2.8 to 3.1 Stroker Pistons RWD

[GearJammerR]

Hey everyone!

Ive got a S10 2.8 TBI for starters, Bone stock, Id like to stroke it with a 3.1 crank and pistons, I know that 2.8 to 3.1 share the same bore so but changing cranks means different pistons.

Ive used the search bar, and all the threads ive read are helpfull but none say exactly which pistons to use. Im running iron heads, would GENII Fwd pistons work? if they dont, a link to summit racing would be appreciated! Also would the crank from a Fwd motor work too? I can probably get both those for free, thats why im curious!

Lastly, I live all the way up here in Canada EH! otherwise id be slapping a 3.4 in there already. To bad theres none around where i live here in Winnipeg!!!!!!
Thanks to all for the info!

[Driver_10]

The 3.1 and the 2.8l share the same pistons, connecting rods and heads. Only the crank is different. BTW make sure that you have an internally balanced flywheel before going forward with your build. Some of the older 2.8l were externally balanced via welded flywheel counterweights.

[geoffinbc]

You can use a FWD crank but not the pistons. Federal Mogul sells a nice set of pistons with coated skirts. You will have to get some machining done but you could turn your 2.8L into a 3.2L. I did it with my Trooper and its a great setup.

[GearJammerR]

ok, so the crank yes! pistons no..... Also my 2.8 is a 87, so i need a neutrally balanced flywheel or can I have mine rebalanced? Also will my harmonic balancer bolt to the crank snout? and my flywheel too?

I looked on the federal mogul website and they list sealed power pistons, with the coating. Im assumming those are them! Summit List price is like $20 bucks a peice, so not too bad at all

Betterthanyou, What kind of setup is in your trooper? Im thinking something sorta similar for my s10 4x4........

Mostly just increase the displacement and a good rebuild, maybe clean up the heads a little bit. And also put a mild cam and the bigger TBI unit from a 4.3

[bob442]

WTF are you talking about no 3400's? theres 30 of them at bucks auto!

[GearJammerR]

Lol not a 3400 but a 3.4 from a '93 to '95 camaro, with iron heads!!!

[bob442]

there is so much room in a s10, its not even worth getting a 3.4 block to start with. using all the accessories right from a w-body would be the way to go.

[Driver_10]

You can use a FWD crank but not the pistons. Federal Mogul sells a nice set of pistons with coated skirts. You will have to get some machining done but you could turn your 2.8L into a 3.2L. I did it with my Trooper and its a great setup.

Is the piston comp height different or something? I was under the assumption that a 3.1l was just a stroked out 2.8l.

[GearJammerR]

yepp, you got it, if the piston travels a longer distance with increased stroke, it would literally pop out of the block

[geoffinbc]

Yes only the pin height changed. That why you just need pistons and the crank but the rods can stay to make a 3.1L.

Here is a link to my 3.2L Trooper build. http://members.shaw.ca/isuzutrooper/isuzueng.htm

If you are interested I sell a big bore TBI kit on my main page. http://members.shaw.ca/isuzutrooper/

[GearJammerR]

Hows the 3.2? Im debating between trying to find a 3.4L and go through the mods....ect. Or make a 3.1 out of my 2.8 and do the same mods. After all this isn't a race car, i just want something with a little highway passing power. The 2.8 thats in there right now can barely pull 130 km/h. After all, Im rebuilding a old Nova with a 355, to go fast with.

With minor head porting, a decent torque cam, new springs, headers, a good rebuild and the bored intake/ TBI unit, im hopeing to be close to the 200HP mark. Whether I do it with a 3.4 or a 3.1, only time and funds will tell I guess !

[geoffinbc]

I would have to say it is damn near identical. When you build a 3.2L it is a true 3.2L while a 3.4L is closer to a 3.3L. The small difference is bore size does not make too much of a difference. If you were going for max performance you might take more time to hunt down a 3.4L block but if you cannot find one then you will be quite happy with a 3.1L/3.2L. After all it moves my 4000 pound Trooper on 33's quite well and I have had it over 130km/h

[bob442]

Its not compairing displacment to displacment when you go from a GEN I 3.1 to a GEN III 3100, there is a whole Decade of advancements to all the internal componants. Better flowing intake, 6 injecters, aluminum heads, better flowing heads, roller valve train, list goes on and on. Really being anywhere in winnipeg its not hard to find a 3400 anywhere. Heck, look on kijiji, i'm sure someone next door has a malibu for sale for 600$ lol

What tranny do you want to end up having behind this anyways?

[GearJammerR]

My trans is a MG-290, its pretty much the same as a NV3500.
Ok, I understand very well that the newer you go with the 60V6 series of motors, the more power im going to make, but the more difficult it is to make it all work for my truck. For example, the accesories, my truck has A/C that I would really like to retain. A GEN III 3100 or 3400 has a completly different accesorie layout as well as exhaust manifolds, starter placement, motor mounts, oil pan (my truck is a 4x4) and the list goes on. Fuel injection and wiring isnt so bad alhough. Building, not even, just rebuilding my simple tbi motor fits into place, and will make a few extra ponies than im experiencing right now, Im happy as a clam!!!! Also time factor and cost factor too, after all my truck is my daily driver and its also not really worth anything either. Manitoba Public Insurance values it at $100 bucks!!!! lol Legit......

***Edit, just to make sure everyone understands that im not saying its impossible, but its not easy neither. Id want to know every single aspect/ modification before i would start to consider it.

[geoffinbc]

Your trans is a Borg Warner/Tremec T5 that came behind all the 2.8L's since they switched from the Borg Warner T4. The NV transmissions were only used behind the 4.3L and the later 2.2L.

A lot of people on here love to advocate the 3X00 swaps but I don't think they full appreciate the extra time and cost involved in doing it. Plus the custom fabrication of headers and engine mounts which many people cannot swing. Add to that the relocation of the starter, re plumbing of the cooling system re wiring of the engine management system, flipping the intake, plumbing the intake and more stuff I cannot think of now.

A 3.4L swap in an S-10 is literally a bolt in. Not even a single hole needs to be drilled or a part ground upon. If your 2.8L is in good shape and you don't need any new accessories you could do this swap in a day.