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Old Jun 14, 2014 | 12:38 AM
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Default help with ptv

Just wanted to get the help of ls1 tech to make sure I'm reading my digital caliper right I measured my ptv via clay method... i got 0.2 215 in on my intake ... and 0.2 585 in on exhaust, the reason in confused because the three digits to the right of 0.2 are smaller... do I have enough clearance? I know I want to be .080 on exhaust and .050 on intake... btw this is my first cam swap. The specs are 231/239 on 113 LSA with stock 243s on a stock 2001 corvette with btr springs etc etc. Any help would be greatly appreciated and I'll post pictures of the clay later but my phone is dying.
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Old Jun 14, 2014 | 03:47 AM
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Digital calipers I don't trust. How exactly are you measuring the clay with a caliper?
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Old Jun 14, 2014 | 05:48 AM
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Any photos of what you are doing? Also, some digital calipers can be switched to read metric, make sure that hasn't happened.
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Old Jun 14, 2014 | 10:33 AM
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digital caliper
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Old Jun 14, 2014 | 10:37 AM
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Intake clay
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Old Jun 14, 2014 | 10:43 AM
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Exhaust clay
Sorry I had to put these on three different post. I am posting from my phone and it's not wanting to work with me, however back to how I measured. I used a solid ls7 lifter I made , Checker springs, pushrod checker after I found the proper pushrod length, mls headgaskets. I assembled everything together then turned the motor over a few times to get a good impression on the clay. The digital caliper Iam using has a button for metric and inches so I'm very sure it's set to inches. Iam just wondering if iam reading this thing right. Thanks again for all the reply this has been a great learning experience, but I can't wait to get everything back together and on the road again.
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Old Jun 14, 2014 | 10:45 AM
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Originally Posted by 01ssreda4
Digital calipers I don't trust. How exactly are you measuring the clay with a caliper?
Sorry I missed your question, iam take the clay impression off the piston very carefully then slicing them down the middle and using the jaws of the caliper to check the depth.
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Old Jun 14, 2014 | 02:11 PM
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ok i'am almost certain I have this thing figured out. I went online and converted the in to MM and it made more sense to me lol.
so stock clearances are...
intake .050 = 1.27mm
exhaust .080 = 2.04mm

my measurements were
intake 0.2215 in = 5.63mm
exhaust 0.2585 in = 6.57mm

I also did them in a fraction measurement as well only because my caliper does fractions. I feel kind of dumb that I didn't think to measure in MM last night but it was late and I was getting frustrated. I hope this helps someone and please let me know if I have any errors in my readings. I was just overly cautious in this cam due to so many people saying they didn't have the clearance when they installed.
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Old Jun 14, 2014 | 04:19 PM
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So you are saying you have 0.250" (approximately) of PTV? That doesn't seem correct. Did you cleave the clay?
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Old Jun 14, 2014 | 06:46 PM
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Originally Posted by vettenuts
So you are saying you have 0.250" (approximately) of PTV? That doesn't seem correct. Did you cleave the clay?
Iam guessing so, you have to forgive me, this my first time using the digital caliper for something like this. That's why I used the mm measurements I feel like I have a better understanding , and that's another reason I wanted to start this thread bc .250 didn't seem right and wanted to make sure iam not doing something wrong. Thanks.
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Old Jun 15, 2014 | 12:32 AM
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Something isn't right. Are you measuring the thinnest area of the clay?
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Old Jun 15, 2014 | 02:10 AM
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Originally Posted by JakeFusion
Something isn't right. Are you measuring the thinnest area of the clay?
Yes sir iam .... i think iam going to try to measure again just for peace of mind.
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Old Jun 15, 2014 | 11:45 AM
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From: Turnin' Wrenches Infractions: 005
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Originally Posted by igtabg1
Sorry I missed your question, iam take the clay impression off the piston very carefully then slicing them down the middle and using the jaws of the caliper to check the depth.
I see what you're doing now. I had a retard moment there for a second
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