Perhaps two of the most mind-boggling things to do on a car are build an automatic transmission and degree a camshaft. At the end of the day, it’s just parts that fit together, and you need to follow a process to do it right. Erson Cams wants to show you that degreeing a camshaft isn’t all that difficult, with its latest video tutorial.
Degreeing your camshaft will ensure that your engine is making the most power it can from a valvetrain standpoint. You’ll need a few special, but relatively inexpensive, tools that include a degree wheel, a dial indicator with a magnetic base, and a deck bridge with dial indicator.
Step one is finding top dead center (TDC) for the number one piston. To do this, mount a dial indicator to a deck bridge, mount that on the cylinder deck surface and make sure the indicator is in the center position over the piston. In some instances, the piston can rock in the cylinder, and having the indicator in the center of the piston will limit any change in piston height should the piston rock in one direction or the other.
Now, bolt up the degree wheel and find top dead center, then back the wheel up .050-inch of an inch before top dead center and record the degree at the pointer on the wheel. Roll the wheel though TDC and add .050-inch and record that degree. True top dead center will be the midpoint between the two numbers, so add them up and divide by two to get your TDC.
Next, move the wheel until the mid-point is registered at the pointer, then reset the wheel so zero is at TDC.
The next step is determining the intake centerline, and to do this, get started by removing the deck bridge and installing a set of lifters for the number one cylinder. Then, mount a dial indicator on a magnetic stand on the deck. Install a push rod between the lifter and dial indicator, ensuring the push rod and indicator are lined up straight.
Determining the intake centerline is very similar to finding true TDC. You will find peak lift on the intake valve, then back it off .020 inches, and then go past peak lift and add .020 inches. Adding and subtracting .020-inch will mitigate any measuring inconsistencies caused by different opening and closing profiles that the camshaft may be ground with. Take the two numbers and divide by two. The number should match the number on the cam card.
Should you need to make timing adjustments, you can accomplish that using an adjustable timing set like the one from PBM used on the Motown small-block engine in the video.
To see the cam degreeing technique in action, check out this video from Erson, which includes additional tips on the process.