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Post by smoothmat on Sept 10, 2011 23:02:20 GMT -5
So today i took out and my sonerai and did some run ups. After 10 min of running i shut it down to check things over. There was a oil dripping from acc case and fire wall. I cleaned it up and started it back up and ran it again for a min and shut it down. There was more oil sprayed along the right side of fire wall and more oil dripping on the bottom of fire wall. The acc case was dripping again. I cleaned it up again and let it sit. No oil dripping or running. I assumed the rear oil seal was damaged(being that i had just had the flywheel off prior) I moved plane back home, removed engine, removed acc case.....and popped out the main seal. It didn't seem to have any major defects?? I am sure that the oil was coming from the main seal b/c there was oil in the acc case, flywheel had oil on it, oil only leaked when engine was running. Everything else was dry and looked great. I tried an old seal(black) i had laying around and it fit a bit tighter than the seal(orange) i removed. Both seals are elring 70-90-10. Last time i ran engine there was no leaks. This time there was. On a side note: engine ram excellent, 3100rpm (forgot to check man pressure) i know manifold pressure was about 15" at 1800-2000rpm. Oil pressure was 40-45psi. Great throttle response. egt 1100, cht 350. Started fisrt crank. I had idle set at 1100rpm and it ran fine there. I am sure it will idle @ 900. All in all was a good day. Attachments:
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Post by smoothmat on Sept 11, 2011 10:45:04 GMT -5
SKF makes a seal exactly the same as elring except the outer race is steel with a teflon coating. It comes up in the part list when searched at some auto parts stores. The elring seal also comes up in the searches.
Has anyone used the SKF seal or have any comments. I think that i am going to go with the elring anyways.
Matt
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Post by splischke on Sept 11, 2011 14:38:29 GMT -5
Welcome to my world. I chased a similar pesky oil leak for years. I replaced the rear seal twice, made sure no oil was not leaking past the dowel pins, poked a wired into the oil drain hole to verify it wasn't clogged, and more. Then one day I blew compressed air into the drain hole and watched to my surprise oil weep out of the case split between the real oil seal area and cam plug. I talked to Steve at GPASC and he said the all-metal cam plug used on my engine sometimes prevents the case from mating tightly in this location even if the plug is "sized" per the build manual. He said they now use the cam plug with the O-ring in their new engines. I really didn't want to split the case for a minor albeit annoying leak so I decided to "band-aid" the sucker. I thoroughly cleaned the exterior of the case from the cam plug to the real seal and ran a thick bead of J.B. Weld. This was 100+ hours ago and NO LEAK yet  -Scott |
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Post by smoothmat on Sept 11, 2011 22:33:15 GMT -5
Well i replaced the seal and hung the engine back on the plane today. The new seal fit more snug and was firmer than the old seal. After looking at the old seal i noticed that the spring inside was crimped as well as the sealing surface was worn uneven around. The old seal was quit a bit flimsier than the new seal. I hope that this one is good to go.
As far as the cam plug goes, i did install a billet alum o-ring plug when i built the engine. I would just pull my plane out and fire it up but i live in a condo development filled with mostly retired people and i have a feeling that the might not be to fond of that.
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Post by smoothmat on Sept 12, 2011 18:50:25 GMT -5
Anyone know if i there is a way i could test the oil system for leaks without having to fire up the engine.
My garage is very limited for space or i have to load the plane up and move out of the city in order to test run engine.
I was thinking of just plumbing in a aux pump with a pressure relief and pump oil through the system till i get a pressure reading on my oil pressure guage. I can inspect the seal and what not to check for leaks while the pump is flowing the system.
I also have a super sump with a drain bung on the front so i could just plumb my pump intake there and essentially it would be the same as the oil system but without running the engine.
Sound like a good idea or bad idea??
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