how to check piston to valve clearance?

DarkoStoj

Founding Member

Sep 4, 2002

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39

Detroit

Apr 18, 2005

#1

• Apr 18, 2005

• #1

I bought a 2nd had rebuilt 351w shortblock, and I want to run a larger cam. I know the piston is a flat top with 4 2cc valve releifs. I am running 2.02/1.6 world windsor sr. heads, and I want to make sure the cam I order will work without hitting the pistons. What is the best way about figuring out whats the biggest lift cam I can run w/o hitting pistons?

 

LMan

Founding Member

Aug 10, 2002

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Mom's basement

Apr 18, 2005

#2

• Apr 18, 2005

• #2

http://www.fordmuscle.com/fundamentals/pistontovalve/index.shtml

btw, the 'biggest' cam isnt always the 'best' cam or the 'fastest' cam

 

DarkoStoj

Founding Member

Sep 4, 2002

929

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39

Detroit

Apr 18, 2005

#3

• Apr 18, 2005

• #3

LMan said:

http://www.fordmuscle.com/fundamentals/pistontovalve/index.shtml

btw, the 'biggest' cam isnt always the 'best' cam or the 'fastest' cam

Click to expand...

well I plan on going ~.6's of lift, and I just want to make sure I won't have clearance problems

 

69Rcode_Mach1

Active Member

Apr 20, 2004

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Salt Lake City, Utah

Apr 18, 2005

#4

• Apr 18, 2005

• #4

You can always use the clay method it is very easy. Just install the cam, line up the timing marks with crank, install a piston into the block, coat the valve reliefs with some oil (So the clay won't stickand ruin accuracy of reading), put two small pieces of clay in the valve reliefs, put the cylinder head on, now if you have a hydraulic cam insert solid lifters into the corresponding bores(a regular hydraulic lifter will collapse so you must use or make a solid lifter, I made two with JB weld), put the cylinder head on with rocker arms, then crank the engine over a couple of times, and then take everything off along with the clay CAREFULLY and measure it with a micrometer and there you go you have your clearance. Or you can also do it with a magnetic base and dial indicator to measure valve travel.

 

brianj5600

Active Member

Sep 19, 2003

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Middle TN

Apr 18, 2005

#5

• Apr 18, 2005

• #5

How much .050 duration? I like to use soft springs and a dial indicator. You can do it w/o removing heads, unless they are too close.

 

Hack

15 Year Member

Mar 23, 2004

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Minneapolis

Apr 18, 2005

#6

• Apr 18, 2005

• #6

how to check valve clearance

Here's another viewpoint.

http://www.rehermorrison.com/techTalk/41.htm

 

brianj5600

Active Member

Sep 19, 2003

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39

Middle TN

Apr 18, 2005

#7

• Apr 18, 2005

• #7

I wonder if their .025 to.30 extra with the real springs holds true for a mortal .600 cam and dual spring vs the monster cams and springs they use? The method they describe for radial clearance will only work wth domed pistons. Clay might be needed for radil clearance on a flattop.

 

B

bnickel

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Aug 21, 2002

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lubbock, texas

Apr 18, 2005

#8

• Apr 18, 2005

• #8

i've said it before and i'll say it again, the lift you are talking about with flat tops will have clearance issues. mid .500's is about max and that's questionable even depending on the duration @.050