Ray's 1987 944 LS1 Build & Swap

This post item is one of the last items on my check list… so I’m getting excited.

Baseline information:

I installed my new clutch MC dry because I really couldn’t imagine priming it without losing most of the fluid while maneuvering the unit into position.

I did not purchase and install the remote bleeder available from Kent at TPC.  (In hindsight, I would have gone this route.)

The bleeding procedure is straightforward as with most other hydraulic systems… working fluid thru the system to push out any captured air.  The process requires AT LEAST two people.

Before you start, be sure the Brake MC is filled to the cap base with DOT4 fluid.  Also be sure your feed line from brake MC is routed BELOW the brake MC at all points along its path to the clutch MC.   Let gravity be your friend!!

Below is the procedure I used:

   1. Move the clutch pedal to the released position (up)
   2. Under the car, loosen the slave cylinder bleeder screw.  There is not much room to operate
       but an 11 mm wrench gets it done…or a 6-inch crescent wrench.
       (I left the screw just finger tight to minimize fluid escaping from the valve seat and flowing
       down on the clutch disc.)

[You must be registered and logged in to see this image.]
< Clutch Pedal Released Position >                           < Clutch Slave Cylinder Bleeder Screw >

   3. Hold a paper towel over the bleeder screw orifice and instruct your assistant to SLOWLY depress
       the clutch pedal and hold it to the floor.  (Note: This should be done by hand,not foot,because
       the pedal is spring loaded and inclined to abruptly slam to the floor when there’s no resistance.)
       Fluid and air will be expelled into your paper towel.
   4. Tighten the bleeder screw.
   5. Instruct your assistant to return the clutch pedal to the released position.
   6. Repeat Steps 3 through 5 a second time but NO MORE.
   7. Refill the fluid level in the brake MC.  This is important because the brake MC has a relatively
       small, built-in clutch reservoir partition that is only refilled when the brake MC is filled to the cap
       base level.  This reservoir partition will nearly deplete in only two (2) bleeding cycles.
       (If it goes empty, the bleeding process will suck air back into the system and you will never  
        achieve an operational clutch. That’s the boat I was in until Bob once again enlightened me on  
        the finer points of the Porsche brake MC. )
   8. Repeat Steps 1 through 7 until you have an operational clutch pedal.

[You must be registered and logged in to see this image.]
< FILLED Clutch Reservoir Partition >                         < EMPTY Clutch Reservoir Partition >

I went through 6 bleeding cycles and got a decent pedal starting about 1 inch from the top.

Testing Clutch Disengagement

The acid test now is to see if depressing the clutch pedal disengages the clutch from the flywheel.  I did this by putting the transmission in 1st gear, depressing the clutch, and attempting to turn the rear axle.  Unfortunately for me, IT DID NOT TURN.

Next, I’m pulling the inspection cover off the engine bellhousing to check operation of the slave cylinder.
    • If it is NOT WORKING as it should, then there is more slave cylinder bleeding in my future.
    • If it IS WORKING as it should, then my clutch plate has seized to the flywheel.  This has
      happened to me before when storing a 4-speed car for an extended period of time.

Update coming soon…

indeed the remote bleeder made it quite easy with wife in the car on the pedal and me holding a catch bucket at the remote bleeder in engine bay.

before my first fire day i merely dropped the bottom of my two piece bellhousing to verify throwout bearing operation with bled clutch pedal. From there i merely let the 2nd surprise of first fire day to seeing if it would properly engage and disengage engine from transaxle on the first shift. Got lucky with no hangups on a full blown litmus test.

I like your check better as i obviously took a small gamble but won. happy hunting, but if you have the old two piece bellhousing like i do, i'd verify it's operation in pushing in your pressure plate fingers with someone pushing the pedal in.

I expected the inspection cover removal to be a simple unbolting procedure.  Man was I wrong!!

Turns out the M8-30mm mounting bolts above the header collectors were too long.  The PS bolt just barely cleared the collector so no real problem.  The DS bolt was a totally different story as the header collector prevented bolt removal.

Loosening the header was an option, but accessing the header bolts would be a nightmare considering the hydro-boost hardware and brake MC that is now in the way.   I opted to drill through the bolt head and remove it (only took nearly 2 hours!!!), then I worked out the remaining bolt shaft.  Fortunately, it came out easily by hand.

[You must be registered and logged in to see this image.]
< DS Header Collector Bolt Interference >                    < Drilled Bolt Head >

With the mounting bolts all out, I then removed the dust cover which is attached to the inspection cover. This allowed the inspection cover to come off.

[You must be registered and logged in to see this image.]
< Bellhousing Inspection Cover Removed >

[You must be registered and logged in to see this image.]
< Clutch Slave Cylinder & Throw out Bearing >           < Pressure Plate Fingers – NO LOAD >

Once again, my neighbor helped me by depressing the clutch pedal while I was under the car watching the slave cylinder.  The good news is everything is working as it should! YAY!!

Below is a pic of the assembly with the clutch fully depressed.
         Blue Arrow:     Pressure Plate fingers fully actuated.
         Yellow Arrow:  Gap between Pressure Plate and Clutch Disc
         Red Arrow:      Gap between Clutch Disc and Flywheel

[You must be registered and logged in to see this image.]

Conclusion:

The previously mentioned attempt to test the clutch disengagement was apparently flawed, in that the clutch pedal must not have been fully depressed.  I guess a third helper was really needed because using a 6-foot 2x4 to depress the clutch while simultaneously trying to turn the rear axle…just didn’t work.

