Ray's 1987 944 LS1 Build & Swap

That's why I said my "intended solution" as I'm collecting parts, but then moved halfway across the country.
The 928 stock air intake setup pulled from an air dam around 3-3.5" tall across the top of the radiator core, and the Express Van filter has an intake that is around 2.5" tall.

This link will fail in time, but GM used them on everything from the 4.3L to the 6.0L (possibly larger, those are just the ones that I've seen them equipped on.)  
For my modest target of around 300HP, the filter should have no issues at all, since some of the stock applications were already higher.

eBay Express Van filter listing

edit: that all said, I'm fairly sure I can prop the filter assembly in place on my radiator and put a piece of putty on top to show hood clearance, if that is of any use. It's in a 928 though, so different latching and dimensions than your 944.

Sorry to interject, but for someone thinking about buying a 944 and swapping an LS, how many hours can I expect from pulling out the old motor and driving with a new motor?
Your 9.5 year long thread has made me concerned....

zenon wrote:Sorry to interject, but for someone thinking about buying a 944 and swapping an LS, how many hours can I expect from pulling out the old motor and driving with a new motor?
Your 9.5 year long thread has made me concerned....

zenon... I can understand your concern but my experience is fairly unique due to family circumstances.  You definitely can not gauge your project duration based on mine.  I guess you can say I was simply over ambitious to undertake a project of this magnitude considering i had very little room on my plate.

My youngest son was born with Duchenne Muscular Dystrophy and was fully disabled (physically) from age 10 to age 28 when he passed. He lived his whole life at home and needless to say, our lives revolved around him until 2018.  

My Porsche project was therapy for me because I love cars and hot rodding in particular.  When I started in 2014, work was very sporadic and limited to an hour or so a couple times a week.  I also took a couple "sabbaticals" as life events and "honey-do" projects took priority.

Back to your question, I would say overall, a dedicated swap project only with all conversion and replacement parts on hand, could be done inside of a month.  Repairs, modifications, upgrades, parts acquisition, and aesthetics all add more time...much more time!  The year, model, and condition of your Porsche and your choice of LS conversion parts will all be factors.

Bob at HotRodzDallas, builds 948s for customers in a controlled business environment and I suspect he will chime in with some accurate estimates on how long it really takes.  Same for Kent at TPC.

I recommend taking the plunge... I would do it again in a minute!!

Ray I'm so sorry to hear about your son.

In manufacturing they call it Cycle time, the time to actually manufacture an item.
Cycle time can vary quite a lot from the time it takes the item to finally complete its journey through a factory....

It seems like you're now at a point where you can drive around while you shake down the rattles?

I'm going to sell my motorcycle, but I still want to go fast and a chopping Camaro just doesn't do it for me...
I've always loved the 944, and I want to build-up an LS, so your build is very much on-point with what I envision.

zenon wrote:how many hours can I expect from pulling out the old motor and driving with a new motor?

zenon, it took me 3 months of evenings and weekends to get my swap on the road. I had all the main conversion parts on hand before I started.

Rich

OTR Air Intake Tube 3D Print – Update

After some hardware mods, new part fabrication, and a couple firmware changes, my nephew’s 3D printer project was ready to print test pieces of our custom intake tube design that would allow us to verify the geometry. Using ABS plastic, he printed a short section of the 4” throttle body end, a short section of the air filter end, and most importantly, a frame section representing the centerline cross-section elevation of the intake tube.  

The 3 pieces fit together for a mock-up piece that I was able to test fit on the car.

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< OTR Air Intake Tube – Test Print >

The next step was to create a cardboard “Lock Carrier” support plate as mentioned in a previous post. Below is a template I made using SketchUp with a maximum rectangular opening.  When making my 1st actual cardboard version, I used an oval opening defined by the air filter element.  

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< Lock Carrier Support Plate Template >

Below are some pics of the cardboard lock carrier mock-up and test fit of the 3D intake tube test print
 I think we have a winner!!

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< Template in Place >                                                      < Air Filter Position – Rear >

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< Air Filter Position – Front >                                                  < OTR Test Print – Front View >

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< OTR Test Print – Rear View >                                                < OTR Test Print – Side View >

When I make the lock carrier support plate from sheet metal, I plan to bolt it in place 1st for adjustability and then have it fully welded for improved strength.

While I’m confident in our design, I still need to check hood clearance one more time, and also make sure the angle of the air filter element provides sufficient clearance for installation of the front panel.

Getting closer…

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First off- thanks for this forum! I've been reading it in detail over the past couple weeks, and I just caught up. Happy to see you're still super active and chugging along.

Also- thanks for the power steering article in Clark's garage!! I used it literally about 6 months ago to do the rack in my 944.

