SailNet Community - View Single Post - rebuilding Oberdorfer Pump
View Single Post
post #25 of Old 08-09-2011
eherlihy
Learning the HARD way...
 
eherlihy's Avatar
 
Join Date: Jan 2007
Location: Boston / Ft Myers Area
Posts: 4,029
Thanks: 158
Thanked 106 Times in 103 Posts
Rep Power: 9
 
degreeoff,

Thanks for the thought, but that is not the case... I had another exchange with someone on the same topic. I am sure that the seals are in in the correct direction.

Yesterday, I took her out for a couple of hours. While someone else was at the helm, I rechecked the engine, and in particular the water pump. I did not see a drop of water, nor signs of a leak in the time that I spent looking at the engine. I ran it at different RPMs, and everything was tight for over 15 min...

Because I did not look at the leak after the engine had come up to temperature, I'm more than a little puzzled...

I have a hypothesis though; I wonder if the water gets between the seals (Number 8 in the illustration above) and the graphite bearing (Number 12) when the engine is cool. After starting the engine, heat causes the shaft (Number 6) to expand and the shaft and graphite bearing close the gap. A few teaspoons of water are now trapped between the end of the bearing and the seal, and this water is heated as the now warm, shaft is in contact with it. Because the ingress hole, between the bearing and the shaft, is now sealed, water has nowhere else to escape but between the shaft and the rubber seal. Thus my elusive leak through the weep hole. Put another way, it is supposed to leak BRIEFLY.

Comments?

Last edited by eherlihy; 08-09-2011 at 09:49 AM. Reason: Illustration references
eherlihy is offline  
Quote Share with Facebook
 
 
For the best viewing experience please update your browser to Google Chrome