I don't know if anyone has experienced the "OS backplate grind" with their 4 stroke, but I have with my modified 52. After replacing the rod and ring, I installed some teflon shims on the wristpin to keep the rod from coming in contact with the backplate. That was months ago, and after pulling the engine apart last night, it seems to have worked perfectly. The shims are both still in place and the rod is in perfect condition.
I'm VERY happy with the way this engine has lasted. It doesn't even need valve adjustments more than a couple times a year. The only maintanence it really needs is to scrape the carbon off the exhaust valve every couple-few gallons.

Also, the next big race for me is this weekend. I'll be racing the thumper Revo against the best MT racers in the Northwest and even some factory Traxxas drivers! Here's a link to the latest pictures of the truck:
http://www.rcccs.com/index.php?showt...ndpost&p=14287