This forum has inspired me to start my own as you've told others, or maybe a youtube channel. I'm also an engineer, and documentation has always been my weak point. I've an '87 944, and I'm in the middle of building an LS1 for it (block is at the machine shop getting a slight bore and other work done, should be picking it up in a couple weeks)

I've a favor to ask- seems like you're well connected in the 944 LS Swap world, and I've seen you reference Greg and his swap manual- I ordered my own manual several months ago and it's not shipped. I managed to get in touch with Greg through LinkedIn (lol) but I've still not been able to get my copy. At this point, I'm happy to buy someone else's copy (I was going to ask to buy yours but clearly you're still in it, and it's something you'd rather keep anyways I'm sure). If you know of anyone who might have a copy, or have a direct line to Greg, I'd appreciate any help in that regard!

Nathan?,

Thanks for the kind words!  ...Always appreciated.

As an engineer and technical author, my objective in documenting my build was 2-fold: 1) share my experience with the people that helped me so much, and 2) my own personal records.  This year, the car is just about road ready and I plan to share both my road and track experiences.

It's exciting to hear you are doing an 944/LS swap.  I have yet to hear of anyone that has regretted doing this and picking up an additional 200 +/- HP.  Most are over the moon, myself included!

Regarding the Greg Sloan manual, the general consensus is you are heading toward a dead-end.  It's unlikely you will ever see your manual arrive...or get your money back.  Many folks have had a bad experience but that was all yesteryear and Greg is pretty much out of the game.  While his manual is a decent introduction to the swap process (in the day), it is actually now outdated and you can find all that you need on this forum.

Kent Marr has taken over the Forum and TPC, and is doing a stellar job!  He is the forum moderator by-the-way, and using current technology and new products, he has developed conversion kits for just about everything.  Many experts on the forum use TPC products for themselves and their clients, and have contributed to their refinement...thus making his current products more plug and play for new projects like yours.

Nonetheless, I do have a Greg Sloan manual and would be happy to discuss and share any part of it. However, as I said, there are new and better ways to get things done... especially if you do not have access to a full machine shop.

A suggestion I have for you is to learn how to use the Advanced Search function on this forum. The directions are in the top left of every forum page. It is going to be your new best friend... not to mention the multitude of forum users that will be happy to help you along the way!

Keep us up to date...we'll be watching!

Yes, my name's Nathan!

Thanks for the update on the manual and forum stuff.

I have access to a full machine shop at work that I'm fortunate enough to be able to use for my own projects (mill, lathe, waterjet, etc.) and I was hoping to do as much of my own fab as I can, within reason. Like I mentioned, I'm a mechanical engineer, actually working at an automotive company, and have experience designing parts and what not and quite enjoy doing it for my own projects. That's what attracted me to Greg's manual. Plus I love having hard copies in the shop. But I'll put it to bed for now,

Anyways, I don't want to hijack your forum- lots of great content and I don't want to muddy the water for others like me trying to learn, so I'll leave it there. I certainly hope to talk more in the near future, perhaps in a better forum (PM's aren't unlocked for me yet, this being only my second post) I'll certainly have more questions for you and the crew here, and I'll be sure to give that advanced search function a go.

Thanks Ray!

Nathan,

You can get your project thread started quite easily. That will make it easy for Forum users to follow your build.

1) From the Forum home page, scroll down to "944 Conversions" and pick the conversion category that fits your build.  Most likely it will be:
LS1 Conversions

2) Click "LS1 Conversions" to open the path and you will see all the other related threads from other forum users.  Note the various thread names.  You will need to create your own unique catchy thread name (TOPIC) in the next step.

3) Click the "NEW TOPIC" button near the top left hand corner (or the bottom left hand corner) and type in your new thread name or topic where it says "Title of the topic"  IE: "Nathan's LS1 Swap"

4) Click on the large open white space and type away.  
general directions were provided by the moderator long ago and you can see these by clicking the link below:
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I can help you along the way with formatting and posting pics and links, as it all takes some practice.

Whenever you post something new, go to your last post with your original thread (Topic) name, and at the bottom of the page select POSTREPLY. You will be able to give a new post title to the "reply" that is specific to your post without changing your thread Title.

There are lots of tricks to posting but this should get you started.

Thank you for detailing this! I had my maiden drive yesterday and have a significant leak from the same area. I ordered some slim wrenches off Amazon, so hopefully the o-ring replacement won't be too bad. If you hadn't already identified your problem and shared with the us on this forum, this would have been much more frustrating.

-Aaron

Raymond-P wrote: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.

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< 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!!

Aaron...you are most welcome!!

We're all in this together...

Soooo…. Before fabricating a Lock Carrier reinforcement plate, I really needed to have a viable intake tube in hand to assure a good fit.  Unfortunately, this is not happening as planned because the 3D printer box heater regulator firmware is allowing the working temperature to fluctuate outside the limits identified for proper printing of Polyphenylene Ester. My nephew hasn’t given up but it’s going to take some time to iron out this issue.

The new short-term game plan was to print the OTR Intake Tube design as a convex mold and make a Carbon Fiber (CF) version. Two (2) half molds were printed in standard black PLA Pro (Polylactic Acid) strand.  Each half required about 12 hours of print time.

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< Initial 3D Print >                                                   < ~8 Hours of Printing >                                

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< OTR Mold Halves – 12 Hours Each >

With the mold halves put together I can finally see what the intake tube actually will look like!

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< OTR Intake Tube Mock-up >                                         < OTR Intake Tube Design >

Note that a lip on the inlet and outlet was added to the mold design to help secure positive connections and reduce the required hose clamp pressure. The overall design was essentially scaled down in size to account for an approximate 1/8” wall thickness that will exist after 4 layers of CF are applied.

The next step is to check the fit of the mold on the car using some 4” neoprene tubing and the Volant cone filter.

STAY TUNED…a test fit is coming soon!

Building the Carbon Fiber Intake

If all looks good, the next step will be to create the CF version…
which once again, is UNCHARTED TERRITORY!

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I would very much appreciate ANY procedures, direction, tips, or tricks from forum members that are knowledgeable of and/or have experience with CF fabrication.

Below is my game plan as gleaned from Internet research.

Each half:
1. Smooth over any surface irregularities.
2. Create a cutting pattern for each area using masking tape and a marker.
3. Flatten each pattern and cut out CF cloth pieces with some excess for overlaps.
4. Coat the mold thoroughly with PVA mold release agent.
5. Mix a batch of resin and apply an even coat to the mold surface.
6. Lay on the precut pieces of CF and press fully onto the mold shape as needed.
7. Apply additional resin throughout making sure the CF mesh is saturated.
8. Repeat steps 6 and 7.
9. Let cure for 24 hours and remove the CF piece from the mold.
10. Remove any inside surface irregularities.
11. Trim the mating surface for a good match.

Next, I plan to use JBWeld to bond the two halves together.  Once the adhesive is cured, I will have a thin shell version of the final product.  Throughout the process, it will take some extra effort to make sure the lip at each end of the tube was discernable.  Once I have the full piece ready, the plan is to add two more one-piece layers of CF that will cover the top seam and overlap on the bottom where it will be out of sight.

Full Piece:
12. Sand the entire surface with 100 grit paper, removing any surface irregularities.
13. Create a ONE-PIECE cutting pattern for the entire tube using masking tape and a marker.
14. Flatten the pattern and cut out a CF cloth piece with excess for an overlap at the bottom.  
15. Mix a batch of resin and apply an even coat to the tube surface.
16. Lay on the precut piece of CF and press firmly into place throughout.
17. Apply additional resin throughout making sure the CF mesh is saturated.
18. Repeat steps 16 and 17.
19. Let cure for 24 hours.

ALL comments and/or corrections are WELCOME!!!

My CF order is scheduled to arrive in 3 days.

My advice is to test fit the mold and take pictures! :-)

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It turns out my hydroboost was assembled with the same (incorrect) o-ring. I bought some slim wrenches which made the process much easier.  The biggest bummer is the mess it made. 

lowform wrote:Thank you for detailing this!  I had my maiden drive yesterday and have a significant leak from the same area.  I ordered some slim wrenches off Amazon, so hopefully the o-ring replacement won't be too bad.  If you hadn't already identified your problem and shared with the us on this forum, this would have been much more frustrating.  

-Aaron

Raymond-P wrote: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!!

BAD NEWS... After getting my hands on the completed 3D mold, a test fit with the Volant cone filter revealed that the filter end was much TOO SMALL!!  Turns out that pulling the design dimensions from the Volant intake tube was a mistake because the kit intake tube was too small for the air filter by nearly 1/2” in the long direction. Go figure!?!

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< 3D Printed Air Intake Mold in PLA >

What this means is that the oval end of the intake tube (using this mold) will NOT have the equivalent cross-sectional area of the 4” throttle body end.  That’s NO GOOD.

A new mold will need to be printed after the design is modified for the correct dimensions.

At this point, I thought my options were either:
         1) wait a week for a revised PLA mold to be printed, or
         2) wait several weeks for my nephew to get his print oven working so he could print a usable
         intake tube with THERMAX PPE+PS.

However, before I could decide, my nephew called me with more bad news.  His computer with the 3D design software just fried the motherboard and he is dead in the water.

Only the plus side, Amazon delivered my Carbon Fiber cloth, resin materials, and mixing cups.

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Carbon Fiber – Composite Envisions
Aerospace Grade Carbon Fiber Cloth Fabric, 2x2 Twill 3k 50" x 36", 5.7oz/193gsm
$43

Resin Materials – East Coast Resin
EPOXY Resin Crystal Clear 16 oz Kit.
$20

Mixing Cups & Sticks – NetSellsit
10 - 8 oz Disposable Graduated Clear Plastic (PET) Cups, and
10 - 6" Wood Stir Sticks
$9

I guess these products are going to sit for a while…

Thanks for your findings on the hydroboost as i have some new funds to begin ripping my car apart and fixing some gremlins. one of them being my leak from hydroboost which as you had mentioned to me could be this o-ring that's too small.

Very interesting stuff on your OTR intake, i have to say that even though i was able to get my temps down with my squishy fit on my cone in the corner approach; i think your hard efforts here are going to be a huge payoff.

