---------------------------------------------------------- Engines-List Digest Archive --- Total Messages Posted Tue 04/20/10: 1 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 08:50 AM - Re: Oil in sump (Monty Barrett Sr) ________________________________ Message 1 _____________________________________ Time: 08:50:49 AM PST US Subject: RE: Engines-List: Oil in sump From: "Monty Barrett Sr" It is common for some oil to be in the plenum. The sump itself is full of oil so I suspect you are referring to the plenum, which is part of the induction system and is below the sump. The reason that there is some oil in there is because when the engine is operated at slow speed, such as taxi speed, the rocker boxes get overfilled with oil, more so on a fresh engine where the ball sockets of the pushrods have not bedded themselves to each corresponding rocker. Then when the engine shuts down the oil in the rocker box will run thru the intake guide, down the inlet pipe to the plenum, assisted by some fuel which, when shutdown, will " dribble " out of the fuel nozzle, diluting the oil and lowering is viscosity. Then the fuel evaporates leaving the oil residue. There are 1/8 NPTF holes in the lower edge of the plenum in which a " sniffle valve " should be installed. Put a sniffle valve in the lower port when the aircraft is sitting on the ground. This valve is used to drain off residual fuel and oil. It's primary purpose is to minimize an induction fire during a balked start. Use the one made by Airflow Performance which has 1/8 NPTM thread on one end and -4 flare on the other. Run a line overboard from underneath the cowling. Monty Barrett Barrett Precision Engines, Inc. -----Original Message----- From: owner-engines-list-server@matronics.com [mailto:owner-engines-list-server@matronics.com] On Behalf Of Speedy11@aol.com Sent: Monday, April 19, 2010 4:09 PM To: engines-list@matronics.com Subject: Engines-List: Oil in sump Engine Experts, I have a Barrett IO-390. When I removed one of the intake pipes from the sump to the cylinder the other day, the sump had oil in it. Should the sump where the intake pipes insert have oil in it?? If so, how much is permissible? Stan Sutterfield ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message engines-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Engines-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/engines-list Browse Digests http://www.matronics.com/digest/engines-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.