I have a 4-spd '86 GT here with a decent powertrain, but the interior is basically gone and the exterior is grim. I have the opportunity to acquire a 5-spd '88 coupe with a dying duke. I'm quite unfamiliar with 88's, other than the fact that they have a superior suspension. I hope to sort of combine both Fieros. In an earlier thread Here, we were having some fun with what the final product will possibly look like.

I'm leaning towards using the Isuzu 5-spd, as opposed to the Getrag 4-spd, as I prefer the gear ratios and the 5th gear overdrive.

What parts will I need to get, that will allow this '86 V6 engine to be swapped into an '88 4-cyl platform?

For example, I believe I've read that the front (passenger side) V6 U-shaped engine mounting bracket is different on the '88 than for earlier years. Is that correct? Does that mean that the actual rubber engine mount is different as well?

So... what other fuel related, electrical, and/or mechanical items will I need to acquire that won't be on either vehicle?

This is probably old hat for you experienced "swappers" out there, but for someone who's never done a swap of this sort before, it's a little daunting knowing what all to get beforehand.

I hope to be doing this swap at a friend's place who lives an hour away from me, so I'd very much like to have everything I need before we start. I can't tie up his garage for weeks while I track down parts I forgot to get (and/or didn't know I needed).

[EDIT] I wanted to add that the '88 coupe has A/C whereas the '86 GT donor car does not, in case that affects what I might need.

[This message has been edited by Patrick (edited 05-14-2013).]

The "front" (under the pulley) bracket and rubber mount (I'm pretty sure) are different.
If you can weld, you can extend the "foot" on the 86 mount, and then drill new holes to accommodate the studs in whatever rubber mount you use. (Don't use the 88 4 cylinder mount. It's liquid filled, and probably shot, anyway.)
You'll need the throwout bearing and cables for whatever tranny you use. The V6 clutch will be larger than the Duke clutch. Use it if it's good.

You'll need the V6 ECM and harness, obviously. Your 86 harness should already have a connector to accommodate the Isuzu reverse light switch.
You'll need a V6 fuel pump, and air filter canister and plumbing.

Your axles will be the same.

You're going to have to do something about heater hoses. They're different between the V6 and 4 cylinder cars.
They're also different between the 85-86 and the 87-88 V6.

You will need the front compartment harness from the 86, as well as the pressure cycling switch from the receiver/dryer.
The 88 coupe does NOT have the circuitry for the pressure cycling switch.
This will allow the compressor to kick on with no refrigerant in the system, which will turn the compressor into a doorstop in very short order.
Don't ask me how I know this.
The harness is an easy swapout.

You'll have to add the 2nd injector fuse to the fuse block.

I'm sure there's more, but that will get you started.

------------------
Raydar
88 Formula IMSA Fastback. 4.9, NVG T550

Praise the Lowered!

[This message has been edited by Raydar (edited 04-25-2013).]

A Lot of the information you need is in Curlrup's thread.

https://www.fiero.nl/forum/Forum2/HTML/127393.html

When I made my 4 cyl 88 a V6. I just cut one wire and added the CCCS into the harness. Lots easier than switching out a harness. I drilled a small hole underneath the brake vacuum line. ran wires out to the dryer. I then spliced in the switch I added to the cut wire inside the cabin. Solder and heatshrink.

About ten minuets total.

You will have to add a V6 heater supply line before you reinstall the cradle. The 4 Cyl one is an aluminum pipe sorta around where the alternator is. It has a quick disconnect, passenger side just inboard of the forward cradle mount.

You can use the 86 exhaust system with the 88 cradle, as long as you do not mix 88 V6 exhaust parts.

[This message has been edited by josef644 (edited 04-25-2013).]

quote Originally posted by Raydar: The "front" (under the pulley) bracket and rubber mount (I'm pretty sure) are different. If you can weld, you can extend the "foot" on the 86 mount, and then drill new holes to accommodate the studs in whatever rubber mount you use. (Don't use the 88 4 cylinder mount. It's liquid filled, and probably shot, anyway.)

