.   The experts all say NOT TO MIX BRANDS for best results.  I used a cut-off wheel and a 360 degree hose clamp to prevent fraying.  It’s important to clean the debris from the hose after each cut.  

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<Clean-up Cut on SS Line>                              <Installing the Summit AN F Hose Adapter>

To install the Summit hose end adapter, the socket nut is pushed on the SS line until it seats on the inner shoulder.  I marked this position with blue masking tape to make sure I maintained full depth.  Next I sprayed some Amsoil MP on the fitting insert tube nipple and began threading the fitting into the socket nut.  I used some electrical tape on the fitting to help prevent marring.  I tightened the connection in accordance with Summit guidelines leaving a 0.030” gap.
Summit warns that this gap is a MUST to prevent the nipple from breaking.

As seen in the following photos, the fuel line cut location I picked was not ideal in that the compression fitting is directly over the brake line connection.  This pushes the fuel line out away from the inner fender and consequently the rear line clamp could not be reinstalled with the fuel line included.  I substituted a couple ZipTies to secure the line.

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<SS Line Connection to the Compression Fitting>        <ZipTie hold-down of Fuel Line>

My goal was to have NO FUEL LINE SPLICES in the engine bay between the fuel rails and the fuel feed lines other than AN connections.  Originally, I planned on running the SS fuel feed line through a new hole in the inner fender, but soon realized the line will NOT fit behind the inner fender liner due to the required bend arc.  I decided to go under the frame rail instead and added a sleeve of 3/4” ID heater hose for protection. (Note: The fuel line is only snug against the frame.)

An available threaded stud on the underside of the frame rail was perfect for a fuel line hose clamp to keep the line secure.

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<3/4” ID Heater Hose Fuel Line Protection>       <Under Frame SS Fuel Line Clamp>

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<SS Fuel Line Mounting Bracket>                        <SS Fuel Line Connection to FAST Fuel Rail>  

The final engine side connection was to the front passenger side FAST fuel rail.  I made an aluminum mounting plate with a 90 degree twist and used an insulated hose clamp to positively connect the SS Fuel Line to the frame.  Conveniently, there is a threaded hole in the frame perfectly located for my mounting plate!  The line is now locked in with plenty of clearance between the heater and radiator hoses.

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<FAST Fuel Pressure Gauge>                             <FAST Fuel Pressure Gauge Extension>

The last add-on was the FAST Fuel Pressure Gauge on the front of the DS fuel rail.  As noted earlier, I had to provide a brass extension assembly to clear a FAST manifold bolt.  I used Permatex Liquid PTFE sealant on all pipe thread connections.

After doing all this research on the fuel line requirements for my build, I wondered if the FAST 36 lb/hr fuel injectors I picked back in 2015 were correct.  Once again, I relied on the JEGS Help Center for guidance on Fuel Injector Size.

Fuel Injector Size Check:
Based on Target Horsepower:
HP x BSFC
--------------- = Required Injector Size (lbs./hr)
# Inj. x DC

Where:
HP = Estimated Horsepower.
BSFC = Brake Specific Fuel Consumption.
This is the amount of fuel it takes
to make one horsepower for one
hour. Use .45 to .50 for efficient normally aspirated performance engines and .55 to .60 on forced induction applications.

# Inj. = Number of fuel injectors used.
DC = Maximum duty cycle of the injectors.
Try to keep your duty cycle below
80%, so a good value here is .80.


My Porsche Project calculation for a target 450 HP: (450 x 0.50) / (8 x 0.80) = 35.1  SAY 35 lb/hr

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<My FAST 36 lb/hr Injectors>

Looks like I’m good to go!!  

Next up, sorting out the Wiring Harness and engine electrical hook-ups.
Fuel Line Modifications…Part 3, Tank Side will follow that but only after I get the transaxle back in the car.

Noticed you are venting your pvc system to atmosphere with a filter on the clean side. This is going to cause you to run lean since you are introducing unmetered/unaccounted for air into the engine. The car will run ok like this, as the 02's and fuel trims will correct fueling, but you may experience a rough idle lean stumbles during tip in and transients. You will also chase your tail some when tuning and trying to dial in fueling. To alleviate any drivability issues, i would tap in the clean side to somewhere in your intake after the MAF.

Leva,

Thanks for your input.  I truly appreciate it!  When I get to starting and tuning this beast, I'm sure I'll need some additional guidance!  BTW, I'll be using a MS3-Pro.

I need a little clarification on your comment.    

My understanding is that the "clean side" is the fresh air intake for the crankcase and this is where I used a mini air filter to keep the bugs out.  

The "dirty side" is where the PCV valve draws out crankcase vapors and it's located on the front of the PS valve cover.  The PCV vacuum source is a manifold nipple just behind the throttle body.  The filter you see in the pic is a universal inline fuel filter to trap any excess oil mist that might be extracted.

If I recall correctly, the MS3-Pro uses a pair of wideband air/fuel ratio meters ($$$), one in each exhaust pipe just beyond the header collectors, vs. an air intake MAF sensor. The FAST manifold does have a MAP sensor in the back which is also feeding data to the ECM.  

Am I missing something??

Disregard Raymond. I assumed you were running a stock ecm. It sounds like you are running a speed density megasquirt. SD will not care about the vacuum leak you created as it meters air with the MAP sensor, and there is no MAF downstream.

Btw, i would suggest investing into a catch can. Just took a closer look at your setup. You will be changing those fuel filters often. These LS motors love to pool oil in the intake. I ran a similar setup to yours for an initial start, and was mopping out the pool of oil from the bottom of my intake when i revised my CAI and decided to open the throttle blade and take a peak. These motors are known to inhale oil from the valve train.

Leva,

Thanks for the advice!  I don't know why LS motors loose so much oil through the PCV system but I'm hoping the design of my Holley valve covers will help mitigate the problem.  The vacuum ports on these covers vent a chamber behind an oil splash shield.

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<Holley VC Underside Splash Shield>

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<Stock LS1 Valve Cover>

Another change that will likely reduce oil consumption is using synthetic oil.  This is because it's mineral oil base is much more stable than refined petroleum.  Light/multi-weight conventional oils are known to "evaporate" 1/2 to 1 full quart every 5000 miles.

I'll know soon...hopefully!!

