Spiffy
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- Jan 14, 2011
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Last November I started to do the installation of my inverted oil system on my Skybolt. The typical horizontal screen tends to have the screen removal port pointed at the tubing of the motor mount. I new that I was going to have a clearance issue so I made an even shorter 45 degree oil pan swivel fitting. Even with this the clearance was a little close. And busting off the fitting is naturally a bad problem. I shimmed up the engine a little bit to try and fix this problem. I put some clay between the fitting and the motor mount and started the engine. The fitting never hit the motor mount, but it did get very close. I chose to take another look. I like to fix my problems dead instead of me being dead.
Since the weld in bung was for sheet metal I turned down the outside.
I then machined the backside of the oil pan to set up the fitting. 
After some grinding to get the new fitting in a place that will clear the motor mount well, I finished welding in place.
Since there is no longer a galley plug in the assembly, I welded up the sump passage.
Looking at the back side of the oil pan now, you will see the blue fitting on the right that opens directly into the sump. The circuit will scavenge from this port into the inverted ball valve. From the inverted ball valve the oil will flow into the black screen fitting as installed. From here the oil will flow through the normal pump input galley. 
Here is a view of the inside of the oil pan. This also gives you a feel of the screen placement.
For a sanity check, I performed a flow test on the new screen fitting as compared to the stock Lycoming screen. The new screen flows a quart of oil about 15-17 seconds quicker. I wanted to make sure that I didn't add any restrictions. This may actually help oil pressure recovery at start up. I can not say that this may be significant. I now have more than adequate clearance and will sleep a little better.
The first thing that I did was to source a -10 screen fitting and weld in bung. I found one through drysump.com.
Since the weld in bung was for sheet metal I turned down the outside.
I then machined the backside of the oil pan to set up the fitting.
After some grinding to get the new fitting in a place that will clear the motor mount well, I finished welding in place.
Since there is no longer a galley plug in the assembly, I welded up the sump passage.
Looking at the back side of the oil pan now, you will see the blue fitting on the right that opens directly into the sump. The circuit will scavenge from this port into the inverted ball valve. From the inverted ball valve the oil will flow into the black screen fitting as installed. From here the oil will flow through the normal pump input galley.
Here is a view of the inside of the oil pan. This also gives you a feel of the screen placement.
For a sanity check, I performed a flow test on the new screen fitting as compared to the stock Lycoming screen. The new screen flows a quart of oil about 15-17 seconds quicker. I wanted to make sure that I didn't add any restrictions. This may actually help oil pressure recovery at start up. I can not say that this may be significant. I now have more than adequate clearance and will sleep a little better.
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