generic washer question

[Wayne K.]

This could apply to a Corvette but I would like to know the proper positioning of a drain plug washer that is used on an oil drain plug that is a washer head bolt design. The copper washer is flat on both sides but one side has a very crisp inner and outer edge and the other has a slightly rounded inner and outer edge. Which is the correct orientation of the washer, sharp edged side facing pan or washer head of the drain plug?

[Dick W.]

Re: generic washer question

All washers are designed to have the radiused side toward the bolt (oil plug in this case). If you turned the sharp side to the bolt it could possible creat an unequal amount of stress on the bolt. I learned this on large engines that were popping the heads off the cylinder head fastners

[Michael W.]

Re: generic washer question

Agree with Dick. This follows aircraft engine convention also.