Many will benefit if you happen to produce a batch of 10 for other people's builds!

BTW your dual borlas sound incredible. seems to fit just on the outside of the torque tube tunnel quite well. i'd bet my single collected 3" from my y pipe hangs just as low as yours. great job there.

GB...thanks for kind words!  Read on for more info on the air intake tube.

In my last post on this subject, I was convinced that my original plan for a 3D printed thermoplastic intake tube was off the table. All because of 3D printing issues with complex thermoplastic filament suitable for use under the hood of a vehicle.  Subsequently, I redirected my efforts to building a carbon fiber unit using a polylactic acid (PLA) mold.

I ordered and received the necessary carbon fiber cloth and epoxy, and I had the new mold but before I could even get started, my nephew contacted me with some good news.

BACK TO PLAN A!!!

To make a long story short, my nephew put forth a huge effort to correct the printer calibration, normalize the filament feed rate, acquire a proper base adhesive, and resolve heat chamber management issues... all of which had stymied our previous efforts with desirable high-end thermoplastic strand.  It took a couple weekends, but he got it done and successfully 3D printed the revised design using Polymaker, PolyMaxTM PC-FR polycarbonate, flame retardant filament (1.75mm 1.00kg).

This filament costs about $55 per spool, retail, and he used about 60% of the spool.  Advertised benefits of this polycarbonate include:
• Ease of printing on a wide array of 3D Printers
• Low warpage
• Excellent mechanical properties
• Heat resistance, and
• Outstanding impact resistance

FYI:3D printing of this magnitude takes a LONG TIME!  Each half took about 18 hours to print.  Warp prevention required an additional 2 hours of annealing, and another 6 hours of drying time.  That's 26 hours total for each half!!

Below are some pics of the completed intake tube fitted with the Volant cone filter:

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< Post Annealed Final 3D Print – Underside >                                  

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< Post Annealed Final 3D Print - Elevation >

In the pics above, the printed halves are not yet bonded together.  I’m waiting on a 1.8mm drill bit to prepare the printed guide pin holes for short lengths of the 1.75mm filament.  The guide pins will ensure perfect alignment for bonding.  Additionally, some minor mating surface sanding is needed for “straightening” and surface texture to assure uniform contact and good glue adhesion. The adhesive of choice is Loctite Super Glue Professional which is a heavy-duty cyanoacrylate formulation with an additive that enables bonding of polycarbonate.  It has the best reviews by far and should work perfectly for this application.

I cut a 2-1/2” length of 4 in diameter 3-Ply silicone air intake piping and connected the intake tube to the throttle body. Below are some test fit pics.

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< Throttle body clamps not on yet >

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< Plenty of Clearance >

The final product looks factory and fits perfectly with ample clearance below the hood and front panel.  Now I just need to prepare and install my new lock carrier reinforcement plate and some rubber edge trim.
 I’m happy as a lark!!  

My nephew and I are considering offering a customized OTR Intake Kit for those looking to accomplish the same result.  It would include the following:
• Assembled 3D printed intake tube using Polymaker, PolyMaxTM PC-FR
  a) IAT and MAF sensor ports optional)
  b) Custom throttle body diameter
• Volant MaxFlow 5, 7” x 2-1/4” oval cone filter
• Silicone throttle body coupler to match your throttle body (straight)
• SS clamps (3)
• Stock lock carrier modification template
• Lock carrier steel reinforcement plate. (Laser cut with bolt-on or weld-in option)
• Rubber edge guard for the lock carrier opening

PM me if you’re interested.

NEXT UP… finishing my Lock Carrier reinforcement plate.

i can already foresee many soon to be 948 projects where people search your goldmine of documentation and stumble across your intake you have here and wish there was some way they could get one long after a limited run has been done.

this is tremendous and if i had been a half year out of step from where i took my build i'd probably be first in line for jumping on board. if my DEI form-a-barrier hadn't worked i would have definitely aborted and went your route but as per my latest write up on my thread, it worked out ok on dropping temps.

definitely not as pretty with the ridiculous array of hose clamps it required to get around the pop up headlight bar but functional and cool on IAT temps.

That clearance is great and will be very keen to see you lock carrier fabrication to stay away from the pesky hood pins.

Well friends, the Lock Carrier reinforcement plate got put on the back burner because I needed to design some hood pin mounts to replace the hood latch.

This is one of the downsides of an OTR intake. More on that in the next post.

Before I got knee deep in that effort, I needed to finalize my OTR air intake installation.  That began with truing up each half interface with 80 grid sandpaper on a flat concrete pad.  Next I ground smooth any print irregularities on the inside, then cut and glued in the guide pins.   Once they were dry, gluing the halves together was next.  This was a little tricky, but the guide pins really helped.  I followed the glue manufacturer’s application instructions and then held the halves tightly together by hand for at least 2 minutes.  Afterwards, I stretch wrapped the air intake with several bands of electrical tape for a 24-hour cure.  MOST IMPORTANTLY, I needed to install my Intake Air Temperature (IAT) sensor.  

