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| Wiring changes needed? (Page 1/1) |
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lyleap-gmc
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AUG 23, 08:32 PM
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I have a 1984 chassis that had a four cylinder engine. I have a 1987 V6 engine. I have a 1985 wiring harness and PCM.
Are there any wiring changes needed to make all this work together? I am most concerned with needed functions to get the car running.
Thank you all again and again,
Lyle
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lyleap-gmc
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AUG 24, 09:36 AM
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Hi all,
I'm making a SWAG that the lack of response indicates that no changes are needed. It is mostly plug and play. Tell me if I'm wrong.
Thank you,
Lyle
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olejoedad
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AUG 24, 01:07 PM
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You're wrong.
The 84 wiring harness is different and does not have the C-500 chassis side connector in the same location as the later cars.
The 84 also lacks the Battery Junction Terminal that the later cars use.
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fierosound
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AUG 24, 01:45 PM
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Blacktree
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AUG 24, 02:56 PM
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lyleap-gmc
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AUG 24, 05:47 PM
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Thanks for the responses.
I have the 1985 wiring harness all the way from and including the PCM to the injectors. It doesn't include the firewall terminal block. That's not a big deal. I probably have one in my "parts department."
My concern is the functionality of the massive collection of wires as far as the engine is concerned.
Have a great day and stay safe,
Lyle
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lyleap-gmc
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AUG 24, 06:00 PM
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I have that article. I believe the builder/swapper is using the 1984 harness and modifying it. Lots of cutting and splicing involved.
Have a great day and stay safe,
Lyle
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fierosound
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AUG 24, 06:24 PM
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| quote | Originally posted by lyleap-gmc:
I have that article. I believe the builder/swapper is using the 1984 harness and modifying it. Lots of cutting and splicing involved. |
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Someone who has done this...
| quote | posted by jelly2m8
Easiest, quickest and best way to put the 2.8 in a 84 is to find a cheap V6 donor car. Replace the passanger compartment, and tail light wiring harnesses in the car with the ones from the donor.
You will use the engine harness along with the V6 engine. Its all plug and play, no cutting and splicing wires.
Fuel pump, sending unit, and fuel lines need to come from the donor. same goes for the exhaust system, air cleaner assembly. You will need the V6 engine mount, and dog bone.
The V6 uses a driveline vibration dampener on the front of the engine near the oil filter, this mounts to the front cross member of the engine cradle. if you use the 84 cradle, just drill the necessary holes to mount the lower bracket.
The drivers side coolant pipe needs to be shortened several inches back on the engine side. Take a measurement from the V6 car, and cut the difference off back there. make sure you smooth the cut end so that it doesn't wear through the coolant hose.
all the rubber coolant hoses in the engine compartment will be from the V6 donor.
The flywheel will need to be from a 85-87 2.8.
You can change the rad if you want. I use a stock V6 rad in my V8, and have no cooling issues what so ever, and I run a stock 195* thermostat in my V8.
You can add the electrical cooling system, from the V6, but again, probably not necessary there. I don't install that when I do the V6 swap, unless the customer wants it ( at an extra cost). On the 84 you will have to cut 2 holes, and drill 4 more to mount the cooling duct in the trunk, and more to get the air intake for the cooling fan motor.
The tranny will bolt right up, but you will need the slave cylinder and bracket from a V6 4 spd car, either that or modify the 4 cylinder bracket to work If you use the 84 slave. Shift cables are the same.
You will need the V6 tach, may as well throw the speedo in it to, so that they have matching faces.
You need to swap the throttle cable with one from the V6.
Thats all from the top of my head right now, I'll post more if I think of any.
If you eliminate the electrical cooling fan, and do it the way I have described, It is all plug and play, except for cutting that coolant pipe, and drilling 3 holes for the vibration damner mount.
Last 85 4 to a 6 swap I did took 8 hours to change everything over, and have it up and running. That included replacing the manifold gaskets,changing the alternator and starter. That was with everything previously removed from the donor car.
The last 84 I did took about 13 hours, because you need to strip the interior, and reinstall it in order to replace the cabin wiring harnesses.
Oh these cars did not have AC, so that saved an hour or so. |
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olejoedad
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AUG 25, 09:29 AM
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Changing out the main chassis harness is a major PITA.
It's much easier to cut the C500 pigtail (inside the cabin, before the firewall pass thru) from a later year car and use it to extend the C500 to the later year location.
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Blacktree
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AUG 25, 11:58 AM
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| quote | | Originally posted by lyleap-gmc: I have that article. I believe the builder/swapper is using the 1984 harness and modifying it. Lots of cutting and splicing involved. |
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To be fair, that article is almost 25 years old. I'm sure someone has figured out a better way by now.
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