Moving forward, recall that I had reported about an inch of clutch pedal free play.  A closer look confirmed that the free play dimension was more like 1-1/2 inches and the pedal was not fully returning to the released position.  

This is a clear indication that the pedal clevis (blue arrow) needed adjustment to INCREASE the stroke of the MC pushrod (yellow arrow).  This will reduce free play and move the clutch engage/disengagement point farther from the floor. My target free play was 1/2 to 3/4 inch.

[You must be registered and logged in to see this image.]
< Clutch Pedal Clevis w/Lock Nut Loosened >

Having the steering wheel and driver’s seat removed made crawling under the dash one more time a little less traumatic. To adjust the pedal free play, I loosened the lock nut on the pushrod and turned the pushrod counterclockwise relative to the clevis to increase its length.  There is very little room for tools in this space, but I was successful with a small pair of needle-nose pliers.  Light pressure on the pedal to remove the free play unloads the return spring and makes turning the pushrod easier.  I increased the pushrod length approximately 1/4 to 1/2 inch.

Recall that when I originally set up the Tilton MC pushrod length, I matched the Porsche MC overall dimensions from firewall to clevis pin.  Clearly some adjustment was needed.  As soon as I achieved the desired free play, the pedal automatically returned to the released position as it should.  I then tightened the clevis lock nut.

Finally, I checked the pedal travel stoke to be sure the pushrod/MC piston was not bottoming out prior to the pedal stop contacting the floor.  ALL GOOD!  This condition would apply undesirable pressure to the firewall and should be avoided.

With the pedal free play corrected, the clutch pedal felt great and shifting through the gears with the clutch pedal depressed was smooth and easy! YAY!

The last steps were to reinstall the inspection cover and dust cover.  This time around, I tapped into my spare bolt box and found an M8-25mm bolt to replace the cover bolt located over the PS header collector.  The bolt located over the DS collector can only be about 20mm in overall length. I didn’t have one, so I just shortened a 30mm bolt.

[You must be registered and logged in to see this image.]
< 25mm Bolt vs 30mm Bolt and the Drilled Bolt>

[You must be registered and logged in to see this image.]
< All Together Again! >

I’m happy the clutch setup is complete and confident that drivability will be good.

Next up… Installing the rebuilt shifter.

Great Post as always there Raymond. you answered a question i had on my thread perfectly with trying to get my clutch engagement point lower to the floor as mine is presently what i would consider where knee is close to my chin. lol.

don't have my seat removed so i'll have to the crazy gymnist bridge under the dash and try to operate the pedal a bit as you say after i undo the jam nut so i can then turn mine in clockwise to get the pedal lowered down. Also my pedal seems to be beginning to stick so i think i am going to do one more bout of purging any air with the remote bleeder.

This occurred after i had the car sitting on a slope so will have to try the bleed and see if it goes away or if i have a further issue somewhere..... not sure how or where though. no drips or leaks anywhere.

GB,

If your clutch pedal engagement point is near the top, your push rod/clevis connection is definitely too long and you may experience clutch slippage due to incomplete clutch disc engagement.  You also run the risk of bottoming out the MC piston which will put pressure on the firewall.  (Not likely however if you barely need to push in the clutch pedal!)

I suspect the clutch pedal stop may not even touch the floor in your current arrangement...and you probably don't have any pedal free play at all.

As you shorten the push rod, you will be moving the overall MC piston stroke (and overall pedal travel) closer to the floor.  As long as you have at least 1/2 inch of pedal free play, the clutch pedal return spring will work properly and you should still have sufficient piston stroke.

If your pedal is still sticking, air in the line may be the culprit, but that would mean your slave cylinder would not be functioning properly.

My factory shifter worked well but the leather boot had seen better days. However, upon disassembly, I discovered a significant amount of wear on the gearshift lever pin that engages the shifter rod.

The logical thing to do was a rebuild, so I purchased a gearshift lever rebuild kit from IAN'S EURO PARTS INC. for ~$50 plus shipping and tax.  I also picked up a new rubber inner sealing boot and leather boot from 944online. Each was nearly $50 which I thought was high…then again they’re Porsche parts. To make matters worse, I needed a gearshift knob cap and dropped another $40 on a nice aluminum cap I saw on the 944online website.  Yes, I splurged…

[You must be registered and logged in to see this image.]
< New and Old Gearshift Parts >                       < Factory (top) vs Aftermarket Nylon Bearing Shells >

I swapped the Vibration Dampers (rubber pieces) from the old gearshift lever to the new one which was easy enough.  They were in good shape. The new Bearing Shell (nylon ball socket) did not have the back curvature to match the torque tube like the factory unit.  This seemed important to me for a good fit and the factory Bearing Shell was in great shape, so I reused it.

The gearshift lever rebuild kit came with a new wave washer and snap retainer clip (replacing the C-Clip) for the shift rod pin.  After repainting the Bearing Bracket (mounting plate), I inserted the gearshift lever bearing ball through the Bearing Bracket, lathered it up with lithium grease, and pressed on the factory Bearing Shell.   The assembly looked like new!  

