9GT

9GT

Well Known Member
Patron
I checked the archives on this and found that most of the threads drift off topic and become argumentative. Here is the problem: On my buddies plane we both built, at the condition inspection last month among the usual, we swapped out the BM EFIS for a Dynon Skyview. Afterwards, the oil pressure was reading 138 psi at run-up. After contacting Dynon, it was suggested the problem may be the oil pressure sensor used for the BM may not be compatible with the Dynon. A new sensor was ordered and installed and we get the same high readings. Pressure readings were verified with a simple analog gauge. The engine is a Superior IO-360 with C/S prop. Superior suggested a possible adjustment is needed in the relief valve. No change when adjusting the pressure screw. They then suggested we remove the pressure relief valve assembly and look for damage or obstruction and run a soft wire down the port hole. Everything seemed good. Reassembled and still reading up to 138 psi. Now we are thinking maybe we got a bad filter and that is causing the high readings since it was changed at the condition inspection and that's when the problem showed up. Any suggestions from the engine guru's out there? We are at our witt's end on this and are awaiting delivery of a new oil filter and case of oil.:confused:
 
Wrong filter?

I think most Lycomings require a filter with a built in by-pass. Maybe the new filter lacks it. Hard to believe that the filter media would generate that kind of back pressure in any event.
 
Did you take the oil filter mount off in the work you did?

If so, the gasket under it could be intalled incorrectly blocking a port...
 
Dan Horton once posted an oil system schematic that showed the pressure sensor being downstream of the oil filter. If this is correct then it doesn't seem likely the filter could be the problem.

How about plugged oil passages near the relief valve?
 
RV8iator said:
Did you just try another filter?

Cheap and easy to do.
Click to expand...

Its a remote mount Wolfe system mounted on the FW. We are waiting for a new filter and oil. Its going to be our Hail Mary for a simple fix. Superior also said its a long shot but is possible the filter bypass is not functioning correctly. Just wondering if anyone has had this problem crop up. Its so coincidental to the CI and panel change out. The high readings with the new panel really threw us off and set us back several weeks.
 
9GT said:
Pressure readings were verified with a simple analog gauge.
Click to expand...

Hmm, that eliminates stuff like new EMS settings.

Where did you tap the oil system? The usual port on the upper right rear of the accessory case is downstream of the filter, thus filter restriction would not cause a high pressure reading.
 
Relief passage

This may or may not be relevant but just in case. During some sort of maintenace activity, a hanger mate had something unknowingly fall into the passage that leads from the pressure relief valve bypass to the crackcase. Enough of a blockage that it over pressured and pushed the gasket out from under the filter.

After a lot of head scratching and advice, he probed the return passage with some doubled up safety wire and found the blockage at the interface to the oil pan.

Any chance of a parallel problem?
 
DanH said:
Hmm, that eliminates stuff like new EMS settings.

Where did you tap the oil system? The usual port on the upper right rear of the accessory case is downstream of the filter, thus filter restriction would not cause a high pressure reading.
Click to expand...

We just removed the electronic sender from the firewall mounted manifold and used that port for the analog gauge Dan. Off hand, I do not remember if its pre or post the remote mounted filter. Nothing was changed except the oil pressure sender, EFIS display, and a fresh filter and oil. I talked to my AP/AI when I picked up my log books for my Cessna he annual-ed for me and he is also at a loss but is interested in the filter theory. I am going to ask my buddy to cut open the last filter we removed for the C/I and inspect. Also cut open the filter on there now when the new one comes in. He usually does this but I do not know if he has yet.
 
Last edited:
We spent a lot of time trouble shooting this. My buddy decided to hire an AP on the field to take a look. He tried to remove the oil galley plug on cylinder #1 and stripped the hex. He tried drilling it out for an EZ Out and the EZ Out broke in the hole. Hired another AP who specializes in power plants. He managed to get the plug out with not too much damage using a torch and special tools he had and hooked up an analog pressure gauge to that galley port. Pressure was good. Wanted to test the other ports but not willing to risk stripping those plugs out, then we would have to remove the engine to get those out. Called Superior engines and found out that when they built the engine, they used Permanent Loctite when they install the galley plugs. We removed and checked all the oil lines for the remote filter, pressure manfold, and oil cooler. All free and clear including the oil cooler. Reassembled and tested again. The manifold port between the remote filter and oil cooler still reads high with the Dynon sensor, but reads normal when installed on the oil galley port. AP was confident that oil pressure was not a problem. Issue is probably caused where the manifold is located due to various reasons we don't understand. The BM transducer and Dynon transducer operates differently and are not compatible. Anyway,,,,everything is good now after paying $600 in AP work and he's back in the air flying the wings off that Cozy MKIV and enjoying his new Skyview panel.
 
A Lycoming 77852 oil filter adapter has a bypass valve built into it so that in the event the oil filter bypass is not enough, that will take over. What kind of bypass arrangement does the Airwolf filter have?
 
What is important...

Is that the bearings are getting what they need. Sounds like you affirmed that!
 
You must log in or register to reply here.