I have an 86 gl wagon that needs an engine, and a friend has a wrecked xt (not sure of year) with a good engine. I know there are differences, (mine is carb, xt is mpfi), but what am I looking at in terms of a swap? I have even considered modding the manifold to bolt on a weber. Not sure what kind of a mess I am thinking myself into. Or should I just spend a little more and buy a matching engine from the boneyard?

I'm scratching the dust off because it's been ages since I've done much with 80s cars.

 

But the motors should be the same. If going from mpfi to carb, just swap your intake manifold onto the new long block. Should be cake for those motors as simple as they are.

 

Wait for someone more knowledgeable to confirm this but if memory serves, they should both be EA82 motors and only differ on the stuff associated with the intake manifold.

Thanks for the fast reply! If I read my info correctly, the heads have dual intake ports on the xt, meaning I have to swap the heads to use my old carb intake. Has anyone tried to mod a carb onto an xt manifold?

Yes, the XT heads are dual port, so you'll have to work around that some how.

 

The simple and direct route would be to bolt carb heads to the XT block.

Or, consider this a great time to throw antiquated carb junk completely and transplant the entire XT engine and ECU - you have the wiring harness connectors and ECU. 

Cut the wires from the ECU in the trunk and splice them into the wiring at the engine harness.

Edited September 17, 201510 yr by grossgary

The XT4 with the ECU in the trunk is one of the easiest self contained EA82 harnesses you will ever find. It takes about 20 minutes to strip the harness out of the donor, no need to pull the fender or dash, and no need to strip it all down. It runs from the front under the carpet and in to the trunk in one neat self-contained harness, and it's long enough to locate your new ECU wherever you like. It's a good time for a MPFI upgrade

 

You can see the ecu and harness as it came out of the donor car in right side of this picture. The large round rubber grommet (visible on the main loom in the right side of the photo) is where it goes through the firewall, right above the passengers feet. This picture does not show the ECU and Fuel pump relays. It should 'tie-in' to the new vehicle with about 10 wires total.

 

Edited September 17, 201510 yr by Crazyeights

Well, that sounds relatively easy. Any other issues I can expect?

nice notes Crazyeights - it just pulls through the fire wall?

If you go all MPFI you should upgrade at the very least all the soft (rubber) bits of the fuel lines to high pressure lines. You'll need the XT pump as well.

as others have said, the heads are different between the MPFI & carb engines

 

fuel differences:

MPFI cars have bigger fuel feed & return lines. Subaru did this by removing the carb return line (up the top near the strut tower) & replacing it with a much larger line that becomes the feed line. The carb feed line down on the chassis rail becomes the MPFI return line. Therefore, the 1 fuel line throughout the car should be replaced. I'm not sure if the SPFI cars had the same fuel line setup as the MPFI, but the XT lines are different.

the MPFI tank has a bigger port to suit the larger feed line, plus a swirl pot (not sure what you call them over there) inside the tank to reduce sloshing of the fuel. The XT tank should bolt up directly but check whether it's a FWD or 4wd tank with a hump over the rear diff.

fuel pumps are different, but bolt up in the same place, just swap over with the bracket

 

engine accessories:

XT's run a multi rib belt, everything else runs 1 or 2 v belts. You can just run the multi-rib stuff throughout, but check that the alternator wiring & A/C lines bolt up. If you go this way, you'll need to recharge any A/C gas.

You can swap over your V belt accessories. swap the brackets over also as the engine blocks are the same. You'll need to swap the water pump also as the shafts are different

 

wiring:

The XT engine loom goes backwards from the engine & directly through the middle of the firewall. The rest go off to the right side, into the fender, and then into the cabin behind the wheel.

 

Personally, I'd remove the injectors & block off the ports (or just leave the injectors in unplugged) and make an adaptor for a carb where the throttle body should be.

 

crazyeights, do you mind checking out the "Spider manifold advantage" thread (I tried to add a link, but it's not working for me...)? Seems you've done some work with a spider manifold & I'm trying to replace a normal turbo engine with a spider manifold turbo & need some help

Thanks for all the responses to my dilemma. You guys are really a great source of information and inspiration. Now I just have to decide how much of a project I want to take on. (make that another project)... . Besides, what isn't a project with ancient Subarus? What do you think of trying to carb a spider manifold? I heard of possible issues with lack of preheat in the manifold due to not being designed for air/fuel mixture.

Pre heat nah considering it will be a side drauht carb conversion I would look at something like a Mikuni Carb normally used on Harleys, Big enough,Jets available and considering engine characteristics probably not that far out of the ballpark as is for a good starting point.

 

After all it would be a single barrel carb to replace a single barrel throttle body and just need an adapter plate and rubber manifold to make it work.

Edited September 19, 201510 yr by coxy

That sounds like it could work. Hmmm. Much better idea than a weber, being more compact. That may be just the ticket. Thanks!