[You must be registered and logged in to see this image.]
< Rebuilt Gearshift Lever Assembly >          

[You must be registered and logged in to see this image.]
< Shift Rod Eye Clean-up >                                   <Connecting the Shift Rod >

Next, some clean-up of the shift rod eye was in order.  It had plenty of rust powder from the old set-up.  Once clean, more lithium grease was applied, and the shift lever was mated with the gearshift lever rod.  Be sure the wave washer is in place against the gearshift lever with more grease.

[You must be registered and logged in to see this image.]
< Installing the Pin Retaining Clip >                    < Gearshift Lever Bearing Bracket Mounted to TT >

Securing the shift rod with the retaining clip is done easily provided you compress the wave washer sufficiently to expose the retaining clip groove.  I used a small pair of needle-nosed ViseGrips and then pressed on the retaining clip with my thumb.

With the shift rod connected, the Bearing Bracket can be bolted in place.  This is an important step to ensure proper gearshift lever function and clearances. The 13mm hex head mounting bolts are M8-12mm and should be installed with lock washers and/or blue threadlocker.  
         1. Install both mounting bolts loosely.
         2. Position the bearing bracket so the slotted holes are roughly centered.
         3. Snug-up the front bolt enough to secure the bearing bracket.
         4. Check that you can engage all speeds and reverse without any gearshift lever components
              impacting the surrounding sheet metal floor.
         5. Adjust the bearing bracket location as needed.
         6. Torque both bolts to 18 lb-ft.

Boots and Gearshift Knob

I elected to first install my fancy aluminum shift pattern knob cap.  It was necessary in my case to remove debris from the tab slots in the shift knob. Also, I chamfered all outside tab edges (blue arrow) with a file to facilitate insertion. The knob cap uses a friction fit to stay in place, but it can be removed easily with tools.

The knob cap perimeter shoulder was slightly deeper than the knob recess so in its final position, the cap was NOT FLUSH with the top of the knob.  I’ll resolve this protrusion issue later…

[You must be registered and logged in to see this image.]
< Chamfer on the Tabs >                                        < Protruding Knob Cap >

Next, the leather boot goes on the gearshift knob shaft, but first it must be stretched over the plastic mounting frame (yellow arrow).  The leather boot has an asymmetrical shape and I opted to put the steeper slope in the front.  I then slid the leather boot neck up the knob shaft to the base of the knob.  I’m really not sure how I’m going to finish the leather interface with the knob itself.

Push the leather boot up out of the way and install the sealing rubber boot.  Be sure the securing groove at the bottom is on the inside, otherwise you have it on inside out.  The neck should be slid up the gearshift knob shaft past the taper (blue arrow) which will hold it in place.

Pull the sealing boot up exposing the bottom of the gearshift knob shaft and push the assembly onto the gearshift lever as far as it goes…which is just past the lower vibration damper.   Install the Retaining Spring to hold the assembly in place.

[You must be registered and logged in to see this image.]
< Installing the Boots >                                        < Installing Gearshift Knob Retaining Spring >

You can now unfold the sealing boot and attach it to the floor metal lip which fits perfectly in the securing groove of the boot.  My car did not have a Sound Absorber (sound installation foam) which would be located over and around the entire gearshift assembly below the sealing boot.

Finally, pull down the leather boot and press the mounting frame into the console until you hear the mounting tabs "click."

[You must be registered and logged in to see this image.]
< Sealing Boot Installed >                                             < Leather Boot Installed >

I’m open to suggestions on how to finish the leather on the gearshift knob.  
(Please send pictures!)

Right now, I’m leaning toward banding near the base of the knob and a nice clean trim cut.

Next up… A New Steering Wheel!

Welding is a skill that I do not possess, and as much as I would like to justify buying a MIG welder for my project and doing this work myself…the learning curve just doesn’t fit my timeline, or anxiety level!

The Solution:  Move the car to another shop where the work can be done.

The shop in this case is my nephew’s where he has been building custom drift cars for about 15 years.  Along with his extraordinary wiring harness and CPM programming skills, he is an accomplished CNC programmer/operator, and a proficient MIG and TIG welder.  To his credit he has built many elaborate turbo and intercooler plumbing applications and the related custom exhaust fabrication.

So…now it’s my turn, and the car needed to be relocated.

First, I had to put the wheels on, and the driver’s seat back in.  No time for the new steering wheel so I threw the old unit back on…just for transport.   Then, I pushed the car out of the garage and into the sunshine for the first time in 4-1/2 YEARS!!!

[You must be registered and logged in to see this image.]
< Moving in the Garage 1-6-2019>                             < Moving out 7-12-2023 >                                  

My nephew arrived with his Cummins Diesel Ram 2500 Crew Cab truck and car trailer. His trailer is not fitted with a winch so our initial challenge was getting the car on the street where we could rely on grade to coast the car onto the trailer.  

This effort started with a short tow up the driveway with my MDX, followed by statigic positioning on the street about 50 feet ABOVE the trailer.  We “backed” it onto the trailer to facilitate unloading at the shop.

Fortunately my nephew was very skilled at drift loading his trailer…he only had one question, “do the brakes work good?”

[You must be registered and logged in to see this image.]
< Tow up the Driveway >

[You must be registered and logged in to see this image.]
< Positioned and Ready to “DRIFT” >

After adjusting the precise ramp positioning to match the Porsche wheel track, one drift attempt and the car was on the trailer.

[You must be registered and logged in to see this image.]
< Successfully on the Trailer >

We used nylon towing straps to secure the car.  

In the rear, we wrapped the straps around the torsion bar ends and used an X-pattern attachment to the trailer tie-downs.  This avoided any contact with the transmission cooler.

