Muscle Mustangs & Fast FordsHow To Engine
Degree a Camshaft Like a Pro
You ordered a custom camshaft to squeeze every last ounce of power from your engine build. But, as the professional engine builders explain, “If you don’t degree in the cam, you’re leaving power on the table.” Why?
Top engine builders and camshaft designers sweat over fractions of a degree, but there’s a long train of parts between the top of the piston and the lobe of the cam. Tolerance stack-ups mean the valves could be opening much earlier or later than planned. A timing set with different alignment options allows the engine builder to compensate for these tolerance stack-ups and get the valves moving on time. This measurement process is called “degreeing the cam.”
There are plenty of resources on how to degree a cam, but as all the top engine builders will tell you: the devil is in the details. A professional showed us a few tricks they’ve learned to make the camshaft degreeing process as accurate as possible.
1. You ordered a top-secret grind from the greatest camshaft wizard for latest engine build—but, if you don’t degree in the cam properly, you’re leaving power on the table.
2. When degreeing in a camshaft, reducing friction is key to getting accurate, repeatable results. We mocked up this Ford Performance Parts BOSS engine block for the cam degreeing process by installing only three main bearings to support the crank.
3. To further reduce friction and avoid damaging the piston rings, we wrapped a layer of masking tape around the ring lands of the piston to take up the piston-to-wall slop as well as protect the cylinder wall. Only using one piston and rod on the crank further reduces friction.
4. With only one piston and rod installed, turning the degree wheel is much easier, which leads to repeatable measurements. To further increase accuracy, we used a large degree wheel and a dial indicator to measure top-dead-center on the number one cylinder.
5. We used this handy lobe lift dial indicator that eliminates any slop and friction that a lifter might introduce. It has ends for both flat- and roller-tappet cams, and fits Ford and, um, “other” brands.
6. Compare your measurements to the specs on the cam card. Even though our camshaft is ground on a 116-degree intake centerline, with the timing set installed “straight up,” all the tolerance stack-ups resulted in a measured center line of 117.5-degrees—or advanced 1.5 degrees. We can now decide how to clock the timing set to dial in the desired camshaft alignment to get the most power from this combination.