Before getting into the electrical...I opted to get all the secondary radiator hoses sorted out.  I posted the details as an edit in my Mon Jan 03, 2022 radiator post.  Below is how it turned out.

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<Final Fill, Overflow, and Steam Vent Hose Connections>

I also connected the fan motor leads and the radiator water temperature sensor lead.

Moving on to electrical now... more on that soon!

Greetings forum friends!!!  

Once again 3 months have slipped by without much progress on my electrical system, particularly my new hybrid wiring harness installation. I attribute this to the fact that I’m way outside my area of expertise. I'm definitely learning as I go....

However, I have been pecking away at other electrical connections that are necessary but not particularly interesting unless they’re still on your project to-do list also:

1. Coil Pack #7 Pigtail Connector Extension
This effort started out as a simple exercise in butt splicing wires.  However, in my effort to understand and document pigtail wire colors prior to any cutting, I discovered a “deal breaker” wiring glitch. The factory coil pack connectors from my stock LS1 harness have the exact OPPOSITE wiring configuration compared to my LS2 coil packs. The decision to go to LS2 coil packs was mandated by my Holley valve covers which do not accept LS1 coil packs.

Consequently, I had to disassembly every LS1 coil pack pigtail connector and re-configure the wires to match my LS2 coil packs.  After that, I was set to extend the pigtail wires as needed.  I used butt splice connectors with integrated shrink wrap but in a test crimp the shrink wrap was damaged.  A piece of new shrink wrap on each wire before crimping the connectors solved the problem.  As you can see below, two splice wires were not matching colors, but I can live with that.  In hind sight, I should have staggered the splices.  

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<Coil Pack Pigtails - LS2 Top & LS1 Bottom> <Butt Splice Connectors with Damaged Shrink wrap>

After making all the crimps with my Wirefy crimper, and heating the added shrink wrap, I slipped a length of heat wrap over the wires and secured it in place with electrical tape.  Looks decent…

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<Coil Pack #7 Pig Tail Extension Splices>              <Completed Extension w/Heat Wrap>

2. Starter Solenoid Signal Wire
This was simple enough.  I had disconnected the Porsche solenoid signal wire (red w/black stripe) connector at the fire wall and at the starter when I pulled the engine.  My LS wiring harness had the factory solenoid signal wire (purple) with a plug-in connector just looking for a home.  Both appeared to be 12-gauge stranded copper wire.  To make the connection, first I reconnected the Porsche wire at the firewall and cut it to the length needed.  I also cut off the Porsche alternator trigger wire (blue) just beyond the connector plug.  Pretty sure I don’t need that.  Second, I cut off the LS1 wire plug-in connector.  I used a 12-gauge wire butt splice connector with a sleeve of shrink wrap to make the merger.

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< Porsche Solenoid Signal Wire>                           < LS1 Solenoid Signal Wire>

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<Solenoid Wire Splice Prior to Shrink Wrap>                  <LS Alternator Trigger Wire Extension>

3. LS Alternator Trigger Wire
There has been a significant amount of forum discussion regarding use of an alternator trigger wire.  At this stage I’ve elected to connect it for two reasons: 1) my new alternator has a place for it, and 2) my LS1 wiring harness includes a trigger wire already integrated into the MS3 Pro ECM.  This is a small gauge wire that I spliced and extension using an 18-22-gauge wire butt splice connectors.  At some point after start-up, I will certainly do some charging circuit testing to see if all is well.

4. Alternator Charging Cable
This was a matter of threading my new alternator charging cable neatly though the maze of existing hoses and lines, clamping it in place as needed, and fishing it through the firewall opening to the battery box.  Normally, the alternator cable can be connected to the primary power post on the starter solenoid… same as the battery positive cable.  I elected not to do that because of limited space between the starter and headers.  The alternator cable now runs along the upper firewall, well away from the headers.  See the yellow arrow in the pic.

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<Alternator Cable “Northern Route”>                     <Battery Ground Cable at Cylinder Head>

5. Primary Ground Connections
The factory Porsche main ground cable to the engine has a copper connection lug at one end for an 8mm bolt and a factory soldered lead battery terminal connector at the other end.  The terminal connector also has a secondary chassis connection wire built in.  I used this factory ground cable as is with one exception… I drilled out the copper lug to fit a 10mm bolt needed to make the ground connection to the passenger side LS1 cylinder head.  I used a plated steel bolt with a serrated locking flange and coated the threads with Permatex anti-seize to prevent galvanic action between with the aluminum head.

I also still needed to connect 3 low voltage harness ground wires with ring connectors for a 10mm bolt.  After a good clean up, I connected all three to the driver’s side LS cylinder head.

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<Harness Ground Wires>                                         <Ground Wires Connected to LS Head>

6. Routing the Battery Cables Through the Firewall
Once I had the primary electrical cables configured, the next step was to get them through the firewall into the battery box.  The factory location was ideal, but the rubber grommet was designed for 2 cables…nothing an X-Acto knife couldn’t fix.  It now accommodates 3 cables.  Recall that I added a separate cable from the alternator to the battery.

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<Modified Firewall Grommet for 3 Cables>

7. Battery Installation
The battery box needed some work before installing the new battery.  It had some pin holes in the bottom that I patched with epoxy compound.  After a thorough cleaning of all visible components, I applied several coats of Rust-Oleum Red to the sheet metal that made it nice and pretty.  After the paint dried for 24 hours, I placed a piece of dense closed-cell sponge on the battery box floor and installed the battery.

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<Original Battery Box Condition and Factory Battery Cables>

The battery terminals needed addressed as well.  The ground cable cleaned up nicely.  I used a wire wheel to make the lead terminal connector look like new, and as previously noted, I drilled out the mounting lug hole and added some shrink wrap at that end to seal the factory insulation.

The factory positive battery terminal connector was not going to work because my new starter cable and alternator cables were both made with lug connectors, 10mm and 8mm respectively.  

In lieu of fabricating a bracket to use with standard terminal connectors, I elected to buy new units that had provision for the multitude of secondary power wires.  For about $8 on Amazon, I got a pair of quick release, 4-way connector terminals from LYCARESUN… yes made in China.     I couldn’t find anything comparable made in USA.  I only needed one and to make it work, and I replaced the quick release mechanism with a suitable bolt and nut which I also used to connect the starter cable.  I used one on the 4 connectors for the alternator cable and the other 3 for the secondary power wires.  The factory insulation on the secondary power wires was brittle and cracked in multiple places so I added some marine shrink wrap to complete the overhaul.

