2.8 -3.1 hybrid

[vladbuick]

So I have a 1985 2.8 fiero engine which ihave pulled apart and was in the process of rebuilding it but work on it has slowed down since the end of the summer . Mainly for two reasons :
- the first I cant seem to find the crank bearings which fit , I have measuredthem to be 72mm but the crank bearings I had ordered where much smaller. Anyone ever encounter this?

-the second reason is that the heads which where on it are not it the best of conditions beacause one of the manifold studs hole is broken off, I was wondering if the top end of a later gm 60*v would bolt on to the older block , more precisely 2000 buick century 3100 heads and intake?

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[caffeine]

Yes the later 3100 top end will bolt on. However you need custom pushrods and it's best to swap in either a 3.1 crank/pistons or Gen II aluminum head 2.8 pistons otherwise the compression ratio will be quite high.

[Blacktree]

Do the bearings fit over the crankshaft? If they fit on the crank, but are not big enough to fill the holes in the block, then the block may have been line-bored sometime in the past.

[vladbuick]

No they dont fit either on the crank shaft or the block, I ordered the peices at a parts store and thats what they had in their catalog for 1985 2.8 engine. Also the ones I bought compared to the ones which where in the engine are much smaller, what confuses me the most is that I checked online and the listed crank bettering size is much smaller than what I have on my 2.8 block.

How high would the compression be withe the fiero pistons and 3100 heads.?

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[caffeine]

Maybe you ended up with bearings for the 82-84 2.8s?

Compression with 3100 heads would end up somewhere around 12:1 IIRC. The head gasket used would have an effect on CR as well.

[vladbuick]

I think you are right I probably ordered an earlier crank bearing size, thanks for yhe help

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[davida1_hiwaay_net]

....85 Fiero engine....

Hi, to clarify some things. There are 2 versions (that I know of) on the iron-head 2.8 heads. The higher performance ones have larger valves. There is (I believe) a triangle mark on the end of the head (top side of bolt boss) to indicate this. If you go looking for heads this can help.

Is the head its self broken, or is there a broken bolt stuck in the head?

The aluminum heads from newer engines will fit the block, but you MUST also change pistons and EVERYTHING above the block (manifold etc). The exhaust manifold bolts are in different position also.

The Fiero engine is s special model and I understand if you want to keep the Fiero setup. I just got through with an iron head build on an 85 Celebrity Eurosport. It's a friend's car and he wanted to keep the relatively rare X-manifold 2.8 MPFI. It's almost identical to the Fiero engine, save for the appearance parts on the Fiero. Thankfully the heads were OK.

Sincerely,
David

[caffeine]

There's a member on here running 3100 heads with stock iron head pistons. So it is possible. You can also use iron head exhaust manifolds/headers on aluminum heads by slotting the lower holes.

All Fiero 2.8 heads are the same I believe as well as the blocks.

[davida1_hiwaay_net]

There's a member on here running 3100 heads with stock iron head pistons. So it is possible. You can also use iron head exhaust manifolds/headers on aluminum heads by slotting the lower holes.

The reverse is also true. I was able to use TGP McLaren turbo manifold (for aluminum head engine) on the iron head 2.8 by slotting both holes on the manifold. It put the bolts very near the manifold body, requiring sleeve spacers.

All Fiero 2.8 heads are the same I believe as well as the blocks.

That's good to know. I ran into this problem when looking for good heads in a pile of heads which were not installed on engines. Got home and started taking them apart to clean and inspect and found different valve sizes.

Is the Fiero block any different from the other transverse 2.8 blocks?

[caffeine]

I believe the Fiero block is the same as the other transverse blocks. The front timing cover OTOH more resembles the RWD style except that all Fieros use a CW rotation water pump (S-10s and F-bodies switched to CCW in 87 when the oil pan-timing cover flange changed as well).

[davida1_hiwaay_net]

I believe the Fiero block is the same as the other transverse blocks. The front timing cover OTOH more resembles the RWD style except that all Fieros use a CW rotation water pump (S-10s and F-bodies switched to CCW in 87 when the oil pan-timing cover flange changed as well).

Thanks for the info.

As an aside, I really like the Fiero style. Some day when I don't already have WAY too many cars, I will get one and do a build on it.

[vladbuick]

Here are a couple pictures,
My car


and here is the head, the machine shop I went too said there was nothing I could do with it,



Heres the crank number 817

[davida1_hiwaay_net]

That's a good looking car! I like the red.

That bites about the broken head. I see that would be nearly impossible to repair.

I have a feeling you can get another head relatively easily. If not, there are probably people here who can help with that.

If you are looking through junk for a good head, see the mark on the attached picture. Look for this mark, I am reasonable sure this is the large valve head mark. Yours probably have this mark. Just make sure the 2 heads are the same.