How to Degree a Camshaft

From Competition Cams, here is some information and education about degreeing a cam.

There are several ways to degree a cam but Gunter Automotive recommends 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. Gunter Automotive recommends positioning 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. Install the camshaft and timing set. Make sure that the timing marks on both the cam gear and the crank gear are aligned per the cam installation instructions.

STEP 2. An example is installing a cam at 102 degrees intake centerline to achieve 4 degrees of advance. After checking the cam card specs, install the rocker arms, lifters and pushrods. 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 rolled easily with your fingers.

STEP 3. Fashion a rigid pointer out of an old coat hanger and attached to the engine block.

Rigid pointer to mark degrees

STEP 4. With your degree wheel installed on the harmonic balancer, you are now 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 were closed, then adjust your pointer to Zero (or T.D.C.) on the degree wheel.

STEP 6. Turn the crankshaft opposite the motor 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.

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

STEP 7. Remove the piston stop and rotate the crankshaft to the mid-point of the two marks. This point is T.D.C. for cylinder #1.
Adjust your degree wheel was 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 7A. A Dial Indicator may be used to determine TDC, instead of Steps 4-7 above.

STEP 8. Attach the dial indicator to the dial indicator mount. Set the tip to contact the retainer of the #1 intake valve. Check to make sure that the indicator plunger is parallel to the valve stem. ** note that 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 reach maximum lift. Maximum lift is attained when the dial indicator changes direction. At this point reset your dial indicator to zero

STEP 10. Rotate the engine in the opposite direction until the dial indicator reads .100". Turn the engine in the normal direction until the indicator read .050" before maximum lift. Record the number on the degree wheel.

STEP 11. After that reading, continue to rotate the motor in its normal direction until the indicator gors 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 and it should confirm your settings.

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