safe overbore for an LS1

vetteguy61 · 12-13-2010, 06:18 PM

Hey guys, how much can a stock LS1 block be enlarged in the cylinder walls?
Can I go .0010 overbore safely?

**Rich Z** · 12-13-2010, 06:36 PM

Uh oh......

RevXtreme 1 · 12-13-2010, 07:14 PM

There really is no safe overbore for the LS1/LS6. You may get by w/.010 over, but then it is a custom piston size. The liners are far to thin.

Now a 6.0 can be bored....

vetteguy61 · 12-13-2010, 07:24 PM

Thanks for the info. I knew with the liners about .005 was about the max. I need to do some serious thinking on this. May end up getting rid of my C5.

Bob K · 12-13-2010, 07:26 PM

But he's asking .001 which is less than cleanup. No problem there Mike. Did you really mean ,001?

RevXtreme 1 · 12-13-2010, 09:04 PM

Good point Bob, if it is just a hone to cut the glaze & put a cross-hatch in you are fine with that. Don't sell the vette for something so minor, a good used block is like $250-$350 that does NOT need to be bored. And good used motors can be had for the $1500 range.

Give us more details on this...

mickeystoysz16 · 12-13-2010, 09:09 PM

OK so this may sound like a stupid question since I am new to the LS engines and all of my mods/hot rodding is old school chevy small block 350's but isn't a 350 with a stroker crank only bored out 0.030 over. So that a boring would be in the tenths range with a honing being less than 0.001? Are the tolerances in the LS series engine that tight that you can't hone a cylinder much less bore one out to a measely little thousandsth?? Am I missing something especially since I do not see how 0.001 makes any difference in the cylinder volume unless combined with a stroked crank anyway?????

I guess I am interested in the answer to this question as well because it seems that I am either misunderstanding the question, don't have all the facts such as crank, cam, and valve train geometry, or my math is WAY off.

vetteguy61 · 12-13-2010, 10:23 PM

okay to clear up some of the questions. I had the motor built to a 383 with a 4inch stroker crank. There was a problem with the balance that caused a vibration in the rotating assembly. Found out the crank weights were way off so had it redone. The finish of the build was never done by the shop I had it in.Had to put it on a trailer and take it to a shop in Panama city to get finished. Anyway to make a long story short I was told that the bores weren't straight and needed to be honed out larger. The machine shop wants to go 10 thousands over on the pistons. Trouble is we can't find a piston that size.I have too much money in the engine to go with a different block such as an LS2.My car has been down since Mar and I just want to get it back together.Rich Z knows all about the problems I had with the first shop.Will try and get more info tomorrow and pass it on to the experts here.

navy2kcoupe · 12-14-2010, 12:53 AM

Mike, that sux! I'm starting to get the impression that modding these cars is
not much fun. I hope that you are able to resolve your issues without spending
a bunch more money.
Andy

RevXtreme 1 · 12-14-2010, 09:00 AM

Quote:

Originally Posted by mickeystoysz16

OK so this may sound like a stupid question since I am new to the LS engines and all of my mods/hot rodding is old school chevy small block 350's but isn't a 350 with a stroker crank only bored out 0.030 over. So that a boring would be in the tenths range with a honing being less than 0.001? Are the tolerances in the LS series engine that tight that you can't hone a cylinder much less bore one out to a measely little thousandsth?? Am I missing something especially since I do not see how 0.001 makes any difference in the cylinder volume unless combined with a stroked crank anyway?????

I guess I am interested in the answer to this question as well because it seems that I am either misunderstanding the question, don't have all the facts such as crank, cam, and valve train geometry, or my math is WAY off.

It is common to bore a old school 350 .030 and even more for comon sized pistons. The stroke of the crank in addition gets you the 383, etc. These blocks had plent of room to bore as such.

The LS1 & LS6 have to thin of liners to go the standard .030 over. Now a .0001 hone is sandard and you can go several hones of that much w/no issue using the stock bore size pistons. The liners in the LS blocks rarely show much of any wear at 100, 150, 200k plus miles when syn oil is used so rarely would we ever need to bore them. Only a hone to remove the hard glos and lay down a cross hatch so the new rings will seat properly. In fact, in almost every LS motor I tear down the original cross hatch is still visable and no wear ridge such as the old school motors had showing just how tuff these motors are.

Quote:

Originally Posted by vetteguy61

okay to clear up some of the questions. I had the motor built to a 383 with a 4inch stroker crank. There was a problem with the balance that caused a vibration in the rotating assembly. Found out the crank weights were way off so had it redone. The finish of the build was never done by the shop I had it in.Had to put it on a trailer and take it to a shop in Panama city to get finished. Anyway to make a long story short I was told that the bores weren't straight and needed to be honed out larger. The machine shop wants to go 10 thousands over on the pistons. Trouble is we can't find a piston that size.I have too much money in the engine to go with a different block such as an LS2.My car has been down since Mar and I just want to get it back together.Rich Z knows all about the problems I had with the first shop.Will try and get more info tomorrow and pass it on to the experts here.

After all you have been through I can see your frustration, but another $250 for a straight block should not kill your build. The entire rotating assy you already have prepped and ready will drop right in and not require ANY more labor....in fact it will be way less as a bore and pistons will be $500-$700 I imagine, so you would be saving $ over trying to use that block.

Another option is to just have him clean up the cylinders as best he can so you can still use your same pistons. A small amount out of round is not unusual and you would probably be fine (not perfect, but fine).

Ls1/LS6 blocks in good shape are all over the place for cheap.