The Cessna 120-140 Association Forum

So my Edo-Aire/Sigma Tek vacuum pump is still going strong after 2160 hrs give or take but when it dies I want to remove all the vacuum accessories (DG and AH) and get rid of maybe 12-14#.

Does the bevel drive gear (31) for the pump get removed when we remove the pump or does it stay in? I have a cover plate for when the pump comes off (44) so that's the easy part.

I don't know if the bevel drive gear provides some sort of tension to the camshaft, my sense is that it doesn't. Question will also be posed to the engine guy on the field.

I've been saying the pump is going to die for probably 10 years now but it just keeps ticking. I can hear the (aluminum?) vanes in it slide about when the pump is off so I know something is going to happen one of these days!

What does your A&P/IA have to say about this?

That's what I'm working on. He's a little busy with some airport stuff at the moment (see Pilot's Lounge)

Well then!
The Gear (#31) remains with the Vac. Pump when removed.
And Just leave the gear that is on the end of the cam alone!! The block off plate
bolts in place of the pump. But not the one in the diagram,( as You stated)
as it has a BIG HOLE in it!
Fresno Aircraft engine parts supplier in Cal. should carry the correct block
off plate!

Yup, I got the correct plate from Fresno years ago and I carry it in the plane with gaskets and some gasket paste/tools. Never know when the pump is going to go belly up.

PM sent to you-

I did that on my O-200. Removed everything in the picture and insalled the flat plate with new gasket. Still going good. 20 years and 1200 (or so) hours.

I've got the flat plate to replace part #44, I wonder if there is a flat plate to replace where part #39 contacts the engine case.

6597 wrote: ↑Fri Mar 07, 2025 5:53 pm I've got the flat plate to replace part #44, I wonder if there is a flat plate to replace where part #39 contacts the engine case.

I fabricated my own. it’s pretty simple. i’m removing the bevel gear drive to reduce weight, but will leave the gear on the camshaft bolted in place. this is for an experimental build, though, not a certified engine.