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<Factory Positive Cable Battery Terminal Connector> <New 4-Way Terminal LYCARESUN Connector>

8. Install the Cruise Control
With the battery cables all where they belong, I was now able to reinstall my cruise control unit which I bead blasted and repainted.  I also cleaned up all the electric connections.  It looks good, but how the wiring connects to my LS1 wiring harness is one of the mysteries yet to be resolved.

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<Cruise Control Unit – Before>                                    <Cruise Control Unit – After>

The throttle cable sheathing was broken but I repaired that with a piece of fuel line and electrical tape.

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<Cruise Control Throttle Cable “Kink” and Retrofit Sheath Repair>

9. Brake Line Blow Out  (Not Electrical)
In prior posts, I documented modification and/or rehab of the brake master cylinder and front brake lines.  The last step before making the final connections to my rebuilt calipers was to blow out the lines with compressed air. This was not needed on the driver’s side as I removed and drained the line in the process of reconfiguring it.  It was however necessary for the rear brake lines and the front passenger side line.
Most of the brake fluid had dripped out already but there was some old fluid that remained, and I was happy to get that out.  The inner fenders will go back on after I do a leak test for the brakes and fuel line.

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<Contaminated Brake Fluid in the Front PS Line>            <Completed Brake Line Connection>

10. Electrical Systems Test
The electrical system can now be energized by simply connecting the negative battery terminal. I figured I might as well do some tests to see what works and what doesn’t.

First, I checked continuity between the positive and negative terminal connectors….nothing, so that’s good.   I then connected the positive and negative cables to the battery in that order… no sparks as expected.

A BIG MOMENT….

After sitting dead for nearly 20 years, I inserted the key in the ignition and successfully cranked over my new LS motor for the 1st time.  YAY!!!!!!   I also had gauge power, dash lights, dome light, HVAC fan, power windows, and parking lights.  This was a big step that was a long time coming.

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<20 Years of Hibernation>                                             <It’s ALIVE!>

Still no power seat response but I’m pulling the seats anyway to get reupholstered.  My voltmeter says they have power so it appears the drive motors might be seized.  

I have pulled the driver’s seat which gives me “comfortable” access to the foot well.  
This will allow me to:
        1. Reinstall the clutch pedal return spring and clutch pedal thrust shaft pin.
        2. Check/Adjust brake pedal light switch
        3. Remove Porsche throttle cable
        4. Install TPC throttle cable

More on those items soon…  followed by reconditioning and installation of the rear cross-member.

I’m still hopeful I’ll get input from my nephew soon on the remaining wiring harness connections.

I got myself under the dash and it was much more pleasant with the seat removed.  I used a thick piece of cardboard to lie on which really helped me slide in and out as needed.

One loose end was reconnecting the clutch pedal to the master cylinder thrust shaft clevis.  I originally set the shaft length to match the factory MC as described in a project post on 12/22/2021.
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Wow, that was nearly a year ago!

Anyway, I had to depress the clutch pedal just slightly to align the pedal connection pin with the clevis. There is still no fluid in the MC so moving the pedal was no problem.

Now on to removing the Porsche throttle cable.  
If you have cruise control, make sure you remove the correct cable (green arrow in the pic below). A large, long, flat blade screw driver did the job.  This was followed by pulling the factory throttle cable through the firewall grommet from the engine bay side.
The cable sheathing has a plastic barb attached at the end that secures it in the grommet.  Give the cable a slow steady pull to extract the barb from the grommet.  The grommet can now be removed from the firewall and the entire throttle cable extracted.

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<Throttle and Cruise Control Pedal Connection>              <Throttle Cable Disconnected>


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<Factory Throttle Cable Grommet Barb>                         <Vacant Firewall Throttle Cable Hole>

With the factory cable on the bench, I was able to compare it closely with the throttle cable provided in my TPC conversion kit.  Unfortunately, neither end is exactly compatible.

Fortunately, I can remove the cable connection hardware on the throttle body end and attach the cable barrel connector that I need.  No problem there.

The cable connection hardware on the pedal end is a clevis, shaft, and cotter pin.  This is not compatible with the shaft on the factory pedal which has a shoulder to retain the rubber connector on the factory cable.

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<Throttle Cable Pedal End, TPC & Porsche>

It seems my best option is to replace the cable wire within the TPC throttle cable with the factory Porsche cable wire.  I can do this by cutting the Porsche cable wire at the throttle body end and removing it from the cable sheathing, complete with the factory pedal end connector.

Other possible options:
1) Splice the Porsche cable end to the TPC cable
2) Modify the TPC clevis and/or pedal pin
3) Something else???

ADVICE NEEDED!!!

Before I start cutting, I’m open to Forum suggestions.  Let me know what worked for you.

Thanks in advance!!

Drill out the clevis to where it will just slip over the pedal post. Then make a grommet to fit between the forks of the clevis and is a tight fit over the post. Snap the clevis over the post similar to the stock cable.

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Thanks Bob!

That's an option I didn't think of! Since I already cut my factory cable, perhaps the rubber connection can be repurposed as the grommet you described.

I now have a direction....Much appreciated!

After getting good advice from Bob at HotRodz of Dallas, I began reconfiguring my TPC throttle cable.

First the pedal end…

The clevis at the pedal end needs adapted with a new grommet to fit the pedal post.  The Porsche throttle cable end connector at the pedal is made of black plastic with an integrated rubber grommet so I could not repurpose it.

However, it didn’t take long to find a grommet substitute which turned out to be a short (3/16”) length of flexible 3/16” ID reinforced rubber fuel line that I had on hand.  The TPC clevis pin is 5mm in diameter and about the same size as the Porsche end connector grommet hole.  Conveniently, the fuel line ID is a shade less than 5mm and makes for a snug fit on the pedal post.  The fuel line OD is 9/16”… which fits nicely within the clevis forks.

