Degreeing a Camshaft

There are several ways to degree a cam, but I will explain the Intake Centerline method. This degreeing method is easy to comprehend and works for a variety of engine applications. The process starts by positioning the center of the #1 intake lobe with Top Dead Center (TDC) of the #1 piston. The Intake Centerline Method still requires accuracy to be correct, but it's somewhat forgiving. You need to position the dial indicator on the #1 intake spring retainer because lift measurements will include any deflection that may occur in the pushrod and rocker arm. This makes the degreeing process as accurate as possible in relation to what's going on inside the engine.

Timing mark alignment

STEP 1. First the camshaft and timing set are installed. Make sure that the timing marks on both the cam gear and the crank gear are aligned per the cam installation instructions.

STEP 2. Check your cam card for the suggested intake centerline. After checking the cam card specs, install the rocker arms, lifters and pushrods. Then set valve lash on the #1 piston. On the #1 intake lobe adjust the intake lash to zero, being careful not to preload the lifter. After checking lash adjust the #1 exhaust lash to zero and check that both pushrods roll easily with your fingers.

STEP 3. Then fashion a rigid pointer out of an old coat hanger and attach it to the engine block.

Pointer and degree wheel

STEP 4. The degree wheel is installed on the harmonic balancer. And you are ready to rotate the engine.

STEP 5. Rotate the crank to get the #1 piston at T.D.C. and check to ensure both the intake and exhaust valves are closed, then adjust your pointer to Zero (or T.D.C.) on the degree wheel.

STEP 6. Then turn the crankshaft opposite the engine rotation approximately 15-20 degrees. The piston should be lowered enough to allow the T.D.C. stop to be installed in the spark plug hole. Screw in the piston stop until it touches the piston. Continue to turn the engine the same direction until the piston comes back up and touches the piston stop.

Then mark (with a felt tipped pen) the number on the degree wheel that the pointer was on. Again rotate the engine in the other direction (engine rotation) until the piston comes back up and touches the piston stop. Again mark the number from the pointer with your pen.

STEP 7. Then the piston stop is removed and you rotate the crankshaft to the mid-point of the two marks. This point is T.D.C. for cylinder #1.
Your degree wheel is then adjusted to read O degrees at the pointer. You cannot rotate the crankshaft to do this so unbolt the degree wheel from the dampner and realign it to read 0 degrees at the pointer. You are now ready to locate the lobe centerline relative to T.D.C.

Dial indicator on #1 intake valve

STEP 8. Attach the dial indicator to the dial indicator mount. The tip will be set to contact the retainer of the #1 intake valve. Check to make sure that the indicator plunger is parallel to the valve stem. Any variance in the angle will produce geometric errors in the lift readings.

STEP 9. Rotate your engine in the normal direction of rotation until you've reached maximum lift. Maximum lift is attained when the dial indicator changes direction. At this point your dial indicator should be reset to zero

STEP 10. Then rotate the engine in the opposite direction until the dial indicator reads .100". Then the engine is turned in the normal direction until the indicator reads .050" before maximum lift. Then record the number on the degree wheel.

STEP 11. After that reading you continue to rotate the engine in its normal direction until the indicator goes past its zero setting to .050" on the closing side of maximum lift. Again record the reading.

STEP 12. Add the two numbers and divide by two. This number is the location of maximum lift of the intake lobe relative to the crank and piston (a.k.a. the intake centerline). Check your cam spec card to confirm your settings.

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