Piston to Valve clearance problem with this cam??
03-31-2004, 08:04 PM
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Piston to Valve clearance problem with this cam?? I'm running an LQ4 6.0 with a whipple charger. Currently in the middle of rebuilding the motor. The build as of right now consist of...
Pistons-diamond dished
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Rods-stock
Crank-stock
comp cam lifters
Thunder racing pushrods-stock length
ARP rod bolts,main studs,head studs
Cam-?????
Looking at a 224/230 581/.588 114lsa running 4 degrees advanced
could I be looking at posibble piston to valve clearance problems running that cam advanced?
Pistons-diamond dished
Heads-stock
Rods-stock
Crank-stock
comp cam lifters
Thunder racing pushrods-stock length
ARP rod bolts,main studs,head studs
Cam-?????
Looking at a 224/230 581/.588 114lsa running 4 degrees advanced
could I be looking at posibble piston to valve clearance problems running that cam advanced?
04-01-2004, 08:41 AM
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most cams have advance ground into them.
is that 4 degrees additional?
Put some clay on the piston, a old head gasket (just use a few head bolts snug), a quick assembly and you will know for sure. you will have to use a soft valve spring in place of the permanent one so you don't bleed the lifter. rotate the engine 2 times, pull the head and measure the clay thickness where the valve flattened it.
is that 4 degrees additional?
Put some clay on the piston, a old head gasket (just use a few head bolts snug), a quick assembly and you will know for sure. you will have to use a soft valve spring in place of the permanent one so you don't bleed the lifter. rotate the engine 2 times, pull the head and measure the clay thickness where the valve flattened it.
04-01-2004, 06:56 PM
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Originally Posted by mr. Jones
most cams have advance ground into them.
is that 4 degrees additional?
Put some clay on the piston, a old head gasket (just use a few head bolts snug), a quick assembly and you will know for sure. you will have to use a soft valve spring in place of the permanent one so you don't bleed the lifter. rotate the engine 2 times, pull the head and measure the clay thickness where the valve flattened it.
is that 4 degrees additional?
Put some clay on the piston, a old head gasket (just use a few head bolts snug), a quick assembly and you will know for sure. you will have to use a soft valve spring in place of the permanent one so you don't bleed the lifter. rotate the engine 2 times, pull the head and measure the clay thickness where the valve flattened it.
Will the clay definatley have marks in it, or only if there is a clearance issue??
Also what measurements am I looking to get? number wise??
04-02-2004, 07:02 AM
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if you put a flat piece of clay about 1/4" thick on the piston where the valve relief is cut (if the piston has reliefs on top and bottom put the clay on the bottom one) assemble, rotate disassemble you will see where the valve has flattened the clay. you can cut the clay in half where it is flattened by the valve and measure (use calipers) the thickness.
you can use art clay or play dough.
I don't remember the minimum required thickness
you will have to check this, the cam manufacturer can provide this info. I think the numbers are 0.080 intake min.,
0.100 exhaust min. more is better, but confirm the numbers.
I agree the cam lift should be fine, but if you check you will know. Over rev. ex. miss a gear and good enough will bit you.
you can use art clay or play dough.
I don't remember the minimum required thickness
you will have to check this, the cam manufacturer can provide this info. I think the numbers are 0.080 intake min.,
0.100 exhaust min. more is better, but confirm the numbers.
I agree the cam lift should be fine, but if you check you will know. Over rev. ex. miss a gear and good enough will bit you.
04-02-2004, 11:25 AM
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Ive got a much larger cam (almost 600 lift) and stock pistons with +2 advance with cut heads and have no issues with p/v clearance. You should be fine, espically with the dished pistons. Unless your heads are cut an extreme amount, you should be fine. JP
