The International Cessna 170 Association

I need some advice as the drawing in the IPC isn't very clear:
I need to know which way the seal should be installed in the housing; with the open side toward the engine, or the solid side toward the engine? The one I'm replacing was with the open side toward the engine but that just doesn't look right to me. I just want to get it right so that I don't have to take it off again.
Thanks in advance...

Remember Bill, you sealing oil in the engine.
The side you see in this picture should be towards the inside of the engine.

Thanks Bruce, that's the way the old one was but it just didn't look right for some reason. A lot of things just don't look right to me any more.

While not applicable particularly to HineywheelBills example... it was pointed out to me in Kelowna by Steve Grimsley that SOME tach drive seals are double-sided/fully-enclosed.... I.E., both sides of the seal are metal. There is one side which has an obvous "seam" where the outside sheet metal overlaps the inside sheet metal cover. That seam should face into the engine if you have such seal.

(I believe that is an older style seal, but may still be encountered if one acquires NOS (New Old Stock). Rubber items such as seals have "shelf lives" that typically are less than 10 years, so hopefully those will not be found in the 22nd century.)

Hope that helps.

I have an old spare housing that had a seal in it like the one you described. I have been chasing an oil leak for a while and I think I finally found it, just waiting for another new seal to come in so I can put it all back together. The problem, I think, is that the housing was warped such that the three corners (bolt holes) are drooped down slightly. This can be seen when the housing is sitting on a flat surface. Of course, this allows oil to leak from under the gasket when the oil gets hot. Quite a messy situation after an hour or two of flying.