Will Aluminum heads work?

[Big_Joebowski]

I've got an 86 Cherokee, with the 2.8V6, it's got burnt valves in cylinder 3, and won't build any compression. I've got the heads off, and was wondering if the heads from a 3.1 Gen II will work on it. I know they have the splayed valves, and my 2.8 has flat top pistons. Will I run into interference problems here???

I'm hoping not, because I would like to use the heads and injection system from my dad's old Buick Regal, and I would rather get the parts for free, and use a fuel injection system than the crappy old Varajet carb.

[sharkey]

RE: Will Aluminum heads work?

unless you change the pistons as well, you will end up with 12:1 compression.

what i would do is rebuild your motor with the 3.1l crank, rods and pistons, aluminum heads, ect. you will need to use the timing cover from the fwd motor and will need to turn the plenum around so it sticks out the front. this will cause problems with the power steering pump, and you will need to custom fab a bracket for the power steering pump.

noiw a better idea for you would be to freshen up the heads you have, and find a multiport fuel injection setup from a camaro/firebird.

[Big_Joebowski]

So there won't be any problems with the valves hitting the pistons or anything?? I Knew the heads had fast burn chambers on the aluminum heads, and it would up the compression, which is fine with me. I've had an 89 Probe GT running 12psi for a couple years now, and I'm used to paying for premium fuel. I'm probably going to upgrade the cam and rockers while I'm at it.

My idea was to swap the entire lower intake manifold and plenum around, so that the heater hoses face forward, and the upper coolant neck does also. My Heep doesn't have AC, which would then be in the way of the throttle body, and the Power steering is down on the lower driver's side.

I also don't know if my block has a reluctor wheel in it, because it came out of a 2.8 MPFI, so I may run into problems with that too. Does the reluctor wheel have anything to do with fuel injection on the GenII or does that just control the timing?

Sorry, I know I'm throwing alot out there. I've got the 2.8MPFI manifold for the iron heads from the firebird, would I be better off just trying to find a wiring harness from a 2.8 or 3.1 firebird? They are few and far between around here anymore.

[Guest]

The reluctor wheel is needed for the ignition system that is needed to be run with the genII (or III) top end. You will need to make one, as I did with my hybrid swap, I'll post pictures if you want, I have posted the pics in a couple threads on this site previously.

There are a few other things that need to be considered, the bolt pattern in the ends of the heads differs quite a bit from the iron head counterpart, so adaptors or new mounting parts are needed for the belt driven accessories.

Heater hose routing is intereasting, and requires the coolant sensor hole to be drilled larger and retapped, if you want the heater hoses to exit both on the passenger side, other wise one hose will have to be routed around the engine, which I did at first, looks like crap, so I changed it, coolant transfer was improved as well.

That's all I can think of for now, if there's anything more that I remember I'll post.

BTW my swap was in a 1985 GMC Jimmy, that was originally a 2.8L Carb POS.

[bszopi]

Here, I'll help out...



The 3 mounting holes aren't in the correct location for a stock setup right now, but everything else is correct. If you have a machine shop that can make it on a CNC machine, I can provide you with the CAD drawing as well.

[Big_Joebowski]

how can I find out if my crank has a reluctor wheel??

Is it on the crank pullet, or in the block somewhere? If it's on the pulley, I think I may have it

If not, is there a plug in the block that I can remove, and take a look?

I figure with approximately 12:1, a new cam, and some tweaking, It'll do MUCH better on the trail. With the stock 2.8, it was sometimes difficult to make it up the steeper hills. It would just run out of steam, and I'd have to get a running start.

[geoffinbc]

In 86 you will not have the reluctor wheel (because it is external balance) nor will you have the hole in the block.

You will have to make what you see posted by brad and chris above

[Big_Joebowski]

Well, the engine is from a late 80's firebird, I don't know what year exactly.