Below are some pics of the process:

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< True-up Sanding w/80 Grit Paper >                     < Cutting the Guide Pins 1.75mm x 8mm >

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< Gluing the Guide Pins >                                                < Joined & Taped Halves >

As previously noted, I used a 2-1/2” length of 4 in diameter 3-Ply silicone air intake piping to connect the Air Intake to the Throttle Body.  This link was the logical place to install the IAT Sensor.  All I had to do was cut a hole in the silicone wall that was just the right size, that being big enough that I could insert the sensor, but small enough to make an airtight seal.

As luck would have it, a 45 ACP casing (and a small hammer) was ideal to cut the perfect hole!! The ribs on the sensor barrel provide the position restriction needed to keep the sensor where it needs to be.

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< IAT Sensor GM 12160244 >                                < IAT – 45 ACP Comparison >                              
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< 45 ACP Size Specs >                                                  < Cutting the Port at 3 O’clock>


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< IAT Sensor Installed >                                                        < IAT Sensor Projection >      

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< Completed Installation >

I used two 4-1/2” SS band clamps to secure the connection.

Next Up – Hood Pins

Some background: Using an OTR air intake required the removal of the factory hood latch. Did I have to take that route?  In short, yes, and here is why:

1. The LS1 5.7 is a bit longer compared to a 5.3 which reduces the available distance from the
           throttle body to the lock carrier.
2. My FAST Intake and 92mm throttle body uses a 4-inch intake tube for which there is simply not
           enough room for a 90-degree bend and subsequent routing.

The alternative hood restraint is a pair of hood pins. I wanted something “hi-tech” and opted for a set of lockable AeroCatch units.

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AeroCatch 120-2100 Above Panel Flush Mounting Hood Latch and Pin Kit.
Amazon
~$80 +tax

Locating the Mounting Point

As you all know, there is very little available engine compartment space to secure hood pins, and any space that is a candidate is far below the hood level.

In my case, the only mounting option available was a small area on top of each frame rail.  Fortunately for me, my ‘87 S car has a pair of threaded inserts in each frame rail for M6-1.0 bolts used to attach the 16V airbox mounting brackets.  I had already used the target PS insert for a fuel line mounting bracket and the DS mount still had the rubber mount in place.  The rubber mounts just screw out of the threaded inserts.

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< PS Mounting Area >                                                   < DS Mounting Area >

Designing Mounting Brackets

To get started, I measured the distance from the bottom of the hood (closed) to the top of the frame rail.  This dimension was about 9-1/2 inches, much longer than the AeroCatch hood pins which are just shy of 5 inches long.

My 1st reaction was to use some 4-inch-long SS C-shapes to raise the mounting surface.  This would have worked perfectly except there was one BIG problem.  The frame rails are DIRECTLY below the hood creases and that doesn’t work for the flat hood pin latches.

So, for practical and aesthetic reasons, I elected to place the hood pins 4 inches inside the hood creases.  

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< Proposed Hood Latch Locations >

With this hood latch location, I needed to fabricate a pair of brackets with the hood pin mounting location about 4 inches inside the frame rails.  I used SketchUp to design the brackets using 1in x 1/8in 6063 T5 aluminum bar.  

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< Mounting Bracket – Passenger Side >                        < Mounting Bracket – Driver’s Side >

The PS bracket required a “Z” shape to clear the headlight motor, while the DS bracket required a “C” shape with a set-back rear brace to clear radiator hoses to the overflow tank. Slotted holes in the top and bottom give me some adjustability.

Next, I made cardboard models to test the fit, and everything looked good!
Before proceeding to fabrication in aluminum, I checked the numbers to make sure the bracket design will get the job done.  

Conservative Capacity Checks  (Just for peace of mind!)

M10 Aircraft Aluminum 7068-T6511 Pin (Assumed)
Yield Strength = 683 Mpa / 99.1 ksi
Threaded Pin  A = 78.54 mm2 / 0.122 in2 x 99.1 = 12.09k capacity
Pin Slot  A = 2.5mm x 5mm x 2 = 25 mm2 / 0.038 in2 x 99.1 = 3.76k capacity
(According to Z1 Motorsports the Pin has an advertised 650 lb pullout strength)

Consider the maximum applied pin load = 650 lbs per pin.

Uplift Check on 1/2 the Hood Area
½ Ah = (51in x 30in) / 2 / 144 = 5.31 ft2
P Wind Pressure = 0.00256 x V²
V = Equivalent Wind Speed
P(ult) = Using one pin @ 650 lbs equates to 122 psf
V = SqRt(122/0.00256) = 218 mph  upward windspeed…..WOW!

Mounting Bolt Capacity Check
M6 Grade 10.9 Steel Bolt
S Yield Strength = 940 Mpa / 136 ksi
Dia. = dmin of 5.52mm
A =πr²= 23.93 mm²
P (cap) = SA = 136 ksi x 0.037 in² = 5.032k

Prying Force (DS Backet controls): Using moment equilibrium.
M(uplift) = 650 lbs x 3.5 in = 2275 in-lbs = M(hold-down)
P (hold-down) = 2275 in-lbs / 0.5 in = 4480 lbs or 4.48k < 5.03k  OK!

