COMP Cams Camshaft Installation and Degreeing Procedure - Manual (Page 8)

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COMP Cams®
3406 Democrat Rd.
Memphis, TN 38118
Phone: (901) 795-2400 Fax: (901) 366-1807
www.compcams.com
Part #145
Revised 5/4/12
permanently and add the difference to the piston to valve clearance. Install a sufficient number
of head bolts to secure the head in place while you are rotating the engine. Install the pushrods,
lifters and rocker arms on the cylinder you have prepared for the clearance check.
4. Adjust the rocker arms to their suggested clearance. If the camshaft you are checking uses
hydraulic lifters, you must temporarily use solid lifters in their place. Hydraulic lifters bleed
down and would provide a false measurement. Once the hydraulic lifters are replaced with
solid lifters, adjust the lash to “zero.” Be sure not to pre-load the valve spring. Be sure to
reinstall the hydraulic lifters before starting the engine.
5. Now turn the engine over by hand in the normal direction of rotation. Be sure to rotate the
engine over two times. This will be one complete revolution of the camshaft and assure you of
an accurate reading on both the intake and exhaust. Remove the cylinder head from the block.
Do this gently, so the clay is not disturbed. It may be stuck to the valves or combustion
chamber, so be careful.
6. With a razor or sharp knife, slice the clay cleanly, lengthwise through the depression and peel
half of it off the piston. The clay’s thickness in the thinnest area will represent the minimum
piston to valve clearance.
7. To accurately check the thickness, use a set of dial calipers. The clay can also be measured
close enough with a thin steel rule.
Camshaft Degreeing Instructions
The purpose of degreeing a camshaft is to ensure that it is phased correctly with the crankshaft. Some
factors that may cause improper positioning are:
Cam or crank gear marked incorrectly
Incorrectly machined cam or crank gear keyways
Mis-indexed cam keyway or dowel pin
Improper machining of camshaft or crankshaft
Accumulation of machine tolerances
The important factor to remember is that camshaft position is extremely important for the engine to
operate at maximum efficiency. COMP Cams® offers all the equipment needed to properly degree in a
camshaft, which includes the following:
COMP Part # Qty. Description
4909 1
1” Dial Indicator
4758 2 Checking Springs
4795 1 14mm x 1.25 Piston Stop Bolt
4790 1 Degree Wheel
4902 1 Cam Fixture @ Valve
4794 1 Degree Wheel Pointer
190DVD 1 Cam Degree DVD