In an earlier video, we covered the process of checking crankshaft end play. As our partners at Summit Racing explained, crankshaft end play, or thrust, is a delicate balance. Too much crankshaft thrust caused by the forward force of the transmission can lead to engine damage, but too little thrust bearing clearance can cause problems as well.
The good news is tight clearance is relatively easy to fix.
In this installment of Engine Building 101, the Summit guys show you how to polish your thrust bearing to gain clearance and increase oil film strength on the bearing. After checking initial crankshaft end play using a magnetic dial indicator deck bridge, the thrust bearing and crankshaft are removed from the engine. Using an emery cloth and oil, a small amount of surface area is removed from the thrust bearing using a figure eight pattern on the cloth.
After cleaning the bearing with acetone, a micrometer is used to measure bearing thickness and then some additional work is done to achieve the final clearance needed for the high-load engine.
Watch the whole process here: