Oil found on No. 1 Spark Plug...

[Stogie6]

The saga continues. Spent last weekend and this past weekend (8 July 2018) working on the little oil leaks that my engine has developed. Simple change out of push rod tube seals, but after pulling spark plugs, discovered my No. 1 top plug soaked with oil. Why would this be? All other plugs are dry. Later investigation reveals one of two options. Option No. 1 - piston rings have aligned their gap allowing oil to get thru or broken. Option No. 2 is that the oil leak at the bottom of the case has leaked onto the aero-injector thus soaking my air filter. So, the easy path was to pull the air filter. Yep, soaked with a small pool in the bottom of the filter. Now, I take the fuel induction pipes off, and they are showing oil along the walls. Pull the intake off of the head on the left side, and same issue - coated with a mixture of oil and fuel. I'm done. The engine is coming off of the mount and over to the bench for a tear down and replacement of all dry rotted seals, etc. My engine was built by another in 2007 (S/N 350). It had been sitting for some time before I got it up and running. Maybe this rebuild will resolve my issues. If not....well, I will have to look at other options for a power source. Am I missing anything here?

[mike.smith]

David:

If you were having an issue with oil in the intake it would be hard to imagine how it would affect only one cylinder and not the others.

As much as a rebuild is a drag, I've done it twice (once to swap Nickasil cyliners for cast iron; and once due to a prop strike). Each time I rebuilt I got a better performing engine in return. It's probably because I was able to apply all lessons learned and knew what hot button items needed the most attention. On the up side, having built my engine 3 times I got the last rebuild down to 2 evenings to tear down, and 2 evenings to put it back together :-)

[Onex107]

I had the same problem with the same cylinder. My problem turned out to be a failed oil ring. The original oil rings that came with the kit have a center separator that looks like a spring. It separates the two steel wiper rings which sit on the edges of the center ring to expand them against the cylinder wall. The center separator has small upturned ends at the split to keep it from overlapping it's self. On mine the little upturned end on one side had broken off letting the separator overlap, taking the tension off the wipers and it becomes an oil pump, pushing the oil up to the compression rings. The new set of rings I bought had larger end blocks molded on the ends of the separator that where red and green. So if you don't see the two colors when you insert the piston you have a problem A new set of rings and the engine is dry.