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<5/16” Reinforced Fuel Line “Grommet”>                     <Homemade Grommet and TPC Clevis>

To provide positive retention of this custom cable end on the pedal post, I considered either a 3/16” (4.7mm) hairpin retainer or a modified 4.76mm U-Type Speed Nut.  I opted for the speed nut because the hairpin technically should be behind a washer that can’t be put on. The speed nut required modification so I could slide it over the pedal post behind the conical shoulder.  This involved cutting a slot in the back plate. I had to use the 4.76mm speed nut because the smaller nut could not be slotted wide enough without destroying the back plate.

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<Doorman Hitch and Hairpin Assortment $3.69>        <Needa Parts Assorted Speed Nuts $4.89>

To cut the spring steel of the speed nut, I used a small diameter, narrow blade, cutting wheel from my Dremel Tool set in my pneumatic die grinder.  I clamped the speed nut in my Vise-Grips for stability and used a small Allen wrench to spread the back plate from the front plate.  This helped prevent cutting through the front plate of the nut.

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<Modified 4.76mm U-Type Speed Nut>                <Custom Pedal Post Connector “Mock-up”>

I did a mock-up of the connection using the TPC clevis pin.  Note that I cannibalized the Porsche throttle cable using the factory firewall grommet in conjunction with the TPC mounting hardware.  

The next step was to drill out the TPC clevis forks to fit over the Pedal post shoulder.  It would have been nice to know the shoulder diameter so I could bench drill it but alas, it was unreachable for measurement.  So….while under the dash, I progressively drilled out the clevis pin hole until it fit over the pedal post.  This was challenging but after 4 incremental attempts, I’m happy to report the required hole diameter is 9/32”!

Once on the car, as Bob indicated, the new custom rubber grommet provides substantial friction resistance on the pedal post… use of a speed nut is just me being extra cautious. The pointed end of the pedal post shoulder provides positive mechanical resistance keeping the retainer in place.
My back and neck are relieved that this part of this build is OVER!!

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<Completed Connection at the Pedal>

Now for the throttle body end…

The TPC post connection cable end is not compatible with the throttle body cam. The LS type throttle cam requires a 7mm diameter cable stop barrel that accepts a 1/16” diameter cable wire.  This barrel was included in my TPC kit but apparently, I managed to lose it over the years.     Until I find a replacement, I opted to use a much more common ¼” diameter barrel with some modifications.  

First, I had to drill out the cable hole with a 5/64” bit.  Second, I had to sleeve it to be 7mm in diameter. I did this with a plastic straw which I cut a bit long and melted the end slightly with a “slightly heated” bevel head screw to form a retaining lip.  After putting the straw through the throttle cam hole up to the lip, I cut it to the exact length I needed.  In hind sight, the lip may be overkill as the cable holds the sleeve in place.  With a bit of oil on it, I’m hoping it holds up for a while.

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<1/4” Diameter Cable Stop Barrel with Custom Sleeve>

The next order of business was the throttle cable mounting bracket on the intake manifold.  Lokar makes a nice finished aluminum bracket that can be purchased at Summit Racing for ~$60 + tax, shipping and handling.
Although I’ve spent a ton of money on this build, I just didn’t want to spend that much on a simple bracket and decided to make my own from a piece of 1” x 1/8” aluminum strap that I had laying around. Below are the plans if you need to make one too.  It only took me about an hour to make.

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<Lokar Bracket TCB-40LS1>                                       <Ray’s Custom Thrift Bracket>

The red line is an optional cut line.  The three detents to the left of the red line accommodate reinforcement buttresses on my FAST intake.  When I was done with the drilling, bending, and filing, I cleaned it all up with a brass wire wheel and spayed it with silver caliper paint.  I secured it in place with 2-M6x20 plated bolt assemblies.

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<Completed Custom Bracket>                                           <Completed Bracket Installation>

Points of interest…the bracket nut flats fit nicely in the molded manifold boss and do not turn.  I used lock washers on the nut head for a secure connection.  Also, because the exact cable wire length is yet to be confirmed, the excess must pass through the barrel which prevents installation in the assembled condition.  Consequently, I had to install the barrel lock in the throttle cam first and then thread the cable wire through the barrel lock hole.  Once adjusted properly, I’ll tighten the locking screw and perhaps add a second locking screw on the opposite side of the barrel.  Then I can cut off the excess cable wire.

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<Engine Bay Update…with Installed Cruise Control and Throttle Cable!>

The next big step… more wiring.

This weekend coming, I have an appointment with my brother-in-law (father of the nephew from MegaSquirt that built my wiring harness).  He has agreed to help me sort out my unlabeled wires by tracing them back to the MS3 Pro pinout connectors.  He has done this before for the LS2/MS3 Pro in his GTM.

Slowly but surely, it’s coming together!!

Autozone, Amazon, and Oreillys have the barrel kits

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Bob....Thanks for the input!

The AutoZone Dorman "kit" you referenced is exactly what I bought at my local store.  The problem is the assortment contains 3 sizes (diameters):1/4" (6.35mm), 5/16" (7.9mm), and 3/8" (9.5mm)

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<Dorman PN 03336 Barrel Stops>


When I told the sales clerk I needed a 7mm barrel, he checked his computer but couldn't offer any solution.  Same thing happened at the Napa store.  I have not tried all my local stores as they all seem to sell the same Dorman products.

I found some on Ebay but I had to buy 20 (about $30 with shipping).

The problem is most manufactures don't specify the dimensions because most folks are looking for replacement parts and store clerks can only seem to find parts based on Make and Model.  In my case the 7mm barrel I need comes attached to an entire LS1 replacement throttle cable assembly.

I've sent a tech question to Dorman regarding barrel diameter and length on their Part# 03339 which they advertise for 1/8" cable but is available in different wire sizes.  It looks more like what I really need with the shoulder nut and closed back.  I don't have a factory LS1 cable so I'm not sure what that connection actually looks like.

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<Dorman PN 03339 Barrel Stops>

I'll post the reply from Dorman.

In the mean time, I'm all ears if anyone has a specific source for 7mm barrel stops for LS throttle body cam applications.

This is the kit that Kent sends with the throttle cable. I don't remember having any issues with fitment. We are doing an install now on a 944. I'll check fitment on it.

Dorman PN 03339 is a bust... Below are the specs send to me via email:

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Obviously way too big!  In my response, I asked if Dorman has a product that was 7mm in diameter... no luck!

