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Camshaft Break-In Guide - How To Break In That Flat-Tappet Cam

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The engine you spent a month carefully assembling has just fired and is running great while you carefully monitor oil pressure and break in the flat-tappet camshaft. The feeling of euphoria that washed over you when the engine lit for the first time is soon followed by a crushing low. You followed all the proper procedures for breaking in that cam, but something's not right. The engine runs sluggishly and a testdrive reveals a disturbing lack of power. A quick investigation reveals that the cam is dead—suffering from round lobe syndrome. That's about the same time your friends all found someplace else to go, your wife or girlfriend hightailed it to her mother's, and even your dog has suddenly disappeared. You are alone with your dead cam and looking for somebody to blame.

If it's any consolation, we've been there, too. The 400 small-block Chevy budget engine that slouched its way through the May issue ("How To Build a 400ci SBC Torque Monster for $2,500!") lathed 14 of its 16 lobes within minutes of fire-up and left us with a lump of iron that had to be rebuilt a second time with all-new bearings. This led us to pay more attention to the details required to make a flat-tappet camshaft engine live these days, because lubricants are changing faster than Charlie Sheen rants on TMZ. This story is as much about lubricants and what works and what doesn't as it is about camshafts and lifters.

First, we'll go through the basic procedure for how to ensure a flat-tappet camshaft will survive its first 20 minutes of life, since that's when these new parts are most vulnerable. Then we'll get into evaluating a whole new world of lubricants and how it's probably a mistake to buy mom-and-pop oil for your old-school flat-tappet engine in this brave new roller cam world. We'll even break down the latest changes in oil and how those numbers are scarier than getting a registered letter from the IRS.

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