sounds like a dodgey cap !
you could be runing no boost and the gasket can go has it always done it
hmm u could have air in the system, but a recent head gasket change leads me to believe that it could possibly be that the head was torqued down wrongly.. which would lead to warping of the hg.. ie ud need to reopen & rechange the hg.. any signs of water in oil? or vice versa?
well as i said, mine did it for 18months and ran several drag strip times, it did however get better when i got a dual core swift rad but it still did it.
maybe they dont have enough capacitiy and the pump pushed out to much pressure?
yea i ran a stock civic cap, then when i put a 1.3 cap on eventually the car shat itself( way to silverstone) lol,
was the head skimmed b4 the new hg was put on?
the head was checked and it was fine. didnt need skimming.