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I did however find a product made in Hong Kong (on Amazon) that has the specifications I need.  I found these and some others from the UK on eBay by searching on "Solderless Nipple Screws!"  The UK offerings wanted $20-$25 shipping.

uxcell 20pcs, 5mm Thread, 7mm Bucket
Motorcycle Scooter Brake Cable Wire
Solderless Nipple Screws

Product Name: Motorcycle Solderless Screw
Material: Metal
Package Content: 20 x Motorcycle Solderless Screws, 20 x Fitting Buckets
Shell Color: Silver Tone
Screw Size: 12 x 8mm / 0.47" x 0.31" (L*Max.D)
Thread Dia.: 5mm / 0.2"
Through Hole Dia: 2.5mm / 0.1"
Bucket Size: 12 x 7mm / 0.47" x 0.28" (L*D)
Total Length: 16.5mm / 0.65"
Cost: $12.18 including PA tax & shipping

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Looks like I'm going to have a few "spares" on hand.

Let me know if you need one!!

Raymond,

I want to convey how helpful this post has been for me and my son as we are amidst an LS swap in his '86 944na.  I come from an engineering background, so your attention to detail resonates with me perfectly.  Like you, we have also enlisted the assistance of Kent's products with TPC for nearly the entirety of the build.  This post has helped me cross reference my concerns and questions without the need to be a pest with Kent.   We are having so much fun with this build, I have secretly started coming up with ways to refine it when/if I do a build for myself in the distant future.  Keep all the updates coming as we are nearly caught up to you.

Regards,
Aaron & Gavin Hunt[You must be registered and logged in to see this image.]

Hey guys...Thanks so much for your feedback... and your project pic! 

Father son projects are the best!!!

I truly enjoy the build process and must say that forum support has made my project possible.  I like producing my project thread and I'm pleased to hear that it helps other folks with their projects.  It's my way of giving back a little.

...Not to mention, I definitely need to document my work performed over the years as there is just too much to remember!

Currently I'm working on restoration of the rear crossmember, primarily replacing the axle shafts.  I should have that posted this week sometime. That will be followed closely by a 5th gear swap and installation of my 5P Turbo transaxle.

By all means, keep us updated on your project and feel free to ask questions.

Happy New Year!!!

Before the holidays, my brother-in-law and I made some good progress identifying the unlabeled LS wiring harness wires relative to the MS3 Pro pin connectors.  A bit more melding of the Porsche harness and LS harness is needed which meant I had to cannibalize the Porsche harness for the connections I needed.  One more wiring session and I should be good to go!

Most likely the remaining wiring will happen mid January so in the meantime, I’m focusing on getting my ’86 Turbo 5P transaxle installed.  For some time now, the TA itself has been externally reconditioned, along with the linkage and speedo sensor.  

Remaining TA work includes:
• 5th gear swap
   (0.68 NA gear set, TPC reinforcement plate, new gaskets, and a new end cap sitting on the shelf.)
• Install new axle seals (sitting on the shelf and ready to go)
• Install new oil cooler seals and new oil cooler looms (sitting on the shelf)

All of this will be covered in subsequent posts.

I also have the TA mounting bracket fully reconditioned with the rubber mount assembly stiffened using the high-density polymer encapsulation method I learned on the forum.  I posted my experience earlier in this thread.   Look-up "Urethane Stiffening of Transaxle Mount"
Post  Raymond-P Mon Aug 09, 2021 2:58 pm

Crossmember Clean-up

My standard approach has always been to bead blast anything I wanted to refurbish.  In this case however, the crossmember was mostly covered with road dirt and some undercoating and it made sense to just use wire wheels and degreaser.  

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<Rear Crossmember Before Clean-up>                           <Connection Bolt Removal>                            

The CV joints are secured to the axle stub axle with 6 – 8mm x 1.25 x 50 mm triple square cheese head bolts.  Care should be taken in removing these bolts as accumulated grime can prevent full insertion of the socket and lead to stripping of the head.  I used a small flat blade screw driver to do a preliminary clean-out of the bolt heads, and then applied a few light hammer blows to assure full insertion of my triple square socket tool prior to applying any torque.

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< Cleaned up Stub Axle Mounting Flange>            <Stub Axle Washer Plates and Bolts>                            

After removing my old axles, my college buddy Bob and I got to work cleaning every bit of dirt, debris, oxidation, and grease from the stub axle housing and ESPECIALLY the CV joint mating surfaces of the stub axle flange.  Special attention is needed to make sure the axle mounting surface and mounting bolts were spotless.  Many of the “CV Replacement” sagas I’ve read seem to leave out this crucial effort.

We scoured everything with a wire wheel and then used brake cleaner to remove all old grease residue…after which I sprayed the clean surfaces with silver paint.  The brake cleaner also did a good job removing grease from the washer plates and bolts, and I used a wire wheel on my power driver to remove any rust and oxidation from the washer plates and the bolt head underside.  However, I didn’t stop there and used an 8mm x 1.25 tap and die to clean and recondition all bolt threads and stub axle threads.  This is paramount to a secure connection that doesn’t come loose.

After removal, I revisited the bolt cheesehead to thoroughly clean out the triple square socket.  I was surprised at how much debris remained hard packed into the socket and I had to get aggressive with my screw driver to get it out.

[You must be registered and logged in to see this image.]        <Thread Cleaning Tools >                                       <Cheesehead Socket Deep Clean>

Yes… I broke down and painted everything just to keep it new looking a bit longer.  

New Axle Installation

After a lot of good forum input and much deliberation on my part, I decided to purchase new OEM GKN Turbo axles from Bob at HOTRODZ of DALLAS.  He knew exactly which ones to order not to mention guys like him that do this for a living, deserve our business because they bring so much experience to the forum.  This decision eliminates the “hit or miss” quality issues with other aftermarket brands and rebuilt units.  The GKN units are pricy but have the best reputation and I only want to do this once.  Some extra axle strength certainly won’t hurt when I finally get this car on the track to see what it will do.
Check with Bob for current axle pricing if you’re in the market.

The new axles arrived promptly and the first thing I noticed was they were clearly “beefier” than my factory ’87 944S axles. I was happy about that!

