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 main bearing caps hold the crankshaft in place, and their proper torque establishes the correct positioning of the crankshaft within the engine block.

When the main bearing caps are torqued to the manufacturer's specifications, they secure the crankshaft and create the necessary clearance for it to rotate smoothly while also allowing for the proper measurement of endplay. Checking endplay before this step would not provide an accurate reading since the crankshaft may not be correctly positioned or secured, leading to inconsistent results.

Endplay is the axial movement of the crankshaft, and it is crucial for engine operation to ensure that this measurement falls within specified tolerances. If the crankshaft is not properly aligned and tightened, it could affect the engine's performance and longevity. Therefore, verifying crankshaft endplay after the main bearing caps are torqued is essential for proper engine assembly.