LS1 Engine Piston to Valve Clearance Question
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From: Charlotte NC
LS1 Engine Piston to Valve Clearance Question
Would any of the Engine Building Folks know what is the Largest Intake and Exhaust Cam Lobe Lift you can safely use with new heads milled to 62cc producing approximately 11.18:1 Compression using .040 Thick Cometic Head Gaskets, WITHOUT cutting reliefs in the pistons on a Stock bottom end LS1 ? 
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From: Charlotte NC
I see. I am looking at these Comp Cams Custom Grinds. Would either one of these give me any PTV problems with the head set up I want to use?
Comp Cam 228/232 .589 /.598 112LSA
Comp cam 228/232 .588 /.595 112LSA
Comp Cam 228/232 .589 /.598 112LSA
Comp cam 228/232 .588 /.595 112LSA
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From: Charlotte NC
Racer
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From: Ithaca Michigan
Gonna be close, with anything around .600 lift I'd mock it up and roll it over with some clay in there. When I had Lingenfelter Perf install a .598 .613 lift cam they flycut my pistons. They have a fixture they hook a vacuum to so they could cut em all right there without even pulling the engine apart, very slick unit. Good luck
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From: Charlotte NC
Thanks! I have read that cutting reliefs in the pistons is not a good thing. How is that working out for you?
Gonna be close, with anything around .600 lift I'd mock it up and roll it over with some clay in there. When I had Lingenfelter Perf install a .598 .613 lift cam they flycut my pistons. They have a fixture they hook a vacuum to so they could cut em all right there without even pulling the engine apart, very slick unit. Good luck
Racer
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From: Ithaca Michigan
LPE did my heads and cam and decided to throw my engine on the dyno just to see how my engine would like the "small" cam and they ended up putting ARP rodbolts in and a "good" timing chain so they could twist it to the moon (I told em to go for it!) and it made 554HP at 7200RPM and pulled hard to 8200. Ive made hundreds of passes on this motor running a T-56 in my 2000 Camaro running deep into the 10s at 135. You tend to wring more out of stock motors when they dont cost as much to replace
so yup working out well.
so yup working out well.Corvette Stories
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Brett Foote
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From: At the beach in little Rhody
Remember, maximum lift is when the piston is well down the bore so the maximum lift is not very relavant. The duration at 0.006" will tell you where the valves are actually opening and closing. To illustrate, I used to run a Crane cam 216/224 at 0.050". I now have a Comp cam, 224/228 at 0.050". One might immediately think that the Comp would have less clearance. However, the Crane ramps were much slower and the actual overlap was much larger then the Comp because they were opening the valves earlier and closing them later.
With a cam in the mid 220's (Comp XER) and the heads milled you will be near minimums. Hard to tell without measuring though. Between the two cams you have listed I don't see any indication they would be very different.
With a cam in the mid 220's (Comp XER) and the heads milled you will be near minimums. Hard to tell without measuring though. Between the two cams you have listed I don't see any indication they would be very different.
Le Mans Master
Joined: Dec 2006
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From: Phoenix Arizona
LPE did my heads and cam and decided to throw my engine on the dyno just to see how my engine would like the "small" cam and they ended up putting ARP rodbolts in and a "good" timing chain so they could twist it to the moon (I told em to go for it!) and it made 554HP at 7200RPM and pulled hard to 8200. Ive made hundreds of passes on this motor running a T-56 in my 2000 Camaro running deep into the 10s at 135. You tend to wring more out of stock motors when they dont cost as much to replace so yup working out well.
so yup working out well.
now i am tempted to do same thing 
whats the torque curve look like?
Last edited by rustyguns; Jan 5, 2010 at 09:41 PM.
