Oil on Spark Plug

rivcokid

rivcokid

Senior Member
Hi all - I decided to change out the spark plugs on my 1931 roadster because I now know that it's been sitting for a few years. All were pretty black, but the No. 3 plug (from the front) had oil on the threads and on the spark portion of it. Not a lot, but a noticable amount. Am I looking at a head gasket replacement now? There doesn't seem to be any problem with the way it drives - but now I'm concerned. Thanks!!
 
Just replace the plugs and cross your fingers.

You might not have to fix something that isn’t broken. Enjoy.
 
Fire it up and run it for 20 miles and then take a look at them. If it hasn't run for a long time condensation could be making things look worse than it looks.
 
Hope I am not asking silly questions, just do not know any better. A Bad head gasket and oil on the spark plugs? Are there oil passages in the head, or on top of the Block? Or would this indicate ring/valve issues?
 
Is it exhausting some blue smoke? Wore rings can cause oil burning, if you are using synthetic oil it won't burn in the combustion chamber as much as regular oil and can cause oil in the cylinder and on/around the spark plugs. If it isn't causing the plugs to foul it can go for a long, long ways yet before anything needs to be done. Do a compression check on the cylinders, you may notice that one a bit lower.
 
Good morning,


do it so like Dave wrotes.
Switch off the hot engine with very short idling-time and check the spark plugs. Dry dark brown to light brown is good.

Do not screw in the down cooled plugs end-firmly in the hot cylinder head!


(I use modern NGK Iridium with adapters.)
 

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Plugs don't go bad from setting, so that's the last thing I'd change when trying to start an engine. The plugs fire easier when you have a sharp edge on the center electrode, so if it's worn rounded, then file it flat.
 
No oil passages in the head or on top of the block. Likely (IF) you have a problem it's going to be a ring problem or possibly worn/loose intake valve guide IMO. Do like others have said and just run it awhile and then recheck to see if actual oil is present. If so, could use a hotter plug till you get around to fixing it.
Brian
 
Do not use irridium or platinum plugs with point based ignition systems,they dont handle deviations in output,they are designed for electronic systems that have stable output.Even with electronics electrodes fail and break off,irridium and platinum raise hell with steel and aluminum.

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Old cob mechanic I worked with had morning shift,the crews would come in and get their trucks..drivers would come up to him and say they "found" something..he would point a crooked finger and squint his eye.." you find it? You fix it!"
 
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