6063 T5 Aluminum Bar
S Yield Strength = 145 Mpa / 21 ksi
A = 1 x 0.125 = 0.125 in²
P (cap) = SA = 21 ksi x 0.125 in² = 2.625k (each bar) x 2 = 5.25k > 5.03k  OK!

I’m pretty sure I will never be going fast enough to get a 218-mph vertical wind speed under the hood, especially with the engine obstructing airflow.  That means it is not likely the hood pins will ever be loaded to their maximum capacity of 650 lbs.  I think I’m good to go!!

My initial fabrication approach was to braise the aluminum pieces together with low temp Blue Demon aluminum weld rods.  I did some test pieces and they looked good BUT I was not able to get the joint as strong as the base metal.  I ended up commissioning my nephew to TIG weld the pieces for me.

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< Blue Demon Test / Braise Weld >                          < Cardboard Models and TIG Welded Brackets >

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< PS Bracket Test Fit >                                                                 < DS Bracket Test Fit >

As it turns out, the DS headlight linkage has a slightly different orientation than the PS linkage and interfered with the hood pin bracket, pushing the pin location back about 1/4 inch.  NG!!

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< DS Bracket / Linkage Interference >                     < Modified DS Bracket >

I loaded up a carbide burr in my die grinder and removed the “offending” material.

The last step was to bead blast each bracket and apply a coat of paint.  I opted for high temp black paint so they would blend into the engine bay a little better.  They turned out pretty nice!!   Can you spot them in the pic below??

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< Completed Hood Pin Bracket Installation >


Next Up – Installing the Hood Latches

Raymond, did you ever find the right way to connect the AC electrical? Such as the Compressor and where to connect the pressure switch? there are two connections on the switch hose just not sure what to do.


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viperbmw69 wrote:Raymond, did you ever find the right way to connect the AC electrical? Such as the Compressor and where to connect the pressure switch? there are two connections on the switch hose just not sure what to do.

 
Sorry, but I'm not quite there yet.

Tuesday April 9th I have an appointment for a full chassis dyno tune.  After that, provided all goes well ([You must be registered and logged in to see this image.]), I'll be free to hit the road.

This includes taking the car to a custom shop that does AC.  I'll give a full report on that when finished.

All I can offer at this point can be found in one of my previous posts... the link is below.

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There is no wiring advice in the post but if you are at that stage and ready to move forward, I'm sure some of the experienced forum experts can shed some light on the subject.

Location – Location – Location

 
The first challenge was symmetrically locating the latch locations on the hood so that they would line up with my new hood pin mounting brackets.
 
I played with this a bit when determining the location and shape of the mounting brackets. 
 
Normally this isn’t too complicated, but the PO had a little fender bender, and the left front fender, headlight assembly, and lock carrier brace were all “slightly” misaligned.  Consequently, my attempts at symmetry based on fixed points on the lock carrier were fruitless.  At the end of the day, because the hood was properly aligned, I located each hood latch with the small end forward, and the pin located precisely 4 inches inboard from the hood crease and 7.5 inches from the front edge of the hood.
 
Note:  Depending on your situation, your placement could be entirely different.
 
Slotted mounting holes in the brackets and the ability to rotate the mounts on the frame rails, afforded me micro-adjustments as needed.  Below is the process I used:
 
1 – Getting the Hood Fully Closed
 
I did have some hood contact with my Jantzer 92mm throttle body that required under hood reinforcement modification.  To identify the precise location of need, I carefully placed a length of electrical tape UPDSIDEDOWN on the forward edge of the TB where the contact was suspected to be most severe.  Then I closed the hood to transfer the tape. This allowed me to accurately mark the entire area above the TB where contact might happen.
 
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The next step was some careful “surgery” with a 3 in cutting wheel.  My objective was to remove only the hood reinforcement.  Before any cutting, be sure to cover your entire engine compartment with a blanket or sheet to catch all the metal shavings. Take your time and be careful not to overheat the metal which can bubble your paint.  Once the rough cut was accomplished, I used a double cut carbide burr in my die grinder to clean up the rough edges. Then I checked the clearance again using a couple spheres of windshield sealant.  3/8-inch final clearance…good to go!
 
A quick shot of RUST-OLEUM acrylic enamel primer+paint in “Gloss Cherry Red” finished the job for the short term.
 
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< Reinforcement Removed>                   < 3/8-inch Final Clearance >
 
2 Making a Latch Hole Template
 
Now that I could fully close the hood, I began the process of installing the AeroCatch latches.  AeroCatch has latch hole templates online for each of their models but printing them to the correct scale can be a challenge. I found it simple enough to trace the inside of the latch retainer plate, including the mounting hole locations, onto a piece of grid paper.  Be sure to center the retaining plate within the grid lines.
 
