Blown out o-ring on head

[Pj Uptmor]

We went  to little Sahara and blew the head gasket. This is the second one I blew. After the first one I had the head check and resurfaced. Thought I was good to go. After 2 day on the sand the o-ring let go. The cylinder is a pro-x 310 old style head. Any suggestions on how to prevent this would be appreciated.Thank u

[Jerry Hall]

Check the top of the cylinder.  Many times the flange on the top of the sleeve was not seated all of the way into the recess machined into the aluminum casting.  The sleeve (where the o-ring groove is) should be even or protrude above the aluminum no more than .003".  If the sleeve is below the aluminum the o-ring will "see the fire" in the combustion chamber and eventually fail.  The head must clamp down on the iron sleeve between the o-ring and bore surface

If the top of the cylinder checks out ok you are having a detonation problem.  Detonation will eat away the 0-ring even when the machine work on the top of the cylinder and head are perfect.

Show me a picture of the top of the piston and the squish band area of the head.

[Pj Uptmor]

Jerry I won't be able get the quad till some time next week.

[Jerry Hall]

You can check the top of the cylinder with a depth micrometer with a 6" bridge, a CMM or a ground straight edge or a feeler gage.