Repowering a 89 Chevy/ Gmc/ Pontiac to Cummins 4bt

[JHyneman]

I have started this project about 6 months ago. I am installing a 4bt in a 1989 Chevy Camaro/ Pontiac Firebird. I am having a time with the wiring being that the car was fuel injected and had all this emissions crap. Has any one Wired a 89 chevy to 4bt? What wires can I leave dangle what needs to stay, what needs to be hooked up? Any ideas? I tackled all the throttle linkage and trans linkage in another forum discussion. Also Can I use the gas fuel pump in the tank or do I need to remove it and put an older sending unit in the tank. I don't know if the gas pump is compatible with diesel fuel and if it will deliver enough fuel for the pressure required. Iam planning to leave the stock lift pump on the engine.



Assistance and help would be greatly appreciated.

Jere

 

[RyanB]

There are not to many wires you need. Im not totally familiar with the Rotary Pump on the 4bt but I believe there are one or 2 wires needed to make it run (search old posts for that and you will find the info you need) As for whats needed from your harness... . not much! I just got done converting a 12valve into my 89 GMC truck and all that was needed was the guage wires. What you need to do is find out which wires are for what guages and then what you need to do is adapt the GM sensors to the 4bt which will make your guages as acurate as the day in rolled off the line. I put a Dodge temp sensor on the truck first and the reading was out to lunch... put the GMC unit on and BINGO!!!!!



There will also be the alternator wireing. Not sure what the ALT is like on the 4bt but I found it best to run the stock alternator off the cummins and then just use an external regulator and its working great and everything looks stock! Also, if you have a tach on the car you can have an ALT shop wire in a tach wire to the alternator for a tach signal... I did that with mine and its perfect.



This winter I am tearing all the wires out of my wiring harness that I don't need to make the engine bay look nice and tidy!



RyanB

 

[HoleshotHolset]

Hi, Jere:



When I read your post - my first response was: "Wow! How in the heck is he going to stuff a 36" tall engine into an older F-body?!"



At some point - you'll have to answer that question! I envision a large cowl induction hood in your future.



Do not even bother attempting to use the in-tank gasser pump. Your 4BT (I'm assuming it has a mechanical VE injection pump... ) should have a lift pump bolted to the driver's side of the block that runs off the camshaft. If that pump is in good health... it'll draw the fuel from the sending unit/tank and supply the injection pump with enough pressure to get things going. So, remove the OEM pump/wiring in the sending unit and patch up any fuel lines that have an air gap issue now that the pump is missing.



As for the dangling wires - I'd try to plumb up as many OEM GM sending units (oil pressure, coolant temp, etc. ) as you can to the 4BT - that way the idiot lights will go out and if your car has gauges to monitor these operational parameters - they'll still work.



Try using the coil wire for the VE injection pump shutdown solenoid... that should be hot anytime the key is on... (Bear in mind... it's been a while since I worked on an older gasser and I could be way off... )



If you look online, there are simple devices that 'fool' the ECM into believing that there is an oxygen sensor attached. This sort of device is easy to make with a 'breadboard' setup.



You could always cut the leads running to any idiot lights that just won't shut off. . :-laf Also - you can remove any/all evaporative emissions BS - you won't be needing them anymore.



Best of luck with the project - feel free to bounce questions off me. I'm looking forward to seeing pics/video/etc.



Thanks,



Matt

 

[RyanB]

As mentioned above about cutting the leads for the idiot lights that just won't go out after the conversion... I just pulled the cluster and pulled out all the lights that wern't needed. The nice thing about the GM clusters is that on the back beside all the lights they actually say what guage or idiot light they are for so its pretty easy and no cutting wires!

 

[JHyneman]

I was planning to try and hook up all the necessary sending units. My problem is the particular engine has that electronic ignition.

1. What wire it hot to the Coil? I have 4 of them. This engine that is comeing out of the f-body is a 2. 8L. 2. Don't I need to keep the ECM for my digital speedometer? 3. The alternator is a GM alternator being that it came out of a Chevy P-30 Van so the alternator won't be a problem. Ryan you mentioned about wiring the alternator for the Tach. I never heard of this. Can you tell me what the Shop did to your alternator to do this. How does this work?



Matt if you look through the Diesel Conversion Forums Look for a Forum that reads "4bt and a 700R4" I have some pictures on that forum already. There is one picture of the engine in the engine bay. The back of the engine is tucked nicely under the hood. The frond of the engine sticks up about 6 inches in the front. I will Play with some fiberglass once I get the car driveable and make a custom hood for the car.



Thanks for your help so far. I appreciate the help.

