Gen 3 2.8L or not...

[carbon]

Well no... its to low to even start...

[SofaKingWeToddDid]

I don't think you could short stroke the 3400 with the 2.8 crank... the pistons have a different pin height besides the longer stroke. I don't think the 3.4/3400 pistons would come far enough up the bore to make compression...

Turbo that shit then. and supercharge it.

[sanjay]

BTW this is a very interesting build trying to get good fuel economy and some performance!

It seems to be gathering quite some interest..More info on the condition of the 3100 tomorrow..

[WrathOfSocrus]

2.8 RWD crank lacks crank trigger IIRC. And it's external balance I think.

The newer blocks such as most of the TBI 2.8's found in the S10's were internal balance and from what I understand they used the reluctor wheel cranks in some of the RWD blocks.

BTW this is a very interesting build trying to get good fuel economy and some performance!

[ghrarhg]

I just finished it this May-ish. 88 2.8 block, crank, pistons. 3400 heads, LIM, UIM and TB. 26986 springs, engle 1605H cam, comp lifters, tgp manifolds hogged out to fit 3400 D shape, tgp crossover and turbo, diy full 3" exhaust from the turbo back.

I have a 3500 UIM, and 3.5 LX5 TB, but unfortunatley, it looks like the tgp crossover puts the throttle body into the turbo. It'll have to wait until I upgrade the turbo and build a new x-over/manifolds.

Idle vid from when I first got it running:

http://www.youtube.com/watch?v=WyJriS5r0RY

[sanjay]

2.8 RWD crank lacks crank trigger IIRC. And it's external balance I think.

That answers that..FWD crank it is..

[IsaacHayes]

2.8 RWD crank lacks crank trigger IIRC. And it's external balance I think.

[IsaacHayes]

More info on your setup ghrarhg ? I never knew you had that setup...

[sanjay]

I'm having trouble sourcing the 2.8 Crank and pistons. Can I use a 2.8 RWD Crank?? I may just buy a complete 2.8 RWD motor to get the parts I need.

[ghrarhg]

I'd be interested to see how a high compression 2800 turned out. My 2.8 hybrid really lacks on the low end. Stock 2.8 bottom end with 3400 heads actually dropped my compression ratio down to 8.5 according to the CR calculator. The turbo + cam really wake it up over 3k though

[sanjay]

I'd use 3500 exhaust manifolds like we did on Redbird's 3500. they're badass.

2.25 would be plenty for this setup.



Abob is driving his 3400 '89Z on a stock clutch. It will slip under load but for daily driving i'm sure it's fine.

As much as I'd love the 3500 ex manis it's just an extra expense that's not needed.

As for Abob's car with a stock clutch well you're making me want to just go with the extra displacement of a stock 3100....But a 2800 would be so much more interesting...

[IsaacHayes]

carbon, yes you'd need custom pistons since nothing in the 3.4l bore had a 2.8 crank in it.

[carbon]

I've always wondered how a gen3 top end will perform on the short stroke crank. I think what would be really neat if one had the money/time would be a 3400 block with the 2.8 crank and 3500 heads... That would be a 3.0/3.1L big bore high compression cammed screamer, with good mpg.

I don't think you could short stroke the 3400 with the 2.8 crank... the pistons have a different pin height besides the longer stroke. I don't think the 3.4/3400 pistons would come far enough up the bore to make compression...

[Superdave]

I'd use 3500 exhaust manifolds like we did on Redbird's 3500. they're badass.

2.25 would be plenty for this setup.



Abob is driving his 3400 '89Z on a stock clutch. It will slip under load but for daily driving i'm sure it's fine.

[sanjay]

The J bodies got 2.25" exhaust stock I hear. My Beretta got 2" press-bent with the stupid 1.60" inside down pipe.

2800 sounds cool for sure. I'm interested in hearing how it runs. Are you going with large port 3x00 heads and intakes? I take it you have a 3400 top end for it.. What manifolds will you use? I hope at least 3100 manifolds. The 3.1 manifolds are really small. W body 3100 manifolds flow better than L body 3100 manifolds (rear is larger), but the downpipe is off to the side instead of in the center. 3400 manifolds flow even better with the short runner on the back. 2005+ 3400 manifolds are even better as they are bigger inside the same as the 3500 log manifolds. And anything else is better of course.

I believe the earlier J bodies got 2.25" and the later years got 2". Either way it doesn't matter. The exhaust on the car is a multi repair cobble job so it's probably 2.25" crush bent piping.

I have will be using large port 3X00 heads and 02 3400 ex manifolds, both ported. Later 3400 ex manifolds are possible if I can score a set for 50$ or less.

The latest news on the motor is that it's an 01-02 3100 with bottom end issues. I'm hoping for a spun rod bearing not a main bearing...