Which replacement shaft seal?

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kacecar

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Hello everyone

After a rope-wrap that appears to have caused some damage to my now elderly propeller shaft seal I have decided to replace the unit. The current fitting is no longer made so replacement means a more extensive change. I know there are quite a few on the market but which one should I go for?

The boat is a Sigma with a 1" shaft (rather than 25mm) and a lipped / smooth metal stern tube with between 30 and 40mm showing on which to clamp bellows or whatever.

A bit of googling indicates that the imperial shaft size rules out the obvious contenders (the Volvo-Penta and the equivalent from Sillette). What are my remaining options and which does the forum suggest is the most cost effective in terms of fitting and maintenance?

Many thanks in advance for the help / thoughts.
 
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About 20 years ago I replaced my 1" shaft seal on a Sadler 29. I was advised by the suppliers that the 25mm Volvo seal would function and that was what I used. It appeared OK some eight years later when I sold the boat. It may be that this advice is no longer given and the product has changed but it may be worth asking.
 
I fitted a PSS seal to my Vega's 1" shaft last winter.
It was simple to install and works well; maintenance appears to be close to nil.

I spent a long time researching the subject, and kept returning to the Cox Engineering web site (above) for sensible objective advice rather than scare stories and opinions.
 
1" Volvo works for me, one grease and burp at the start of the season (assuming you remain afloat) then forget about it. I did look at PSS - do check the end of gearbox to end of stern tube distance as the uncompressed PSS is longer than the Volvo. I also had limited access and didn't fancy trying to compress with any accuracy the PSS bellows whilst lying flat on my stomach with minimum arm & head room. If the stern tube diameter is too small for the Volvo you can buy spacers (for the PSS!) from Aquafax which fit a treat.
 
What sort of drive shaft coupling do you have?
For the Volvo seal (which is definitely available in a 1" size) it is recommended to have a rigid shaft coupling not flexible. I expect the Radice would be the same.
 
Good afternoon:

Before having anything to do with a PSS seal I suggest you read about the problems this seal has caused me over the past two years (Post 39 onwards) - http://www.ybw.com/forums/showthread.php?t=289854

To add insult to injury the makers in the US do not even bother replying to efforts to contact them. I sent a message to a company in France where I attempted to obtain some spare grub screws earlier responded almost immediately even though today is a holiday in France.

Cheers

Squeaky
 
Good evening:

bert49uk: dont think its a problem with PPS you say in your post you think its non genuine ?

At the time I posted that remark I was so darned angry that I tried to think anything in an attempt to cool down. I have no idea if it is original, fake, made in some local workshop or what and don't think I will until PYI respond to my messages which were politely written and phrased so as not to give them any excuse for refusing to reply.

Yes, I have the same address as you posted although my two attempts so far have been via their "contact us" form on their web site.

Was impressed with the response from the company in France I had been in contact with earlier concerning grub screws - http://www.seavieweurope.com/en/product_categories#

Their web site is very similiar to that of PYI so suspect there is some connection but will have to wait until tomorrow when I expect to hear from them again - today is apparently a holiday in France.

Cheers

Squeaky

P.S. PCUK - never a problem for me.

I am sure there are thousands of seals in use that have not caused any problems but the two that I purchased certainly did have problems - over a year apart, by the way. I don't know what your post was meant to imply or add to the discussion but suggest that the images attached to my posts would indicate that your experience was markedly different from mine with the PSS seal.
 
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Volvo is cheap but don't go for it if you have difficult access, for it needs it's burp and regular greasing. This is a proceedure that regularly gets requests for help. Dont consider the Volvo if you ar not 100% sure that the shaft is round and undamaged or if you have a flexible engine drive (eg Technodrive).
I would not go for a PSS if you have very limited clearance between the shaft and the stern tube and/or a single cylinder engine with soft mounts. I have seen complaints against all the main types of stern gear on these pages. We all wait for the outcome of PSSgate with baited breath, was it was a pretend one or the real thing?
 
Troubadour said:
What sort of drive shaft coupling do you have?
For the Volvo seal (which is definitely available in a 1" size) it is recommended to have a rigid shaft coupling not flexible. I expect the Radice would be the same.
Click to expand...

Not sure where this idea comes from. Many installations, including original equipment use a Volvo seal with a flexible coupling. There are very, very few setups that have a totally rigid drive these days as engines are on flexible mounts, so something in the drive train must be flexible, either the coupling or the shaft itself which usually floats except at the aft end where it goes through a bearing. Many installations have both a flexible coupling and a floating shaft

The OP will have no problems with a Volvo seal in his application should he choose it.
 
Tranona said:
Not sure where this idea comes from. Many installations, including original equipment use a Volvo seal with a flexible coupling. There are very, very few setups that have a totally rigid drive these days as engines are on flexible mounts, so something in the drive train must be flexible, either the coupling or the shaft itself which usually floats except at the aft end where it goes through a bearing. Many installations have both a flexible coupling and a floating shaft

The OP will have no problems with a Volvo seal in his application should he choose it.
Click to expand...

This idea comes from Volvo Penta actually.

Here's a quote from the installation manual for all the D1 and D2 series engines as an example
"When using a flexible shaft seal and flexible engine
suspension, a flexible shaft coupling must not be fitted."
Also see http://www.boatdesign.net/forums/boat-building/volvo-penta-shaft-seal-flexible-coupling-40379.html - but I have to admit my rather old copy of the seal manual does not include the bit quoted by the poster.

I agree the whole thing can't be completely solid - I am assuming flexible engine mounts. Then the engine can wobble, the back end of the shaft is relatively firmly located in the P bracket, and the seal follows the shaft movement. I can't really see why a flexible coupling is bad - but VP should know better than me or you!

As a sideline, the VP manual for the seal gives a shaft diameter tolerance for the 25mm seal of 25 +0.1, so if the OP does want to use a Volvo seal, it seems advisable to seek out the correct 1" one. I suspect the small tolerance must be more to do with the inbuilt cutless bearing than the rubber lip seal.

PS Just to be clear, I think the Volvo seal is excellent, I'm not in any way knocking it. Burping and greasing is nothing to worry about unless really inaccessible. Grease using a drinking straw - fill it with grease and squeeze it in.
 
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Troubadour said:
Here's a quote from the installation manual for all the D1 and D2 series engines as an example
"When using a flexible shaft seal and flexible engine
suspension, a flexible shaft coupling must not be fitted."
Also see http://www.boatdesign.net/forums/boat-building/volvo-penta-shaft-seal-flexible-coupling-40379.html - but I have to admit my rather old copy of the seal manual does not include the bit quoted by the poster.
Click to expand...

I think you will find that is standard advice, nothing to do with the seal type. There are three components that can be flexible in any installation - engine mountings, coupling and seal mounting. However, if all three are flexible the installation will be uncontrollable. The rule of thumb is that any two can be flexible but one must be fixed.
 
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