By Craig Brougher
|Howard Wyman asked:|
> 1. Should there be a felt strip, and should it be on both the inside
> and outside valves? Should it be over the wire that goes down the
> center of the inside valve openings and how wide should it be?
> 2. Reblitz also mentions that often the valve "seats" are rotten.
> Should there be leather valve seats for the leather flap valves to
> seat on rather than just the bare wood?
Ampico pump outside flap valves seat on just the wood. They are not as critical, because they do not have to hold a vacuum for the entire system, as do the inside valves.
Art Reblitz is correct about inside flaps and seats, both. Never rebuild an Ampico pump without replacing these all important seats, as well as valves, and the inside flaps do sit on a wire, not a felt strip. However, you cannot simply throw another flap on, cover the bellows and call it done. The new inside flap valves have to be "formed" by moistening them and stretching them with a rounded tool which creates a molded dent in the center of each flap, allowing the flap to sit tight on its seat while at rest. You should be able to tape over the feeder through holes, put a cork in one having a suck tube, and suck the flap down easily by mouth. If you can't do that, your flap needs to be adjusted and molded until it is seating without effort.
A thumping pump can be caused by any imbalance which is able to cause one bellows to pump less than the others, or any group of bellows to outpump. I can find an offending bellows by grabbing one of the connecting rods while it is running and feeling the click in my fingers. I can also stop it temporarily. But you have to be quick. Those things can tear you up if you miss, so I don't recommend everybody doing this. Very occassionally all you need to do is squeeze the wooden wedges tighter in the rods all around, but very seldom does this work for long. If that worked, then your only problem was an uncompensating wooden wedge.
(Message sent Sat 26 Oct 1996, 17:44:44 GMT, from time zone GMT.)