giszo

Is it possible to create a 3.4 V6 block from a 3.1 with boring the 3.1 to the 3.4's piston size and using 3.4 pistons in the bored 3.1 block?

Scorpner

iTrader: (4)

Edit: IIRC, you can just get a 3.4.

giszo

I'm just considering a 3.4 swap, but unfortunately it's hard to get a 3.4 block here, that's why I'm thinking on getting a 3.1 block and create a 3.4 from it with boring.

Scorpner

iTrader: (4)

Oh, sorry didn't notice the location.

AM91Camaro_RS

Unfortunately, no, you can't. There's not enough meat in the cylinder walls.

"up to a 4.3 as a direct bolt in" ...no. 3.4 is the biggest motor that will just bolt in.

giszo

Yeah, that's what I was afraid of ...

Scorpner

iTrader: (4)

Thank you. I corrected my initial post.

C_D_Z

If you can't bore a 3.1 to a 3.4 then how did the shop that my dad our old jeep Cherokee's 2.8 bored and stroked to a 3.4 work then? it had a 3.1 crank and 3.4 rods and pistons.

AM91Camaro_RS

I'm not sure but the story has always been that the cylinder walls will be too thin. Just an FYI 2.8s, 3.1s, and 3.4s all use the same rods.

InfernalVortex

iTrader: (4)

A smallblock chevy V8 can only go .040 over usually... people go .060 but that's pushing it. With 8 cylinders and a 3.48 inch stroke, that's still only a 10 cubic inch increase. That's 5.9 Liters... really less than a .2 liter increase.

You can't just drill most blocks out that far. The cylinder bores are generally a certain thickness.. a 305 is not the same block as a 350. You can't bore a 305 block out to a 350. You can bore it out to a 312 or so, but thats about it.

And stroking is a whole different deal than boring. Stroking gets you a whole lot more displacement. Boring gets you such a small displacement gain that it's generally only done to get the cylinder walls round again. You never just bore out a block as far as it will go unless you know for sure that block has some extremely thick cylinder walls like some aftermarket racing blocks.

DeathStarr89

iTrader: (1)

Yep, not enough meat to do it safely although people have claimed to do it. Most likely the machine shop either modified the crank to gain a little stroke or fudged the numbers.

a 2.8/3.1 block bored out .060 with the 3.31" stroke crank is a little over 3.2L. it would take .118 to get 3.349L (which is the actual displacement of a 3.4 iron head engine)

the HP increase from 3.1 to 3.4 isn't much, you'll get a little more torque but that's it.


If you want to stay N/A the best way to get more power is with a gen3 top end swap.

C_D_Z

well what ever they did it was a good engine at 227rwhp it loved to stay above 4grand

oh yea if you want to build a good 2.8 read Chevrolet power catalog shows how to build a 400hp engine like they used in indy cars,offroad racing, and stuff like that. My dad has it and it was made in 1988 6th edition.