I lost my top piston, and that cylinder was rather clean, like I had cooling water leak into it. I had no evidence of any burn-through on the compression rings of the head gasket or other marks on the sealing surface. I will check the block carefully, but I still suspect that the water came in through the head gasket.<br /><br />The Merc. manual says to check the head for warpage by placing in on a piece of plate glass and using a feeler gauge. The manual says to replace it if the warpage is greater than 0.012 inches and to resurface it if it is less than that. No tolerances given. <br /><br />My warpage is about 0.007 inches, and not right where the bad cylinder was. It's not on an end of the head, either. It's along the long side of the head.<br /><br />Has anyone ever ran a head with this much warpage? Does it seem like too much to put it back on with a new gasket without refacing? Opinions welcome. <br /><br />Thanks,<br /><br />Carl
