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drives a LSX zr2
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Discussion Starter · #1 ·
ok guys heres what i wana do. i have a 5.3 that im going to put 799 heads on. I know a guy who will cut me a deal on boring out my 5.3 to a 5.7 for $100 bucks. i know a few machine shops who told me boring them to a 5.7 is fine but you dont want to go any more than that. i guess my question to you is would that be ok. i already have ls1 rods and crank. i can get a brand new set of forged ls1 pistons with rings and wrist pins for 450 shipped. let me know what you think. thanks
 

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yep
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ok guys heres what i wana do. i have a 5.3 that im going to put 799 heads on. I know a guy who will cut me a deal on boring out my 5.3 to a 5.7 for $100 bucks. i know a few machine shops who told me boring them to a 5.7 is fine but you dont want to go any more than that. i guess my question to you is would that be ok. i already have ls1 rods and crank. i can get a brand new set of forged ls1 pistons with rings and wrist pins for 450 shipped. let me know what you think. thanks

It will be fine unless the heads or block is decked much. the compression will be up a bit and you might have to watch what cam you run for valve to piston clearence.
 

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drives a LSX zr2
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Discussion Starter · #3 ·
It will be fine unless the heads or block is decked much. the compression will be up a bit and you might have to watch what cam you run for valve to piston clearence.
the cam im running is a comp cams part # 54-412-11 it has a 522 and 529 lift. mild cam i think they consider it.
 

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Bowtie Til I Die
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I personally wouldn't do it. You are walking a very fine line by boring it out that much. You cant sleeve the block like you can ls1s. If something goes wrong after its built and the cylinder walls have deep scars you will have to throw it out and start over and that $$$ spent on machine work was for nothing.

check out these forged 5.3 pistons from Wiseco.

These two have a 3.622" stroke but Wiseco also has some for 4" stroke
3.780 bore 578.95 shipped part# K474M96

3.800 bore 567.29 shipped part# K474M965
 

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I think he means it's not optimal because of the small gain of cubic inches for the money. You have to buy new pistons, and even though it's $100 for the work, IF anything happens at that point, you have nothing left to work with. I agree, I would spend the money else where unless you HAVE to bore it, and if that were the case, in my opinion, I would probably just find something else in better shape anyway.
 

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i need a paint job
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i think about 25 cubic inches is kind of a big gain? its not like your boring it .030 over... and you can pick up stock used ls1 pistions on ls1tech for 150 bucks. and why couldnt you sleeve it after it had been bored about .118 over? im just having a hard time seeing how it wouldnt work.
 

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drives a LSX zr2
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1,071 Posts
Discussion Starter · #10 ·
I personally wouldn't do it. You are walking a very fine line by boring it out that much. You cant sleeve the block like you can ls1s. If something goes wrong after its built and the cylinder walls have deep scars you will have to throw it out and start over and that $$$ spent on machine work was for nothing.

check out these forged 5.3 pistons from Wiseco.

These two have a 3.622" stroke but Wiseco also has some for 4" stroke
3.780 bore 578.95 shipped part# K474M96

3.800 bore 567.29 shipped part# K474M965

i thought about using wiseco pistons but you have to use there rods which are like 700 bucks on top of buying wrist pins for 180. like 1600 in pistons rods and bushing there on something thats crazy. way to much money for me school full time work 20 hours a week. i understand what your saying but i can grab blocks for 150-200 bucks. ive talked to many shops including texas speed and performance and they said its no problem going to a 5.7 its like 119 thousandths. many shops say its perfectly fine.
 

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Bowtie Til I Die
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For a dry sleeve it should be a minimum of .060" thick. So you have to add that into the .118" that you are getting bored out to begin with. Which ends up being .178" that you bore out of a block that it wasn't designed to be done to in the first place. Cylinder wall weakness is increased by doing this and depending on how much material is left after the machine work you may have to resort to wet sleeves instead which are even more expensive. Like i said not optimal by any means. You would be better off getting a 6.0 block by this time with money you would have in machine work. Hell for the money you would have in that machine work you could get a 6 bolt LSX block.
 

