bugy

are LS-series engines reliable for boring cylinders? i've heard they are not for oversizing. if they could, what'd be the maximum oversizing you guys believe as safe to run strip/street.

Sales2@Texas-speed

iTrader: (5)

It really depends on which block you are working with? Which do you have or are you considering?

bugy

i'm considering, but i'm meaning stock blocks LS gen III some like 6.0L LQ9, LS1 5.7L aluminium or LS1 5.3L, what do you think?

redz_02

iTrader: (4)

LQ9/LQ4 yes
LS1 no
LM4 5.3 yes

It's not a good idea to bore a an ls1 block, with the exception of a hone/clean, b/c it's a aluminum block with iron sleeves. The other two are iron blocks, and better suited for boring. If you want to go Iron block you're better off just going LQ9 or LQ4 (easier to find).

bugy

alright, what do you think about this, LM7 5.3L stock bore 3.78" bored to 4.000" it's about 0.220" opened. this guy came to me asking me if this is gonna last or work well, also he's planning to use 150 shot. i think this is risky and not realiable, i just want him to see anyone else's opinion.

redz_02

iTrader: (4)

Only heard of 3.905 bore on a 5.3 block, and even that was sonic tested. I wouldn't trust it. If he wants a 4" bore why doesn't he just find an LQ4 block? It already has a 4" bore and would probably be cheaper after all the machining.

As for my LM4 statemnt above. Meant to put LM7, LM4 is an aluminum block and is alot harder to find than an LM7. Plus I would steer away from doing anything larger than a cleanup hone on an aluminum block with stock sleeves.

bugy

that's exactly what i told him, idk where he got that senseless idea from, in fact he spent significant cash machining it, well it's done, thank you for supporting dude

chrisfrost

iTrader: (8)

A few weeks ago there was someone on here that said they had their LM7 bored to the 6.0 bore 4.007" or whatever it is and He claimed that the blocks cylinder walls were still thicker than a gen1 350's walls . He said it was sonic checked or whatever there is for checking wall thickness . I forget what he said the walls were after the material removal . Even if the cylinder walls were ok I'd be concerned about the blocks over-all strength being affected .

Randy WS6

iTrader: (69)

I have the aluminum LS2 6.0L bored .030" over = 4.030" . its now a 418cid. and run many passes under nitrous and been in the car for five years now with no problems at all the specs are in my sig. And right now im building a new LS3 aluminum block bored .025" over = 4.090" its going to be a 431cid. when im done with it.

bugy

oh, i see, that's interesting about the LM7, but i wouldn't trust that far neither, i created this thread because i heard some Ls-series engines were not good for boring, as far as now i've realized some of them can work well doing it moderately.
thanks guys

FlamingTA

iTrader: (8)

It's nice to know your combo has worked great. I'm getting ready to send my ls2 block off to ERL to have them build one of the stock sleeve short blocks. They will bore it to 4.03" and 4.125 crank for 421. I know alot of ppl on here won't like that combo but I think it should make for a good street engine with some good mid range torque.

Randy WS6

iTrader: (69)

When i started my LS2 build 5 years ago , i was told by a lot of guys that i could not bore the LS2 block .030" and a 4.100 stroke crank was just to big and would not stay together, and i also use a lot of nitrous with my 418 and shift it at 7400 rpms,and its still running strong . But now i see the LS2 bore .030" over alot and the 4.100" crank used alot to. And im building a LS3 with a 4.090" bore with the 4.100 crank = 431cid. Good luck on you build, you should have a strong motor