most accurate way to check P-V clearance
03-23-2005, 10:04 PM
#1
most accurate way to check P-V clearance i plan on doing heads and cam soon, i need to know the best way to do this, a professional way. i have been reading but mostly just hear people ask if something will fit but nothing about how to actually check. please let me know, or direct me to where i can find more info. when i searched i saw mostly claying it, which i will not do.
read somethign about a gauge and soft spring, didnt have much on it just something brief, this sounds like a better way.
read somethign about a gauge and soft spring, didnt have much on it just something brief, this sounds like a better way.
03-23-2005, 10:42 PM
#2
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Originally Posted by WS6FirebirdTA00
when i searched i saw mostly claying it, which i will not do.
If you do the other method you're talking about, that's with the piston at TDC. You'll always contact the piston when you do it like that, so that really tells you nothing. The only way to have a noninterference valvetrain is to have deep valve reliefs... which stock pistons have none.
03-23-2005, 10:56 PM
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LOL Clay what a joke. You are going to have to get a dial indecator and a magnet that has an arm for the indecator. You will also need test spings. If you set it up right you can get to the .001 and know your P/V. Call tsp and ask trever how it is done it is hard to exsplane in writing.
Clay is not even close to telling you your P/C.
Clay is not even close to telling you your P/C.
03-23-2005, 11:09 PM
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Clay will tell you whether your hitting the valves though, right? Does P-V clearance increase or decrease hot/cold?
I'm curious as well cause I will be putting some milled 5.3L heads on my car ina few weeks and I was planning on using clay on the pistons, slap the heads on, hand turn crank, pull heads off, and look to see if anything was hitting/ coming close.
Is there a better / easier way? I don't care whether I have .010 clearance or .040 as long is it doesn't make contact and I have some cushion.
I'm curious as well cause I will be putting some milled 5.3L heads on my car ina few weeks and I was planning on using clay on the pistons, slap the heads on, hand turn crank, pull heads off, and look to see if anything was hitting/ coming close.
Is there a better / easier way? I don't care whether I have .010 clearance or .040 as long is it doesn't make contact and I have some cushion.
03-24-2005, 12:21 AM
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I agree most accurate way, which is what was asked for in the post, is to setup a dial indictor and measure. Clay is very good, but not the most accurate!
Charlie
Charlie
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03-24-2005, 01:50 PM
#8
clay is very good, as long as you use good modeling clay which will not expand. Just take a mic to the clay afterwards and it will be acurate within a couple of thousandths. True that the dial indicator and test spring method is accurate within the thousandth, but you then have to find exactly where the P to V is closest. It could be anywhere between 4 to 12 degrees BTDC and ATDC. How accurate the dial indicator measurement is will depend on how accurately you can find the angle where P to V is closest.
-Tony
-Tony
