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newbieStudentPilot

I'm New Here
Earlier today my preflight revealed approximately 7 quarts of oil in an engine (Continental IO-240-B3B) calling for 4 quarts minimum, 6 quarts maximum. The mechanic on duty said not to worry about it because the excess oil would be dumped out of a valve at the bottom of the cowling, probably as soon as I fully opened the throttle. I opted not to go up since my experience is minimal and something about dumping a quart of oil on the numbers on takeoff didn't seem quite right. I'm comfortable with my decision, but I'm curious if it was necessary. Thoughts?
 
The biggest danger of "too much" oil is the chance of the crankshaft dipping into the oil and causing it to foam. If this happens, the pump will not pump foam. This is not a problem with horizontally opposed engines.
Usually one extra quart will not hurt, but I think you are wise to refuse to take the airplane in that condition.

PS. I never heard of an "excess oil dump valve" on one of these engines. I think the mechanic just figured that excess oil would be blown out the breather.
 
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One way to get rid of the excess would be to push negative G's for a second or so while recovering from a botched attempt at a hammerhead turn. The breather will happily paint the belly of your airplane, your tailwheel, and some of your horizontal stab with oil. About a half-litre, near as I could tell after wiping it up.

Ah, I mean, or so i've been told. :p
 
My experiences with too much oil have always resulted in getting to clean it off the entire underside. I would take some out.
 
really 7qt?

I'm not sure you were looking at 7 vs 6 quarts in the same way. I suspect the drainback valve isn't doing it's thing, and resulted in the oil filter, roughly a quart, to drain back into the sump. With the engine just off of shutdown or running, you probably have an operational 6 qt per the dipstick. Just a guess . . . .

Rick 90432
 
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