In the front, we came straight off the Porsche tow bracket on each side.  No X-pattern because the straps would have applied undesirable load on the radiator and/or condenser.

[You must be registered and logged in to see this image.]
< Secure and Ready to Roll >

It was an easy 15-mile drive to my nephew’s shop.  We got a lot of attention along the way from pedestrians, other drivers, and even the local police.  All that with the car still on the trailer!!!

[You must be registered and logged in to see this image.]
< On Route Through Beaver, PA >

[You must be registered and logged in to see this image.]
< Arrival Safe and Sound >

Once at the shop, it was an easy roll off the trailer and into the waiting lift bay.  The 20 foot high ceiling and a full height lift is perfect for exhaust work.

[You must be registered and logged in to see this image.]
< The New Workspace >

Now my nephew can wrap up the wiring harness for start-up and pull together the exhaust.
The remaining work for me includes installing the OTR air intake, light bar, front cover, bumper, and lower valance.

Next up… Could be Initial Start-up!!

Sorry, no new steering wheel yet…but this is BETTER!

My nephew finished wiring my MS3 Pro into the LS1 harness and using a new pin connector, tapped into the necessary Porsche leads for the ignition, fuel pump, engine temp sensors, EVAP relay, and oil pressure and voltmeter gauges as applicable.  

He also fused my alternator charge cable and the power lead wire to the MS3 Pro.  

[You must be registered and logged in to see this image.]
< MS3 to Porsche New Pin Connector >                      < Charge Wire Fusible Link >

[You must be registered and logged in to see this image.]
< Pre-Start Workspace >                  

Using the MS3 programming software in TEST MODE (and our ears), we went through the
customary pre-start system checks:
         • Coil function – all good except #8 seemed to have intermittent power.
         • Injector function – all good
         • Fuel Pressure – almost 40 psi
         • Oil Pressure - ~80 seconds of cranking in 3 sessions yielded 1.5 BAR (~22psi)  on the gauge
            but the gauge needs zeroed which means the reading was closer to 40 psi.
         • Transmission in NEUTRAL (Although the car was on the lift…just off the floor)
         • Fire Extinguisher handy
         • MS3 Software Datalogger turned on

[You must be registered and logged in to see this image.]
< MS3 Software in TEST Mode >                                           < Safety First >

…and now for the moment of truth!!  
Turn up the volume for a 10 second video clip)

Initial Start-up Video

< SUCCESS!!!!! >  

What a relief it was to start this engine!  I started building it in 2014 so I’ve had more than enough time to question if everything was done right.  So far…it looks like it was.

Next up… Final wiring and the 1st full warm-up!

Sorry folks but I incorrectly assigned the wrong "sharing" status for the Start-up video in my last post.

All fixed now and anyone with the link provided should be able to watch the video.
Actually not much to see... it all about the sound!

Below is the link again:

Initial Start-up Video

Very nice Ray and she sounds AWESOME!!!!

Ray that is indeed awesome! super happy for you as i am quite sure you were just as overjoyed as i was on my day this last june 17th. such a great and rewarding milestone!

Guys, thanks for the encouraging words on my initial start-up!  I still go back occasionally and listen to it!!  There's a new video in this post....and more to come!

It’s been slow going with the exhaust fabrication, so I spent some time picking up some parts still needed to put the car on the road.  Below is the list just in case you might need similar items:

Premium Ignition Coil Harness Connectors (2 PK)
Blue ELF - GM replacements for Truck Relocation Applications
       PN: BlueYWM-1079-4 - Amazon ~$37
       (These are for LS2 Coil Packs and replace PN: 89017477… No pin adjustments in the main
       connectors were necessary to fit my LS1 harness connectors.)  This is my solution to the
       intermittent/random coil pack connections that we ran into during ignition testing.  
       Going for reliability here that was missing with the original 2002 LS1 connectors.

Hood Lift Support Shock Struts (2 PK)
A-Premium, PremiumpartsWhosale – Amazon ~$21
Item No.: H102211016 / GS44690 (Made in China)

Trunk Hatch Lift Support Struts (2 PK)
Stabilus Sachs, Lt & Rt (w/rear defrost leads) - Amazon ~$57
Lift-0-Mat, SG206004 005, 3F-942863 & 3F-7778BZ (Made in Germany)

Rear Hatch Lock Seal
5150motorsport Item ID: 143790057713 - E-bay ~$12
Genuine Porsche PN: 924 944 951 968 (Decklid Trunk 477827529A)

Air Intake Coupler Hose
Blackhorse Racing – Amazon ~$25
‎HM1659, 3-Ply Silicone, 4" Inch ID x 12" Long Straight (Black)
(This fits my Jantzer 92 mm throttle body inlet housing which has a 102 mm OD.)

All these parts were easily installed…

Exhaust System Fabrication

As mentioned in prior posts, my plan was to use a 2-1/2” Borla SS dual exhaust kit with X-pipe for a Cadilac CTS-V ’09-’13, PN:60524, and a pair of Borla 10”x5” SS mufflers.  The kit came with a pair of S pipes at the transaxle and SS band clamps for the connections.
     
[You must be registered and logged in to see this image.]
< Borla Cadilac CTS-V Exhaust >                                  < Borla “Stinger” Mufflers >

For custom fabrication needs, I picked up a FGJQEFG 2-1/2” DIY universal exhaust kit on Amazon for about $125.  These pipes were China made using polished 0.05” wall T-304 SS and mandrel bends.  They were not as thick as the Borla pipes but mated well.  Honestly, it’s a nice kit for the money.

