To use Plastigage, you should follow these steps:
Clean the bearing surface and the crankshaft journal where the bearing will be installed. Make sure the surfaces are free from oil, dirt, and debris.
Cut a piece of Plastigage to the length of the bearing surface. The Plastigage should be placed lengthwise along the center of the bearing surface. It is recommended to use the appropriate size Plastigage for the bearing clearance specification provided by the manufacturer.
Install the bearing onto the crankshaft journal, making sure it is properly aligned.
Torque the bearing cap or other retaining mechanism to the manufacturer's specifications.
Remove the bearing cap or retaining mechanism.
Measure the width of the Plastigage at its widest point using the scale provided on the Plastigage packaging. The scale is usually color-coded to help you easily determine the clearance value.
Compare the width of the flattened Plastigage to the clearance specification provided by the manufacturer. If the Plastigage is within the recommended range, then the bearing clearance is correct. If it is outside the recommended range, then the bearing may need to be reinstalled or replaced.
It is important to note that Plastigage is a one-time use product, meaning it should be discarded after use. It is also recommended to consult the manufacturer's instructions and guidelines before using Plastigage, as the procedure may vary depending on the application.