I figured it's time I start documenting this before I forget everything. The car that I am performing the swap on has 89k miles in the chassis, and is a perfect rust free southern car.



This is kind of a continuation of this thread, as I decided to pull the engine/suspension from my '88 GT and install it into my '85 GT.

When finished, this car will have:
- 65k mile 4.9L V8 from a 1991 DeVille
- Intake manifold from a 1990 Allante
- Hybrid M17/MY8 Muncie 4-Speed with 70k - 90k on all components
- '88 GT cradle and rear suspension with full poly bushings, new struts, and 7/8" rear swaybar
- '88 rear brakes
- Spec 3 clutch / LSC flywheel
- Full poly bushings on stock front suspension, new shocks
- 1" front swaybar
- Grand Am front brakes / vented rotors
- Big bore master cylinder
- Mr. Mikes seats
- 120 MPH speedo

Nate

[This message has been edited by NJD85GT (edited 06-02-2012).]

Many of these pictures were carried over from the previous thread, I like to keep everything in one place. Here is the engine when I first got it:



Here is the Allante intake when I first got it:



Valve covers off...



Pushrods:



Rocker arms:



Everything off and ready to prep for the Allante manifold.



The underside of the Allante lower intake manifold.



The top of the Allante lower intake manifold.



The top of the Allante lower intake manifold after I painted it glossy black.



Newly painted valve covers.



Upper manifold painted.



Throttlebody, painted.



Mock up on my living room floor.....



Nate

Looking really awesome! Can you take a picture of the crossover installed whenever you get to that, so I can visualize what I would have to do to it more clearly?

Looks like you put the adapter plate on the wrong side? (I may be wrong, for MY sake I hope not)
The "new hole" should have been towards the front...huh right???

Other than that looks really neat!

quote Can you take a picture of the crossover installed whenever you get to that, so I can visualize what I would have to do to it more clearly?

Will do in the next couple days, it is already in the car and running, I've been slacking in my documentation, still got more catching up to do.

quote Looks like you put the adapter plate on the wrong side? (I may be wrong, for MY sake I hope not) The "new hole" should have been towards the front...huh right???

For your sake, you are right, my hole is in the correct location, forward of the old hole. Those pictures are of the passenger strut tower, looking towards the front of the car.

Nate

I was just realizing something as I read over the details in the first post again. You are building what I have, for the most part. I have an 86 SE with the 4.9/4t60e on an 88 cradle. I had the exact same brake setup you said you are going to create, and there IS a flaw with that. They didn't work well AT ALL. I don't know if you had the grand am brakes all round like I did before the 88 cradle swap, but they were really nice. The problem is, with having stock 88 brakes in the rear now, you will loose 30% clamping pressure in the rear just because of that. The piston is much smaller in the 88 calipers, and the bigger master cylinder reduces caliper pressure with the smaller 88 caliper. You will have (like I did) front brakes that are too powerful (bad thing, they lock up QUICK), and barely working rear brakes. This front bias was dangerous, I skidded in any form of heavy stopping.

After my 88 cradle swap, my brakes were always sub-par. After I added larger 16" rims they were very poor. So recently I added Corvette rotors in the front with 88 calipers, and an 88 master cylinder. Problem solved, brakes were awesome. Recently I added a big brake booster too, and now they are nothing short of shocking.

[This message has been edited by mattwa (edited 05-31-2012).]

Nice license plate!

quote Originally posted by mattwa: I was just realizing something as I read over the details in the first post again. You are building what I have, for the most part. I have an 86 SE with the 4.9/4t60e on an 88 cradle. I had the exact same brake setup you said you are going to create, and there IS a flaw with that. They didn't work well AT ALL. I don't know if you had the grand am brakes all round like I did before the 88 cradle swap, but they were really nice. The problem is, with having stock 88 brakes in the rear now, you will loose 30% clamping pressure in the rear just because of that. The piston is much smaller in the 88 calipers, and the bigger master cylinder reduces caliper pressure with the smaller 88 caliper. You will have (like I did) front brakes that are too powerful (bad thing, they lock up QUICK), and barely working rear brakes. This front bias was dangerous, I skidded in any form of heavy stopping. After my 88 cradle swap, my brakes were always sub-par. After I added larger 16" rims they were very poor. So recently I added Corvette rotors in the front with 88 calipers, and an 88 master cylinder. Problem solved, brakes were awesome. Recently I added a big brake booster too, and now they are nothing short of shocking.