[You must be registered and logged in to see this image.]
< FGJQEFG Universal DIY Exhaust Kit >

I purchased a pair of 4” long SS braided Flex Pipe from BLACKHORSE-RACING for about $30/pair.  The 1st set I purchased was too long because I mistakenly assumed they could be deformed enough to reduce fixed bends!
A flexible link between headers and the exhaust system is generally acknowledged to reduce header weld failures.  
To round out the hardware, I used a pair of 3” SS, black powder coated, rolled angle cut tips from the LGGP store, purchased on Amazon for about $45/pair.  They are very nice except for the mechanical clamping bolt which looks marginal.  Not using that anyway.

[You must be registered and logged in to see this image.]
< SS Flex Pipe >                                                           < Black Angle Cut Tips >

Fabrication started with building pipe bends to connect the Borla X-pipe to the header collectors incorporating the sections of flex pipe.  My nephew used TIG welded pie cuts to create the custom bends.  Not exactly mandrel bends but certainly acceptable for street use and a straightforward approach. An important part of the process was to weld in threaded bungs for the AEM wide band O2 sensors. I used the Super Shops (Amazon) AEM (30-4110) UEGO Air/Fuel Ratio Gauge Kit - $165 and purchased a second AEM sensor for $40 so I could check both banks (although not simultaneously).

[You must be registered and logged in to see this image.]
< O2 Sensor Bungs & Flex Pipe >                                   <  AEM Wide Band O2 Sensor Kit >

Extending the exhaust back to the transaxle required use of some straight pipe, followed by the Borla S pipes in parallel, and then some custom pipe fitting to get the Borla mufflers lined up properly.  
Personally, I’m amazed at how the Borla kit matched the contours of the Porsche floor, both vertically and horizontally.

[You must be registered and logged in to see this image.]
< Borla X-Pipe Excellent Fit >                                         < Exhaust Mock-up Tacked >

My nephew was very picky about the tail pipe alignment…as was I.  To get it right required narrowing the outlet extension pipes to obtain about a 1” space between the 3” tips and also marking the extension length so the tips extended just about ½” past the bumperette.

The outboard pipe was set a bit shorter to match the curvature of the bumper.

[You must be registered and logged in to see this image.]
< Exhaust Tip Set-up >

With everything marked and tack welded, the mufflers and tail pipes were removed for full TIG welding. To keep everything aligned properly, my nephew made a couple SS C-rods to permanently connect the muffler and tailpipe assembly.  Note the rotated mufflers so the embossed Borla logo was upright and visible on each side!!!  (He did apologize for the ratchet strap buckle dent!! LOL)

[You must be registered and logged in to see this image.]
< Fully Welded Muffler and Tailpipe Assembly >

Final Steps

The last bit of fabrication needed is some custom hangers that will work with the factory hanger brackets and mounts.  I bought all new Porsche replacement muffler mounts (rubber) for about $50 but not sure exactly how they will be used.

That part will be included in Part 3…

One thing I did while the complete tack welded exhaust system was in place, was run the engine to operating temperature and while doing so, run the transmission through the gears.  I’m happy to report no leaks from the cooling system, the transaxle or oil cooler, the transmission shifted smoothly, and all the gears worked as they should.  At least as far as I could tell with the car still on the lift.

Below is a short 12 second video clip of the engine running with the exhaust system in place. Operating temp was about 190 and the max RPM was a short 3K burst.  Obviously running rich with the base tune at this point.

Video - Running In Gear

Attack of the Gremlins!

With the exhaust system on, I could finally hear the engine “song” and I didn’t like what I heard. Although the engine was running fine, there was a SYMPHONY of shallow metallic clattering!!
After some detective work with a make-shift stethoscope, it was apparent the clattering was coming from the valve covers.  I suspect the rockers have clearance issues… Not happy!

Then while scratching my head over the clattering development, I noticed a large puddle of power steering fluid on the floor right under the Hydro-boost unit.   There is a profuse leak between the HB unit and the HB adapter plate for the pump connections.  Even less happy!

Solutions to the Gremlins in my next post…

As mentioned in my last post, I could now hear severe engine clatter that was apparently emanating from the valve covers.  I used a long 3/8” socket extension as a stethoscope and confirmed that the noise was indeed limited to the valve covers. There was absolutely no vibration coming from the heads, and I was extremely happy about that!

To determine the significance of this condition, the next step was to remove one of the valve covers and see what was actually going on.  It was a no brainer to pull the PS valve cover because only the coil packs had to be moved.

Discovery…
As it turns out, the clattering was the result of the Exhaust Rockers contacting the rivets that attach the oil baffle plate on the underside of the valve cover.  Fortunately, the interference was minor, and the rivets are a soft alloy.  

This wasn’t supposed to happen because I thought I had purchased the “tall” Holley valve covers.  However, after checking my receipt records, I learned that I had accidentally purchased the standard height covers.  This was a blessing in disguise because there was no way the tall cover would fit under the Hydro-Boost on the DS.  More on that later…

Below is the damage caused by rocker/rivet contact at #8 Exhaust Rocker.  Similar damage was found at #2, #4, and #6 Exhaust Rockers.

