Does anyone use autolite 51s? I still get alot of carbon fouling on my 292 and have tried RC14Y and autolite 46s. I think my fouling is caused by leaky valve guides but would like to see it reduced.

Anyone tried these, or are they way too hot?

 

I've never read of anyone using that plug. Leaking rings and/or guides come to mind. Retarded timing maybe, due to setting and timing set wear. Carb jetting shouldnt be the culprit. One other thought: CR may be too low for full burn of A/F mixture. Had that experience first hand.

 

I could buy the CR being too low. Autolite 51 is the next available hotter plug.

I advance the timing any further and I experience power loss. But no detonation.

That leaves leaky valve guides.

 

Watch the plugs real close if you go with the 51s. There are some great sites for reading spark plugs with very good pictures.

 

So I finaly bring the truck out for the year. I go into order a set of 51s............DISCONTINUED!

Damn it.............

Any Ideas on a plug hotter than a Autolite 46?

 

Found a match in champions book.

RF18YC

RF14YC is equivalent to a Autolite 45 or 46. RF18YC is hotter yet.
Worth a try, I ordered eight of them.