what causes oil on spark plugs?

[Dreco]

I've noticed that I have some oil on my spark plugs. My engine has 10,000 on it. Could this be from valves out of adjustment? I'm hoping?? ( I checked and the valves were out of adjustment). My car is not sluggish, it's just as quick as when I first put the motor in. I don't notice any smoke.

[2ManyZs]

Only a couple ways oil can get on the plugs, either past the rings, or past the valves...

An oil ring that isn't seated correctly, valve seal dried out and brittle or a valve guide with too much wear and loose tolerance around the valve stem are the ones that come to mind....you don't want to think about any others.. those would be the really expensive ones....

[Dreco]

I kind of knew that, but was hoping for a cheaper answer.. thanks.

[2ManyZs]

Could also be a product of a somewhat weak spark too.... In any engine there is going to be some oil getting into the combustion chambers to a certain degree... the point is to burn it completely and exhaust what is left after combustion....

[GTZZZ]

If the plugs are black and wet looking it might not be oil on them. It could be carbon. This happens because your carbs are running to rich a mixture.

[Gav240z]

Quick question for 2 Many Z's. I have a similar problem with my Z and believe it to be the valve stem seals on a couple of cylinders of course If I was gonna do 1 I'd do them all.

However alot of people have said not to bother until I do a full rebuild but I'd prefer to not be burning any oil as it's bad for the environment and I have to keep topping up the oil in the car every 2 months or so being a daily driver it is.

Would you recommend in your experience to fix the issue or wait for rebuild?

Thanks

[Mike]

Originally posted by DRECORD

I've noticed that I have some oil on my spark plugs. My engine has 10,000 on it. Could this be from valves out of adjustment? I'm hoping?? ( I checked and the valves were out of adjustment). My car is not sluggish, it's just as quick as when I first put the motor in. I don't notice any smoke.

Oil on the spark plugs is caused by oil getting into the cylinder. Simple.

[2ManyZs]

Gav, I wouldn't worry about it until one of three things starts to happen.

1. Smoke at start up gets to be excessive or annoying.

2. Leakdown or compression test shows weak compression in the cylinder or possible problems with the valve or seat themselves.

3. Oil consumption suddenly increases

Or, until you find you have to remove the head for any other reason.

[carguyinok]

New valve seals are not a bad start for the"cheaper answer". You can replace them easy enough for it to be worth the work.

Get the fitting that hooks-up in the spark plug hole that will allow you to fill the cylinder with air pressure from your aircompressor.

This will make it so the valves wont drop. Then replace the valve seals and move on with the next cylinder.

It looks alot harder then it is. Far better then ripping into the lower-end for a guess on rings.

If it is still acting like a ring.

take some automatic trans fluid and pour alittle in each cylinder and turn the motor over a few times (without starting it) let it sit overnight. I have had this free hung-up rings in the past. When you first start the car it will smoke till the trani fluid burns off but that wont take long.

Hope it helps.

[GTZZZ]

What makes you think you have oil on your spark plugs? If there is oil on your spark plugs you would be burning oil and your car would smoke. You said it doesn't smoke. If oil is on your spark plugs it's in your cumbustion chamber if your car is running well it is firing like it should. This would burn oil.

Read my first reponse on this thread, about running to rich. A lot of repair manuals have spark plug diagnostic pictures with explanations as to what causes them to look the way they do. If your plugs are black and shiny and look like they have oil on them they probably don't It is probably carbon and gas. If you keep running it this way your plugs will start fouling and your performance will become very poor. Adjust your carbs.

[Dreco]

well, I'm going to look at the plugs again, but I'm sure it's oil. The spark plugs were still wet with oil. My car does smoke when I first start it up, and it's smokes a little when I excelarate hard. I have had to add oil before. I'm going to take it to the guys that built it, and see what they say. Thanks for everyones input. Hopefully it's something they did.