Shaft Seal

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gavin400

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I am replacing my engine and am considering changing the original shaft seal (packing and greaser) to a modern type

Ideally one that doesnt require burping because access is very restricted

Does anyone have any recommendations

Many thanks
 
We have a PSS and it seems to work well. The only problem that might affect you is that it needs to be "unstuck" after a longish period without being used.
 
Radice, which is a version of the Volvo type seal but with a vent that removes the need for burping. Also a port for greasing which avoids the need to go to McDonalds to get a straw (the recommended tool for greasing the standard type. Of you have problems fitting the Radice because of the external diameter of of the stern tube then a Tides Marine is also a vented lip seal, although a different design, but has a greater choice of bore size for attachment to the tube.
 
gavin400 said:
I am replacing my engine and am considering changing the original shaft seal (packing and greaser) to a modern type

Ideally one that doesnt require burping because access is very restricted

Does anyone have any recommendations

Many thanks
Click to expand...

Out of interest, why are you considering changing your stuffing box? I have been contemplating doing the opposite and changing my lipseal stern gland back to a traditional stuffing box
 
SlowlyButSurely said:
Out of interest, why are you considering changing your stuffing box? I have been contemplating doing the opposite and changing my lipseal stern gland back to a traditional stuffing box
Click to expand...

Now the engine is out and access is good I thought it would be a good time to modernise the system - the original has never been a problem, but i have been moving the shaft back and forward quite a bit for the engine works and Im pretty sure the existing will leak and need adjustment etc when back in the water and access will be difficult and possibly more peace of mind with a dripless seal
 
Tranona said:
Interested in why you are thinking of going backwards?
Click to expand...

The shaft has been scored by the lip seals. Each time I have changed the seals I have cut about 6mm off the rubber hose that connects the stern gland to the stern tube to move the lipseals onto a new bit of shaft. There is not enough clean shaft left to do this again so next time the seals need replacing (which I do every 1000 hours) it will need a new shaft, or fit a stuffing box which will tolerate the scoring on the shaft.
 
I have removed the old stuffing box in preparation for a new lip seal - probably radice

I have noticed 2 things:

1. The shaft is unsupported and not centred in the stern tube - the photo shows the stern tube end at a half bulkhead
It appears the original stuffing/packing was the only thing keeping the shaft centred
Should there be a bearing/spacer to centre the shaft in the tube, and if so what material should it be?
What would stop this overheating?

2. The shaft has been worn where the packing material was - down from 1 inch to 0.960 inch - is this a problem?

All advice gratefully received

Many thanks

Gavin
 

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SlowlyButSurely said:
The shaft has been scored by the lip seals. Each time I have changed the seals I have cut about 6mm off the rubber hose that connects the stern gland to the stern tube to move the lipseals onto a new bit of shaft. There is not enough clean shaft left to do this again so next time the seals need replacing (which I do every 1000 hours) it will need a new shaft, or fit a stuffing box which will tolerate the scoring on the shaft.
Click to expand...
Sounds like an ideal candidate for a PSS face seal which does not run on the shaft. If you have not got the stuffing box and hose already then a PSS may well be cheaper as well.
 
gavin400 said:
I have removed the old stuffing box in preparation for a new lip seal - probably radice

I have noticed 2 things:

1. The shaft is unsupported and not centred in the stern tube - the photo shows the stern tube end at a half bulkhead
It appears the original stuffing/packing was the only thing keeping the shaft centred
Should there be a bearing/spacer to centre the shaft in the tube, and if so what material should it be?
What would stop this overheating?

2. The shaft has been worn where the packing material was - down from 1 inch to 0.960 inch - is this a problem?

All advice gratefully received

Many thanks

Gavin
Click to expand...
Quite common for the shaft to float in the stern tube. You need to centre when you lone the engine up without the seal, then disconnect the shaft put the seal on and reconnect.

If that were my boat I would remove that inner rube housing, have a bearing (length of cutless or you could have one made in a composite like Vescomite or Maritex) inserted and the outside machined to take a Radice seal. you would have to use a good flexible coupling like a Bullflex or a Centaflex as the shaft will be fixed. New shaft needed with that amount of wear IF it is where the Radice seals will run.

This exactly what I am having done with my new Beta installation in my GH. My shaft length is on the limit for having no intermediate bearing. I like this arrangement as that is what I eventually ended up with when I re-engined my old Eventide and it worked very well - I am using a Bullflex coupling, again the same as I used before.

Hope this helps.

BTW where are you located? Lake Engineering in Poole are doing the machining on mine.
 
Tranona said:
Sounds like an ideal candidate for a PSS face seal which does not run on the shaft. If you have not got the stuffing box and hose already then a PSS may well be cheaper as well.
Click to expand...
Thats just what I did following crevice corrosion with my nearly new Tides marine shaft and seal. ( thought to be due to the very fouled 'dead' water in calliagari marina)
 
SlowlyButSurely said:
Unfortunately there isn't enough space for a PSS otherwise that would be a good solution.
Click to expand...
That is a shame. Wear in the shaft at the lip seals is a potential downside of the Volvo type seal, but maybe due to difficulty of greasing with the standard type. In my new installation we are putting in a water feed because of the length of the stern tube. Not sure it is strictly necessary but not difficult to arrange.
 
gavin400 said:
I have removed the old stuffing box in preparation for a new lip seal - probably radice

I have noticed 2 things:

1. The shaft is unsupported and not centred in the stern tube - the photo shows the stern tube end at a half bulkhead
It appears the original stuffing/packing was the only thing keeping the shaft centred
Should there be a bearing/spacer to centre the shaft in the tube, and if so what material should it be?
What would stop this overheating?

2. The shaft has been worn where the packing material was - down from 1 inch to 0.960 inch - is this a problem?

All advice gratefully received

Many thanks

Gavin
Click to expand...
The lip seal has a bearing at the back of it. So when you fit it you have a bearing
See here on Vyv Coxs site https://i0.wp.com/coxeng.co.uk/wp-content/uploads/2017/07/DSC_6040a.jpg
 
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