Blown out spark plug in RB

Jc cooper said:

Thanks for input always good to get quality help but was considering a NGK if could find out from one of the guys which one is right the one that blew out was r12yc champion! Or a Ry12c can’t remember right now

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mine was a rj12yc

The only NGK plug with the correct heat range for your combo is a race plug.

R5670-6

I generally stay away from the race plugs on street driven vehicles.

All plugs can and do blowout I have seen it many times in 50 yrs. shop experience. Nothing wrong with Champion plugs.

Had something similar back in 68. A 62 Chevy 283 going down 81 engine got so hot it literally blew two plugs out of the head, hanging by the plug wire. I could hear the the plug hole popping while running. The rest the porcelain just wobbled in the metal. All the car had was an idiot light that didn’t work. I let it cool down enough to screw back in then drove to nearest station. Short story got new plugs then made it to Roanoke. Found out it had no thermostat, put one in and no more overheating. That 283 never ran better after that, cleaned it out I guess.!

I had that exact thing happen on a boat I owned...was a 350 chevy (mercruiser) that the former owner put steel intake gaskets on....and it had raw water cooling. Didnt take the salt water long to eat through it...apparently that cylinder leaned out so bad that the porcelain became molten and popped out...ricocheted around in the engine room (bilge) and landed in my spare coil of nylon anchor line...needless to say ...smoke..small fire....luckily was able to blow it out...my wife at the time was right behind me with the fire bottle ready to go...I hollered "WAIT!"....and blew it out. Could have ended much differently....just realized that was 20 years ago...and they were Delco plugs.