MoodySabre
Well-Known Member
I had my reservations but they were unfounded. 4lt/min is only a small amount compared to the output of a raw water pump.
Shaft seal water feed
- Thread starter maej
- Start date
Tranona
Well-Known Member
Not sure why they say that as the whole idea of a flexible coupling is to reduce movement of the shaft relative to the engine. From what I have seen plenty of OE installations such as Beneteaus and Jeanneaus (and earlier boats such as Westerlys) use them with flexible couplings. Mine was originally used with a bouncy Yanmar 1GM and a Bullflex coupling (now a Nanni 14), but the shaft does not float as it has bearings at both ends of the tube.
One of the less obvious features is the fluted rubber bearing that takes up most the length and effectively acts like a cutless providing some support for the shaft.
One of the less obvious features is the fluted rubber bearing that takes up most the length and effectively acts like a cutless providing some support for the shaft.
exfinnsailor
Well-Known Member
Get a collar made for your housing that takes it from 1 1/2" up to 1 3/4" wall thickness of 1/8" will be Ok. Glue it into place and fit your Volvo seal. They make a 1" to 1 3/4" . It will be cheaper than messing about with other versions and will probably last longer. Any decent engineering shop would make one for you it's hardly rocket science 
Sorry Tranona missed your post .. Great minds think alike
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Sorry Tranona missed your post .. Great minds think alike
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Simondjuk
Well-Known Member
The PSS is a possibility and I know of another Sadler 34 that uses one, but I can't help but be swayed by all the hype over them. Still, my current thinking is I would rather the face seal than start messing around with my engine coolant.
So we have Radice and PSS that can both be vented without forced cooling.
Can anyone tell me the distance between stern tube and the bit of a PSS that sits on the shaft? Potentially if it is longer than my old seal I won't need to replace the shaft as it will sit on an unworn bit which would be a nice saving
Where in the UK can the Radice seals be bought from?
What's the hype you hear? All I hear is that they generally give many years of trouble free service.
The total lengths (both uncompressed when fitting and compressed once 'set') are given here... http://www.shaftseal.com/en/categories/300000001
I fitted one recently and found it to be a well made piece of kit, a breeze to fit and it sealed straight out of the box, with barely a mist or any dust when first run.
The one concession I have made is to back up the grub screws in the rotor with the addition of a couple of jubilee clips on the shaft immediately forward of it to prevent the rotor moving up the shaft should the grub screws lose their grip on the shaft. They probably never will but why not have a safeguard when it's so easy to provide.
David2452
Well-Known Member
Worth a mention that the VP seal can and often is used with an open vent or a pressure feed and then needs no burping or lube, the lube is only to help untill the water gets there properly on non vented aplications.
keesvugts
Member
For what it is worth, I have a pss seal on a Sadler 34 for 2 years, simply vented without any leaks or problems. There are two O ring to seal against the shaft so a little wear is no issue. Seal runs cool even with 20 hours non stop motering. Result nice dry and clean bilge, much better than the old stuffing box.
Staight forward to fit, O rings are a tight fit and the grub screws are backed up, nut. The suggested hose clamp as additional safety is a good idea.
Staight forward to fit, O rings are a tight fit and the grub screws are backed up, nut. The suggested hose clamp as additional safety is a good idea.
maej
Well-Known Member
My current stern tube has 2 dogs protruding outward that are supposed to engage with the stuffing box. Should these be cut off for fitting one of these other types of shaft seal? Sorry for the dum question.
Simondjuk
Well-Known Member
Yes, with the PSS you do need the forward end of the tube to be circular to accept the seal bellows, but only for the insertion depth of tube into bellows which isn't that huge.
Ridax
Well-Known Member
I don't think the VP seal is available with a connection for pressure feed or venting. It is probably the Radice seal you are thinking about in that case.
I have the Radice seal with venting. Only used it for one year, so has nothing special to report, but so far it is working well at least. Another improvement with the Radice seal over the VP seal is that it is easier to apply grease.
David2452
Well-Known Member
No I mean the VP seal, but perhaps I should have been a little clearer, the ones I have seen and the ones Beneteau and some other makers fit from new have the feed or vent at the top of the shaft tube rather than in the `seal itself.
Ridax
Well-Known Member
But I don't believe VP are making any such seal. See their broschure at http://www.volvopenta.com/SiteColle...Parts brochures/Rubber Stuffing Box (Eng).pdf . Radice on the other hand has "improved" the design a little with a feed/vent and grease hose. See their picture at http://www.elicheradice.com/imgsize...siale_RMTA_RMTO.jpg&w=500&h=450&constrain=yes
vyv_cox
Well-Known Member
No, I left mine on when fitting my PSS. You can see them in the Aquadrive section of my website.
David2452
Well-Known Member
The fact you don't believe it does not alter the facts, VP seals are fitted to new Bennys and others (have been for at least 6 years) and the vent is provided at the top of the prop tube, as I said it has nothing to do with the seal itself, the vent is tapped into the tube and has nothing to do with the seal. got it ? Actually I think the ones in your photo have a potential to fail where the vent is joined to the rubber, the VP ones with the tap in the top end f the prop tube have less as they are a metal to metal joint.
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Ridax
Well-Known Member
So... Then the VP *seal* is not available as vented. Just as I said.
David2452
Well-Known Member
Indeed so, but it can easily be vented if required.
Simondjuk
Well-Known Member
Only if you have enough exposed tube aft of the seal collar once fitted over the tube, which some boats will not.
ghostlymoron
Well-Known Member
I would have thought that the air vent needs to be at the highest point of the system otherwise some air will be trapped inside. As all? drive prop shafts rise towards the engine, the air is better vented from the seal itself rather than the stern tube. Agree though that a metal to metal connexion should be more robust.
Another thing I noticed on the VP website is that their seals are unsuitable for use with a flexible coupling. Does that include the R and D as that's what I've got.
I think the main advantage of the traditional stuffed gland is that it's unlikely to fail catastrophically. You can tighten the gland if you notice more leakage than usual and that will allow you to proceed to somewhere where you can do more maintenance. The Tides/PSS/VP seals can all fail in a serious way.
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Tranona
Well-Known Member
It will vent from that position. Do not know why Volvo advise against use with flexible couplings as the whole idea of such couplings is to reduce movement of the shaft relative to the engine. Many OE installations combine flexible couplings and Volvo seals. Mine has been like that for over 10 years.
It is important to understand the differences between the types of seal. The fundamental difference between a Volvo/Tides/stuffing box is that the seal is around the shaft, whereas the PSS type rely on a face seal between a fixed and a rotating disc held together in compression. Seals that run around the shaft wear slowly and do not fail catastrophically. The only difference between lip seals and stuffing boxes is that the latter have some degree of adjustment to compensate for the wear.
Simondjuk
Well-Known Member
There's not always much in it failure wise. When my old lip seal failed it let water in at about the same rate as the replacement face seal does in an compressed failure state.