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Bowtie Til I Die
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i thought about using wiseco pistons but you have to use there rods which are like 700 bucks on top of buying wrist pins for 180. like 1600 in pistons rods and bushing there on something thats crazy. way to much money for me school full time work 20 hours a week. i understand what your saying but i can grab blocks for 150-200 bucks. ive talked to many shops including texas speed and performance and they said its no problem going to a 5.7 its like 119 thousandths. many shops say its perfectly fine.
HAHA! im enrolled in 18 credit hours and only work 24hrs a week. Your preachin to the choir but I still manage to pull it off slowly. You don't have to use their rods though FYI. Eagle and Scat rods are cheap as hell and ok if your wanting to stay NA
 

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drives a LSX zr2
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Discussion Starter · #13 ·
For a dry sleeve it should be a minimum of .060" thick. So you have to add that into the .118" that you are getting bored out to begin with. Which ends up being .178" that you bore out of a block that it wasn't designed to be done to in the first place. Cylinder wall weakness is increased by doing this and depending on how much material is left after the machine work you may have to resort to wet sleeves instead which are even more expensive. Like i said not optimal by any means. You would be better off getting a 6.0 block by this time with money you would have in machine work. Hell for the money you would have in that machine work you could get a 6 bolt LSX block.
i didnt plan on resleeving the cylinders. 100 bucks and im done. ive only had like 2 people out of a dozen or more tell me its not a good idea. i understand what your saying but im gona take my chances. i appreciate you helping me this much seriously youve helped me out more than anyone on here, i really appreciate it.
 

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Bowtie Til I Die
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I understand what you're saying 5.3 blocks are CHEAP i can get an entire engine for $350 here. I was just explaining to s106banger why sleeving wasn't a good idea on the 5.3 bored to 5.7
 

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i need a paint job
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For a dry sleeve it should be a minimum of .060" thick. So you have to add that into the .118" that you are getting bored out to begin with. Which ends up being .178" that you bore out of a block that it wasn't designed to be done to in the first place. Cylinder wall weakness is increased by doing this and depending on how much material is left after the machine work you may have to resort to wet sleeves instead which are even more expensive. Like i said not optimal by any means. You would be better off getting a 6.0 block by this time with money you would have in machine work. Hell for the money you would have in that machine work you could get a 6 bolt LSX block.

whats the difference between a wet sleeve and a dry sleeve? im in machining at school now and noone has said anything about wet or dry sleeving, but our instructor has said that if you bore into a water jacket you can still sleeve it and it should be fine. i might be looking at this with out the cost of machine work because i dont have to pay for it now, i can just do it myself.
 

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Bowtie Til I Die
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A lot of machinist have different ideas about sleeving blocks but if you were to bore into a water jacket you can't simply use a dry sleeve. Dry sleeves are a lot thinner than wet sleeves. Basically you use dry sleeves to bring a block back to its original bore by ONLY boring out the thickness of the dry sleeve. You need a lot more wall thickness that .06" between you piston and your water jacket and that is were the wet sleeves come into play. with a thicker wall thickness you don't have to worry about the cylinder pressures and the heat cycling splitting the sleeve. Doe that make sense enough? Im going on no sleep here and can't think straight
 

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A 5.3 block can be bored out to 4" bore with no problems at all. I know this because I am a machinist and I just got done boring one out and sonic checking it a few weeks ago. At 4", a 5.3 block will have more cylinder wall thickness than any regular SBC at .060" over. The thrust axis of the block will check out around a consistant .180-.200" and the lowest I saw on the wristpin axis was about .090" on a couple cylinders with it mostly averaging between .100 and .120". I am throwing this engine together with stock low compression 6.0 pistons/rods and a pair of 241 LS1 heads to go into a 2000 2.2 flex fuel truck that I have in storage.
Now, as a disclaimer: before everyone starts voicing their opinions about how much thickness is "enough", know that .080" wristpin axis thickness will stand up to 850hp in a BBC (which has a .5" taller cylinder than LS) and I have seen many >600rwhp .060" SBC blocks last whole seasons in dirt late models. Most SBC blocks have as little as .100" wristpin axis thickness on some of the cylinders with a standard 4" bore.
 

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i need a paint job
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^alright, in school they teach us minimum of .200 for a 500hp engine??? why do they teach us that?

btw ive been looking for that info for a week now..
 

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Realize that cylinders on OEM blocks do not have a uniform thickness around the whole circumfrence. That's why I refer to the "thrust axis" and the "wristpin axis". The thrust side of the cylinder takes the side load from the piston as it travels up in the bore and thus needs to be thicker, while the wristpin sides have no load other than cylinder pressure and ring pressure so they do not need to be as thick.

The .200" you were taught is just a good overall guideline. Kind of like the old .001" clearance per 1" of journal diameter, or the 10psi per 1000 rpm for oil pressure. Those get you in the ballpark, but in the real world things can be just fine beyond those limits. Example: the insane amount of power people are making with stock boosted 6.0L shortblocks (with their hypereutectic pistons, powdered metal cracked cap rods, and cast iron crankshafts). Schools and books will tell you that you will need forged crank, rods, and pistons to make the same power.

That's why I included a disclaimer at the end of my post.. because every time I talk about cylinder wall thickness on a forum people reply with the "well I was told" or "I heard" numbers. It's 100000% dependant on the application. I am using my judgement from what I have personally experienced throughout the past 7 years of doing machine work.
 
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