: Marathon gasket install session today....verdict is...



urbanski
09-03-05, 04:15 PM
there is NO gasket that alone can stop leaks.

I spent hours and many pieces of sandpaper trying to perfectly flatten the flanges. The flanges were actually shiny. Using a straight edge I thought I was dead on. Even mated the flanges with no gaskets to check flatness. I thought I was 100%.....
torque on the bolts w/ gaskets and suddenly a 1mm gap opens in the middle between the bolts....front and back. Both heavy's and BBs didn't seal, leaked horribly. Swapped them front/back, too.

http://img350.imageshack.us/img350/2821/gaskets44uh.th.jpg (http://img350.imageshack.us/my.php?image=gaskets44uh.jpg)

Of course I went with my old standby, copper RTV, thicker layer in the center, thin around the bolts. Torque to 90ish. No leaks on quick test. Will retighten in a few heat cycles.

Seriously, i know my flanges were dead flat, i think tightening the bolts bends them and opens that center gap. Maybe i'm just doing something wrong...i think i'll buy some stock in copper RTV, lol
peace

CVP33
09-03-05, 05:11 PM
The engineering is the issue. A two bolt flange is far from ideal as you'll have flex somewhere. The factory unit has the heat resistant "donut" that seats into the opening. I fear that this is the only solution, besides RTV that will work. Oh well.