All,
I spent the last 15 years of my career in the aircraft hydraulic pump
business. We used the PYI type face seals for all of our pumps,
electric motor pumps and hydraulic motor driven generators. Many of the
older units used the carbon graphite nose pieces. The newer units use
Tungsten Carbide nose pieces. These seals have a life of about 30,000
hours (the carbon graphite have a life of about 10,000 hours) running at
speeds of 2,000 to 12,000 rpm at 35,000 foot altitude. At these speeds
we try to control leakage to 5 drops per hour in hydraulic oils. Our
boat environments are a little easier. That being said, what the carbon
graphite nose pieces hate is shock and misalignment. We controlled
flatness on the pieces to .000070 inches (6 helium light bands).
Our last boat (C&C 35-1) had an old style (no vent tube) for 16 years
with no problems. Burped it on launch and it worked great. Just put a
PYI Packless Shaft Seal in our new boat (C&C 35-3).
We have a lot of places on the boat that can allow the water outside to
come in. This is just one other.
Neil Schiller
1983 C&C 35-3, #028, "Grace"
Whitehall, Michigan
WLYC
On 10/22/2018 9:50 AM, Della Barba, Joe via CnC-List wrote:
I have had 0 problems with mine since about 1987. The hose and seal were
swapped out in 2014 I think while the shaft was out as preventative
maintenance. That apparently should have been done in 1994! Anyway, modern
Teflon packing has made the conventional stuffing box pretty easy to deal with.
Joe
Coquina
C&C 35 MK I
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_______________________________________________
Thanks everyone for supporting this list with your contributions. Each and
every one is greatly appreciated. If you want to support the list - use PayPal
to send contribution -- https://www.paypal.me/stumurray
