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Hello, had a change of events with my project. Lifter bores are trashed in my block, cost for repair is pretty expensive compared to this alternative. Looking for a piston that matches my build. Im having a hard time finding one that keeps my CR to just under 11:1. Its a 6.0 with stock ls1 rods and crank, machine shop recommended to keep it under 4.030 bore.
Plan to run a 100 shot with it. Called Wiseco, they recommended a forged piston set to me with a -9.0cc dome but when i did the math calculation for the CR, I keep getting 11.6 which is way more than I want.
the piston they recommended is the k0044x1 which works with my stock wrist pin but doesnt add up for CR for me (according to the calculator). Any other recommendations besides google? I keep finding correct size pistons but the wrist pin is wrong. Is it cheaper to just go with a forged internal rotating assembly instead of using my stock crank and rods?
btw... Heads are ported 243s: 67cc
If you are stuck on using stock rods, have you played around with different head gasket thickness along with the selected piston?
a thicker gasket may lower it enough. (It won’t be much but you did not state what your target compression was)
Curious why your ok with 10.9:1 but not 11.6:1 is way more than you want?
Summit has a really nice set of forged pistons/rods for a good price but I dont see 4.020 They do have 4.005 Many people have bored Lq4/lq9 blocks to 4.065 without issues, maybe your block is different.
Also what does the lifter bores being trashed have to do with the cylinder bore? Im guessing your using a different block with good lifter bores but the cylinder walls are rough?
Last edited by Ls7colorado; Feb 11, 2021 at 07:38 AM.
Thanks for all the replies... To answer all the questions:
a: goal CR is 10.7-10.9: 1 ( unless someone can show me or show me how anything over is still safe on pump gas and work for nitrous in the near future
b: plan to setup for a 100-150 shot on the bottle
c: stock 5.7 block lifter bores are causing loss of oil pressure. Shop said i can reuse my crank and rods that have already been worked on and swap over to a 6.0 but the wrist pin size and rod length are whats limiting my selection. Found another set of wisecos that are for 880.00 but looked today at a set of summit pro ls series that im going to ask my builder about. He seemed hesitant about them (pushing for wiseco, mahle, or diamond= $$$) so im gonna wait and hear back from him.
243 heads ported by TSP. Machine shop measured the combustion chamber at 67cc
well Idk, their supposed to be a reputable shop im going to for the build. Im checking my paperwork I wrote from TSP, they said the chamber was 63.2 cc. Gonna check back tomorrow with him on the heads and go from there. They said they were going to clean them up since there was a few nicks in the head surface (from me handling them probably...). But wouldnt that lower the CC if they are going to mill just a little bit on the heads?
a: goal CR is 10.7-10.9: 1 ( unless someone can show me or show me how anything over is still safe on pump gas and work for nitrous in the near future
.
Stock ls2 is 11:1 and people have been running 150 shot with ease since 2005 lol.
Most nitrous Ls's that I see being built with forged stuff have close to 12:1 or even more unless your stuck using pump gas?
Maybe im wrong but Ive never heard of anyone lowering compression to run nitrous?
Also if they have to MILL the heads it would raise compression, but if they only do a cleanup it shouldnt be enough to really make a difference.
Thanks for all the replies... To answer all the questions:
a: goal CR is 10.7-10.9: 1 ( unless someone can show me or show me how anything over is still safe on pump gas and work for nitrous in the near future
b: plan to setup for a 100-150 shot on the bottle
c: stock 5.7 block lifter bores are causing loss of oil pressure. Shop said i can reuse my crank and rods that have already been worked on and swap over to a 6.0 but the wrist pin size and rod length are whats limiting my selection. Found another set of wisecos that are for 880.00 but looked today at a set of summit pro ls series that im going to ask my builder about. He seemed hesitant about them (pushing for wiseco, mahle, or diamond= $$$) so im gonna wait and hear back from him.
