Millions have been built with no washers. All the flywheel bolt manufacturers DON'T supply washers. Good enough for me !!!
Millions have not been built with 750hp moving 3600lbs through a solid disc clutch/aluminum flywheel to plant sticky 10.5" slick tires at 5000 rpm. That begs the question.
Some of the flywheel bolt manufactures that cover the entire motorsports spectrum *do* offer flywheel bolts with washers:
Example #1Example #2Example #3I though maybe I was missing something.