When the engines we rebuild go through the rebuilding process, one of the most important procedures is to remachine the crankshaft. If the crankshaft is machined properly, it may have closer tolerances and be more precise than when it was new. Some companies may use a good crankshaft over, we won’t take the chance, read how we rebuild the crankshaft in every rebuilt engine we sell.

Most crankshafts can be repaired by machining. Specifically, crankshafts are ground (also referred to as turned) using a crankshaft grinding machine. Because the machining process takes off additional material from the rod and main journals, under-size bearings are required for installation. The most typical under-sized are .010, .020, and .030 of an inch. Even severely damaged crankshafts may be repaired by welding.

Grinding the crankshaft is a relatively straight-forward process. The crankshaft nose is placed into the head stock chuck and the crankshaft flange (in some cases the crankshaft seal surface) is secured in the tail stock chuck. At which point the main journals can be ground. The rod journals are ground after the machine is set to the proper stroke and after the counter weights are set. After the crankshaft is ground, the oil holes are chamfered and deburred. Then, the crankshaft is polished with a fine grit belt to achieve a satisfactory micro finish.

If you have a worn/damaged crankshaft, it is important to bring it in to the automotive machine shop to be inspected. This will allow the automotive machinists an opportunity to properly inspect your crankshaft and determine the extent of the damage. While the majority of cranks only require a typical undersize grind, others may need to be straightened, or simply chamfered and polished. On ocassion a weld may be needed to bring the crankshaft journals, thrust, and/or the crankshaft seal surfaces back to OEM specifications.

For reverse rotation marine applications, the crankshaft is reversed in the machine and then ground. This helps to achieve a better finish for reverse rotation motors. The goal is to extend bearing life and make the break in period as smooth as possible.

The idea is to make sure every sub-assembly is rebuilt to factory specifications or better. By improving certain areas and upgrading some of the components that affect gas mileage, GotEngines.com supplies a better rebuilt engine, or rebuilt motor, whatever you call it. With this in mind, we have built a lot of confidence in our customers over the years. For all rebuilt engine needs, Call us @ 1-888-344-8044.