This plug is FUGLY!

[blown motor]

A buddy and (shy) member here started pulling plugs on his 440 the other day and found this. The engine was rebuilt about 8 years ago with KB pistons and a stock cam. This past summer he put on a 750 Eddy carb replacing the 600 that was on it and had the carb set. That did wake up the car a little as I had always thought it was under powered for a 440. He has 5 plugs out and this is the worst one, it's No. 7 and they are RJ12YC Champion. He said the others aren't much better. Thoughts?

[RJChallenger]

Hows The oil consumption  on the motor. maybe valve seals letting oil in the combustion chamber

[BIGSHCLUNK]

Timing ok? Maybe a hotter plug to burn up some of that residue? A little water right down the carb should clean that up. Just keep the revs up.  Then to find the actual issue.

[blown motor]

Timing ok? Maybe a hotter plug to burn up some of that residue? A little water right down the carb should clean that up. Just keep the revs up.  Then to find the actual issue.

I wondered about a hotter plug. But that's a LOT of junk. There's got to be something more than just needing a hotter plug.

[BIGSHCLUNK]

Agreed, that plug did not get that overnight.

[jimynick]

Murray, I'm guessing this is Dougie's? There's 2 things I'd do- 1: do a compression test and 2: see what's on it for valve seals. I wouldn't be surprised if the rebuilder used the old oem umbrella seals and they're not the greatest. Sometimes repeated cold starts and short drives can foul plugs too and an "Italian tuneup" can help prevent some of that by blowing it off. I'd also go at least one range hotter on the plugs, as mentioned. If it's got sloppy guides and loose/lousy seals, it's going to crud up. Fun, eh? 

[blown motor]

Ya, it's Doug's. I told him he just wasn't driving it hard enough. 

[JS29]

@jimynick  What is an Italian tuneup? Making my best time getting to the pizza shop. 

[Chryco Psycho]

That is not fuel residue from a rich condition , that has to be oil contamination , something is not right , valve seals / clearance in the guide or bad rings / ring gap .
Cmpression test 1st , whoever rebuilt it missed something 

[70 Challenger Lover]

I agree that it's oil. How many miles on this engine? I'm going to take a wild guess that it's only a couple thousand and the rings never properly seated.

I had an issue like that once but in one cylinder only. When I pulled the head, that one cylinder was slick with heavy oil and the rings were just skating across and not actually seating. Cleaned it out and put a tint bit of an abrasive like powder on the wall given to me by an engine builder. Worked like magic.

[IRON MAN]

I had about five plugs in an engine that looked exactly like that fugly spark plug. New valve guides fixed the problem.

[HP_Cuda]

Geez it looks like you dump 8 quarts of oil on that one.

Definitely a compression check will illuminate the problem. This is exactly why I don't believe anyone who tells me "I just rebuilt it" before they sell it.

[71-440]

@jimynick  What is an Italian tuneup? Making my best time getting to the pizza shop. 

Never heard that before....

[ToxicWolf]

Italian tuneup. From Wikipedia, the free encyclopedia. An Italian tuneup usually refers to a process whereby a motor vehicle engine is run at full load for extended periods in order to burn carbon buildup from the combustion chambers, spark plugs, and exhaust system

[RJChallenger]

A compression check will only tell if the compression is normal or low compared to other cylinders . If it is low you can then test the rings by squirting a little oil in the cylinder. I don't believe the compression test can tell you the condition of the guides or seals. To do that you would have to pull the valve covers and springs to check if seal is there and in good condition. I Myself would be thinking of pulling the heads and checking the guides and seals.