didn't check valve clearance - problem?
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Racer
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didn't check valve clearance - problem?
I'm almost ready to start up my refreshed LT-1 with a new original spec LT-1 cam. Although its a '72, I have 70 spec domed pistons. I also went with a thinner head gasket .015 - the old one was .039. I was able to turn the crank by hand and had no issues spinning it...but I'm thinking I should have checked my valve clearance. Am I worrying too much or will I be OK?
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Unless anything else is weird, you should be OK. The cam is OEM spec...not a Crane or Comp special with tighter LSA? That would decrease intake clearance. If you aevanced the heck out if it it could cause issues too..but still not likely.
Is block decked? How much total quench do you have?
Either way, unless you have different valves, heads or pistons, you should be OK.
BTW- that's a sweet cam that responds well to some 1.6 rockers
JIM
Is block decked? How much total quench do you have?
Either way, unless you have different valves, heads or pistons, you should be OK.
BTW- that's a sweet cam that responds well to some 1.6 rockers
JIM
Thread Starter
Racer
Joined: Aug 2000
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Originally Posted by 427Hotrod
Either way, unless you have different valves, heads or pistons, you should be OK.
BTW- that's a sweet cam that responds well to some 1.6 rockers
JIM
Thanks, but I do have different pistons...Maybe I should have provided some more info. For '72, the stock LT-1 had flat top pistons. My '72 has the '70 LT-1 pistons which are domed...but everything else is stock.
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Joined: Jan 2000
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From: Corsicana, Tx
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That's fine, as long as they have the stock dome shape and you haven't kicked valve size over the 2.02/1.60 stuff.
Lift doesn't cause much problems with PV clearance. The piston is going down as it approaches max lift on intake side. Valves and pistons aren't even close. On the exhaust stroke it's the same deal..max lift is when piston is down at the bottom of cylinder.
What gets you is the I-C/L and E-CL and how fast the valves open. That's why LSA and duration will cause more issues than lift.
You should be OK. Is engine in car already? I'm assuming yes?
One cheap and dirty thing you can do is take a piece of solder and stick it through the spark plug hole and align it with the valve. Slowly roll motor over and allow the solder to be "pinched" by the valve and piston. It's very soft and won't hurt anything. The tightest places will be 10-15* BTDC and 10-15* ATDC. Then pull the solder out and measure its thickness. You might find that it doesn't even *catch* it..in that case you have LOTS of clearance.
JIM
Lift doesn't cause much problems with PV clearance. The piston is going down as it approaches max lift on intake side. Valves and pistons aren't even close. On the exhaust stroke it's the same deal..max lift is when piston is down at the bottom of cylinder.
What gets you is the I-C/L and E-CL and how fast the valves open. That's why LSA and duration will cause more issues than lift.
You should be OK. Is engine in car already? I'm assuming yes?
One cheap and dirty thing you can do is take a piece of solder and stick it through the spark plug hole and align it with the valve. Slowly roll motor over and allow the solder to be "pinched" by the valve and piston. It's very soft and won't hurt anything. The tightest places will be 10-15* BTDC and 10-15* ATDC. Then pull the solder out and measure its thickness. You might find that it doesn't even *catch* it..in that case you have LOTS of clearance.
JIM
