2.8?

[Mr_Efficiency]

But the cam you are talking about, is it the 3.4 cam or an after market one? and how much better is the 3.1 cam over the stock 2.8/3.1 piece

[3100 MPFI]

The only time I ever got lucky with the dealer was when I needed a new HUD DIMMER cable for my Cutlass Supreme. I got one of the last few at any GM dealer in all of North America. That was when I was living in New York, and it was shipped from Florida.

[ForcedFirebird]

So what exactly is that, the stock cam from GM? thats cheap and it even comes with lifters

wouldnt happen to have a part number would you?

Like I said, I bought from Delta and someone mentioned the 2.8/3.1 cam from GM shortly after I got mine.

I have good luck just walking into the dealerships and asking questions. They don't always stock an item, but usually is only a few dealerships away or can have it delivered for you.

[Mr_Efficiency]

So what exactly is that, the stock cam from GM? thats cheap and it even comes with lifters

wouldnt happen to have a part number would you?

[ForcedFirebird]

ok thanks

what about the cam? i know i dont have the $$ for a new one but i was doing some research and found that the fiero 2.8 HO (L44) uses the same cam from the 3.4 in the firebirds and camaros. how much better is this cam over the stock 2.8/3.1 cam?

For the flat tappet, you can get the 262 (or 260 depending on mfgr) grind for $125 with lifters from GM. Delta will also do a 262 re-grind with lifters for $100 - or they did the last time I bought a cam from them.

[Mr_Efficiency]

ok thanks

what about the cam? i know i dont have the $$ for a new one but i was doing some research and found that the fiero 2.8 HO (L44) uses the same cam from the 3.4 in the firebirds and camaros. how much better is this cam over the stock 2.8/3.1 cam?

[ForcedFirebird]

yeah i was going to ask about that, so the 3100 head gaskets are thicker?

Gen3 pistons protrude .020" out of the block, hence the reason for .060" compressed height gaskets (gives you exactly .040" quench).

The RWD gaskets are .040" compressed height, and you may have valve slapping the pistons with high RPM's with only .020" clearance.

[Mr_Efficiency]

yeah i was going to ask about that, so the 3100 head gaskets are thicker?

[3100 MPFI]

I think the only thing that might change with the compression will have to do with which headgasket you use. I think if you use the 3100 head gasket, you will lose some compression, but the 2.8/3.1 headgasket will keep it the same.

Something like that.

Once again, I am trying to think on an empty stomach. No food = no brain.

[Mr_Efficiency]

thanks a lot, i have some good calculators for that but just didnt have the specs, I'll give that a try now.

... it says the 3100 and aluminum head 2.8 and 3.1 have the same combustion chamber cc's so my compression wont change.

[bszopi]

To test for CRs for various combos, use the site calculator:

http://wiki.60degreev6.com/index.php?title=Compression_Ratio_Calculator

To get values for the different engines, just do a stock engine calc and copy the numbers down.

[Mr_Efficiency]

yeah its an 88 2.8, so its the good one. I'm thinking of leaving it a 2.8, and since the 3.1 and 2.8 heads are the same that means if i use the 3100 heads, I'll get the same compression ratio as if i was using a 3.1, correct?

what does the compresion of a hybrid come out to anyways?

[ForcedFirebird]

The 2.8 hybrid will be the same as the 3.1 hybrid.

In fact, I threatened Ben that if he kept pissing me off about using a 3100 instead of a 3400, or 3500, I would stick a 2.8 crank and rods in there and have a 2800.

All the 2.8 is is a destroked 3.1 MPFI. I think that the 2.8 revs up faster and higher (due to the shorter stroke). I know my 3100 revs higher than a 3400, but that is a built-up engine.

Don't you mean use 2.8 pistons and crank in a 3100? The rods are the same, the pin height is different on the pistons.

I am planing on building a hybrid motor and boosting it, but i want minimal down time on my car and instead of rebuilding the motor in the car I was looking at getting another motor and building it then taking the car off the road for a weekend to swap in the new motor.

I was planing on using a 3.1 but i came acrossed a complete 2.8 for free.

What would be the downsides to using a 2.8? its the exact same as a 3.1 isnt it, except for the stroke obviously. I would get better gas mileage, lol

there is only a five hp and 5tq diffrence in the two motors, so its not a huge deal to me, im not looking for all out race motor, just something boosted to have fun with.

is the 2.8 and 3.1 cam the same?

anyone ever hybrid or boost a 2.8?

atleast i'd be diffrent

Yes hybrids and boosted gen1's have been done.

Since you are doing a rebuild anyways, you can use 3.1 pistons and crank and it will be a 3.1. You need some 3100 (or Gen2 3.1) pistons with those heads if boosting. OR you can use the 3.1 pistons and have a high compression torque monster.

*But* as Brad said, make sure it's an '86 or later or you may be wasting your time.

[bszopi]

The question I have is for the original poster. If the free engine he is getting is a pre-85 (??), then it has the smaller journal crank which is crap.

[3100 MPFI]

My 2.8 heads are 1988 and 1989 (from 2 different cars).

I am not sure about all the years, but I know for a fact the 2.8 was used 1987-1989 in the gen 2 form.