Next, I took the actual latch and centered it in the tracing of the retainer plate to determine the exact pin location and marked that on the template.
 
3 Cutting the Hood
 
To get started, I used blue painter’s tape to establish a longitudinal parallel line 4 inches off the hood crease, and a horizontal line 7-1/2 inches off the front edge of the hood. The intersection of these lines is the target pin location and the tape edges themselves assure a strait installation.
 
Next, I aligned the template pin hole and axes with the hood position tape lines and secured the template to the hood. I elected to drill the mounting holes before the latch hole due to their proximity to the latch hole edge.  Starting with a 1/16” bit and moving up to a 5/32” bit helped me get the mounting holes where they belonged. 

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< Latch Template Placement >                  < Cutting Out the Latch Hole >
 
With the mounting holes drilled, I cut out the center of the template and traced the outline onto the hood with a Sharpie.  Then I drilled consecutive holes around each radius and cut the straights with my cutting wheel.  Once again, I cleaned up the rough edges with a carbide burr until the latch fit perfectly into the opening.
 
CAUTION:  Be careful with the carbide burr that it doesn’t get away from you and do a little dance across your hood!!  
 
I found out the hard way…see pic below!   A new paint job is on my bucket list.
 
4 Mounting the Latches
 
The AeroCatch mounting hardware includes nuts with self-locking nylon inserts.  These nuts need to be pressed into the mounting flange (by hand) where they are held in place nicely.  When installing the Allen head screws, be careful to start them by hand without pushing down too hard and dislodging the nut.
 
Once all of the Allen head screws are engaged, each is tightened with the supplied Allen wrench.  No need to over tighten.

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< Fitted Latch >                                      < Mounting Flange Modification >
 
During the installation process, I discovered the mounting flange interfered slightly with the hood edge reinforcement (yellow arrow).  The offending flange section was easily removed, but in hindsight, moving the latch location back 1/4 inch more would have solved the problem.
 
5 Adjusting the Pin Mounting Brackets
 
The last step was to micro-adjust the hood pin mounting brackets, lock them down, and adjust the hood pin height.   Oh Yes… and a bit of touch-up paint on my little “burr dance.”
 
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< Finished Installation >
 
All Done!!  YAY!
 
Next Up – Front Panel and Head Light Gaps

I mentioned in my last post that my next post would be Front Panel and Headlight Gaps.

That went well once I learned how to adjust the position of the headlight buckets. The body shop that “fixed” the PO’s fender bender set the new DS fender back about 3/16 inch too far.  Subsequently, they matched the position of the headlight bucket with the fender line which consequently created the small hood gap and resultant interference.

I adjusted the hood gap and front panel gap by moving the headlight bucket forward but now I have some interference between the front panel and the forward most point of the DS front fender because it’s too far back (yellow circle).  However, it still looks much better and when “Repaint Day” comes along, I plan to let the professionals take care of it.

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                                 < Adjusted DS Headlight Bucket >
 
Instrument Cluster Rehab
 
In my preparation for “Dyno Day” it was important to get a functional instrument cluster so the tuner could tell me if the gauges were reading properly.  Hopefully most of you will never have to deal with gremlins in your instrument cluster, but erratic gauges and dim or burnt out dash lights just didn’t cut it for me.
 
Background
 
In my case, outdoor storage under a car cover did a lot of damage inside the car due to humidity, namely the carpet and leather surface mold, and electrical CONTACT CORROSSION.  All that I knew was that everything worked fine when I parked it nearly 2 decades ago.
 
My instrument cluster rehab started with a much-needed exterior clean-up.  The target corrections started as cosmetic only, namely removal of an unusual piece of paper resting under the speedometer, and removal of what appeared to be some “bio-organism” growing on the plastic bezel or “covering frame” surrounding the gauges.
 
Disassembly
 
I could access the bezel easily by removing the steering wheel (horn pad & 24mm nut), dash trim (8 screws – yellow arrows), and the acrylic lens over the bezel which just pulled off.

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                                 < Original Dashboard Trim Screw Locations >

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                             < Original Instrument Cluster >
 
As you can see above, there was no shortage of grunge.  Below is what the growth looked like and the screws that held the dash trim piece in place.  There are 3 screws across the top in front of the gauges, 2 on the bottom on either side of the steering column, and 3 in the dash trim vent area. (Yellow Arrows)
 
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< Bio-organism Growth & Unusual Paper >     < Dash Trim Screws >
 
Clean-up
 
Alcohol and Q-Tips worked best on the growth, but nothing completely removed it.  The bit of paper was glued on, and I had to carefully scrape it off with a blade and then remove the underlying adhesive with alcohol.  The painted gauge faces were decent, and just needed a quick wipe down with alcohol.  And then it happened… I accidentally snagged the tach needle and bent it!  Suddenly my cosmetic efforts became a bit more complicated.
 
