valve clearance question?
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valve clearance question? hey gang, running a very mild setup for some street fun, 02 Z28, wanna run the 02+ LS6 cam and 243 LS6 heads but........ i wanna change to 1.85 rockers for some increased lift on the cam, will i experience any PTV clearance issues??? yes i know i will be changing the springs to accomodate the increased lift, but would like to run 1.85's to make the cam breathe harder but stay stealthy so to speak, so will there be clearance issues?
dont want a diff cam........
dont want a diff cam........
Last edited by 01ssreda4; May 24, 2011 at 01:40 AM.
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From: Turnin' Wrenches Infractions: 005
Buy a sleeper cam and keep your stock rockers. I know thats not what you want to hear but I think it would cost the same and gain more then your plan.......
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i know that with the 1.85's the LS6 cams lift numbers are at around .600/.600, no plans of milling the heads at all so i will be keeping the 64cc chambers, was just hoping this isnt too much lift on stock LS6 heads to cause any PTV clearance issues
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bad noise or just a bit more than stock? any ways to quiet valvetrain noise? will i have any problems with the faster valve acceleration?
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From: Turnin' Wrenches Infractions: 005
Planning more hp around one "can't live without" mod like 1.85 rockers is dumb. Put together a combo that works well together and puts out good hp per dollar spent. Why are you so hell bent on an LS6 cam? Why are you so sure that the 1.85 rockers will make the cam better? How much hp do you think the rockers will add? And at the expense of what, a noisy valve-train? Anything you have that you don't need can be sold to fund parts you do need to make your combo work better. There is a reason why almost nobody on this site runs 1.85 rockers.
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Planning more hp around one "can't live without" mod like 1.85 rockers is dumb. Put together a combo that works well together and puts out good hp per dollar spent. Why are you so hell bent on an LS6 cam? Why are you so sure that the 1.85 rockers will make the cam better? How much hp do you think the rockers will add? And at the expense of what, a noisy valve-train? Anything you have that you don't need can be sold to fund parts you do need to make your combo work better. There is a reason why almost nobody on this site runs 1.85 rockers.
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From: Turnin' Wrenches Infractions: 005
Dude I'm not trying to bust your *****, I'm just trying to help you. For how much the rockers cost ($400), you can buy a better stock idling cam then an LS6, such as a custom grind or there are several shelf grinds that would make great power. The only reason people would run the LS6 cam is to keep yellow factory .550 springs, but with the rockers you have defeated that purpose. Stock rockers are plenty good for most applications, there is no reason to dump them off. I think stock 243s and something like a CheaTR cam would be a nice stealthy combo.
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i didnt necessarily have a particular reason for this set-up other than trying to think outside the box, was thinking of a set-up no-one else was running instead of falling into the same line of set-ups that most seem to follow, i have done and seen many of the set-ups that are common was just trying to come up with something not as common, i'm definitely not interested in a noisy valvetrain and if that is what i would get going with the 1.85's then its an idea i dont want, i was unaware that the 1.85's were so loud
the reason for the LS6 cam and head plan is i can get them really cheap, so another idea i wouldnt mind throwing out there is.........LS6 H/C and milling the heads to a smaller combustion chamber for a compression bump, now my same question applies here even though i have a feeling it wouldnt be a problem, if i mill the stock 243's (using the stock LS6 valvetrain), how far can i mill (or chamber cc size) without having any clearance issues??? would like to get as much compression as possible
the reason for the LS6 cam and head plan is i can get them really cheap, so another idea i wouldnt mind throwing out there is.........LS6 H/C and milling the heads to a smaller combustion chamber for a compression bump, now my same question applies here even though i have a feeling it wouldnt be a problem, if i mill the stock 243's (using the stock LS6 valvetrain), how far can i mill (or chamber cc size) without having any clearance issues??? would like to get as much compression as possible
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From: Turnin' Wrenches Infractions: 005
You should be able to mill pretty good with a stock cam. Im not as up to date on that kind of stuff as some here so listen to the experienced guys advice. If you want to check for yourself you could get the ****, dummy the heads up and check for ptv clearance. Then mill the heads down while keeping your safe distance based on your measurement. Say you had .050 over X safe distance in valve clearance. You know you could mill .035 and still be .015 on the positive side of your set safe distance. One sure fire way to know whats going on 
Generally a rule of thumb is about .35 or so is a safe amount to mill before you have to worry about intake alignment and things of that nature.
Generally a rule of thumb is about .35 or so is a safe amount to mill before you have to worry about intake alignment and things of that nature. Joined: Aug 2007
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From: Turnin' Wrenches Infractions: 005
There is a simple formula to figure it up, I just dont know it off the top of my head. I think .010 is a CC. So 30 would be about 3CCs. I think the LS6 heads are 64cc stock. LS1 heads are 67cc. 3cc is a compression point I believe.
Last edited by 01ssreda4; May 25, 2011 at 12:10 PM.
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yes the LS6 are 64cc, i always see companies on here offering 59cc LS6 style heads but i am assuming they arent using the longer valves that the stockers use so therefore they have more clearance to play with
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From: Turnin' Wrenches Infractions: 005
Not all 243s had the hollow valves. I think the GTO and truck versions had regular valves. I think only the Z06 got the good valves. 799 is an identical casting and it got regular valves as well. I have even heard of some truck 5.3s getting a 243 on one side and a 799 on the other. 5.3 truck heads the 762 (or whatever it is) casting got even smaller chambers, like 61cc. Keep that in mind when you are comparing "59cc" heads....they may be the 5.3 version.
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the heads and cam are 02 ZO6 so i will have the longer hollow valves and i think milling them for some compression is the way i will go, also going to get them ported, so i am trying to max out the stock 243 i guess, which isnt a bad head to do that with
