Hi,
Took out the finally finished , really nice 300C convert this AM (Gauguin (sp?) red!) ,promptly lost a core plug in first two miles, of course the one behind the motor mount (hey it could have been one on the head) .
All were new, supposedly Pro installed, by marine Chevy engine shop in California before I bought the block from them (300D block) ; at bottom of empty hole is what looks like RTV or Silicone , probably both wrong (Indian head, or Permatex, to me, belongs there ) ,but even more important , they were the thick flat disc type..looked dented in, but how can you tell if dented enough ? It did not hold.
I have new ones I sort of hoarded 25 years ago, of brass, to replace it, they do work--- it seems ---if in right , so this one was NOT in right , no rust issues, clean.
So not hit hard enough? How do you tell. I know brass cup type is “preferred” but that means ?machining? step out of hole ,engine is in car , all new and painted . I am SURE someone in 300 land knows all about this. Now I am afraid some other one will pop out, not pretty at all. Removed ?incorrect? 15 psi cap for 7 psi , but overheating not involved,--not set in right in hole is my diagnosis . Cannot bring myself to put in rubber ones..
Help help !!