Thanks for the heads up. I will proceed as planned since I already have everything on hand, but will watch the brakes closely.

Nate

How is the 4-speed Muncie compared to the 4T60e?

Today I decided to install my 120 MPH speedo and modify my tach for the V8. It cost me $3 to modify my tach. One of the ways to modify the tach is to cut one of the traces on the circuit board, and install a new resistor. I really didn't want to cut any traces, should I decide to restore the tach to original specs for some reason, so I decided to add another resistor in parallel. After measuring the current resistance, I got 223 k ohms. Since I am going from 6 cylinders to 8 cylinders, I needed to bring that resistance to 3/4 of that, or 167.25 k ohms.

Option 1 is to cut the trace and add a 167 k ohm resistor. Option 2 is to add a resistor in parallel. Any time you add a resistor in parallel you lower the overall resistance, after a quick calculation I needed a 669 k ohm resistor to get to my target of 167.25 k ohms. I decided that I wanted to make my tach adjustable on the fly, in case I needed to re-adjust and fine-tune it later. So I went to Radio Shack and bought a 1 M ohm potentiometer. This is basically a variable resistor from zero to 1,000,000 ohms. Putting it in parallel with my existing resistor gives me a range of zero to 182 k ohms. I verified this with my digital multimeter.

After I installed it as shown below, I put the gauge cluster back in the car but with no plastic cover so I could play with the needles. I took the car out for a drive with the laptop hooked up, and stuck the needle on at 0 RPM (car off, key on). I then started it, revved to 2,500 or so, and adjusted the potentiometer until the tach showed 2,500. I then verified the whole RPM range, and adjusted until I got it perfect. I did the same with the speedo, making sure the needle was in the right spot at speed. After that re-installed the plastic cover, and then verified the gauge again. Any time I need to adjust it all I have to to is take off the decklid popper cover and turn the knob.


My old '88 GT gauges that I'm stealing the speedo out of.



120 MPH speedo.



Nasty looking odometer out of the '88 GT. I'm swapping in the one from my '85 GT so the mileage stays correct, and the thenths is whiter too.



Pulling the face off to swap the trip odometer too since this one looks very weathered.



Old trip odometer pulled off.



My '85 GT gauges. I'm keeping the '85 tach as I like the orientation much better versus the '86 and up tachs, as well as it has the oil pressure on it. I never liked the aux gauges in the later cars, they look out of place to me, like an afterthought.



Old 85 MPH speedo.



Here is my 1 M ohm potentiometer.



Two wires soldered onto the back of the tach to add the potentiometer remotely.



Potentiometer soldered onto the wires.



I had to use the '88 GT needles, but I needed to make them look like the other '85 GT needles. So I mixed up some paint to match the orange and painted them. The gauges are not backlit, so it still looks stock.



Putting everything back together.



Potentiometer wires routed out of the back.



Potentiometer mounted into the passenger side of the gauge pod.



The shaft that you turn to adjust the RPM readout/resistance. It is above the decklid popper connector.



Finished and fine-tuned gauges.



Nate

[This message has been edited by NJD85GT (edited 08-22-2012).]

Great thread. Very well documented. Keep going. BTW, I have your living room floor in my kitchen. My wife would freak out if I assembled an intake there!

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I did the temp gauge fix this morning and took it for a test drive. The needle likes to waver by two ticks sometimes, it didn't do this when the V6 was in the car. I am hoping that better ground straps will fix the issue. We will see.

quote Originally posted by 1MohrFiero: Great thread. Very well documented. Keep going. BTW, I have your living room floor in my kitchen. My wife would freak out if I assembled an intake there!

Haha, yeah I am single at the moment, and didn't feel like working in the garage that day...

Nate

quote Originally posted by mattwa: Can you take a picture of the crossover installed whenever you get to that, so I can visualize what I would have to do to it more clearly?

Here are some more pictures of the crossover pipe, it is kind of hard to get a good picture. Basically, I cut the middle, and added a 6-8" tube that maybe had a 45 deg. bend in it. I put each half of the cut crossover pipe onto the manifolds, and rotated the cut end up, and out just slightly, until the new piece fit, and cleared the shift cables and slave cylinder heat shield by an inch or so. I then tacked them together, pulled it off, and welded it up. I then wrapped it all in a bunch of header tape. With most of the crossover pipe being double walled and having the tape on there it stays much cooler in the engine bay, I can watch my intake manifold temps (since the intake is right above this pipe), and it is usually 10-20 deg. cooler C. than when I had the single wall pipe in the '88 GT without tape.







Nate

quote Originally posted by NJD85GT: ...The needle likes to waver by two ticks sometimes, it didn't do this when the V6 was in the car.

Does it twitch?
If so, there's probably air in the system.
Drilling a pinhole in the thermostat will help.

quote Originally posted by Raydar: Does it twitch? If so, there's probably air in the system. Drilling a pinhole in the thermostat will help.

It does sometimes. I do have a hole in the thermostat. I have been topping it off after it cools off every time, and it is just about always at the top now. Wouldn't the PCM readout be affected too? It doesn't vary like the gauge does, it is always a steady value.

Nate

Looking good!
What are you doing with the 88 GT/notch?

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11 Camaro SS/RS
86 Fiero GT 4.9
84 Fiero V6 Choptop?
03 Silverado 3500 Duramax! (Stacked, Tuned, Mean as Hell)
07 Suburban LT2
09 Avalanche LT3

quote Originally posted by pontiackid86: i'm sure i could fly a plane no problem.

quote Originally posted by NJD85GT: ...Wouldn't the PCM readout be affected too? It doesn't vary like the gauge does, it is always a steady value.

Hmmm... A very good question. I could speculate that the PCM is buffered, in order to stop rapid fluctuations, but I really don't know.

Nice job. Very nice indeed!

quote Originally posted by Raydar: Hmmm... A very good question. I could speculate that the PCM is buffered, in order to stop rapid fluctuations, but I really don't know. Nice job. Very nice indeed!

So no matter what I tried I couldn't get the bubbles out of the system, that gauge moved all over the place, and with the fan on I couldn't get the coolant temp below 98 deg. C. I ended up taking the old 2.8 thermostat housing, and welding the old DeVille mount onto the bottom of it, so that I could put it on this engine and have a Fiero-style system. I'm currently running without the thermostat to try and get all bubbles out (think I finally succeeded, the gauge stays put now and the temp quickly drops below the fan shutoff speed).

I also wired up the radiator fan to the PCM pin A11 so that it controls it...there were so many errors in this harness, I have no idea where that old A11 wire went. I programmed it to turn on at 100 deg. C and shut off at 95 deg. C for now.





Nate

[This message has been edited by NJD85GT (edited 06-08-2012).]

Great looking swap and I love the custom touches. Nice work on the tach. When I did mine 10yrs ago, I could of sworn the resistor fix was really simple. I cant remember the specifics though! lol

Also, on swaps I did in the past. I liked to keep the Fiero v6 t-stat housing. I just found them easier to burp the system.

[This message has been edited by BV MotorSports (edited 06-09-2012).]

Looks great!

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88 Coupe: 2.0L Turbo 4 Cylinder
84 Indy #64: Restoration Project!

So I've been seriously slacking in updating this thread. Next step was to re-do the front suspension with new ball joints, rebuilt steering rack, poly bushings, Grand Am brakes, ect.

Steering rack housing cleaned up!


Getting ready to install Rodney's bushing.


Bushing installed and snap ring in place.


The rack and teeth all cleaned up.


Getting ready to put the pre-load assembly back in.


Weird lock nut tightened with Rodney's wrench.


New inner and outer tie rods installed.

I swear I've seen a Cavalier Getrag with 3.42 gears. Is that something you think you could do for the Getrag?
Also, did you ever measure the resistance you set your pot to so I could just try to make one that works?
Can you detail me the changes you made to the programming to fix the deceleration? I have a chip burner now.
What did you hook up the PWPS to? My pin F on C203 didn't cut the mustard, still reads "Not Present" on TunerPro RT data log. :/

Thanks,
Lou

that's a really nice build thread your documenting. I liked the closeup pics of your re-do of the gauges.

The car looks great!

Now I just went back to 2010 in my stack of MHFC calendars (best on the board IMO!)... and I did not see your fine car there!...

Why not?... get that sucker posed for some beauty shots... I want to see it in the 2013 calendar!

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<---- did you buy Cliff a beer?
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