Tach Oil Seal Installation, See Picture

[M Towsley]

Hi all,

I robbed this photo from Rob Lees, (haha), and want to make sure I install my new one correctly.

I am assuming the blue seal has an open side, (at least mine is even thought it is brown), with the small spring showing. (Not shown in this picture). From what I can tell, and from the Continental manual, the seal actually gets flipped around from what the photo is showing, part number to the inside of the tach drive housing, correct?

The Continental manual doesn't explain and the drawing is somwhat ambiguous compared to the the seal I have.

Common sense would indicate the open side to the engine allowing oil pressure, etc., to help the seal, seal around the shaft.

My old seal was enclosed and had two sides to it. My new one only has one enclosed side and one open side.

Thanks!!!

I took this photo of the green-colored seal from the internet. This is what the other side of my seal looks like. Does this side face the engine?

[Larry Lyons]

Re: Tach Oil Seal Installation, See Picture

Although I can not address your installation directly, as I have not worked on mine yet, oil seals are typically installed like you said, with the lip facing in so the oil pressure helps make the seal work. How ever just to muddy the waters a bit there, are some installations that have the seal facing out to keep dirt out and not oil in. L

[M Towsley]

Re: Tach Oil Seal Installation, See Picture

Thanks, Larry. I installed it with the open portion 'in' toward the engine/oil pressure. That is my understanding from some previous posts, though those posts weren't perfectly clear. I suppose I will find out soon enough, though my tach line and 90 degree fitting were 'well-oiled' prior to me installing a new seal so I suppose it can't get too much worse.

Instead of fixing the seal the prior owner wrapped the 90 degree fitting and the rear of the tach with a rag to catch any run-off. I found that hi tech fix when I pulled the instrument panel top cover off.

[gcgilpin]

Re: Tach Oil Seal Installation, See Picture

Your last photo is correct. The spring should be towards the engine (so the oil pressure will help do the sealing).

I had the exact same issue... a small but annoying oil leak. Finally narrowed it down to the tach seal, so I pulled it off and found it had been installed backwards. The overhaul manual I have actually shows it installed the wrong way!

Anyway, my leak is now gone.

[M Towsley]

Re: Tach Oil Seal Installation, See Picture

Great to hear, thanks for the input.

[Larry Lyons]

Re: Tach Oil Seal Installation, See Picture

Instead of fixing the seal the prior owner wrapped the 90 degree fitting and the rear of the tach with a rag to catch any run-off. I found that hi tech fix when I pulled the instrument panel top cover off.

Damn, you mean I am not the first to figure this "rag fix" out! We still use it in the field. L

[bashibazouk]

Re: Tach Oil Seal Installation, See Picture

Instead of fixing the seal the prior owner wrapped the 90 degree fitting and the rear of the tach with a rag to catch any run-off. I found that hi tech fix when I pulled the instrument panel top cover off.

Damn, you mean I am not the first to figure this "rag fix" out! We still use it in the field. L

Worked great for me until the oil migrated into the back of the tach. Harder to read the rpms when it's pegged!