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PTV Clearance Question

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Old Feb 21, 2011 | 04:34 PM
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I am getting ready to put a 235/239 comp cam in my 2006 LS2, I wasn't planning on taking the heads off and wondered if there was a way to check my PTV with my heads on?
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Old Feb 21, 2011 | 06:15 PM
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Yes, you will need checker springs, adjustable push rod, dial indicator and a degree wheel. I would compress the lifter and let it bleed for a good ten minutes. Then with zero lash measure accurately with the degree wheel.
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Old Feb 22, 2011 | 03:19 PM
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Thanks for the help!
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Old Feb 23, 2011 | 09:36 AM
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Ok, last question.

Is there software or something I can plug my cam numbers into to see if I need to go to these lengths to check the PTV clearance?

I have an LS2 with stock block/heads but want to put in my 235/239 .620/.621 lift 112 + 4 cam.
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Old Feb 23, 2011 | 09:42 AM
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it is always recommended to measure your piston to valve clearance, especially when installing a large camshaft. That being said, we have fit larger camshafts on stock block/stock head LS2s. That cam is somewhat similar to our Tsunami camshaft which will fit in a stock motor as long as its installed correctly.
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Old Feb 23, 2011 | 02:58 PM
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Thanks for the info John, my installer told me I had a baby cam lol
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Old Feb 23, 2011 | 04:22 PM
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Originally Posted by Neumonic2002
Thanks for the info John, my installer told me I had a baby cam lol
Look for another installer.
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Old Feb 24, 2011 | 11:09 AM
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Originally Posted by Neumonic2002
Thanks for the info John, my installer told me I had a baby cam lol
Lol, yeah that is definitely not a baby cam. Good luck with the install!
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Old Feb 26, 2011 | 10:02 PM
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You can also use a dial indicator and check Z height
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Old Mar 22, 2011 | 09:02 AM
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Just to put my 2 cents worth for future reference...

Stock LS1 block, stock 243 heads, stock LS1 compressed head gasket, 54-456-11 comp cam (219/227 @.050, .607/.614, 112 + 5...installed at 106.5). Exhaust PTV is fine. Intake isn't even in the ballpark. About .035. It really makes me wonder where some of these specs and clearances are coming from and why the huge differences we see from engine to engine, cam to cam.
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Old Mar 22, 2011 | 11:13 AM
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Originally Posted by 94Conv
You can also use a dial indicator and check Z height
That is not good enough. I did that and found 3/8" clearance before the valve bottomed out inside the relief.

Then I verified with clay and found out the intake valve was barely missing the edge of the relief ~.07".



Use clay.
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