[You must be registered and logged in to see this image.]
< #8 Exhaust Rocker >                                          < #8 Rocker Rivet Contact >

The Solution
To assure the requisite clearance, I drilled out the offending rivet heads and used my die grinder with a small cutting wheel to remove the surrounding baffle plate portion and remaining rivet head down to the cover casting.  That may be overkill as the Intake Rockers are located in between the rivets and do not contact the baffle plate.  Just being extra cautious….

[You must be registered and logged in to see this image.]
< Baffle Modification at #2 >                                   < Completed Baffle Modifications >

The drilling and cutting operation generated plenty of metal shavings which I meticulously collected with my Shop Vac, followed by a thorough blow-out with compressed air for good measure. Once it was all clean, I went back and filled the holes I created in the baffle using Permatex Permashield gasket sealer.  Recall this is the same fuel/oil resistant product I used to rebuild my FAST Intake Manifold.

[You must be registered and logged in to see this image.]
< Permashield Repair >                                            < Gasket Growth Surprise >

NOTE: I removed the valve cover gasket for cleaning, but THAT WAS A MISTAKE!   Once free from the confines of the valve cover, the gasket immediately grew about 1 inch in length!!  I was surprised by this and tried to shrink the gasket to its original size by freezing for 24 hours, boiling water bath for 30 minutes, and plain old air exposure for 48 hours, but nothing worked.  

The surefire remedy was a new valve cover gasket set which I ordered off Amazon that includes new attachment bolt sleeve gromets.

FEL-PRO Store (via Amazon)
Valve Cover Gasket Set
PN: FEL-PRO VS 50504 R-1  
~$18

Driver’s Side Challenge
In my build, the DS valve cover is COMPLETELY covered with other engine components, so much so that it is barely even visible.  Removing it was going to be arduous at best and turned out to be a 2-hour effort!

I used the following disassembly sequence:

   1. Remove the spark plug wires from the coil packs.
   2. Remove the coil packs and all custom coil pack mounting hardware and wiring.  
   3. Drain the Brake MC reservoir.
   4. Disconnect the brake lines and remove the Brake MC.  (2-Hex Bolts)
   5. Remove the MC to Hydro-Boost adapter plate. (2-Allen Head bolts)
   6. Disconnect the upper Hydro-Boost high-pressure lines from the adapter manifold and HB housing.
       (I needed to do this because I ran those lines along the top edge of the valve cover.)
   7. Completely remove the back lower coil mounting tower adjacent to the Hydro-Boost.
       (This tower was already partially removed during engine installation for general clearance with the
       HB.  Once again, my Sawzall with a LONG metal cutting blade to the rescue.)
   8. Remove the valve cover mounting bolts completely.
   9. Lift, tilt, rotate, and slide out as needed to remove the valve cover.
       (This was just barely possible with the Holley valve cover.)

I was over the moon excited that I did NOT have to remove the Hydro-Boost unit!!

[You must be registered and logged in to see this image.]
< Driver’s Side Valve Cover “Jungle” >                         < High Pressure HB Lines >                  
             
[You must be registered and logged in to see this image.]
< DS Valve Cover Removed >                                      < Repainted DS Holley Valve Cover >

As with the PS valve cover, I modified the rivets and oil baffle for clearance with the Exhaust Rockers.

Once the DS cover was off, I spent some extra time and completely filed off the back lower coil mount tower and the one in-front of it… just for good measure (red and orange arrows).   The finish was damaged from the “extraction” effort and filing off the mounting towers, so I repainted it with VHT Satin Black engine paint.

I put the valve covers back on with new gaskets and moved on to the next challenge before reinstalling the Brake MC.

Gremlin #2 – Hydro-Boost Manifold Leak...that’s next!

With the valve cover modifications complete, I took another look at the Hydro-Boost (HB) connections to see precisely what connection(s) might be leaking with the engine is running.  While I was hoping for a loose high-pressure line, all the hose connections were dry.

However, when I felt around the underside of the HB, I detected fluid between the HB housing and the TPC aluminum adapter block/manifold.  This was unexpected because it came preassembled in the TPC HB conversion kit.

To get “the rest of the story” I proceeded with a recommendation to remove the adapter block to see what was going on with the O-rings that seal both the high-pressure and low-pressure orifices.  This would be easy if you had hands the size of a 5-year-old…otherwise, it’s a test of patience.

The TPC adapter block is secured with a single large banjo-type bolt with a ~3/4” hex head that threads into the HB housing (red arrow). Fortunately, my nephew happened to have an off-brand wrench in that size, and because it was thinner than professional tools, it fit in the minimal space available.  I was able to remove the bolt, albeit only 1/8 turn at a time.

To make the wrenching a bit more efficient, I removed the hydraulic line (yellow arrow) to the throw-out thrust bearing which was limiting wrench travel.

[You must be registered and logged in to see this image.]
< TPC HB Adapter / Manifold >                                        < Original Adapter O-rings >

[You must be registered and logged in to see this image.]
< Original 1/16" High-Pressure O-ring >                                    < O-ring Comparison >

Upon inspection, the high-pressure orifice O-ring suspiciously did not protrude above the mating surface of the adapter block. Kent at TPC advised me that the correct size was 7/8” OD / 11/16” ID x 3/32” thick.  The O-ring in place on the adapter block was only 1/16” thick.  Without some mechanical compression, there can be no sealing.  Mystery solved!!