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<OEM GKN Turbo Axle – Top     OEM GKN 944S Axle - Bottom>

Externally, the “Turbo” axles are ~32.5mm and taper to ~29.6mm at the CV joints.  The “S” axles measure ~27.4mm full length.  Internally, I suspect the CV joints are likely more robust, but I have no details to confirm that.  The new axles are labeled as made in Spain and appear to be high quality.

Assembly was straightforward with the crossmember out of the car.  It was clear from reading the forum that cleanliness is of utmost importance to the long-term success of axle replacement.  As a result, I used a “white glove” approach just like for engine assembly.  Also, proper bolt torque is critical.  

To get it done, I gleaned what forum advise I could find and derived the procedure below:

1. Remove ALL grease from the mating surface of the new CV Joint flange.
Push any errant new grease back into the CV joint.
Use brake cleaner on the joint flange until it’s perfectly clean and dry.
Note: Be sure to maintain a STRAIGHT axle alignment with the CV joint as movement will squeeze grease back out of the joint on onto the flange interface.

2. Remove ALL grease from the bolt holes in the new CV joint flanges.
A Q-tip soaked in brake cleaner worked well.

3. Remove ALL old grease/dirt/debris from the mating surface of the stub axle flange.
This was done previously as noted above.
Just before assembly, I removed the applied paint with brake cleaner.

4. Apply a thin coat of motor oil to the connection bolts - threads only.
Thin coat = about 1 drop spread uniformly with excess removed
No threadlocker compound.

5. Install 3, 8 mm guide pins in the axle stub flange in a triangular pattern, to provide precise alignment of the CV Joint flange.
I cut 3, 7-inch steel guide pins from 5/8” zinc plated rod stock.
I then cut 8mm x 1.25 x 12 mm threads on the end of each rod.
The guide rods are threaded hand tight into the stub axle flange.

6. Support the TA end of the axle assembly by tying it up to the crossmember brace.

7. Partially install the wheel end CV joint flange of the axle assembly onto the 3 guide pins.

8. Slide the axle assembly along the guide pins into full contact with the stub axle flange and hold firmly in place by hand.
This should generate a distinct dry “metal on metal” contact sound.
(If you were unable to maintain a straight axle alignment and think you contaminated the mating surfaces with grease, remove, clean and try again.)
I was successful on the DS axle using only one screwdriver positioned at 12 o’clock, but admittedly I got lucky.

9. Install a connection bolt in the first accessible remaining flange hole.
Start this bolt by hand and turn finger tight.
Again, maintain a STRAIGHT axle alignment with the wheel end CV joint

10. Carefully rotate the axle assembly and install the remaining 2 connection bolts in the same manner.
Snug these 3 bolts with a socket tool and ratchet to maintain a flush and dry contact of mating surfaces.
Depress the CV rubber boot slightly as needed.

11. Rotate axle assembly 180 degrees and remove one guide pin and one adjacent connection bolt.

12. Install one washer plate and restart two connection bolts by hand.
Install washer plate with bolt marks up.
Snug bolts with socket tool and rachet.

13. Repeat Steps 11 and 12 to remove the remaining two guide pins and install the remaining connection bolts and washer plates.

14. Secure the wheel hub to prevent rotation.
See “Word of Caution” at the end of this post.

15. Mark your 8 mm triple square socket for full depth insertion to avoid stripping.

16. Torque connection bolts in a 6-point star pattern in three rounds
a. 15 lb-ft (apply a red dot with nail polish)
b. 25 lb-ft (apply a 2nd red dot with nail polish)
c. 35 lb-ft (apply a 3rd red dot with nail polish)
Note that 35 lb-ft is a 13% increase over Porsche Manual spec of 31 lb-ft and was recommended by Bob at HOTRODZ of DALLAS based on track experience.

The factory connection bolts are M8 x 1.25 x 50mm, Grade 12.9.  Based on one of my favorite resources, Engineering Tool Box.com
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The recommended maximum torque for this bolt is 35.6 lb-ft with a light lubricant on the threads.

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<Max Bolt Torque Table>                              <M8 x 1.25 Grade 12.9 Connection Bolt>

Now the question is…, how much torque can the 8mm threaded hole in the stub axle flange handle without stripping?  The answer depends on steel strength and thread depth.

I don’t know what grade steel Porsche uses to make their rear stub axles, but a common industry material is SAE 4140 which has an advertised tensile strength of 95,000 psi or 655 MPa. That’s low compared to the tensile strength of the Grade 12.9 bolts which is ~1220 MPa or 180,000 psi.
Just FYI, to convert ISO to familiar SAE numbers, 1MPa = 1N/mm2 = 145 psi

Some info on 4140 steel…
“This alloy has high strength, high fatigue strength, toughness, torsional strength, and impact and abrasion resistance. Additionally, 4140 steel is highly ductile when annealed, though it requires more pressure as it is tougher than most carbon steels. 4140 is easily welded, but if this is done after hardening, it will also require a post weld heat treatment. This material is typically used in aerospace, oil, gas, automotive, agricultural, and defense industries, specifically gears, shafts, spindles, fixtures, and collars.”  REF: OnlineMetals.com

4140 Steel Composition (by %)
Chromium, Cr 0.80 – 1.10
Manganese, Mn 0.75 – 1.0
Carbon, C 0.380 – 0.430
Silicon, Si 0.15 – 0.30
Molybdenum, Mo 0.15 – 0.25
Sulfur, S 0.040
Phosphorous, P 0.035
Iron, Fe Balance

The fabrication rule of thumb for the minimum required bolt thread engagement is 1x bolt diameter. This is generally considered acceptable to develop the full torque capacity and clamping force of a bolt.
However, this is for like materials.

Our scenario has dissimilar materials, therefore we need to apply engineering principles to compute the required engagement depth of a stronger material in a weaker material based on tensile strength and shear strength.  Below is how it’s done:

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Thread engagement formulae

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In conclusion, to fully develop the 12.9 Grade connection bolts, the thread engagement length in a 4130 axle stub needs to be at least 11.6 mm.  Once I learned this, I immediately went down to the garage and measured the available thread depth in the axle stub, and the CV joint flange thickness.  Below is the “tale of the tape”:

Available Stub Flange Thread Depth     16 mm
Measured Connection Bolt Shaft           48 mm
CV Joint Flange Thickness                  33.2 mm
Plate Washer                                      2.5 mm

Bolt engagement: 48 – 33.2 – 2.5 = 12.3 mm > 11.6 mm Reqd.  Good to Go!!
Excess hole depth 0.70 mm

Looks like my German ancestors already figured this out!!!!  

