Should This Be Loose? Possible Oil Leak Location

[AaronDC8402]

We did the first oil change on 1ZX last week. This was the first time since buying that we had both the top and bottom cowlings off of the plane. There seems to be a small oil leak on the back of the engine. I attached a picture of where the leak seems to be coming from. Hopefully, there's enough of a picture to be helpful. I've got two questions:

1. What is this thing? My best guess is a tach sending unit, but i expected there to be a cable for the tach instead of electric. 
2. How is this fitting attached to the engine? The whole sending unit moves up and down a little. Seems to only move in one axis. 

The oil change went great otherwise. Nothing "extra" in the oil filter. A quick drain was already installed, and works like it should. I've got some ideas for making less of a mess with the oil filter next time. The oil leak must not be too bad. No puddles under the plane, and we've only put in about 1 quart every 7 or 8 tach hours.

 

 

[carusoam]

The label usually has enough detail on it to identify what it is.  That's what labels are for. 

It is also in the area where the tach output goes for the O360.  The cable output was pretty dry on the side the cable screwed onto...

What type of display does your ship have for rpm?  (Updated by PO?)

probably not:

- MP - closer to the air intake side of things of a cylinder.

- FP - closer to fuel pump.

- OilT - thermistors are simple devices.

- OilP - hmmmmmm  (the oil gear pump is back there somewhere?

- FF - on the fuel line headed to the engine.  Often on the firewall.

 

PP guesses of what it might be.  Not a mechanic.

best regards,

-a-

[AaronDC8402]

Oh yea, the label is there, but a little damaged. In particular, where the part number is located. Picture below. The date on the label is May 1988, so I'm guessing it's original to the plane. It's got the original tach over on the far right of the panel.

 

[cnoe]

My A3B6D has the tach cable in that location. The label has "? rpm" in one field. Is it an electric tach sender as previously mentioned? I'd guess yes (just a guess though).

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[Guest]

That is the tachometer generator, same location on every Lycoming I've encountered.

Clarence

[cnoe]

Never heard that term before but that's no surprise. Sure enough though, the parts manual lists a tach generator for model numbers 24-3014 and on. I learned something new tonight; now I can go to sleep.

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[AaronDC8402]

8 hours ago, M20Doc said:

That is the tachometer generator, same location on every Lycoming I've encountered.

Clarence

Thanks! It looks like I was headed in the right direction. Any idea how it is attached to the engine? The tach generator threads onto another piece (adapter?) that attaches to the engine case. The adapter piece to the engine is what seems a little loose, but only in the up/down direction. Is there a seal in there that might need to be replaced?

 

[Guest]

8 hours ago, AaronDC8402 said:

Thanks! It looks like I was headed in the right direction. Any idea how it is attached to the engine? The tach generator threads onto another piece (adapter?) that attaches to the engine case. The adapter piece to the engine is what seems a little loose, but only in the up/down direction. Is there a seal in there that might need to be replaced?

 

I have to look at the engine IPC to determine how it is assembled.  Needless to sat there will be some form of seal.

Clarence 

[N201MKTurbo]

The tach drive has a seal in the accessory case. If you unscrew the knurled cap and remove the generator you will see the rotating shaft. there is no seal between the drive and the tach generator. 

The part number of the tach shaft seal is LW-14260. You probably have to remove the accessory cover and pull out the tach drive shaft to replace it. I would just wipe up the oil periodically.