Summit PRO LS Pistons Clearances
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Summit PRO LS Pistons Clearances I just purchased the Summit Pro LS Pistons for my LS3 Build along with Summit (Scat) I Beams (6.125-.927), Summit Gas Ported Rings and King HP Bearings.
This engine in going into a 2009 avalanche. I just rebuilt the 6L80 with upgraded clutches along with Transgo and Sonnax parts. Using ZL1 Converter.
This will be an NA build for a Daily Driver. 20-30k a year. Running a TSP 216/228-113 .600 Lift Cam.
I'm trying to come thru what the PTW Clearance should be as I've seen 2 different charts from Summit.
One Chart talks to PRO LS pistons should be set at .004 and I've seen another that talks to different usages for forged pistons and what their clearances are.
I'm looking for no pistons slap and long life so I don't want it too loose or too tight and having ring/wall wear.
Does .003 sound like a good compromise and if I ever want to slap an LSA on top and run 8# of boost would that be an issue?
This engine in going into a 2009 avalanche. I just rebuilt the 6L80 with upgraded clutches along with Transgo and Sonnax parts. Using ZL1 Converter.
This will be an NA build for a Daily Driver. 20-30k a year. Running a TSP 216/228-113 .600 Lift Cam.
I'm trying to come thru what the PTW Clearance should be as I've seen 2 different charts from Summit.
One Chart talks to PRO LS pistons should be set at .004 and I've seen another that talks to different usages for forged pistons and what their clearances are.
I'm looking for no pistons slap and long life so I don't want it too loose or too tight and having ring/wall wear.
Does .003 sound like a good compromise and if I ever want to slap an LSA on top and run 8# of boost would that be an issue?
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On The Tree
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I did. They just stated what was on the documents. Didn’t give me a minimal clearance and so as don’t go over .004 or you’ll get cold slap. Said .003 should be fine. Just want to make sure I won’t see ring wear with being too tight or bore issues.
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Thank you. It won’t be an all out performance build and don’t plan to run above 6500. Just looking for longevity with some performance.
I have a 3.5 Ecoboost tuned on 93/e85. Love the torque of the turbos. With this ls3 being my daily driver I may opt later to add an LSA for the low speed torque and don’t want to go too tight as the 2618 will expend.
I have a 3.5 Ecoboost tuned on 93/e85. Love the torque of the turbos. With this ls3 being my daily driver I may opt later to add an LSA for the low speed torque and don’t want to go too tight as the 2618 will expend.
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@Carp,
Here's some info from our piston designer Brian Nutter.
The good news is our Pro LS piston skirt profile has been refined over the years to reduce taper and cam to prevent rock. Our general recommendation in the instructions for all Pro LS pistons is .004" piston to wall clearance. With the 1,000s of Pro LS pistons we've sold we've had two known cases of pistons seizing at .004". One case was overheating. The other was an incorrect cam with too much overlap and a turbo with too little turbine flow. Our piston skirts have approximately .0006" worth of coating per side to take up additional clearance and net less than .004". Going with .0035" should be doable with a torque plate hone. An aluminum block might get by with .003" to the gauge point. LS’s from the factory with cast pistons slap when cold. This is because the engines need to be loose enough to start at -30*F and run in Death Valley at the other extreme. So while our pistons may not be completely silent, they are quieter than most other forged pistons on the market.
Here's some info from our piston designer Brian Nutter.
The good news is our Pro LS piston skirt profile has been refined over the years to reduce taper and cam to prevent rock. Our general recommendation in the instructions for all Pro LS pistons is .004" piston to wall clearance. With the 1,000s of Pro LS pistons we've sold we've had two known cases of pistons seizing at .004". One case was overheating. The other was an incorrect cam with too much overlap and a turbo with too little turbine flow. Our piston skirts have approximately .0006" worth of coating per side to take up additional clearance and net less than .004". Going with .0035" should be doable with a torque plate hone. An aluminum block might get by with .003" to the gauge point. LS’s from the factory with cast pistons slap when cold. This is because the engines need to be loose enough to start at -30*F and run in Death Valley at the other extreme. So while our pistons may not be completely silent, they are quieter than most other forged pistons on the market.
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Thanks Summit! That was the unknown for me was how much growth it could having being an aluminum block. I plan to have it torque plate honed when the pistons come in. Just wanted to get it as tight as possible without have excessive wear from it. Sounds like .003-.0035 should be fine.
would bearing clearances below work for the ls3.
main -.0015-.0025
rod - .0020-.0025
would bearing clearances below work for the ls3.
main -.0015-.0025
rod - .0020-.0025
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