Cam Lift at Top Dead Center.
12-24-2003, 07:34 AM
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Cam Lift at Top Dead Center. My cam came this past Tuesday and I'm going to be putting it in this weekend, piston to valve clearance permitting. I will be measuring the piston to valve clearance by a method suggested on here. You bring the number one piston up to TDC (top dead center) after removing the valve springs for the intake and exhaust valves on this cylinder. You then let the valves drop on the top of the piston and measure the difference between the distance when holding the valve up against the seat and letting the valve hit the piston. After you get this number you then take your cams lift at top dead center and subtract it from the corresponding valve (intake or exhaust).
What is the absolute minimum clearance required for a stock valved motor.
If you know them, please tell me what cam you are running, all specs (icl, lsa, duration at .050 and advertised) and what the lift is at top dead center. If you ordered a cam from thunder racing this will be on your cam doctor sheet or on any other cam measuring device sheet. I need this for comparison reasons. Thanks.
P.S. The cam's final specs ala cam pro are 230.8/235.6 107.1lsa 107.1icl .576/.573.
What is the absolute minimum clearance required for a stock valved motor.
If you know them, please tell me what cam you are running, all specs (icl, lsa, duration at .050 and advertised) and what the lift is at top dead center. If you ordered a cam from thunder racing this will be on your cam doctor sheet or on any other cam measuring device sheet. I need this for comparison reasons. Thanks.
P.S. The cam's final specs ala cam pro are 230.8/235.6 107.1lsa 107.1icl .576/.573.
Last edited by DAPSUPRSLO; 12-24-2003 at 07:38 AM. Reason: Adding information
12-24-2003, 09:29 AM
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Originally Posted by DAPSUPRSLO
My cam came this past Tuesday and I'm going to be putting it in this weekend, piston to valve clearance permitting. I will be measuring the piston to valve clearance by a method suggested on here. You bring the number one piston up to TDC (top dead center) after removing the valve springs for the intake and exhaust valves on this cylinder. You then let the valves drop on the top of the piston and measure the difference between the distance when holding the valve up against the seat and letting the valve hit the piston. After you get this number you then take your cams lift at top dead center and subtract it from the corresponding valve (intake or exhaust).
The valve is not closest to the piston at TDC. You should put a pair of soft checking springs in the heads and check P/V by rolling the engine over slowly, checking the P/V at 10* increments before and after TDC. You can install a drop indicator to the top of the valve to get an actual number. Also, use clay on the top of the piston as a double check and to verify edge of valve to edge of valve relief eyebrow of the piston.
What is the absolute minimum clearance required for a stock valved motor.
.080" intake .100" exhaust...
If you know them, please tell me what cam you are running, all specs (icl, lsa, duration at .050 and advertised) and what the lift is at top dead center. If you ordered a cam from thunder racing this will be on your cam doctor sheet or on any other cam measuring device sheet. I need this for comparison reasons. Thanks.
P.S. The cam's final specs ala cam pro are 230.8/235.6 107.1lsa 107.1icl .576/.573.
P.S. The cam's final specs ala cam pro are 230.8/235.6 107.1lsa 107.1icl .576/.573.
That's one tight LSA... Better be very carefull on the install...
Ed
12-24-2003, 09:42 AM
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Thanks Ed. By the way, I have enjoyed some of the previous posts you have engaged in with 93pony. Good reading!
Is there anywhere locally, i.e. Autozone; Napa; Advanced Auto, that sells soft springs for checking purposes. If not, I am just going to go about it as said previously.
Is there anywhere locally, i.e. Autozone; Napa; Advanced Auto, that sells soft springs for checking purposes. If not, I am just going to go about it as said previously.
12-24-2003, 09:51 AM
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Originally Posted by DAPSUPRSLO
Thanks Ed. By the way, I have enjoyed some of the previous posts you have engaged in with 93pony. Good reading!
Is there anywhere locally, i.e. Autozone; Napa; Advanced Auto, that sells soft springs for checking purposes. If not, I am just going to go about it as said previously.
Is there anywhere locally, i.e. Autozone; Napa; Advanced Auto, that sells soft springs for checking purposes. If not, I am just going to go about it as said previously.
Crane or Comp has them..
Check with a NAPA store that has a machine shop. A local store to me has this kind of stuff...
Be safe and check.. That cam is TIGHT!
Ed
12-24-2003, 10:07 AM
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Just ordered the soft springs from comp. The gentlemen wasn't sure they would work for an ls1 but he said they are very small diameter. Is there a specific soft spring for the ls1 or can it be used with any motor?
12-25-2003, 05:55 PM
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The springs Comp sells will work just fine. I use them all the time on the flowbench, checking PtV,etc.
Good luck with the install!
Oh, and the method Ed described will work very well for your PtV check.
Jason
Good luck with the install!
Oh, and the method Ed described will work very well for your PtV check.
Jason
