Piston to head clearence??
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From: St. Charles, MO
Piston to head clearence?? Went to install my heads on my new short-block. Was going to check piston to valve clearence and put the head on with no gasket. Try to turn the motor over and the pistons are hitting the heads. Used a set of calipers to roughly check how far the piston is coming out of the block, and it was around 25 thousands. My question is what is the minium piston to head clearence? Should the pistons be coming that far out of the block? The gaskets I have are 41 thousnds crushed. Do they make a thicker head gasket for these motors? Any help appreciated.
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From: Texas and Qatar
You have to rock the piston back and forth in the bore at TDC and get the highest reading, and the lowest reading and halfway between that will be the number you need. So if one reading was .018" and the other was .010", your piston is .014" outta the bore. Stock is usually .007-.008" The highest I've run has been .018" with GM .055" thick gaskets, with the .041" Fel-Pro gaskets I like 0-.007" minimum.
You can also use a straight edge metal ruler and feeler guages to measure how far its out. Measure Front to back on the piston as close to the middle as you can.
You can also use a straight edge metal ruler and feeler guages to measure how far its out. Measure Front to back on the piston as close to the middle as you can.
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From: Texas and Qatar
I'd recommend at least .060" head gaskets if its .025" outta the block. What pistons are they and what compression height?
SCE (scegaskets.com) makes a copper .062" head gasket, and IIRC the M.L.S. GM head gasket is .060" compressed, it may have been the graphite - don't remember now.
SCE (scegaskets.com) makes a copper .062" head gasket, and IIRC the M.L.S. GM head gasket is .060" compressed, it may have been the graphite - don't remember now.
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Thanks Joseph for the help. This is a MTI 427 so I am going to wait and call them on Monday before I do anything. These are Diamond pistons and I am not sure hat the compression height is (final compression is supposed to be 12:1). How are you supposed to check piston to vavle clearence when you cant even turn the motor over with the head on. If I run the thicker head gasket is there a dis-advantage? Will the motor live cause its gonna get ran? Sorry for all the questions just worried cause I have a fortune invested in this set-up, so it has to be right.
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From: St. Charles, MO
Originally Posted by Pro Stock John
.025 are you sure?
LOL @ David's comments I almost fell out of my chair.
LOL @ David's comments I almost fell out of my chair.
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From: KS
Sounds a little high but would work with a .060 compressed gasket as stated above. I'm ready to see that thing run.
Forgot to add yes, check p-to-v clearance with a gasket so you can and remember what the difference between the gaskets is when you get the thicker one.
Chris
Forgot to add yes, check p-to-v clearance with a gasket so you can and remember what the difference between the gaskets is when you get the thicker one.
Chris