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6811
02-01-2008, 09:35 PM
Hi I have a PA22/20-150 with a wet vacuum pump.The engine uses a qt of oil in 3hrs. 30hrs on a crome top overhaul. IT is still on Aeroshell mineral oil. All the oil seems to be coming out the breather line from the vacuum pump air/oil separator.My IA said he never sees them go bad. SO Im Knot shore if the pump needs to be rebilt or the separator has gone bad or is pluged. It is not to exspenseve to install a dry pump but I like the wet pump it lasted 50 years and 3800hrs and I fly a lot of IFR. Any advice would be great. THANK's

taildraggerpilot
02-01-2008, 10:11 PM
My wet vacuum pump pumped 4 quarts of oil out of my engine on a 2.5 hr. trip. When I landed I had two quarts of oil left, needless to say I had to overhaul the engine. I have since switched to a dry pump.

JohnW
02-02-2008, 06:44 AM
tgp; That's interesting (still, very sorry about your misfortune)! I'm surprised that engine damage incurred, as Lycoming says two quarts is the MINIMUM oil quantity for operation (not that I would intentionally ever take off with only two quarts in the sump!). What internal damage did you experience? ...or was this a precautionary overhaul so you could sleep at night?

taildraggerpilot
02-02-2008, 09:57 AM
Fortunately there wasn't any noticeable damage, but I wanted to overhaul it as a precautionary measure and because 42 years had passed since the last overhaul. Needless to say the cam was pitted very badly and I'm surprised they were able to grind it. It was a bit interesting when I would hit some turbulence, the oil pressure would fluctuate. I"m glad I was close to my destination.

joewcasey
02-02-2008, 12:44 PM
I've got a wet pump as well, and I also see a bit of seepage out of its breather. My consumption for my O290 is about 1 qt per 4.5 hours. Compressions are good, just the way it goes I guess. As far as air/oil seperators failing, I did have one freeze up on me, puhsed out my front seal.

6811
02-03-2008, 08:12 PM
HI again I think I will change to a dry pump to stop the mess on the belly as I can do it for the price of the pump. I will install a dry pump and a 90deg oil filter adapter at the same time at the next oil change.Thank's for the help.

JohnW
02-03-2008, 09:10 PM
I, for one, would not install a dry vacuum pump on my own airplane unless I had no certain need for a vacuum system.
I never see 'em go bad, either.

I would [further] steadfastly recommend that until you get to SIXTY hours on a chrome top that you not even BEGIN to wonder when the oil consumption will start to taper off and am surprised no one else picked up on the details in your original post! At a HUNDRED after a chrome ring job I would begin to consider there may have been something done incorrectly (such as chrome rings in a chrome bore. Grey iron rings go in a chromed cylinder; chrome rings will likely NEVER break in). If it works the way most do ("average") you will see a notable drop in your oil consumption relatively soon. When it DOES stabilize finally, THEN you know it is time to change to ashless dispersant, not when some piece of paper tries to tell you what your engine will do. It's "broke in" when it TELLS YOU it's broke in. I am not a firm believer in synthetic oil, but knock yourself out it that's what you want to buy when the time comes (if the whole engine leaks using synthetic multivis...just go back to ashless dispersant, it'll stop. Nine times out of ten, synthetics leak where "real oil" won't).

Steve Pierce
02-03-2008, 09:30 PM
Good observation John. Always seems to take longer to break in chrome cylinders. I prefer not to use semi synthetic oils because they tend to leak and blow out more oil. I have switched to Phillips because it is a mineral based multi viscosity oil I can use year round. Here it is 70 degrees one day and 20 two days later. :shock: You might try to isolate or remove the wet pump just to verify that is where your oil is going.

Gilbert Pierce
02-03-2008, 10:24 PM
AeroShell engineer at Sun'N Fun admitted to me that synthetic oils shrink seals and leak where good ole mineral oil with ashless detergents won't. Quit using Aeroshell 15W-50 and my leaks went away.

Frank Green
02-04-2008, 07:49 AM
Good article in EAA Sport Aviation this month on Vacuum pumps. I just bought a Rapco 215 dry pump to replace the venturi. Tired of setting the DG on climbout.