LS6

I'm thinking of making 442ci with LQ4/LQ9 block, boring to 4.070" and using 4.25" stroke with compression of 11.8 against LS3 heads. I'm seeking 600rwph with 540rwtq. This will be a weekend toy...

Has any one done this kind of project?

dmelvin

iTrader: (8)

I think with the iron blocks and a 4.25" stroke, you run a risk of going into consumption issues, also the piston will a lot of rock at BDC with an iron block using a 4.25" stroke.

FlamingTA

iTrader: (8)

no way. 4.125" stroke is the max on a regular sleeve block and that is pushing it.

redtan

iTrader: (5)

Even a 4.100 stroke is pushing it on the stock block.

Stick with a 4.000 stroke.

bww3588

iTrader: (49)

Agreed, I've also seen 4 inch stroke engines with oil consumption and ring seal issues. More prominent on longer stroke engines but still

87silverbullet

iTrader: (11)

As everybody else has stated, it is ill-advised to do so.

LS6

Eric at HKE seems done lSX engine with 4.25" stroke, but i don not know if done 442ci?
https://ls1tech.com/forums/generatio...ed-blocks.html
See post no. 11

6D9 Matt

I dont think I would recommend it, but hey, anything is possible these days.

LS6

I think their is a problem founded with the 4.25" stroke, it require longer cylinder wall which at end may require re-sleeving. I have to check.
https://ls1tech.com/forums/generatio...50-stroke.html
See post no 8

redtan

iTrader: (5)

Yes you need new sleves for that kind of stroke. Not on the stock block.

MrEracer

iTrader: (3)

I'm running a 6L iron block with 4.125 x 4.125 bore and stroke for 442 cid. I have sleeved the block with 6 sleeves to maintain adequate cylinder wall thickness. I'm using a set of off the shelf Wiseco pistons and WCCH LS7 heads running 13.8 cr on E85 with EFI on a carb manifold. This engine is making over 700 fwhp. The iron block is required by the rules for the class I run (Comp Jet circle race boat). This is a very difficult environment for an engine as I must run for 5 miles wide open... This engine is very competitive against the best in the class, especially since the class allows 515 cid and I have to run against 509 cid BBC's tricked out the the max... And this is my small engine...

My big engine is a 492 cid LSX engine that has a 100 hp advantage over the competition. But that is another story...
MrE

03_Denali

iTrader: (1)

You sleeved an iron block?

bww3588

iTrader: (49)

What's wrong with that?

CAMSTER

iTrader: (10)

Why not a real LSX block for about $2200. brand new and you end up with a real lsx engine, and no oil consumption, with 4.185 bore and 4.00 stroke you have a 440 CI you can do anything you want with, and is rock steady. Oh and don't tell me about the extra weight, if you use all the tricks you are considering, to use the lq9, you may end up with a zero weight block LOL...

redtan

iTrader: (5)

Nothing wrong with that, question is why sleeve only 6 of the 8 bores?

MrEracer

iTrader: (3)

Core shift leaves one cylinder on each side that has thick (enough) cylinder walls... Too bad GM did not siamese these blocks because they have plenty of cylinder wall thickness everywhere except between the cylinders.
MrE

LS6

The cost of stoker kit with 4.125" stoke is the same cost as 4.25" stroke.
With the 4.125" stroke the engine will be 429ci

03_Denali

iTrader: (1)

I have just never heard of sleeving an iron block.

bww3588

iTrader: (49)

Fair enough.

Before aluminum blocks came around, sleeves were used for repairing cylinders. Back then, 350 Chevy's weren't by the thousands in junk yards like they are now. You couldn't just scrap the block and hit your neighbor up for one of the 40 he has in his back yard.