Boring out LS1
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Boring out LS1
So I have a question, I have my block at the machine shop right now (LS1 Block) & they're recommending me go .020 over which will put me at a 3.91 piston/bore. I'm skeptical on it due to the cylinder lining reliability let alone just reliability in general. I have 3.903 pistons for it already and wanting to go that route first but was wondering if anyone has had luck with a 3.91 bore? Also kinda curious how it could have gotten that out of whack as well so I could know how to prevent in the future. Thanks
Its a 1999 Vette that the block is coming out of.
Its a 1999 Vette that the block is coming out of.
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Thats what I was thinking in my mind & was skeptical but apparently the cylinders are that out of whack from what I was told. I plan to get it honed to 3.903 since I have the pistons along with getting the deck cleaned up along with heads as well for smoothness and putting arp mains since I plan on boosting it. I dont understand how it could have gotten that bad though which seems odd to me.
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Moved to C5 Tech for more discussion.
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Isn’t it pretty common to make an LS1 a 383??? I don’t know what your bore sizes mean. I had a 350 block back in the day bored out to a 383. Professional done, a place in California called speedomotive. Wonder if there still around.
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A LS1 can't be bored out to a 383, there simply isn't enough metal between the cylinder bores. When 350 engines were changed to 383 they installed a stroker kit which means that the crank was swapped out which increased displacement by increasing the stroke. The same can be done to a LS1.
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From: Dyer, IN
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Engine boring is when the cylinder diameter is increased. This is done by machining the walls of the cylinder so that it becomes wider but remains functional. For example, it is not uncommon to bore out the cylinders of a 400 cubic inch engine to make the engine displacement 500 cubic inches.
Yes stroke adds cubs also
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Sorry lucky, this the first time i think your wrong, Yes cleaning up the bore don't get xtar cubs. Dont yell at me.
Engine boring is when the cylinder diameter is increased. This is done by machining the walls of the cylinder so that it becomes wider but remains functional. For example, it is not uncommon to bore out the cylinders of a 400 cubic inch engine to make the engine displacement 500 cubic inches.
Yes stroke adds cubs also
Engine boring is when the cylinder diameter is increased. This is done by machining the walls of the cylinder so that it becomes wider but remains functional. For example, it is not uncommon to bore out the cylinders of a 400 cubic inch engine to make the engine displacement 500 cubic inches.
Yes stroke adds cubs also
Last edited by lucky131969; Oct 18, 2024 at 02:30 PM.
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I certainly do not mind being wrong 
, but I'm not following your point. Are you trying to point out that I did not specifically say an engine builder may have to go over .010 or .020 to clean up the cylinders? The stroke on a 383 SBC comes from changing the crank. What am I missing?
, but I'm not following your point. Are you trying to point out that I did not specifically say an engine builder may have to go over .010 or .020 to clean up the cylinders? The stroke on a 383 SBC comes from changing the crank. What am I missing?Just reread your post your right cleaned bores does nothing to make more cubs
mDame it i though i had you.
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Yes, thats why i said your right but you can bore out in engine to get more cubs, As far as max. bore keeping the engine safe i don't know. Maybe thats what u were trying to get through, This block cant by bored to a 383, but blocks can be bored for more cubs. That's all i meat. Yes you have to start with at least .030 over and more to make a difference. Hope you understand, what said in my brain sometime don't translate to paper.
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From: Guinness Its whats for B'fast JAWGA
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That is on a 350 Gen1/Gen2 motor. 350 cubic inches 4.00" bore 3.48" stroke
Gen3 5.7 Ltr 346 cubic inches Bore 3.898" Stroke 3.622"
LS1 383 is .005 over and a 4.00" stroke crank.
Max bore can depend on the LS1 block but .005 to .010 is common.
Gen3 5.7 Ltr 346 cubic inches Bore 3.898" Stroke 3.622"
LS1 383 is .005 over and a 4.00" stroke crank.
Max bore can depend on the LS1 block but .005 to .010 is common.
Last edited by 93Polo; Oct 18, 2024 at 03:37 PM.
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Last edited by 93Polo; Oct 18, 2024 at 03:37 PM.
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I'm so glad people with actual knowledge came in at the end here.
Gen1 / Gen2 small blocks share almost nothing with LSx engines.
Yes, Gen1/2 engines could be over-bored up to .060 (most commonly .030) and yes that makes more displacemt a Gen 1 350 over-bored .030 becomes approx 355cid
LSx engines have cylinder sleeves and can take almost no overbore. .005 is the max number I've always heard. If a machine shop wants to take an aluminum LS1 .030 over; find another machine shop.
Gen1 / Gen2 small blocks share almost nothing with LSx engines.
Yes, Gen1/2 engines could be over-bored up to .060 (most commonly .030) and yes that makes more displacemt a Gen 1 350 over-bored .030 becomes approx 355cid
LSx engines have cylinder sleeves and can take almost no overbore. .005 is the max number I've always heard. If a machine shop wants to take an aluminum LS1 .030 over; find another machine shop.
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I'm so glad people with actual knowledge came in at the end here.
Gen1 / Gen2 small blocks share almost nothing with LSx engines.
Yes, Gen1/2 engines could be over-bored up to .060 (most commonly .030) and yes that makes more displacemt a Gen 1 350 over-bored .030 becomes approx 355cid
LSx engines have cylinder sleeves and can take almost no overbore. .005 is the max number I've always heard. If a machine shop wants to take an aluminum LS1 .030 over; find another machine shop.
Gen1 / Gen2 small blocks share almost nothing with LSx engines.
Yes, Gen1/2 engines could be over-bored up to .060 (most commonly .030) and yes that makes more displacemt a Gen 1 350 over-bored .030 becomes approx 355cid
LSx engines have cylinder sleeves and can take almost no overbore. .005 is the max number I've always heard. If a machine shop wants to take an aluminum LS1 .030 over; find another machine shop.
The thrust bearing doesn’t look like normal wear but maybe I’m wrong. I’m just going to get it honed to 3.903 and send it since I already have pistons for it.
Last edited by jamed30; Oct 18, 2024 at 07:29 PM.
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Take the engine to another machine shop, these guys don't know Aluminum LS engines. It doesn't mean it's a bad shop, Aluminum LS' are their own thing. If they try to rebuild this like a Gen 1 Iron motor there are going to be all sorts of issues.
Where are you? Maybe someone here can recommend a good local shop for this.
Where are you? Maybe someone here can recommend a good local shop for this.
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Take the engine to another machine shop, these guys don't know Aluminum LS engines. It doesn't mean it's a bad shop, Aluminum LS' are their own thing. If they try to rebuild this like a Gen 1 Iron motor there are going to be all sorts of issues.
Where are you? Maybe someone here can recommend a good local shop for this.
Where are you? Maybe someone here can recommend a good local shop for this.
Do the bearings look like normal wear or is something going on that I need to look for when I get it back?
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They told me they would hone it to the 3.903 pistons that I have and if they say it is a must for a 3.91 then I'll be taking it out of there regardless. I'm in Madison AL if it helps at all.
Do the bearings look like normal wear or is something going on that I need to look for when I get it back?
Do the bearings look like normal wear or is something going on that I need to look for when I get it back?
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Yeah I understand that I just couldn’t find what was the culprit when I had it apart before I took it over to the machine shop. Just seemed odd I guess oil pressure was fine also.