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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:
1. Cam or crank gear marked incorrectly.
2. Incorrectly machined cam or crank gear keyways.
3. Misindexed cam keyway or dowel pin.
4. Improper machining of camshaft or crankshaft.
5. Accumulation of machine tolerances.
The important factor to remember is that camshaft position or phasing to the engine is extremely important for the engine to operate at maximum efficiency.

Equipment needed to properly "degree" in a camshaft is Available at COMP Cams and is as follows:
1. Degree Wheel
2. A rigid pointer that can be attached to the block
3. A dial indicator to accurately measure cam lift.
Note: Refer to your spec card for maximum lift and check your dial Indicator to be sure it has sufficient range to measure the full cam lift.
4. Either a magnetic or attachable base to affix the dial indicator.
5. A Top Dead Center piston stop.
6. A solid lifter to fit your engine. Engines that have non-adjustable pushrod length checker to accommodate that engine.
7. A means to attach the degree wheel to the crankshaft.

A "Cam Degreeing Kit" is available, Comp Cams (part # 4796) (fig. A)A

The intake Centerline Method There are several accepted ways to degree a camshaft. At COMP Cams, we feel the Intake Centerline Method is the Easiest and most accurate. This method of cam degreeing is very practical and indifferent to design characteristics. It simply involves positioning the center, or point of maximum lift of the #1 intake lobe with top Dead center of the #1 piston. The intake Centerline Method still requires accuracy to be correct but it is somewhat more forgiving. Once you have degreed a camshaft using this method, you will be surprised at its ease. We also rec- ommend, positioning the dial indicator on the #1 intake 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 actually goes on inside the engine.




Time to Go to Work

Step 1: The camshaft and timing set have been installed. Make sure that the timing marks on both the cam gear and crank gear are aligned properly per the cam installation instructions. Use chalk or similar marker to better define the marks.

Step 2: For example, we have our cam card and it suggests we install the cam on 106 degree intake centerline. Install all the rock- er arms and pushrods in the engine as normal. On #1 intake lobe, install the solid lifter in place of the hydraulic lifter, if a solid lifter or roller cam is being checked, use the respective lifter. Adjust the #1 intake lash to exactly zero. Do not pre-load on the lifter. Next, adjust the #1 exhaust lash to zero. You should be able to turn both pushrods with your fingers easily.

Step 3: Attach your COMP Cams pointer (part #4194) to the block. Many people will make a pointer out of some sort of rigid, yet manageable wire. A stiff coat hanger wire works well (fig. B). B

Step 4: Attach the degree wheel to the balance and install the assembly on the crankshaft. There are several ways to attach the degree wheel to the crankshaft. In our example, the degree wheel is mounted to the balancer. The crank may be rotated from either the from or from the flywheel end. Obviously, if the engine is in the car, you must rotate from the front. Remember, the greater the leverage, the smoother the crank rotation, thus more accuracy. NEVER use the starter to turn the engine while degreeing the cam.

Step 5: Before installing the piston stop, rotate the crankshaft to get the #1 piston in approximate T.D.C. position with both the intake and exhaust valves closed. This can be a rough guess, but it can save you from mak- ing a mistake later. Adjust your pointer to zero or T.D.C. on the degree wheel.

Step 6. Turn the crankshaft opposite the engine rotation approximately 15-20 degrees. This will lower the position 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, (fig. C).C

Continue to turn the engine in the same direc- tion until the piston comes back up and touch- es the piston stop. Mark the degree wheel with a pen or pencil on the number the pointer is on (fig. D.),D

Turn the engine in the other direc- tion, same as engine rotation, until the pis- ton comes back up and touches the piston stop. Make a mark on the number the pointer is on (fig. E).E


Step 7: Remove the piston stop after marking the two points on your degree wheel. Rotate the crankshaft to the midpoint of the two marks. This point is T.D.C. for cylin- der #1. Without rotating the crankshaft, adjust the degree wheel to read 0 degrees at the pointer (fig. F).F You are now ready to locate the intake lobe centerline relative to T.D.C. If you are not absolutely sure that your 0 degree mark is set at T.D.C., repeat this procedure. This step is critical to proper cam align- ment.

Step 8: Attach the dial indicator to the dial indicator mount. Position the dial indicator mount so the tip will contact the retainer of the #1 intake valve (fig. G).G It is important that the indicator plunger be parallel to the valve stem. Any variance in the angle of the indicator will introduce geometric errors into the lift readings.

Step 9: Rotate the engine in the normal direction of crankshaft rotation until you reach maximum lift. The dial indicator will change direction at the point of maximum lift. At this point, set the dial to zero (fig H).H

Step 10: Back the engine up (opposite normal rotation) until the indicator reads .100". Turn the engine back in the normal direction of rotation until the dial indicator reads .050" before maximum lift. Record the degree wheel reading.

Step 11. Continue to rotate the engine over in its normal direction of rotation until the indicator goes past zero to .050" on the closing side of maximum lift. Again, record the degree wheel reading.

Step 12: Add the 2 numbers together and divide by 2. That num- ber will be the location of maximum life of the intake lobe in rela- tion to the crank and piston. This is the intake centerline. For example: The first degree wheel reading was 96 degrees. The sec- ond reading was 116 degrees. These 2 numbers (96 + 116) added together will be 212. 212 divided by 2 will equal 106. Your actual intake centerline is 106 degrees. Reference back to your cam spec card and we see that the recommended intake centerline for your camshaft is 106 degrees. Everything is where it should be.

In the event that your camshaft did not degree in as per manu- facturer’s specs, it will be necessary to either advance (move ahead) or retard (move back) the cam to meet suggested intake centerline. Depending on the engine application, there are several different suggested methods for advancing or retarding the camshaft.

One common method is by use of a crank gear with multiple keyways-each one being at a slightly different relationship to the gear teeth. A 2nd method is to use offset bushings that fit on the cam pin and in the cam gear. The offset will advance or retard the cam depending on how the bushing is placed on the cam pin. Another method is by offset keys that fit into the crank gear key way. A more elaborate system uses an adjustable timing gear. Contact COMP cams or your local COMP Cams dealer for the method best suited to your application.

NOTE: When degreeing a cam, remember to look at the degree wheel as a full 360 degrees no matter how the degree wheel you’re using is marked. Many degree wheels are marked in 90 degree or 180 degree increments. On wheels that are marked in 90 degree increments, keep in mind that you must continue to count the number of degrees past 90 degrees. Be sure all readings are taken from Top Dead Center.

Keep in mind that to advance the cam, you must lower the intake centerline. For example, if our cam has a lobe separation of 110 degrees, the cam is "straight up" when the intake centerline is 110 degrees. Moving the centerline to 106 degrees advances the cam 4 degrees. If we change the centerline to 112 degrees, this would be 2 degrees retarded.