Crankshaft end play is a delicate balance.

Too much crankshaft thrust can lead to lead to engine damage, but too little thrust bearing clearance can cause problems as well. If endplay is too tight, the crankshaft can bind and result in serious damage to the engine block. The difference is tight thrust bearing is relatively easy to fix if you know the right technique.

In this installment of Engine Building 101, we show you how to polish your thrust bearing to gain clearance and increase oil film strength on the bearing. Using our Summit Racing LS engine build as an example, we remove the bearing and crankshaft from the engine and move to our tabletop. With emery cloth and oil, we work to remove a small amount of surface area from our thrust bearing using a figure eight pattern. After cleaning the bearing with acetone, we use a micrometer to measure bearing thickness and do some additional work to achieve the final clearance we need for our high-load engine.

Be sure to check out our How to Check Crankshaft End Play video here:    • How to Check Crankshaft End Play or T...