Jere

 

[RyanB]

Any alternator shop will be able to put a tach wire on it for you... its really simple... just pull the rear cover and solder in a wire. Now there are a bunch of spots that it can be soldered to and the trick is knowing which spot! thats why I had a shop do mine but if you have the TDR mags a few issues back (do a search on this forum under my name) you will see an artical about someone doing it to a first gen ALT and you can do it yourself!



RyanB

 

[JHyneman]

Thanks for that information I was wondering how that was done. I am gonna put a picture on this thread with the engine bolted in the car. Nothing is hooked up yet, but the positioning is final. Check it out and tell me what you all think.

 

[JStokes]

Sweet

It is hard to see from the pics but from what I can make out it looks good. What are your plans for preformance? This is a neat project.

 

[JHyneman]

I don't expect the car to be fast, however I am guessing that it may run around a 13 or 14 sec. I am running a GM Overdrive transmission, 3. 42 rear and the stock 28 in tires. If my math is right I should be able to run 70 at 1900 to 2000 RPMs. I am planning for stage II injectors, and a different turbo. I am hoping that I will be able to fit a Hx-35. I need something that isn't larger in size (diameter) My clearance is pretty tight. I am hoping for my mileage to be around 40 mpg. :-laf

 

[JHyneman]

I am having trouble finding the oil pressure sending unit for my 4BT. I looked in the location where it would be on the 6bt and do not see it. I do however see a plug there. Do I just remove the plug and intall a sending unit in there?

 

[JHyneman]

Lots of exciting things going on with the Pontiac project. I have everything hooked up, the fuel system is in, and I cranked the engine for the first time since I purchased the engine. All was going well then I got a nice smell of hot wires comming from the negative battery terminal. Guess I will have to step up the Wire size. Any way. I am in the process of bleeding the fuel lines and hopefully I can get this beast to roar to life soon. I just can't wait. Some feed back would be great. Thanks.

 

[MRector]

I cant wait to see more pic & hopefully some video of this COOL project. I have been following your progress silently until now, good luck with finishing it up!



Mikey

 

[HoleshotHolset]

I think this is a cool project and will be interested to see how the 700R4 holds up to the 4BT.



Here is a link to a thread talking about a 3000lb 2wd Ford Ranger that allegedly went 12. 47@102mph in the 1320.



According to his list of mods, the 4BT in that truck is VERY mildly built.



Later,



Matt

 

[moparguy]

Jere, my hat's off to you. That is one huge undertaking. My first thought was the weight issue on the Camero subframe. But I guess if you go with a trunk mounted battery, light hood, and a few other tricks, it'll work.



I would think 40mpg is within reach with the light weight you be at compaired to the typical truck conversion, not to mention the great aero advantage.



Good work and keep us posted.



And good luck, RJR

 

[ECannady]

Very impressive cant wait to hear how it runs. So is this a firebird or a camaro? I know one in the same but I am a fan of the firebird.



Eric

 

[JHyneman]

Well Lots of progress today. Last night I got the engine to crank for the first time, however I ran into some problems. Before I could get the fuel system fully bleed I melted my Battery cables. Today I went down to the battery shop and got some 2/0 cables made up and put them on. I then finished bleeding the system and Got a chance to hear the engine run or rather clatter at first. This is the first time it has run in about 2 and 1/2 years. The engine quickly smoothed out as the engine warmed up and what a beautiful sound. Any way to answer some questions The battery is still in the front the hood will have to be trimmed and all in all under the hood looks like a factory installation. I didn't have a chance to get pictures yet, but they are comming. The front of the car is only 100 pounds more than the stock V8 was. I did put heavier springs in the front. I converted from the stock firebird springs to a set of Big Block Z28 springs. I am suprised the vibration is really not noticeable. I didn't use the stock rubber mounts that the engine came with. I changed them out to 1989 Dodge Ram rubbers. That makes a world of a difference. It really cuts down on the vibration. WEll got to go for now There will be more to come.

 

[JHyneman]

Well I promised some pictures. I have the car running and I have my wires under the dash and along the fire wall all cleaned up. I am still in question about the A/C I am not sure what I want to do with it yet. I am trying to keep the stock Unit. Some Ideas would be great.

 

[MRector]

Glad to hear it is running now. I bet that Haynes manual wont help too much anymore

 

[JHyneman]

:-laf Well the haynes manual still helps out alot just doen't help with the engine. :-laf Time to start buttoning up the A/c working on custom mounts for the compressor. Seems strait forward " I think" Then on to the hood.

 

[HoleshotHolset]

The front of the car is only 100 pounds more than the stock V8 was.

Wow! I'm not doubting your numbers, but that sounds almost too good to be true. (... and is making me more optimistic about my swap!) Aren't SBCs around 450lbs? 4BT's are 700+...



Nice work, man. I'm glad she's coming together.



Later,



Matt