At my friend's place where the swap will take place, there's welding equipment and he's proficient with it. Good to know that the '86 V6 bracket can be "made" to fit if I can't find an '88 V6 bracket. I have a brand new rubber mount for an '84 duke here that I've never used. I wonder if that could be made to work with a "modified" '86 V6 bracket.

quote Originally posted by Raydar: You'll need the throwout bearing and cables for whatever tranny you use. The V6 clutch will be larger than the Duke clutch. Use it if it's good.

Okay, that seems straightforward.

quote Originally posted by Raydar: You'll need a V6 fuel pump, and air filter canister and plumbing. Your axles will be the same.

Got it.

quote Originally posted by Raydar: You're going to have to do something about heater hoses. They're different between the V6 and 4 cylinder cars. They're also different between the 85-86 and the 87-88 V6.

This sounds a bit more complicated. I think I'm going to have to take a good look at an '88 V6 to see what exactly the differences are.

quote Originally posted by Raydar: You will need the front compartment harness from the 86, as well as the pressure cycling switch from the receiver/dryer. The 88 coupe does NOT have the circuitry for the pressure cycling switch. This will allow the compressor to kick on with no refrigerant in the system, which will turn the compressor into a doorstop in very short order. Don't ask me how I know this. The harness is an easy swapout.

The '88 has A/C, but the '86 donor car does not, so the front harness from the '86 won't help me here. I would hazard to guess that the A/C compressor also uses a different mounting bracket on the duke than it does on the V6? Initially I was going to remove the A/C on the '88 (as I seldom would ever use it), but I imagine I'd then have to change all the heater/blower stuff in the dash as well. Might be simpler just to keep the A/C.

quote Originally posted by Raydar: You'll have to add the 2nd injector fuse to the fuse block.

Hey, that I can handle!

quote Originally posted by Raydar: I'm sure there's more, but that will get you started.

That's great. Thanks Raydar.

[This message has been edited by Patrick (edited 04-26-2013).]

Heater hoses...

Specifically, the return line for the 88 (and 87) is plumbed directly into the right side coolant return pipe, under the rocker.
(Look, on your 88. You'll see the connection, right before the back end of the pipe.)
In earlier V6 cars, the return line would come all the way around the engine compartment and up to the pipe on the water pump.
In your case, you're going to want to remove that pipe from the water pump and replace it with a plug. (You're going to have to cap one fitting or the other. Easier to do that one, than the one on the return pipe.)
While you have the engine out, I'd just replace the water pump, and install a new plug. I don't think the pump will come with one, but could be wrong.

There is another heater hose that connects to the smaller fitting on the V6 thermostat housing. That hose is usually crimped to a hard line that goes down the firewall, across towards the battery, down to the bottom of the firewall, and back over to a quick connect towards the center of the car. On your 88, it will probably be the hose that goes to the bottom of the intake manifold. (I THINK. Don't hold me to that.)
This will be the hose/pipe assembly that does NOT go straight from the center of the car over to the right side coolant pipe.
You will need to find that V6 hose/pipe assembly. Or fabricate something like it.
It can switch from rubber hose to pipe anywhere along the route. Just that pipe is more difficult to damage.

I should stress that the hose that loops around the side of the 88's engine compartment is NOT the same as the hose that loops around the side of the V6 engine compartment. They're at opposite ends of the heater circuit.

Kind of confusing. I hope it helps.

As for the pressure switch...
The 88 coupe harness replaces the switch wiring with a jumper in the plug. If you want to cut wires and splice in the two that go to the switch, that's fine.
I just had a harness available, and don't like cutting wires. It was plug and play. (It's a separate harness from the headlight harness, so you don't have to mess with all that.)

Edit - if you keep the V6 compressor and lines, everything plugs in. There's a connection "manifold" in the left front corner of the engine compartment. 10 mm bolt.
I debated whether or not to use my Duke compressor, but didn't want to mess with any wiring.
The V6 stuff is plug and play. (Other than that dumbass switch in the front. )

[This message has been edited by Raydar (edited 04-26-2013).]

quote Originally posted by Raydar: Heater hoses... Specifically, the return line for the 88 (and 87) is plumbed directly into the right side coolant return pipe, under the rocker. (Look, on your 88. You'll see the connection, right before the back end of the pipe.)