The Solution
I purchased a Universal SAE O-ring Assortment Kit made of Nitrile rubber that contained about 10 of the size I needed!  Nitrile rubber is the material of choice for hydraulic fluid.  The new O-ring fits perfectly and should function as intended.

[You must be registered and logged in to see this image.]
< Nitrile Rubber Specification >

[You must be registered and logged in to see this image.]
< New 3/32"  O-ring in Place >                                                           < Close-up >

Lesson Learned:  
We all make mistakes.  Always double check pre-assembled components for correctness prior to installation.

I’ll be reassembling everything in a day or so and will know soon enough if the new O-ring solves the problem!

Next up, Exhaust Part 3 – Final Installation

While I was addressing my Start-up gremlins, my nephew completed the final TIG welding of the exhaust system including the necessary hanger connections to engage the factory supports.  I was now able to hang the system and install the wide band sensor so we could manage the fuel/air mixture.

It’s all stainless steel and I’m happy with how it turned out!

[You must be registered and logged in to see this image.]
< Header Gasket Sealant >                                              < Header Connection Prep >

I applied Permatex Optimum 750-degree gasket sealer on ALL mating faces including Copper Gaskets which are not shown.  I placed the convex side of the gasket sealing grove against the flat header flange.  SS bolts, lock washers, and hex nuts secured the connection.  I tightened these bolts just "wrist tight" to avoid warping the clamping flange but still crushing the cooper groove as needed.

[You must be registered and logged in to see this image.]
< Flex Joints and X-Pipe >                                             < Front Section Rear Hanger >

[You must be registered and logged in to see this image.]
< Rear Section Front Hanger >                                            < Completed Rear Section >


 [You must be registered and logged in to see this image.]
< Muffler Hanger Fabrication >                                      < Muffler Hanger and Heat Shield >

I used VHT Flat header paint as needed…

[You must be registered and logged in to see this image.]
<  Completed Exhaust System >

The final installation is pulled up tight, and closely follows the contour of the factory floor pan.  The 5” diameter Borla S mufflers are much less of a visual magnet  than the large factory muffler.

Next Up…Gremlin #1 - Engine Clattering - UPDATE

The only way to test the effectiveness of my valve cover modifications was to run the engine.  That meant reinstalling the valve covers, putting the Hydro-boost manifold adapter back together, reinstalling the brake MC, and reconnecting all the electrical and hydraulic lines.  This was no simple task in such tight quarters and took several hours.

With the exhaust completed, the next step was to plug in the laptop to the MS3 to log the event, and turn the key… With the wide band sensor connected, we could see the engine was running extremely rich as we suspected (like 2x).  Only took a minute to adjust it to where it belonged.

SUCCESS!!

Check out the VIDEO LINK below.  Engine compartment sounds good (NO CLATTERING!) and the exhaust note is even better!  

VIDEO - Start-up & Walk Around

Next Up…Gremlin #2 – Hydro-Boost Manifold Leak - UPDATE

As noted in my Gremlin #1 update, reassembly was a challenge, especially the HB manifold.  The TPC adapter block is secured with a single large banjo-type bolt with a 7/8” hex head and it’s barely accessible with a thin wrench.  There is NO ROOM for a hand to hold the manifold in place and also turn the bolt with any size fingers!!!.  On top of that issue, the downward slope of the unit allows the bolt to easily slide out of the manifold block, away from the target engagement threads.   Then when you push the bolt back in, the O-ring goes flying!!  The word IMPOSSIBLE certainly came to mind.

After multiple unsuccessful tries, I thought of a couple tricks to get the job done:
     1) Permashield sealant on the O-ring so it would stay put.
     2) Inserting the banjo bolt in the manifold and using zip-ties to secure it flush with the HB
          housing exactly where it belonged.
    3) Leverage a long flat blade screwdriver to apply just enough pressure to the bolt head to
         engage the HB housing threads while turning the bolt with a THIN 7/8” wrench.

[You must be registered and logged in to see this image.]
< 1/16” VS 3/32” High-Pressure O-ring >                 < Banjo Bolt >

Success!!

In the end, the new Nitrile 3/32” O-ring sealed properly and now I’m good to go!  YAY!!  

I learned from Kent at TPC that his early HB conversion kits (like mine) used the smaller factory O-ring, with hit or miss success.  Upon learning this, TPC upgraded the kit with the larger 3/32” O-ring.

With no leaks, sealed exhaust, and no rocker arm chatter, we did another test run to full operating temperature.   The test run went well with the cooling system working as intended with no leaks, a functional thermostat, and a steady final temp around 190 F parked.  

However, I did discover two more minor gremlins... 1) one of the cooling fans was not turning on, and 2) brake fluid was leaking from the brake master cylinder reservoir cap.   These will be challenges for another day.

With the air/fuel ratio mostly correct, no fluid leaks, and stable operation at full temperature, it was time to rev this engine a bit beyond idle RPM.  Below is a VIDEO link of a 5K RPM rev.
Throttle response is amazing!

VIDEO - 5K RPM Rev

I finally drove the car under its own power after nearly 20 years… but only about 150 ft from one garage to another.  

Installation of the air intake, hood and rear hatch latches, front bumper, front panel, and lower front valance remain.   Then a ROAD TEST!!

Raymond, your engine and Torque Tube assembly is pristine! I appreciate the background info in your posts.

