Originally Posted by
Cat 1
Valve seat is ok and valve seals well - Made a delrin plug and held it in with a 3mm cap screw though the guide. filled the head and small pressure on the port and bubbles showed it definitely coming from the seat /head interface. I think I'm just going to accept the fact that compression is mushy on this one as it runs so well.
If you have the access to a deep vacuum chamber, apply a bead of high strength high temperature Loctite or other sealant/threadlocker and place the head in a deep vacuum chamber. Expose the head to vacuum for a minute or two, then release. The air being drawn out of the crevice will cause the sealant to be drawn in when vacuum is released. The Loctite will cure in the crevice and remain liquid on the outside, so after 30 minutes to one hour, you can wash off the excess Loctite.
It is a bit similar to how small cracks in car windshields are repaired. There they use UV to cure the resin, but that prolly won't work on more opaque parts like cylinder heads