Raydar, I haven't taken posession of the '88 duke coupe yet, so I have no '88 of any sort to look at here. However, I do have an '87 duke coupe in the yard. Is there anything on there that would be helpful for me to look at, or is it completely different either due to the year or to the engine?

quote Originally posted by Raydar: As for the pressure switch...

Keeping in mind that the '86 GT donor car does not have A/C, is this pressure switch a common part to be found at the wreckers?

quote Originally posted by Raydar: I debated whether or not to use my Duke compressor, but didn't want to mess with any wiring. The V6 stuff is plug and play. (Other than that dumbass switch in the front. )

Seeing as how the only compressor I have is the one on the duke, it's that or nothing!

quote Originally posted by Raydar: Kind of confusing. I hope it helps.

Ah man, without an appropriate vehicle to look at, much of your excellent instructions are kind of wasted on me at the moment. I know they'll make a whole lot more sense when I have something in front of me to look at. So, although I'm thankful for your (and anyone else's) help as it's being posted, I'll be even more thankful when I can see with my own eyes what's being referred to!

The 87 Duke should be essentially identical to the 88. They use the same heater hose setup and A/C systems.

The pressure/cycling switch is very common. You can probably buy a new one for just a few $.
I forgot about the 86 not having A/C. (Brain cramp.)

Having said all that...
If you use the Duke compressor, you can likely ignore the switch completely. The Duke compressor is a variable displacement compressor, that doesn't need that switch. You will, however, have to wire up the Duke compressor so that it acts like it did in the original installation. (Not sure what kinds of pressure switches it uses, etc.)
I think the compressor is physically similar enough that it will bolt into V6 brackets if you can obtain them. It might be a little shorter.
You'll also have to change the clutch/pulley for the V-belt type used on the V6.
Or else mount the Duke compressor in line with the other pulleys and then find a serpentine belt that will drive everything. Way too much fabrication for my lazy azz, however.

[This message has been edited by Raydar (edited 04-26-2013).]

quote Originally posted by Raydar: The 87 Duke should be essentially identical to the 88. They use the same heater hose setup and A/C systems.

Okay, from this I gather that looking at my '87 duke coupe will give me somewhat of an idea of the heater hose challenges I'll be facing in regards to dropping a 2.8 into the '88 duke coupe. That should be helpful then (as I don't have the '88 to look at yet).

quote Originally posted by Raydar: Having said all that... If you use the Duke compressor, you can likely ignore the switch completely. The Duke compressor is a variable displacement compressor, that doesn't need that switch. You will, however, have to wire up the Duke compressor so that it acts like it did in the original installation. (Not sure what kinds of pressure switches it uses, etc.) I think the compressor is physically similar enough that it will bolt into V6 brackets if you can obtain them. It might be a little shorter. You'll also have to change the clutch/pulley for the V-belt type used on the V6. Or else mount the Duke compressor in line with the other pulleys and then find a serpentine belt that will drive everything. Way too much fabrication for my lazy azz, however.

Heh heh, the more of this I read, the more I think I should just rip ALL the A/C stuff outta the '88 and sell it. I don't even like A/C, so trying to convert this duke A/C system to work with the 2.8 seems like a lot of trouble for very little personal gain. I do have all the parts required to change over the heater controls etc to a non-A/C system, so it might be a helluva lot easier in the long run to just remove the A/C. And if I can get a couple of bucks for it from somebody who uses A/C and needs parts... bonus!

Raydar, thanks for your suggestions and advice.

Here's another question... Does the '88 still have a "hole" (possibly covered by a plate) on the right side of the trunk for the earlier year V6 blower/cooling system? Since I'll be dropping an '86 2.8 into the '88, I plan to install the blower system. (I don't wish to debate the need for the blower, I want it. ) I have all the parts required, but this leads to a second related question... What's the best way to tie into the electrical system for the fan blower, keeping in mind that the fan is supposed to be powered up at the same time as the rad fan comes on?

quote Originally posted by Patrick: Here's another question... Does the '88 still have a "hole" (possibly covered by a plate) on the right side of the trunk for the earlier year V6 blower/cooling system? Since I'll be dropping an '86 2.8 into the '88, I plan to install the blower system. (I don't wish to debate the need for the blower, I want it. ) I have all the parts required, but this leads to a second related question... What's the best way to tie into the electrical system for the fan blower, keeping in mind that the fan is supposed to be powered up at the same time as the rad fan comes on?

