Oil Coming From Spark Plug

ryan_thompson87 · May 30, 2007

Hi everybody I'm new here and I have what is apparently a unique problem. I have oil working its way through the threads of the spark plug on #3. As far as i know ive never seen or heard of anyone else with a problem like this. The engine is a 355 with Vortec heads an intake a mild cam and headers. Its got about 10:1 compression, as a side question whats that in PSI? its not the plug as i have switched various plugs around. Its only got about 1300 miles on the motor since the complete rebuild. The heads are rebuilt also. Another problem it has that perplexes me is it burns oil on start up which seems like valve seals but it only does it if I run it up to operating temp and shut it off for about 20 minutes an hour. If it sits overnight it doesnt puff at all. Are the two possibly connected? Im at wits end about this d**n plug, any help is appreciated.

facn8me · May 30, 2007

there's only a couple of ways for oil to get in the cylinder like that. Rings/piston, valve guides, Intake manifold. I'd suggest a compression test. If compression is good check the intake gasket. Possability the heads were surfaced and the intake is not sealing well. Just a guess over the net.

Mike G · June 15, 2007

Did you build up the motor or did you buy it? Could be that your ring lands are lined up as they should NOT be on that piston and allowing oil up. I would guess you could pull probably 140-160 PSI in your cylinders, but would check the problem cylinder as well as another for comparison purposes.

Just brainstorming (because there is nothing else up there)... --Mike

lost_in_alabama · June 18, 2007

Hi everybody I'm new here and I have what is apparently a unique problem. I have oil working its way through the threads of the spark plug on #3. As far as i know ive never seen or heard of anyone else with a problem like this. The engine is a 355 with Vortec heads an intake a mild cam and headers. Its got about 10:1 compression, as a side question whats that in PSI? its not the plug as i have switched various plugs around. Its only got about 1300 miles on the motor since the complete rebuild. The heads are rebuilt also. Another problem it has that perplexes me is it burns oil on start up which seems like valve seals but it only does it if I run it up to operating temp and shut it off for about 20 minutes an hour. If it sits overnight it doesnt puff at all. Are the two possibly connected? Im at wits end about this d**n plug, any help is appreciated.

Make sure that the valve cover gasket isn't bad. The oil may be leaking out from under the valve cover. Any oil on the exhaust manifold would burn off, leaving the oil on the spark plug. Replacing the valve cover gaskets is cheap, and would rule that out. If that isn't it, then you may have a cracked head.

ryan_thompson87 · June 23, 2007

Definantly not valve covers. Ran the compression it has higher that the others. Me and my brother built it, and the rings lining up had crossed our mind. still not sure, really aggravating.

facn8me · June 23, 2007

If it has good compression and actually higher in the cylinder that has oil your rings and valves are good. Save a cracked head. Still sounds like a intake gasket to me. Gaskets are cheap. Pull the intake and look for oil in the intake valve runner. What intake do you have on it?