Ckecking PTV clearance with clay
Thread Starter
Joined: Apr 2004
Posts: 430
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From: West Palm Beach, FL
Thread Starter
Joined: Apr 2004
Posts: 430
Likes: 0
From: West Palm Beach, FL
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Actually, it is very accurate if you use the proper procedure and you don't even have to remove the heads. This is what I was going to recommend, BUT you already had your heads and everything else off. You actually start @ 15 degrees BTDC and measure the allowable clearance between the piston and valve as it drops. Start off with broad range, like rotate engine and check every 5 degrees, and then dial it in from there until you find the maximum. This is with a dial indicator above the valve with checker springs.
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Verdad Gallardo Thread Starter
Joined: Apr 2004
Posts: 430
Likes: 0
From: West Palm Beach, FL
Actually, it is very accurate if you use the proper procedure and you don't even have to remove the heads. This is what I was going to recommend, BUT you already had your heads and everything else off. You actually start @ 15 degrees BTDC and measure the allowable clearance between the piston and valve as it drops. Start off with broad range, like rotate engine and check every 5 degrees, and then dial it in from there until you find the maximum. This is with a dial indicator above the valve with checker springs.
I did it every 2 degrees starting at 20 before through 20 after TDC on the exhaust stroke. This is much more accurate. Clay can get distorted and provides inaccurate measurements. It is good as a confirmation of measured values. The only thing that isn't taken into account when you use dial indicator is flex of the valve train so it will be a bit conservative which is what you want.
I did it every 2 degrees starting at 20 before through 20 after TDC on the exhaust stroke. This is much more accurate. Clay can get distorted and provides inaccurate measurements. It is good as a confirmation of measured values. The only thing that isn't taken into account when you use dial indicator is flex of the valve train so it will be a bit conservative which is what you want.
