Oil on #3 plug

[David Kirby]

Just Changed the plugs on dads speedster, engine is a 58 (68167) and the #3 plug had some oil on it, all others looked ok. Would this be caused by bad rings? Or Maybe carbon and oil?

[Thomas Sottile]

The oil could be caused by a number of things , Bad plug , bad plug wire , head gasket leake bad rings or just lack of driving.

[Vic Skirmants]

Guides. Head gasket leak????

[C J Murray]

It's not a great picture(can't blow it up), but the plug looks oily and if so then it's usually rings or guides. Do a leak down test.

[Ron LaDow]

See below; fixed

[Ron LaDow]

Do a leak down test.

I was gonna suggest that also, but it won't tell you anything about guides. Any way to check those other than disassembly? I can't think of anything reliable.

[C J Murray]

Do a leak down test.

I was gonna suggest that also, but it won't tell you anything about guides. Any way to check those other than disassembly? I can't think of anything reliable.

A leak down might eliminate ring problems as a cause and bad guides can expose themselves as valve leaks since they are not aligned correctly on the seats. In actual truth Ron is correct to suggest taking the engine apart for inspection because tests don't always reveal the problem. If the plug is oily I would remove the heads and have them rebuilt. If a problem is found at that cylinder and if there is no cylinder scoring then I might just put it back together but it might be wise to take the cylinders to the machinist also to have them measured for wear.

[Martin Benade]

Did it take years for the plug to get that way, or fairly quickly?Was it still running decently when you changed the plugs? If so, maybe the engine is getting a little tired but still useable for now. I have seen plenty of plugs like that from cars that generally ran OK for a long time, I doubt if it is anything leading you to a major failure, if it isn't rattling and isn't using lots of oil.

[David Kirby]

Thanks every one. It probably took a while to get that way, since the car is not drivin that much. It doesn't us oil as far as I can tell. I'll keep checking on it periodically. After I get the carbs back on. Got some other plans for car before I can tear engine down.

[Cliff Hanson]

Just Changed the plugs on dads speedster, engine is a 58 (68167) and the #3 plug had some oil on it, all others looked ok. Would this be caused by bad rings? Or Maybe carbon and oil?

It's kind of hard to see in your photo but it doesn't look like wet oil, just mostly carbon with a little oil mixed in. If you just installed new plugs I'd drive it for a few miles and pull the #3 plug again. If not I'd install a new set of plugs and repeat. Your mixture might be a little rich and that will soot up the plugs. And of course a compression test will tell you about how well the rings are sealing.