Hi Patrick,

From what I understand, the 88 V6 exhaust redesign allowed the removal of the blower so if an 86 V6 exhaust is going in, makes sense to keep the blower although I do not know if the provisions are there in an 88. You could use the AC relay from the 86 and fab a power supply with that and the fan temp switch on the engine.

BR's,

Mark

------------------
86 SE V6 4 speed
86 SE V6 Auto
2008 G6 GT "Street" Coupe
2005 Buick 3.6 Rendezvous
2001 Olds Silhouette (AKA The Band Van)

[This message has been edited by MarkS (edited 04-28-2013).]

The 88 does not have the holes in the trunk compartment (either for the blower, or for the "pipes".) It was eliminated in all 88 models.
The car harness probably doesn't have any provisions for wiring it.

As for ripping out all the A/C stuff and selling it, I'm not sure what kind of a market there will be for used A/C stuff. Probably more trouble than it's worth to remove both systems and swap the non-A/C stuff over.
I would be tempted to leave everything in place as if the A/C were there. Just cap off the lines in the front corner of the engine compartment.
That way, if you ever change your mind or sell the car, it will still be mostly complete.

quote Originally posted by MarkS: From what I understand, the 88 V6 exhaust redesign allowed the removal of the blower...

And I believe the alternator used in '88 had a more efficient built in fan as well.

quote Originally posted by MarkS: ...so if an 86 V6 exhaust is going in, makes sense to keep the blower

Yes, everything to do with the 2.8 engine (intake, exhaust, etc) would be transplanted from the '86 GT.

quote Originally posted by MarkS: I do not know if the provisions are there in an 88. You could use the AC relay from the 86 and fab a power supply with that and the fan temp switch on the engine.

A couple days ago I had the opportunity to remove the rear electrical harness (taillights, etc) from an '85 V6 Fiero. It has the proper wiring coming off of it to power the blower. My question would be... even if I used this harness (or the one from the '86 GT), would there need to be something else added to the '88 ahead of that rear harness that would send power down the line to the trunk blower when the rad fan kicks in? Or would simply plugging the rear harness in allow it to tap into whatever it is that powers the rad fan?

Thanks for your feedback, Mark.

[This message has been edited by Patrick (edited 04-28-2013).]

quote Originally posted by Patrick: A couple days ago I had the opportunity to remove the rear electrical harness (taillights, etc) from an '85 V6 Fiero. It has the proper wiring coming off of it to power the blower. My question would be... even if I used this harness (or the one from the '86 GT), would there need to be something else added to the '88 ahead of that rear harness that would send power down the line to the trunk blower when the rad fan kicks in? Or would simply plugging the rear harness in allow it to tap into whatever it is that powers the rad fan? Thanks for your feedback, Mark.

There is the largest possibility that the 85 taillight harness is wired differently from the 86 and later.
This, because the 85 was never designed to accommodate a fastback, which used different circuitry for the GT taillights.
It may work, but don't be surprised if it doesn't. All you can do is plug it in and try. Remember to hook up the grounds.
(This is also based on some '85 fastback swaps I've seen where the fastback taillight harness was plugged into the 85 electrical system.
All sorts of odd things happened.)

Also... As I said, the wiring to run the blower may not be part of the 88 car harness. The blower was designed to run whenever the front radiator fan is running, so it would probably only require the addition of one wire.
I only have an 88 manual, so I can't help with the earlier wiring.

quote Originally posted by Raydar: There is the largest possibility that the 85 taillight harness is wired differently from the 86 and later. This, because the 85 was never designed to accommodate a fastback, which used different circuitry for the GT taillights.

Interesting point. It may be simpler just to add some additional wiring to power up that blower.

quote Originally posted by Raydar: The blower was designed to run whenever the front radiator fan is running, so it would probably only require the addition of one wire.

Yeah, I'll see what I can find in some non-'88 V6 wiring diagrams.

Thanks for your help, Raydar.

[This message has been edited by Patrick (edited 04-30-2013).]