Oil Filter adapter fun

[jelecroy]

Our 1981 R182 developed a grand oil leak last month. I flew the airplane to the radio shop for some upgrades, and they sent me a disturbing video of oil coming out by the right exhaust when they ran up the engine to verify that the new radio works properly. OH. MY.

Back story. We bought our R182 in 2014. It had about 20 hours on a freshly overhauled engine, and I had the mechanic doing the pre-buy change the oil. A month or so later I went to change the oil. I've changed oil on big Lycomings nearly a hundred times, so I didn't expect any surprises. But I got one. I put my usual oil filter wrench on the filter, pulled. Nothing. Pulled harder. Nothing. Pulled REALLY hard. Wrench broke. Repeated this process twice more with successively heavier duty oil filter wrenches.

I assumed that the pre-buy mechanic had WAAY overtorqued the filter. But for ten years no matter what I did at installation the oil filter removal torque was way too high. I tried switching to Tempest EZ filters, both installed dry and with DC-4. Removal torque was consistently over twice what it should have been.

What happened was that at the last oil change the filter removal torque was high enough that the oil filter adapter plate spun just a tad. Enough to compromise the gasket. I replaced the gasket according to Lycoming Service Instruction 1453B. While I had the adapter plate off, I took a hard look at it. The surface that the filter gasket seats against had clearly visible machining marks across the entire face. My guess is that the pattern of machining marks gave the oil filter gasket enough of a bite to require excessive removal torque. I took the plate to my shop, smoothed off the seal surface, starting wet sanding with 320 paper and ending with 1200. I feel pretty confident that the next oil change won't require as much drama.
I would not rework the adapter plate in situ. Way too big an opportunity for sandpaper grit to find its way into the engine. But if you are struggling with oil filter removal on an O-540 with dual magnetos, an adjustment to the adapter plate might prove to be a fix.

[scottrsellers]

Jerry - Can you include photos - particularly of the machined surface? Surprised the DC-4 didn't help.

For more than 20 years I've torqued oil filters using the following method: 1)spin on by hand until contact with the sealing surface(can't turn anymore by hand), 2) torque with wrench additional 180-270 degrees and stop.

Even with the TCM oil filter adapter issue have never had a leak or issue with the oil filters, so I laugh when I see mechanics(particularly new/young ones) getting out their torque wrenches and carefully torque oil filters to the filter manufacturer's published values.