Well, I've dug around the archives, but wasn't able to come up with a whole heck of a lot of info.

Basically, the plan is to slap my nicely running 86 2.8l into a friend's 84 4-spd

I'll break down into several categories. Please, if you have anything to contribute, ANYTHING at all, post it here. I'll sort through it on my own time:

1) Engine: The donor car is an '86 SE v6 auto. The motor is being given up for a Caddy conversion (yay!). Because it is an auto flexplate going into a manual car, I do know that we'll need a flywheel. Because the '86 is externally balanced (yuk!), we can have a different flywheel rebalanced to match the flexplate, can't we?
The mounts SHOULD line up, correct?

2)Transmission: The recipient car has a tasty, and nicely working 4:10 4-spd. It SHOULD just bolt right up, right? Are there any modifications that need to happen to the tranny bellhousing or mounts? Shift cable rerouting?

3)Fuel system: We'll need a new fuel pump, for sure. I know that. Is there any rerouting of fuel lines required, and to where?

4) Cooling system: Would a larger v6 rad be advisable? The weather isn't TOO extreme up here... What sort of pipe rerouting can we expect to need?

5) ELeCtRIcAl!: This is the biggie, I know! So, what's our best option? Do we splice and dice the old 84 harness to the v6 one? Are we better off finding a wrecker, and rewiring the dash? Besides the engine management systems, what is different?

6) Anything anyone can think of would be greatly appreciated!

I've never actually done a conversion like this, but after looking at my 88 GT and my former 84, here are some issues.
The fuel line routing is different. The 84 lines are routed around the drivers side of the engine bay and hook up to the engine near the trunk. The V-6 lines run along the lower passenger side and hook up to the engine next to the battery tray.
The electrical will be a big job. If you take the entire fuel injection harness out of the donor car it should go in the 84 without a lot of fuss. The big problem is the main car harness. If you look at the 84 you'll see a large connector mounted to the firewall in front of the engine near the center of the car. This plug has the non-injection engine wires in it (guage sensors, alternator, ignition, etc.) and it has the wiring for the tail lights, cruise, trunk light, and other body items. This plug is right where the forward exhaust manifold will need to be on the V-6. You'll find this plug has been moved back near the battery on the 85 and up cars. The easiest thing would probably be to find the entire harness out of an 85 or newer car and replace the entire thing. It's a big job, but so is trying to lengthen the existing harness to make it work.
Spend some time comparing the two different layouts and you'll see what I'm talking about.

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Rod Schneider, Woodstock, Ga.
White 88 GT :)

Cool. I think we are leaning more and more towards finding an exploded v6 car, and stripping what we need. The fuel line routing shouldn't be a problem assuming that we can find a complete set. The wiring will be the challenge here, I think. But it's one that I'm willing to take on.

Small item maybe but I think the 84 also uses a couple extra relays, located just below the fuel pump and a/c relays. They are for the rear lights, I believe. Don't know if that will affect you or not. Also my 84 has the 2 speed rad fan, with a different temp sensor on the head.

To the top...

Gonna keep this active for a few days

Looking forward to it

But I think we can use a few parts off of Dan. I think we can use his fuel pump, can we?

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AIM: CanadianFiero

Another Bump! I'm compiling a database

Mach10..I am undertaking this same swap...u pritty much have it all there...the only thing I am also worried about is rewiring the dash...when I do it I will be drawing extremely accurate diagrams and pictures for ppl who plan to do this swap in the future...

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Lance
Click Image to go to site.

If anyone that has experience can think of anything else, it'd be MUCH appreciated!

Thx!

quote Originally posted by Ferrari_cdn: Looking forward to it But I think we can use a few parts off of Dan. I think we can use his fuel pump, can we?

I will be glad to contribute whatever you will need for this project seeing as how I won't need the stff anymore. I already told Ice that I'll giv ehim my ECM, but then again, Sean, you won't need your ECM so can't you just give that and the harness to Ross? But anything else, fuel pump, whatever, just let me know, I'll see what I can do for you.

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Dan
1985 Silver GT

400HP LT1 Conversion has begun......

quote Originally posted by sloth85GT: I will be glad to contribute whatever you will need for this project seeing as how I won't need the stff anymore. I already told Ice that I'll giv ehim my ECM, but then again, Sean, you won't need your ECM so can't you just give that and the harness to Ross? But anything else, fuel pump, whatever, just let me know, I'll see what I can do for you.

Well, I'll need to keep my harness for my own conversion, and I have an Auto ECM. No good for a manual conversion. I'll glady give up whatever's needed that I can spare, though.

I thought you might need a new harness for the Caddy, ah well, and I forgot, you are an auto, okay well the harness and ECM will soon be Ross's.

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Dan
1985 Silver GT

400HP LT1 Conversion has begun......

hehehe
My garage is going to be such a mess

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 dampner 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 doesnt 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, but in Manitoba you might be fine with the 4 cyl rad. 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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Kick ARSE!

Thanks a bunch! I was suspecting most of this. The cradle bit is new to me, but more than do-able.

We'll keep an eye out for a wrecker v6 to scavange wiring from!

Can you describe what the problem with the 4-cyl bracket/slave is? It's from the original trans. Are there clearence problems with the V-6?

Thanks!

[This message has been edited by Mach10 (edited 01-26-2002).]

quote Originally posted by Mach10: Can you describe what the problem with the 4-cyl bracket/slave is? It's from the original trans. Are there clearence problems with the V-6? Thanks! [This message has been edited by Mach10 (edited 01-26-2002).]

The problem with the 84 slave bracket is that it is a long metal bracket which mounts to the transaxle, and to the cylinder head.

With the V6 the cross over pipe is in the way where the 84 slave bracket will go.

When I put the 4 spd in my V6, which was an auto, i cut the slave bracket ( was 84), and welded a plate so I could pull 2 tranny case bolts, and slide the bracket down on the outer case back side, stick the bolts back in, and have a solid mount.

Much easier if you can scrounce a 85-86 4spd slave bracket and slave., but modifying the 84 one is do-able.

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Thanks! I figured that it was something stupid like that. Ice needs a new clutch system anyway, so we'll probably go with a v-6 SC

Currently bidding on a master and slave cylinder system.
The mechanic says we only need the master replaced.

I guess I will have the gauges changed for that V6. As well as have that be backlit, not sidelit. But time and money will tell.

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AIM: CanadianFiero

Unless you are a purist. Then you need to switch VIN plates from an '85

Well, you'll need the MC anyway... You can probably hawk the slave cylinder, since we will be using the v6 getup

quote Originally posted by Mach10: [B]Unless you are a purist. Then you need to switch VIN plates from an '85

lol

Looking in the Haynes the fuse box has fuses for the fuel injection for the V6. Would we need to add the wiring to the fuse box?

Electrical is no problem for me (done electrical work at my cottage), but it looks like a LOT of electrical work is expected.

No problem.

quote Originally posted by Ferrari_cdn: Looking in the Haynes the fuse box has fuses for the fuel injection for the V6. Would we need to add the wiring to the fuse box? Electrical is no problem for me (done electrical work at my cottage), but it looks like a LOT of electrical work is expected. No problem.

Thats the reason I mentioned replacing the interior wiring harness. If you can find one, which shouldnt be hard, all you need to do is pull the console, dash, and a few other odds and ends, swap it in, and plug everything together.

Much faster and easier this way.

Modifying the 84 Harness is do-able, but much more time consuming, and might be a ***** if you need to trouble shoot the wiring in the future.

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