Reply To: 1931 Model 42 Mosquito Sprayer

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Bill, thanks for adding this info on the exhaust valve. This a sequence I propose happened with your engine for your consideration:

a)The rings on cylinder 4/5 slowly degenerated or perhaps didn’t seat properly when placed in service with the last ring work, eventually allowing significant amounts of oil into the combustion chamber 4/5, and of course, giving lots of blue smoke.

b)The oil in the combustion caked on the exhaust valve in 4 to the point the valve was lifted, giving poor compression, thus poor combustion, allowing oil in its liquid state to foul the plug. I bet 5 was heading the same way.

So, if the exhaust valves are cleaned/reseated and the engine placed into service , combustion will be restored, performance will improve and rpm’s will increase (for a while) but the car will eventually return to b) in the sequence above. I believe the rings are the root of your troubles as Greg L has indicated and perhaps that is part of the block work you indicate for the next few days.

I wish you the best on the weekend project!

John W.