1990 Suburban Spark Plugs are cracking

[bbdobbins]

The plugs are being put in gently with utmost care. For some reason within 6 months my vehicle starts missing really bad and when I go in my mechanic finds that one of the plugs are cracked. Other than faulty installation what can be causing this?

[MT-2500]

Are you using OEM AC-delco plugs?
Any water splashing up on them?
Like no splash shield or running/driving threw water.
MT-2500

[bbdobbins]

Thanks for the advice. I've heard 2 people mention the moisture posibility.

[Ryan685]

I've read in a few mechanic's newsletters about this. Seems like manufacturers are getting cheap in the ceramic department, foreign countries pushing the limit on poor quality. I use NGK plugs at this time. AC hasn't had good quality spark plugs for so long, it's tough to recommend them to customers. Autolites used to be a good choice. Right now NGK Gold palladium spark plugs with the fine-wire electrodes have the best ceramic so say the experts. I've put four years on the one's in my BMW and it's suppose to be a Bosch specific engine. I just didn't tell the car I was screwing in NGK's instead of Bosch's. As a bike drag racer I've run NGK's in a fuel injected turbocharged race engine with 30psi of boost, which calculates to 23-1 compression. I've run two seasons on the same set of plugs without trouble.

[MagicRat]

Are you using a proper spark plug socket, or just an ordinary socket?

Spark plug sockets are larger inside. Sometimes the plug will contact the side of ordinary sockets and crack the ceramic. At this time, the plug is only held together by the iron or copper electrode.
After a couple of hundred heating and cooling cycles or the engine, the ceramic will break entirely.