PSS Shaft seal lubrication

lumphammer

lumphammer

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The inlet for the cooling water on my PSS Shaft seal is very close to the cabin floor when installed in the upright position, and there is danger of the hose rubbing and being worn through due to vibration as the engine is running.
I would like to rotate the carbon bearing so the hose fitting is at the 3 o'clock position. This will obviously leave the possibility of a small airlock at the top of the fitting. Is this going to cause me problems due to overheating?
The boat is a Moody 36, so not high speed:)
 
lumphammer said:
The inlet for the cooling water on my PSS Shaft seal is very close to the cabin floor when installed in the upright position, and there is danger of the hose rubbing and being worn through due to vibration as the engine is running.
I would like to rotate the carbon bearing so the hose fitting is at the 3 o'clock position. This will obviously leave the possibility of a small airlock at the top of the fitting. Is this going to cause me problems due to overheating?
The boat is a Moody 36, so not high speed:)
Click to expand...

why not tee the feed from your raw water inlet or the engine side of the raw water pump
 
I would do what the chap above said but make sure it's on the downhill side of your anti-syphon valve. I have done it on my contessa26 and it works great.
 
I would check with PSS, but that should not cause any problems.
I believe the original PSS seals came without vent, the vent was an option for boats that went over 10 knots. They later changed to make the vent standard ( and recommend water injection for over 10 knots).

BTW my vent leads to 2m above the WL, but I still get a few dribbles of water out of it when setting the anchor and reversing hard. I had to lead the vent to a small collection bottle that needs emtying every few months. (My bilge is always kept completely dry)
 
Last edited:
lumphammer said:
The inlet for the cooling water on my PSS Shaft seal is very close to the cabin floor when installed in the upright position, and there is danger of the hose rubbing and being worn through due to vibration as the engine is running.
I would like to rotate the carbon bearing so the hose fitting is at the 3 o'clock position. This will obviously leave the possibility of a small airlock at the top of the fitting. Is this going to cause me problems due to overheating?
The boat is a Moody 36, so not high speed:)
Click to expand...

We have had the earlier, non-lubricated, PSS Shaft Seal fitted for nearly eight years and have had no problems with it. In that time it has done more than 10,000 miles.
 
The vent's purpose is to avoid the need for burping. If you had some doubts about the rotated vent position, separate the faces briefly at convenient times to burp the small air pocket that might form. I doubt that it would be a problem though, so long as some of the seal face is immersed it will wet out the rest as soon as the unit revolves.
 
As Vyv says, the hose is simply to make the seal self-priming and avoid the need for 'burping' after drying out. There's no such thing as a non-lubricated PSS seal, unless it's running bone dry.

The hose on mine has been at 3 o'clock (or is it 9?) for six years with absolutely no problem.
 
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