GM 10048682 Crankshaft

It is advisable to inspect the end play when an overhaul of the crankshaft is to be done by mounting a dial indicator such that the stem is parallel to the crankshaft and touching one of the crank throws. Rotate the crankshaft to the rear and set the dial indicator at zero, rotate the crankshaft forward and read a value of the end play. If it go beyond the said limit, then check the thrust surfaces of wear; if there is none, then new main bearings may rectify the problem. Incase one cannot find a dial indicator, use feeler gauges, pull the crankshaft towards the front and ease the gauges in between the crankshaft and the thrust main bearing to get the clearance. Remove the main bearing cap bolts an eighth turn at the time until they could be pulled out by hand and the caps are often numbered from front to rear, thus these marks are useful for the proper positioning of the cap bolts. If unlabeled they can be marked by the use of a stamping die or a center punch. As mentioned earlier most of the caps are marked with a cast-in arrow symbol that points to the front direction. Tap the caps lightly with a soft-face hammer to provide the required clearance and you can easily lift the caps off using the bolts and ensure that the bearing inserts are not dropped when doing so. Lastly, remove the crankshaft from the engine and it is recommended to do it with help, then put back the bearing caps to their positions on the head of the engine, tighten the bolts with fingers only.