Thread: Cam Help!

Tweet

Agree with Glenn. If the cam is used, it's best future use is as a door stop.

The CWC stands for Campbell Wyatt and Cannon, the foundry that cast the cam blank. The blanks are then sold to various OEM and aftermarket manufacturers to be finish-ground into a useable product.

When manufactured, a flat tappet camshaft lobe will have an angle to it as you hold the cam out in front of you and look along its length. The taller side of a lobe will be several thousandths of an inch taller than the shorter side of the lobe. It is this tall side that engages the convex surface of the lifter to spin the lifter in its bore. The lobe therefore does not scuff on the lifter face, but rather engages the lifter face and more or less stays at that particular point of the lifter face to walk the lifter around in its bore. Camshafts and lifters "wear in" to a particular pattern, just as piston rings do in the cylinder bore. If you remove the cam from one motor and install it in another motor, there is little chance that the relationship of each and every lobe will be exactly the same as it was when the cam and lifters were broken in in the previous motor and the majority of the time, the cam/lifters will fail.

Sometimes a guy will get lucky, using a used cam in another motor with new lifters, but most of the time, this is a fool's game. Cams are relatively inexpensive, so the best bet is to begin with a new cam and new lifters and let them wear in together. If you use a dial caliper or micrometer and measure from the heel to the nose of each lobe, you will be able to determine if the cam is reuseable or not. For instance, if one side of the lobe measures 1.250" and the other side of the lobe measures 1.254", then the angle is still there from one side of the lobe to the other and the cam can probably be reused with new lifters. If it measures, for instance, 1.250" on one edge and 1.250" or 1.251" on the other edge, then the cam is worn out and should be used only as a door stop.

The previous explanation applies only to flat tappet cams and lifters. Roller tappet cams and lifters are a whole different animal and can be re-used motor to motor indefinitely as long as they remain structurally sound. Holding a roller cam out in front of you in the same manner as described above will reveal that there is no difference in dimensions from one side of the cam lobe to the other. They are cut "square" because the lifter does not have to spin in its bore. Matter of fact, that would be catastrophic. The roller tappet wheel must be restricted to one position so that the wheel of the lifter rolls on the cam lobe. To turn the lifter wheel one way or the other would scuff both the lobe and the lifter wheel, sort of like a screeching tire on the pavement when a car "pushes" going into a turn (steering wheel is turned one way or the other and the car is still pushing straight ahead).