Checking Rod Clearances & Hanging Pistons - Tech - It's In The Measurements - CHP Step By Step

Bearings have to withstand brutal punishment, from buildup of engine-oil crud to extreme heat and pressure. Not surprisingly, a bearing will fail when it's been subjected to enough of these naturally occurring problems, as well as human-induced ones such as an improper install or a false reading in your measurements. It only makes sense to pay close attention to your bearings, and the extent to which you take into account rod-bearing clearances will dramatically affect the longevity of your engine.

You see, an engine bearing's main job is to support the film of oil between the bearing itself and the friction surface. It's crucial not to overlook this; it is this typeof carelessness that could induce catastrophic engine failure and, yes, shouting words your mother wouldn't approve of. Taking it a step further, proper rod preparation also involves the marriage between the rod, the pin, and the piston, which all require proper lubrication and setting of the retaining rings. Do it right and you'll keep friction to a minimum and prevent your pin from binding up-which ultimately means mo' power.

When measuring for rod-bearing clearances, you have your choice of using a bore gauge, an inside micrometer, or a snap gauge. Obviously, the most accurate method-but not always the most affordable-is with a properly calibrated bore gauge. However, depending on feel, an inside micrometer or a snap gauge can also be perfectly acceptable for a budget build. A plastic gauge, on the other hand, is not recommended for measuring rod-bearing clearances-or anything else.

We spent the afternoon at Quarter Mile Performance and learned how to avoid some of the more common mistakes, and we got valuable tips on how to get the most out of your bearings, in nine easy steps.