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< Bent Tach Needle & Replacement >               < Tach with no Axle >
 
Replacing the Tach Needle – “NOT”
 
Once again, Bob at Hotrodz of Dallas came to my rescue and hooked me up with a replacement needle.  However, my needle came off without the tach axle post, while Bob’s needle had the tach axle post still in place. When I tried to remove my tach axle post from the tach, the axle broke off. Now I needed another tachometer!
 
Fortunately for me, Bob had my back and shipped me a spare parts instrument cluster that he believed had a good tach.  At this point I had to remove the instrument cluster to swap the tach.
 
Removing the Instrument Cluster
 
This required removal of four (4) mounting screws and disconnecting three (3) wire loom connectors. The loom connectors have a latch on each side in the back (yellow arrow) that must be disengaged prior to removal.  Of course, two of my loom connectors had broken latches.  I have it on good advice that this historically is not a problem, but if that day ever comes, a replacement kit is available from Ian at 944online for $50/each. Connector Kit
 
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< Wire Loom Connector >                       < Disintegrated Speedometer Gear >
 
With the instrument cluster on the table, it’s evident that the gauges come out the front which required further disassembly.  As I was about to start removing the tach, I noticed that the gear set in my speedometer had completely disintegrated!  This revelation explained why my short trips around the neighborhood were not advancing the odometer!!
 
New Status: Now it was clear that my instrument cluster had both a non-functioning speedometer and a broken tachometer, not to mention an abundance of contact corrosion…especially evident at the bulb sockets.
 
Switching Instrument Clusters
 
The instrument cluster I got from Bob had no obvious corrosion, good speedometer gears, and was in much better visual condition than mine except for the speedometer face plate which was marred and missing the speedometer needle.  At this point, it made sense to swap the entire instrument cluster even though gauge function was unconfirmed. 
 
Moving forward, I successfully removed and transferred the speedometer needle and face plate from my instrument cluster, and reinstalled the tachometer needle Bob had already removed and previously mailed to me. While it was convenient, I removed and checked all the gauge warning, and signal lights (#37 Bulb) and replaced the three (3) dash lights (#194 Bulb) with LED units.
 
Importantly, I worked the bulb bases in and out several times each to assure good contact with the flexible printed circuit board.
 
From researching the RennList forum, I learned that any amount of oxidation between the circuit board power contacts (yellow arrows) can result in erratic gauge behavior.
So…I reconditioned these connections as well.  There are 2 at each end of the circuit board, each secured with a single 7mm brass nut and wave washer.
 
CAUTION: Treat the circuit board with kid glove care.  Some capacitors may still retain voltage and various connections may have become fragile.  Reportedly these boards are getting hard to come by and therefore more and more expensive.
       
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< LED #194 Dash Bulb Replacement >     < Circuit Board Power Contacts >
 
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       < Power Contact Pre-Clean >                 < Power Contact Post-Clean >
 
I cleaned all the circuit board and the connector contact pieces using metal polish and Q-Tips, and then gave all the contact surfaces a good rub down with alcohol to remove any polish residue.  According to the experts, these electrical connections should be reassembled dry for optimum conductivity.
Do not OVER TIGHTEN!
 
Reflector Prism Reconditioning
 
To improve my dashboard light, I opted for extra bright LED replacement bulbs as previously noted.  However, upon further inspection, the covering frame reflector prisms had lost over 50% of their factory reflective coating.  This I’m sure was contributing greatly to dim lighting.
 
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< Degenerated Factory Prism Paint >

The prisms are acrylic so cleaning them must be done carefully and only with products designed to clean acrylic.  Below is advice about products to avoid:
 
As published by “The Plastic People”
Never use chemicals to clean acrylic – they will damage it. Here are ones to avoid:

• Any ammonia based cleaner e.g. window and glass cleaners.
  
• ​Abrasive or caustic cleaners.
  
• WD-40 or any other petroleum-based chemical.
  
• ​Scrubbing pads or other abrasive pad.
  

…and according to A&C Plastics, Inc
“When cleaning acrylic sheeting, never use ammonia, acetone, carbon tetrachloride, or gasoline as a cleaning solution. These kinds of solvents can cause cracks in acrylic sheeting and give the surface a frosted appearance.”

I used Meguiar’s plastX acrylic restorer ~$8 which worked perfectly.  For the paint, I used RUST-OLEUM Mirror Effect paint ~$15 which is designed to create a mirror finish on the bonding surface of acrylic and glass, which is exactly what is needed.
 
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                               < Repainted Prisms Bottom & Front >

After using the PLASTX and in preparation for painting, I washed the prisms with warm soap and water and dried them thoroughly with compressed air and my heat gun.  I followed the manufacturer’s directions and applied 5 coats of mirror paint.
The final result turned out great!! 

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                                         < Finished Result >

Even better, all of the gauges and warning lights work as they should except the fuel gauge, which I suspect is a tank sending issue problem.
 
Some of you may have noticed that my instrument cluster now has a Boost Gauge!  That is compliments of Bob's turbo instrument cluster, along with shaving almost 15,000 miles off the odometer.   I assure you there is no turbo!
 
Next Up – Fuel Gauge Gremlin