Dripless shaftseal?

[Captain-Hook]

Greetings. I am upgrading my Perkins m30 with a new to me hbw 150 in place of my blown hbw50 r. I must raise my engine 11mm and move my engine forward 2.5 inches because my Endeavor 32 has only 2.9 inches between the shaft coupling and my stuffing box and I cannot replace packing if I take away 2.5 of the 2.9 clearance. Question. Is there a dripless seal that would fit into my present stuffing box space so I can just cut my shaft for the new gear? Moving forward has its own issues like adding 3 inches to both stringers and expanding my engine cover and water pump sticking into galley and................... That volvo seal looks relatively small but does it replace the stuffing box or add to it? Thanks again for patience at my lack of knowledge on these seals.

[nuku34]

a photo or 2 of your engine and propshaft and existing stuffing box would be worth a 1,000 words.. I've not seen a dripless seal that would fit in a 2.5" space.

[seaexplorer]

PSS Shaft seal?
You haven't stated shaft diameter so its not possible to answer your question.

[Captain-Hook]

I will get a picture shortly today.

[OldManMirage]

You must have an earlier Endeavour, as my 1980 model has at least a foot of room behind the coupling. I have noticed this before in other conversations. I don't have an answer for you. Yet.

I do believe the shaft is still 1 inch, I don't they ever used anything other than that. Do you know the size of your shaft log ? The part that the stuffing box tube is attached to, where the shaft comes into the stern.. I believe they were always 2 inches BUT, I am not certain if that was true on the early models like yours.

I would appreciate if you could let me know just for my own information. And it may help us all help you.

And yes, pictures definitely speak a thousand words for us here.

[SailingHarmonie]

Just an observation or two about shaft seals in general.

Let's make two assumptions that I will grant are frequently NOT true, but should be:
1.) The shaft is as smooth as it should be,
2. The engine is properly aligned.

In this case repacking the shaft should be a rather infrequent operation. Yes, you do need to adjust the gland nut occasionally, but fully pulling it out and replacing packing is rare. Even rarer if you use a product like DripLess Packing. or the all teflon braided packing.

Other types of seals, usually lipseals or carbon face seals, might not drip, but do not assume that they are forever either. They need to be replaced, with even more hassle than repacking because in most cases you need to pull the shaft. The PSS seal for example needs to be disassembled and have parts replaced every 6 years. Lipseals tend to need replacement every 1000 engine hours or so.

My point is not that you should not use a "dripless" seal, but that you should be aware that you might not actually be saving the work that seems to be your motivation for going that route. It might be different if you simply do not have the room to actually properly adjust a packing gland net. If this is the case, consider changing to the gland that use two bolts to compress the packing. These are WAY easier to adjust in tight quarters.

There are downsides to a lipseal or face seal. Either of these can fail suddenly and catastrophically. It's rare, but it most certainly does happen. If you are far offshore, or far from a boatyard, you might have a real problem. Packing glands do not have this issue. When they fail, they drip faster.

[Pete7]

Originally Posted by SailingHarmonie

There are downsides to a lipseal or face seal. Either of these can fail suddenly and catastrophically. It's rare, but it most certainly does happen. If you are far offshore, or far from a boatyard, you might have a real problem. Packing glands do not have this issue. When they fail, they drip faster.

Are you aware of a Volvo seal failing suddenly and catastrophically?

We have used volvo seals for about 14 years now. They fail very slowly and start to drip in use but still hold water pressure when the shaft is stationery and will run for a long time like this. We do carry a spare but always wait until the next lift out to change it.

Pete