Oil quick drain issue

[MoonlightVFR]

Interesting Puzzle - Deserves an explanation.

One thought to explore may be the engine mount itself.

The engine block and engine support. Have they been married for fifty years ?

Engine mounts get Rebuilt, usually a one up rebuild from custom jigs at a custom shop. Who is Reading the ruler?

Bruce has an excellent thought - How is this going to fit together out at the prop w clearances with the cowlings?

[c170b53]

Gary, You took one for the team, I dislike disturbing a through bolt and it’s o’ring. I question the mount as this owner found the issue after the engine build, likely a time of more scrutiny. His mount from the picture looks like it could use some attention but that could just be the picture and “ on condition” is just that, it’s subjective. If the rest fits then it’s been there, if not it’s something new.

[170C]

Why do the instructions on some quick drain units say to never leave a hose attached to the drain? I have had a hose attached to mine every since I installed it 20+ yrs ago and have not had any issues. I know of others who do this as well.

[N2625U]

Why do the instructions on some quick drain units say to never leave a hose attached to the drain? I have had a hose attached to mine every since I installed it 20+ yrs ago and have not had any issues. I know of others who do this as well.

That may be because some would install it on an aircraft with retractable gear and when the nose wheel retracts it would push the hose and drain the oil making life interesting. Seem to remember reading something about that years ago.

[n2582d]

AD 81-11-02 R1

[170C]

Perhaps the thought Miles had regarding possible vibration issues might be the reason if on fixed gear aircraft.

[MoonlightVFR]

From a comment your shop made about a slight geometrical difference.

Is this newly rebuilt engine utilizing the same block "Case Halves" or did shop provide "NEW" case halves that have never been in your aircraft?

Bruce is right something is amiss.

[GAHorn]

From a comment your shop made about a slight geometrical difference.

Is this newly rebuilt engine utilizing the same block "Case Halves" or did shop provide "NEW" case halves that have never been in your aircraft?

Bruce is right something is amiss.

In his original post he mentioned they replaced the “engine case”.

[MoonlightVFR]

Leaving a hose attached to Quick Drain.

Vibration problem mentioned.

Here is where the problem rears it ugly head.

If you leave 12- 14" piece of Hose attached - You MUST fasten the hose with plastic ties to the metal engine mount.

If you leave the plastic drain hose end loose inside the cowl it is not vibration as the culprit. It is a constant fluttering of the hose that is transmitted to the quick drain plug . Big time fluttering at cruise speed. The O Ring gives way and full 100% oil lost while in flight. Engine heats up seizes before you realize what is happening.

Technology not developed to give you a little warning.

[OTIS]

Update......no solution. We decided to remove the quick drain and go back to original plug and gasket. There is not enough clearance to tighten the plug. Waiting on the engine shop to respond.

The engine mount never left the airframe. We did clean it up, primer and paint it. And yes, we replaced all the firewall mounts, bolts and nuts. The rebuild included the motor mounts and yes, we replaced all that hardware. And yes.....I had the prop inspected and painted.......and yes, new bolts.

If anyone thinks of anything........please post it. I’ll keep you posted.

Gerry

[Bruce Fenstermacher]

Gerry, your situation may have us all stumped. Not what you want to hear.

Perhaps someone can go to their 170 and accurately measure from the fire wall to spot on the back of the accessory case casting such as the forward edge where it meets the sump, and give that measurement to Gerry. He can see if his engine is sitting closer to the fire wall than others. Also, though I can't see how it would change, a measure from the accessory case forward edge to the sump drain.

[OTIS]

Bruce, getting measurement is our next steps. Could someone take a few measurements for us?

1. Firewall to the seam created by the engine case and accessory case on the underside of engine.
2. Seam created by the engine case and accessory case to center of back oil drain plug.
3. Firewall to front of crossbar.

Thanks everyone.

Gerry

[GAHorn]

The “change” in dimensions seem to be the relationship of the engine-to-engine mount... not that of engine to firewall.

Where did your rebuilder source the “engine case” and exactly what “case” was replaced? The crankcase halves? Or the sump? Or both?

Has your engine mount been altered from the previous engine’s mount? Or was it also rebuilt? (And by whom?)

[OTIS]

George, they replaced both halves, the sump is mine. The engine mount was not altered, just cleaned up while remaining on the airframe. The new engine fit back into the engine mount very easily. If not for the quick drain, we would not have seen this aft shift issue. I have looked through 18 years of pictures, but can’t find one that is useful in showing previous location of the quick drain.

Looks like we will be taking the engine back off to better inspect and verify all parts. Then try hanging it again and see what we have. Shot in the dark.....

At this point, there are four A&P mechanic’s, the engine shop and this forum involved. It will be figured out! lol

Thanks everyone for your input.

Gerry

[c170b53]

I'd like to thank the poster for giving us all a grey matter deep stir / swirl, I think its done me some good. Its kind of enjoyable to ponder such a problem, albeit not enjoyable for the owner here. Its going to take a collective effort to sort it out and that's exactly what I think we strive to provide here. Otis sorry if at times we ask a question or observe something that appears to be obvious to you but we are not in right front of the problem. Originally I mentioned my quick drain just to confirm that the space from the slip ring was quite close before the rebuild and now non existent whereas Bruce's picture suggests there's about an inch of clearance. Sounds like the discrepancy in distances was there before the rebuild. Either way, new or an old problem lurking, I'd like to see the distance between the two main cross tubes of the mount, measured and compared.