When is the best time to check for crankshaft endplay?

The best time to check for crankshaft endplay is after torquing the main bearing caps. This is because the endplay, which is the axial movement of the crankshaft, can only be accurately measured once the main bearings are secured in place. When the caps are torqued to the specified tension, they provide the necessary support and adjustment for the crankshaft, ensuring that any measurement taken reflects the true operational state of the engine rather than the unanchored position of the crankshaft.

Checking for endplay at this point allows the technician to confirm that there is neither excessive nor insufficient play, which could lead to operational issues such as premature wear or crankshaft failure. At earlier stages, such as before installing the caps or during initial assembly, the crankshaft may not be fully constrained, giving a misleading indication of endplay. Thus, waiting until the caps are properly torqued ensures the integrity of the measurement.