Oil Consumption Increas[ing] ?

[Mike H]

Originally Posted by BillFear

We just found a pretty substantial leak in our Saf-air quick oil drain. Only happens when engine is running at higher RPM and it only recently became obvious on belly just behind cowl hinge line. never had any oil on inside of cowling. We were up to using a quart every 2-3 hours.

Saf-air sent new O-rings to rebuild the oil drain, hoping for the best with this simple fix.

Do you keep a hose attached to this quick drain all the time, even when the aircraft is operated?

[BillFear]

Originally Posted by N520TX

How did you diagnose the problem to the oil quick drain? I've been chasing a pesky leak for a while now, with the same symptoms you describe -- on the belly behind the hinge with none on the inside cowl .. not 2-3 hrs per qt tho, yet.

--Ron

cleaned the engine real good with de-greaser and got it good and dry. Then ran it with the cowl off. Ran at 1750 for about 10 minutes watching the temps and looking the engine over with bright flashlight (be very careful this close to the prop!). oil started to slowly drip out of quickdrain valve.

Assumption is it does not drip on the inside of the cowling as it is right in the high speed air flow coming out of the engine and gets carried out with the air. Some of its gets picked up on the edges of the outlet and shows up just behind the hinge line. That is the theory anyway.

[BillFear]

Originally Posted by Mike H

Do you keep a hose attached to this quick drain all the time, even when the aircraft is operated?

No, have never had a hose on it. We always pull the cowling for oil changes to give everything a good inspection.

[vic syracuse]

Yes, I've noticed that the safe-air valves will leak, and seem to be worse with a hose on them.

Vic

[Mike H]

Originally Posted by vic syracuse

Yes, I've noticed that the safe-air valves will leak, and seem to be worse with a hose on them.

Vic

I have never had a safe-air valve that leaked yet, but I will definitely keep a closer eye on them. I have had several Curtis valves leak.

The reason I asked about the hose is because a hose that is left attached to a quick drain valve during engine operation (flight) will induce vibration and side loading on the drain valve which will cause wear and leakage. I am sure almost everyone already knows this, but thought it would be worth mentioning for safety reasons.

[g zero]

Never got the quick drain thing . I prefer a 2 foot AN8 or 10 hose fitted to the oil drain and a plug or cap on the other end . When you change the oil the hose goes out the bottom of the cowl , when done attach the capped end to the engine mount with a zip tie or adel clamp .

[Vlad]

Oil consumption on my near TBO O-320 increased to 1 qt every 5 hours or so. There are couple tiny leaks I am watching them closely. Blow by is about the same.

[krw5927]

Might be time for a leak-down (compression) check Vlad?

[Vlad]

Originally Posted by krw5927

Might be time for a leak-down (compression) check Vlad?

It's too early Kurt the engine isn't at TBO yet

[BillL]

Originally Posted by Vlad

Oil consumption on my near TBO O-320 increased to 1 qt every 5 hours or so. There are couple tiny leaks I am watching them closely. Blow by is about the same.

When you are flying under load, how do you know that the blow by has not changed?

Anyway, blow by increase, from new, is an indication that the top not second rings are not sealing as well. The oil ring is primarily responsible for the oil use control. That can happen independent from the compression and scraper ring. Not usual, but it can happen.

One reason (just one of many) for oil use increase can be the wear of the cross hatch. This allows a thicker oil film to form under the ring on the down stroke and that oil gets pumped back up on the up stroke. There are other reasons, but it also can occur as the oil control ring lands become too wide and begin allowing hydrodynamic lift along with the decrease in crosshatch. Again - leaving too much oil on the cylinder on the down stroke. Typically, all of this happens together - and is why a leak down test is a good indicator for wearout.

This is not much help for your issue, but, like above, it is either burn, blow or leak. This is only the burn portion.