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How to Check Cam Timing - A Few Degrees Cooler
We Show You Why And How To Check Cam Timing, Degree Your Cam, And Impress Your Buddies!
If there's an elusive animal in the amateur performance world, then degreeing a cam is it. Few know how to do it, and even fewer understand the benefits.
If you're following our 347 build from the previous issue, then you already know we're assembling a cost-effective, home-built stroker for our SSP coupe. Not long after the short-block was finished, Editor Smith strolled into our well-equipped air-conditioned shop to check up on his sophomore associate editor and the progression of the engine build. He asked if I checked for piston-to-valve clearance (which I hadn't yet), and I replied with a casual, "That's next." His next question caused a lump to creep up my throat: "Did you degree the cam?"
Since I didn't know how or why to degree a cam, it was a great opportunity to not only teach myself (read: call someone with knowledge and experience), but to also relay my newfound knowledge to you, our loyal readers. You can share this knowledge with your buddies and increase your cool factor a degree or two.
So, why degree your camshaft? Well, in bygone days of big "three-quarter race cams," engine builders relied on one-off grinds by less-than-precise cam-grinding equipment. Therefore, you had to index your cam to the proper degree-meaning the intake cam lobe would be in perfect relation to the location of the piston on the intake stroke.
In other words, it's a way to maximize camshaft-timing advance beyond what the camshaft manufacturer includes in the profile. This allows air to begin filling the cylinder earlier, causing better cylinder filling, and allowing more torque production.
Now you know why to degree your cam, but what benefits will it provide?
"Degreeing your cam may add a few horsepower," says Ron Robart of Fox Lake Power Products. "And it can move the power band to a different portion of the rpm range." In other words, advancing the cam in our 347 may give us a little better power curve through the mid-range, but we would lose a little up top.
The bottom line remains the same-degreeing your cam sounds cool, looks cool, and can help you make more power. We're in.