The Chevrolet Main Bearing Set is the metal components that are between the crankshaft and the engine block. The main bearing sets are made to exacting tolerances so the correct clearance of the crankshaft as it moves is not only supported without binding, but lubricated inside of your Chevrolet engine.
The typical mounting of the main bearing sets to the engine block is with a cap held in place by 2 bolts. If your engine is of a racing variety, it could have a 4 bolt main, but they are rare. What is important is the clearance the bearings have with the crankshaft.
Because each crankshaft is slightly different, the bearings used in each engine are not only identified by model and displacement of the engine, but also the clearance. This is why the Chevrolet owner can not just walk into an auto parts store and say I need a main bearing set. Before that is done, the crankshaft will have to be measured.
If the wrong Chevrolet main bearing set is installed in your engine, the crankshaft will freeze up in a short allotment of time when the clearance is too little. If the clearance is too large then the crankshaft will move vertically in the engine causing damage to other components.
To ensure the right main bearing set is installed the crankshaft will have to be measured with a micrometer first. It is possible for the owner of the Chevrolet to do this but most of the time a technician at a machine shop is more qualified and trained for this delicate procedure. This is one component on your vehicle you don't want to get wrong.
When referencing the Chevrolet Main Bearings the topic are the bearings that hold the crankshaft in place with the engine block. If there is a need for these contact points to be replaced in your engine the correct part would then be the Chevrolet main bearing sets.
Just like the connecting rod bearings, the main bearings clearance on the crankshaft will have to be known on your Chevrolet so not only will the crankshaft be able to spin with as little friction as possible but lubrication of these components will be possible. This measuring of the main bearings is done with a micrometer. This is a precise set of measurements in which all of the places the main bearing set are to be located in the engine have to be known and recorded.
The most common place to conduct this type of measurement is at an engine machine shop but an owner of a Chevrolet can perform this function if they know just how to make this type of measurement and have the correct instrument to do so. The precision in this type of measurement has to be within a thousandth of an inch so the correct size of bearing can be fitted to your engine.
The reasoning behind the need for such precision when ordering and installing the correct main bearing set in your engine is so the crankshaft will be held to the right level of firmness in the engine block. If the bearings installed are too large, slop will developed in the interior of your engine causing damage not only to the crankshaft but also the connecting rods and the block itself from the excessive movement of the crankshaft as it spins. This is one procedure you really want to get right for the longevity of your Chevrolet.