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piston to valve clearance question ---> need help

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Old 12-13-2008 | 05:52 PM
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Default piston to valve clearance question ---> need help

hello guys

actually i just got my 215 TFS 64cc for my forged bottom ls1 5.7L
my cam shaft : 235/239 .621/.624 114 LSA
stroke : 3.622"
piston valve relife : -2 ----> diamond flat top
gasket thikness " .040" ----> cometic

and i'm thinking to mill my 64cc cylinder heads to spec. 60cc chamber volume
so that's will raise compression ratio from 10.63:1 up to 11.18:1
and i think this increasment shouldn't be a problem with tuning in 95 gas pump

so the only thing that i'm really worry about it is the piston to valve clearance .
so guys did any body run somthing like that b4 ???

any suggestions will be appreciated
thanks

Last edited by alharbi; 12-13-2008 at 06:25 PM.
Old 12-13-2008 | 05:56 PM
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How deep are your valve reliefs? They should give you plenty of clearance?
Old 12-13-2008 | 06:00 PM
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Originally Posted by Monroe98SS
How deep are your valve reliefs? They should give you plenty of clearance?
it's -2 as shown up in my post
Old 12-13-2008 | 06:09 PM
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Originally Posted by alharbi
it's -2 as shown up in my post
Thats probably a .125+ relief?
Old 12-13-2008 | 06:19 PM
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I have a similar setup.
232/236 cam, -2cc diamond pistons, 57cc 5.3L heads, .040 gaskets.
I measured PTVC and wound up with close the minumum safe clearances of .080/.100.

You should be OK, but be sure to measure just in case.
Old 12-13-2008 | 06:21 PM
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Originally Posted by Monroe98SS
Thats probably a .125+ relief?
ohh really
if i may ask , how did you know that ?

so i thik i shouldn't worry about that
coz as i know that The intake valve must have at least .100? clearance to the piston and at least .120? clearance on the exhaust valve.

am i right ?
Old 12-13-2008 | 06:27 PM
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Originally Posted by alharbi
ohh really
if i may ask , how did you know that ?

so i thik i shouldn't worry about that
coz as i know that The intake valve must have at least .100? clearance to the piston and at least .120? clearance on the exhaust valve.

am i right ?

2cc is that size on most pistons, if you look at the manufactuers spec it tells you the depth. For the diamond flat tops its .165 inatke/.107 exhaust

.080 intake/.100 exhaust is the minimum clearances you are looking for.
Old 12-13-2008 | 06:32 PM
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should i feel alright now ?
i think i already did

any way , thank you guys
appreciate it




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