Thank you Bluemongoose!  I’m glad the documentation is helpful and I appreciate the feedback.  Now that I have the engine running, I feel pretty good about the build.  There’s always a shred of doubt until you turn the key and it fires!!!   I hope to be posting my test drive in a week or so.  Should be fun.  Then off to the dyno for a good tune.

Your posts have been critical to my project. I am at the stage now that I need to start looking at the AC lines. I have the TPC AC kit. I have the stock AC hard lines. Im not sure I still have the pressure switch. Do you know of anyone on this forum or anywhere really that might just have the hose specifications to order from Coldhose? Or maybe a good diagram would get me closer.

viperbmw69 wrote:Your posts have been critical to my project. I am at the stage now that I need to start looking at the AC lines. I have the TPC AC kit. I have the stock AC hard lines. Im not sure I still have the pressure switch. Do you know of anyone on this forum or anywhere really that might just have the hose specifications to order from Coldhose? Or maybe a good diagram would get me closer.

When I was in the “teardown” mode, I tried to keep track of what AC components I had in place because I fully intended to have operational AC in the end.

Below are links to my AC conversion documentation so far.  The 1st link contains an AC diagram I found on the Internet... I upgraded it in the last link for my actual application.   It could prove helpful.

4 AC Considerations
[You must be registered and logged in to see this link.]

5 AC Compressor Replacement
[You must be registered and logged in to see this link.]

7 Condenser Installation
[You must be registered and logged in to see this link.]

9 Drier Replacement - Relocation
[You must be registered and logged in to see this link.]

The above link has the modified AC Line Diagram that I plan to use…however, I will not be doing the work myself (other than component part installation).  I just don’t have the right tools or equipment.  Come spring I’ll take the car and all the Porsche hardline tube ends etc, to a local custom AC shop and let them make the proper hoses and connections.

Hopefully it won’t cost me my 1st born!!

In your case... Kent at TPC or Bob at HotRodzDallas can likely provide the specific information you need to have Cold Hose make your lines.  Other people on this forum may also have direct experience. In my limited knowledge, once the proper connector end is established, the critical specs are length and end orientation as AC lines are not exceptionally flexible.

Note:
FYI…To get to any of my documentation, go to the Project Post INDEX CLICK HERE at the end of most of my posts.  You can search the index using “CTL F” and key words which can really help with the digging. I use it myself!!

Well folks… my project has been bogged down a bit in my efforts to build a nice Over The Radiator (OTR) Air Cleaner intake tube.  I can’t hit the streets without clean air!!

The delay is all because of the size of the intake tube.  My nephew’s current 3D printer was too small to handle it, so he is in the process of designing and constructing a bigger and better one… he’s quite ingenious in this area.

The initial challenge was to design a custom intake tube that transitions from my 4 in diameter throttle body intake to the 7 in x 2.25 in oval outlet of the Volant MaxFlow 5 Conical Filter, PN 5126 (~$93).  The circular Volant/Camaro transition tube interferes in a big way with the Porsche hood and cannot be used.  A custom unit will need angled downward approximately 15 degrees and must taper quickly from a circle to an oval.

[You must be registered and logged in to see this image.]
< Volant Conical Filter & OTR Camaro Transition Tube >

Any OTC setup will require some surgery on the radiator mount cross frame which Porsche calls the “Lock Carrier.”  I mocked up a steel sheet metal reinforcement plate I intend to fabricate that will restore the strength of the modified frame but allow the oval intake tube to pass through it.  It can be bolted or welded in place.

I’ll provide more detail later during the fabrication process…

[You must be registered and logged in to see this image.]
< Porsche “lock carrier” w/Proposed Reinforcement Plate >

Below are some design software screen captures of the custom intake tube:

[You must be registered and logged in to see this image.]
< Transfer Tube – Top 3/4 View >

[You must be registered and logged in to see this image.]
< Transfer Tube – Elevation View >

The transition tube will be 3D printed using THERMAX PPE+PS (Polyphenylene Ester), and is an engineering grade material that offers high heat resistance, excellent chemical resistance, and is non-halogen flame-retardant.

My nephew has assured me that he will have his 3D printer bed ready after Thanksgiving, so I should be seeing a custom intake tube soon.  Stay tuned!

[You must be registered and logged in to see this image.]  

HAPPY THANKSGIVING EVERYONE!!

Nice drawings Ray! When you get the correct intake tube printed, you should print several and sell them. I know I can definitely use one on my project car. Let me know.

Thanks

Much fancier than my intended filter solution in my 928...

I snagged a stock Chevy Express van canister filter housing that has a side inlet that peeks over the core support.

87Roadracer,

I'm sure we could get some kind of package together for anyone who wants an OTR air intake.  Replication has been a topic all through the design stage.  I'll definitely keep you in mind!

Hey_Allen,

I'm sure this forum community would love to see pics of your set-up...me included!

My considerations in developing a custom intake transition tube included:
1) A suitable air cleaner element
            a. Sufficient capacity: The Volant unit I used is designed for a Camaro LS1.
            b. Proper Size:  It needs to fit under the front panel.  Yes it does!
            c. Reusable and replaceable.  Yes!
2) Sufficient air flow volume
            a. The cross-sectional area of my 92 mm intake (4" OD) is 12.57 in²
            b. The immediate transition to an oval shape at 7.25" x 2.25" does the trick.
3) Matching the hood contour
            a. A downward angle almost immediately off the TB is required.
4) Front Panel Connection
            a. The top flat of the "lock carrier" must remain intact to secure the front panel.