Below are some process photos…

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<New CV Joint>                                                       <6 Point Star Tightening Pattern>

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<Super Clean Stub Axle Mounting Flange>                <Super Clean CV Joint Flange>

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<Marking the Socket for Full Insertion>                     <Removing Grease from the Flange Holes>    

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<Fabricated Guide Pins>                                           <Guide Pins Test Fit>

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<Joint with Preliminary Bolt Installation>                    <Round 2 Torque Documentation>

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<Round 3 Torque Documentation Marks>                    <Lug Nut with “Popped Top”>

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<Crossmember as Pulled>

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<Refurbished Crossmember with New GKN Turbo Axles>

Points of interest…

White Glove Treatment
I made a big deal about super clean mating surfaces and proper bolt torque.  The reason is I’m convinced this connection was designed as a “slip critical.”  This means the successful function of the joint is dependent on the clamping force of the connection bolts to generate a calculated amount of friction between the mating surfaces.  If the mating surfaces are not perfectly clean, the coefficient of friction is compromised, and the connection will begin to slip under load.  This is a “critical” fail. Likewise, if the bolts are not torqued properly, insufficient clamping force will also lead to slippage.  If slippage does occur, the bolts only offer rotational resistance in single shear, and while grade 12.9 is the strongest fastener on the market, they are not designed to accommodate this load function and will fail.

Regarding Threadlocker
I think it’s about a 50/50 split between pros and cons of using threadlocker on the CV joint connection bolts.  Some favor threadlocker to compensate for bolt loosening caused by the perceived “inevitable” proliferation of errant grease between the mating surfaces and on the bolt threads.  Others oppose threadlocker because of its unknow effect on the bolt’s torque application and subsequent clamping force on the mating surfaces.  Considering the joint connection is designed as “slip critical,” I fall into the latter camp and elected to replicate the factory Porsche installation without threadlocker.  

If you happen to be a proponent of threadlocker, be advised that its lubricating characteristics (unknown at this point) can reduce the maximum allowable tightening torque by 30 to 45 percent.  Consequently, when the “lightly lubricated” maximum tightening torque is applied to a quasi “lubricated” condition, thread failure can result… especially in the weaker material of the axle stub flange.  

We can only hope that someday Permatex will do an empirical study on the effects of their threadlocker on applied torque and resulting clamping effect.

Word of Caution:
I used a power bar and a 19mm socket on one of my wheel lugs to secure the wheel hub while applying torque to the connection bolts.  On the 1st bolt of the 3rd round, the wheel stud popped the center section out of the lug nut.  Solution:  Use a line wrench as a spacer under the lug nut.

The next big step… reinstalling the Crossmember.

First and foremost, most high praise from another fellow engineer who has gleaned a tonne from your attention to detail and documentation. For a forum mechanic like myself your thread has been an ingenious source of information to double check my learn by doing with your pictures and write ups. I myself have seriously gotten back into my conversion after a 8-9 year hiatus with life getting in the way.
Was very stoked to see your update on an attempted first start after your vehicle being dead for so many years. Hoping to be only a couple months away from that myself.

Couple things i noticed in your most recent posts as of late. To which i hope this expands the question further on a few things and hopefully your response enhances the education behind your comprehensive thread here.

First off, absolutely great write up with great pics that has enlightened me greatly on having to redo my own cv's for my replaced 944s transaxle with the turbo unit of which i just got my endcap machined and have permatex gasket maker'ed the reinforcement plate on and now going to do the other side to fully reassemble and then put the whole thing back in. I noticed you had bought this reinforcement plate but haven't wrote anything on getting that installed. Couple things i found out through the help of Kent who then referred me to Bob of hotrodz of dallas is that the guide cites a main bolt after you remove the endcap (note to anyone on this step you don't pull the rubber off you need to take a chisel and slowly hammer tap/pry it up for it to pop off; i almost ruined mine by thinking it was truly just a rubber seal but nothing some jb weld won't fix). instructions say its a 17mm bolt and that may be true for a normal transaxle but on a turbo LSD TA it is not. it is a 12mm triple square and after going terribly scary with a breaker bar THIS WILL NOT CRACK OFF. need an air or corded impact, cordless is useless and has has no jam to crack this. I used screwdrivers to stop the cv takeoffs on the transaxle from spinning through the cv joint bolt holes to lock it up.
anyways after talking to Bob, use blue loctite to put that bolt back in and simply air or corded impact it back in as it just holds the end bearing in place between the bearing cups.

But going back to your new half shafts from Bob, mannnnn i'm a tad jealous of how beefy those look. I got mine from xschop (Rob) many moons ago back in 2014 or so and also got his solid billet mount with polyurethane bushings. His shafts he made for me are the same diameter but are solid 4130 chromoly if i remember right so should be far better than stock ones but i'm not as tagged up on my understanding of materials as you are (btw great write up on investigation in to going past torque and whether they could handle it based on thread length and other things!). Also another thing I did with regards to the bolts was just bought new same length and thread pitch of metric cap screws in 12.9 rather than re-use the triple square's. Didn't cost much from bolt supplier but will still oil the threads just as you have noted. Will definitely make those guide pins you talked about, excellent idea to help alignment and maintain clean mating surfaces.

next item i wanted to comment/question on was your note about use a wrench as a spacer for the breaker bar for keeping the lug nut from opening up or busting open on the top? can you provide more explanation of what is happening here? i am not sure i follow here and i'd prefer to understand the warning before i do something bad or worse than the damage you had shown on the lug nut.

lastly going to reach back to your blue wire from the bundled two wires of which the red with black is the starter solenoid wire. now in my case i ran that wire directly to the solenoid of the ls1 starter since when i had saved and harnessed the starter cables i had the other half of it and simply just had to split the wiring harness to separate that and then i could click that wire into the porsche harness and simply put the ring connector right on to the solenoid of the starter. As for the blue wire i had improperly assumed that this was to be the alternator tap to show the status of your charging system on the 944 gauges (battery gauge). although each year is a tad different with its wiring schematics as per the porsche shop manuals here's the snippets of what i extracted that pertain to my case with the 88 model of 944s which also is the same for turbos if i recall correctly.

