Mark Houlahan
Brand Manager, Mustang Monthly
October 12, 2010
Photos By: Steve Baur

Like most things we're not familiar with, many look at degreeing a camshaft as some sort of black magic voodoo that only the most expensive of engine builders in brightly lit "clean rooms" know how to perform. We can understand that ourselves because we were, at one point, on the same side of the fence looking in. We too wondered what the heck that big wheel on the front of an engine with all the tiny numbers on it meant when reading our car magazines. What do the numbers mean and why is the guy rotating it back and forth and what's the gauge on the top of the engine for? Sound familiar? Of course it does, and frankly, like asking for directions, the last thing a car guy is going to do is go to his other car guy pals and ask how to degree a camshaft for fear of having his man card revoked. No worries here, as we're about to go through the process, step by step, on this 331ci stroker that we tested at Horsepower by Hedrick in Jacksonville, Florida.

So why do you want to degree your camshaft during a cam swap or engine build anyway? There are several reasons why you'd want to take the time to do so, and honestly it's a fairly easy and quick procedure after you get the hang of it.

First and foremost, when you're building an engine or even just swapping a camshaft, you're working against a stack of tolerances. We've all seen the specs for an engine and they are never an absolute, but more of a "window" if you will, of what's OK. Engine blueprinting, which is a whole other story, is when you take those clearances and ensure they're even across the board (to put the definition loosely). If these machining tolerances were exact from engine to engine, then there'd be no need to degree a cam short of just wanting to advance or retard it on purpose. You'd simply bolt it in "straight up" as they say. But since engines are not that exact, it's a good idea to bolt up the degree wheel and make sure the cam you have is machined like the spec card says, and that any other engine parts, such as the timing chain, cam dowel pin, and crank keyway don't change what the cam specs should be. Essentially, you are verifying the valve opening and closing events are where they should be according to the cam manufacturer's specs.

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Degreeing your cam can also aid in engine performance by placing the cam's powerband where you use it most. When you see cam specs in a catalog or on a website, the powerband is often shown in a chart or simply listed as "2,500-6,000 rpm." Advancing or retarding the cam can move this powerband lower or higher in the rpm range as needed.

Advancing the cam will bring the power and torque in sooner at lower speeds, but you could see some loss of high rpm power and torque. When retarding the cam, you'll see the opposite, with low-speed power taking a hit to give you that higher rpm charge. Adjusting the timing of the camshaft is easily done on most Ford engines with an adjustable timing chain setup. The crank gear is machined with multiple keyway slots in it, and is marked with the amount of advance or retard, usually in two-degree increments, at each keyway.

Once you've determined the correction amount needed, or the amount of advance or retard you wish to run your new cam at, it's simply a matter of relocating the crank gear to the correct numbered keyway and lining up the cam and crank gears indexing marks. See just how simple the whole process is on this 331 stroker we're building.

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