According to them, they said they noticed too much play im the lifters lateral movement in the bore. They said they measured it to be outside its clearances, more than likely happened from me not making sure there was enough assembly lube on the lifters prior to its first start it up and it wore out the bore. (Dumbass move on my part... First build and unfortunate expensive lesson). They didnt look that bad when I felt them but he said its not within tolerances.
I hate being in the middle between 2 places, but they seem to think TSP gave the wrong measurement/"if they wrote you an invoice showing that amount then something isnt right." For the heads. They said they could mill my heads down for me to meet the need CR but Idk, something seems odd about it and there is no other reputable builder around here id take it to. Gonna look at some options and might just count my loses with this one at this point, sell my rotating assembly and get a short block through ATK or something.
Gonna look at some options and might just count my loses with this one at this point, sell my rotating assembly and get a short block through ATK or something.
According to them, they said they noticed too much play im the lifters lateral movement in the bore. They said they measured it to be outside its clearances, more than likely happened from me not making sure there was enough assembly lube on the lifters prior to its first start it up and it wore out the bore. (Dumbass move on my part... First build and unfortunate expensive lesson). They didnt look that bad when I felt them but he said its not within tolerances.
I hate being in the middle between 2 places, but they seem to think TSP gave the wrong measurement/"if they wrote you an invoice showing that amount then something isnt right." For the heads. They said they could mill my heads down for me to meet the need CR but Idk, something seems odd about it and there is no other reputable builder around here id take it to. Gonna look at some options and might just count my loses with this one at this point, sell my rotating assembly and get a short block through ATK or something.
did they ask to keep your “bad” block?
let me tell you this, oil will get to the lifter bores very quickly so “not having enough” lube on it is not a likely cause. I’d wager that the bores are fine.
According to them, they said they noticed too much play im the lifters lateral movement in the bore. They said they measured it to be outside its clearances, more than likely happened from me not making sure there was enough assembly lube on the lifters prior to its first start it up and it wore out the bore. (Dumbass move on my part... First build and unfortunate expensive lesson). They didnt look that bad when I felt them but he said its not within tolerances.
I hate being in the middle between 2 places, but they seem to think TSP gave the wrong measurement/"if they wrote you an invoice showing that amount then something isnt right." For the heads. They said they could mill my heads down for me to meet the need CR but Idk, something seems odd about it and there is no other reputable builder around here id take it to. Gonna look at some options and might just count my loses with this one at this point, sell my rotating assembly and get a short block through ATK or something.
TSP advertise 58-63cc They probably mill them to ensure flatness. So at minum they would be 63cc and if you had additionall milling down you could get them down to 58cc https://www.texas-speed.com/p-4-prc-...-outright.aspx
let me tell you this, oil will get to the lifter bores very quickly so “not having enough” lube on it is not a likely cause. I’d wager that the bores are fine.
no I have it, only thing they have there is my rods and crank to use for the 6.0 they are supposed to setup for me. Ive posted about trying different oil pumps and replacing new oil feed system components (pickup tube, ring, new bar bell, checking the front for the press in plug). Only work they did was measure clearances, honed the cyli der walls and did a line hone for my mains. They also put new cam bearings in whick I checked the positions for them, none were backing out or anything. Install i did my self (preliminary block cleaning/blow out, chased threads, installed all plugs as needed since block was hot tanked, then proceeded with the install of everything up to it running im my car.
Would start with about 50psi, hot it would drop down to 12psi. Under load of anything seemed to make it worse. Tried a high volume and a high pressure pump. The lifters bore dont look bad, but i found minor shqvings in the oil when i drai ed it to check for excessive metal.This is my first build so a little bit of metal to me may be alot to someone else. I contacted livernois, might send it up there to get it checked over and see what they can do about the bores if they do need bored and sleeved. I personally didn't want to put a iron block in the car but if I'm going to I want a decent shot of nitrous for it, or have a lighter aluminum block with a stroker n/a build or a small shot of nitrous. So this is where im at. Would be nice to find a good ls2 block or a cheap ls1 short block for sale, id definitely bite on it if they didnt cost so much but hey, its the name of the game. Gotta pay to play
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What pistons for 6.0 build 