you can see i have the blue wire scabbed on to the end of my ls1 alternator but after digging into this when you mentioned not hooking it up, my snippets with red arrows seem to show that it feeds the alarm control unit. So perhaps it is really not needed but i'm almost wondering if the locking system with regards to the alarm if a person has that option (no idea if i even do been so long since mine ran) needs this blue wire on the alternator for the transistor based switching to work for alarm control unit to function?

i'm electrical in discipline so this is the one thing i was supposed to have as an advantage in this conversion but even with google translator at my fingertips to figure out what drehzahlmesser is (tachometer) and others its a bit of a cryptic schematic at times.

my understanding is that on the 944 alternator (no idea if GM schematic of alternator is different), the 3 forward biased diodes on the 3 windings of the alternator provide a half rectified dc output to the G of the alternator which i could only assume is a pull down resistor maybe? then this trails along till it hits what i could only assume is the gate of the transistor on the alarm control unit by following the drawing coordinate references.

If you or Bob or anyone else has any additional insight on this it would be really helpful to the 944 conversion group by virtue of advanced search to put a definitive pin on "what to do with the blue wire" but for now i think i am inclined to pull it off the alternator and wrap it back out of the way and deal with that distraction after future discussion or when i find something that isn't working once my own machine is breathing fire.

End of book for now, look forward to the continuation of your thread. I'm going to do another book of a post under my resurrected thread from many years ago on the trials and tribulations of designing an intake with all the space constraints. Had some considerable help from Bob on that too. link here to my thread for details on cold air intake [You must be registered and logged in to see this link.]

Also many thanks for all the info on the throttle cable modes. my grommet staying the firewall so i ended up massively grinding down all the outside dimensions of the barrel for it to finally slip through firewall but no i fear i might have hooked myself for now having to drill the inside of the clevis to 9/32 for it to fit over the shoulder of the pedal. Have to say, still not quite clear as to how this assembles on the pedal but i figure with your hints, tips and writeup it will make more sense when i take a peak under the dash at that god forsaken back breaking bridge that i had to do for the clutch pedal master and brake pedal.

Cheers.


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Wow!

Thanks Gutterboy for taking the time to write your post.  I appreciate the kind words and I'm thankful my documentation can help others traveling the same path.

Soon I will be posting my adventures in rear axle seal replacement and a 5th gear swap.  I bought all the gaskets and seals I needed some time ago from Ian at 944OnLine [You must be registered and logged in to see this link.] I sourced the steel reinforcement plate from Kent at TPC and the 5th gear set from Dimi at Flying Horse Motorsport LLC.

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<5th Gear Stack, Case Gaskets & End Cap>    

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<Axle Seals, Oil Cooler Looms, and O-rings>

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<TPC Case Reinforcement Plate>

Regarding Removal of the End Cap and End Shaft Nut – I have a full write-up on this coming as part of the 5th gear swap procedure.  You figured it out in the end but there are a few helpful tricks to make the job easier.

1st Question about 4130 Chromoly Steel: 4130 steel has less dissolved carbon (0.30 avg) than 4140 (0.40 avg) and therefore it is slightly less strong.  It is however more ductile in its unannealed condition which is why it’s more popular for use in sheets, tube, and wire.  It is still a good choice for an axle and has added corrosion resistance.

2nd Question about the lug nuts: The fundamental problem is the wheel stud length is greater than the wheel lug depth.   So, without a wheel in place, tightening the lug nut all the way down to the wheel disc results in the wheel stud pushing out the center of the alloy lug nut.  I used a line wrench as a simple spacer to prevent this.  I wasn’t too upset because I have a set of ’86 Turbo rims that are pristine and I’m contemplating new lugs anyway… only $5/ea!!

3rd Question on the “Blue Wire”:  There is a boatload of information on this forum and the RennList about this.  What I’ve found so far is that there are multiple applications because of the many component/car combinations.  Newer alternators don’t need the trigger wire, certain ECMs don’t or won’t interface with the alternator anyway, and the Porsche master warning light in certain years is powered by the “blue wire” and lights when the alternator is not functioning…or the wire in not connected.  There are reportedly other systems that run off the master warning light as a power source.  I’ll do my best to consolidate what I've found and document the procedure I end up using.
The electronics of this swap is by far my biggest challenge!  

4th Question on the Throttle Pedal Clevis Connection: Sounds like you had some difficulty with the firewall grommet around the throttle cable.  The key here is to remove the factory grommet from the firewall and install it on the new cable in the proper position.  This means you must disassemble the new throttle cable.
 
1. Remove the cable wire stop at the throttle body end of the throttle cable
2. Pull the cable wire completely out from the pedal side of the throttle cable
3. Remove the threaded nut from the pedal end aluminum connection hardware
4. Thread the cable wire through the threaded nut
5. Thread the cable wire through factory grommet
6. Reinsert the cable wire through the SS throttle cable housing
          (Some masking tape on the end will prevent wire snagging)
7. Thread the aluminum nut back on the connection hardware… keep it loose

The entire assemble can now be pushed through the firewall hole.  Reinstall the grommet in the firewall using a small flat blade screw driver as necessary and then tighten the aluminum nut to secure the connection assembly in the grommet.  The clevis assembly is then pressed in place over the factory post on the throttle pedal pivot frame.  

In the “mock-up” photo below the clevis pin that comes with the new throttle cable is not used.  This pin is replaced by the factory post shown with the green arrow.
     
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<Pedal End Mock-up of the Throttle Cable>      <Factory Post on the Pedal Pivot Frame>

BTW... I pulled the driver's seat to save my back!

Wow well that makes a tonne more sense on outing throttle cable assembly together. Thanks for that. 

For now I am going to pull my blue wire off and just tape it back till more is discovered on this. Will do some more advanced searching. 

Just put my transaxle back together with the machined endcap and tightened everything up. Unfortunately when I removed the transaxle the 8mm tapered bolt on the shift carrier sheared off leaving me to drill it out and re tap it to 10mm and make my own tapered bolt. Word of wisdom to others probably could have avoided this if you tap the end of the shift linkage to try to unseat the taper end in the socket of the linkage before wrenching it out.

Putting it back in today hopefully. Cheers!