I run vented can motors in my 2wd rear motor buggies on a VERY dusty track out here in the Middle East. After a few runs I'll take it out remove the end bell and just blow it through with an airline. Re-oil the bearings and they've been totally fine. Personally I don't think it makes much difference on wear between a vented and non-vented can. Over here the ambient heat means vented is probably best for me!!