Thread:

Generic spark plug question

Will a hotter plug be more likely to create detenation? Example I have been looking at NGK iridium plugs for a 468BBC I have been running R43TS delco and am looking at NGK UR4IX (R44TS) or UR5IX (R43TS)There are no currect signs of detenation on the current R43TS plugs but I noticed some black soot on them. The factory 425HP 454's use one step hotter plug.

Originally Posted by ap67et10

some soot on the plug is not a reason to change heat ranges, especially since it sounds like you simply pulled the plugs after extended use and saw this soot.



Andrew

ding ding ding!!!!!!!

Originally Posted by ap67et10

first off, why in the world would you want iridium plugs for you BBC? Exotic metal plugs are only for longevity. They are the reason new cars have 100k mile service intervals for spark plugs. You are better off with the copper V power NGK's. Also, yes, "hotter plugs" simply dissipate less heat as the porcelain has less surface area touching the metal body. This causes the ends of the plugs to retain more heat, which makes you more susceptible to detonation.

Messing with plug heat range is one of the last things you should do, after you know the tune is correct (that means wideband O2 or precision spark plug reading to get A/F ratio correct and timing correct), unless of course you are having fouling issues you know are being caused by having too cold a plug. Some soot on the plug is not a reason to change heat ranges, especially since it sounds like you simply pulled the plugs after extended use and saw this soot.



Andrew

You answered my question Thank you