TurboSE Posted January 23, 2009 Share Posted January 23, 2009 I've asked this question on a few RB forums and always received mixed responses and reasons. I'm in the process of rebuilding my block and I've looked at several head gasket manufacturers, and the big names (Tomei, Cosworth etc.) don't seem to make a gasket in any size smaller than 87mm. I haven't pulled my internals yet, but the rest of the motor has been in excellent shape so I don't think I'll have to bore all the way up to 87mm. My questions: If I'm running 86/86.5mm pistons and and use an 87mm head gasket, will I run into any problems? Also, what is everyones opinion on Cometic head gaskets? Quote Link to comment Share on other sites More sharing options...
cheftrd Posted January 24, 2009 Share Posted January 24, 2009 No problem. In fact, it helps protect the gasket by being back away from the edge of the cylinder. Cometic is just as good as any of the other standard MLS gaskets. Gaskets with stoppers (like Tomei) seal around the chamber better, but are more expensive. Quote Link to comment Share on other sites More sharing options...
TurboSE Posted January 24, 2009 Author Share Posted January 24, 2009 No problem. In fact, it helps protect the gasket by being back away from the edge of the cylinder. Cometic is just as good as any of the other standard MLS gaskets. Gaskets with stoppers (like Tomei) seal around the chamber better, but are more expensive. Thank you for your answer, I've been chewing on this question all day. So for 700-750whp is a Cometic good enough, or would you go higher end? PS - That answer makes more sense than any of the others I've received... Quote Link to comment Share on other sites More sharing options...
Careless Posted January 24, 2009 Share Posted January 24, 2009 good to note that the smidgen of compression you lose in your compression ratio is negligible too. as noted by matt, keeping the gasket away from the ring lands is not a bad thing considering RB pistons have a positive deck @ TDC. this practice is mentioned in the engine building books I have too. Quote Link to comment Share on other sites More sharing options...
TurboSE Posted January 24, 2009 Author Share Posted January 24, 2009 good to note that the smidgen of compression you lose in your compression ratio is negligible too. as noted by matt, keeping the gasket away from the ring lands is not a bad thing considering RB pistons have a positive deck @ TDC. this practice is mentioned in the engine building books I have too. also a good answer...I really appreciate all the help! Quote Link to comment Share on other sites More sharing options...
TurboSE Posted January 24, 2009 Author Share Posted January 24, 2009 Mods, I guess this can be closed....thanks for the help! Quote Link to comment Share on other sites More sharing options...
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