shaft seals, lip seals,..oh my

[Matt Johnson]

Originally Posted by perchance

The problem with rotary face seals is any amount of dirt or grit will cause them to leak.
Mechanical seals with graphite and ceramic components will not even tolerate the oil from your fingers.

Can the face be cleaned? Maybe grease on the face is why mine leaks so bad.

[delmarrey]

Originally Posted by funjohnson

Can the face be cleaned? Maybe grease on the face is why mine leaks so bad.

If you were to take it off you might be able to soak it in a brake cleaner or acetone. If you have the PSS, I'd call PYI Inc. and ask them first.

BTW it's not graphite. It's a solid carbon ring against SS.

[sailorboy1]

Originally Posted by delmarrey

I don't know what the big deal is with the PSS. If one does regular maintenance like they should then they are dry and maintenance-less. And if the bellows ever did leak due to lack of self initiative, then one could just shove a rag in around the shaft and that would get one home just fine.

I'm not anti shaft seal and have had them on my last 2 boats. But the biggest IF in this whole thing for me is IF I'm on the boat when the bellows started leaking, which may be right after I left the boat on Sunday.

I've been doing a lot of reading and reviews and have come across lots people saying that their GFO packing systems don't leak at all. But even if it does it isn't a big problem because I think I'm going to route the drain to the little shower sump and keep it out of the bilge.

But I haven't decided anything yet for sure!

[propellanttech]

Originally Posted by delmarrey

If you were to take it off you might be able to soak it in a brake cleaner or acetone. If you have the PSS, I'd call PYI Inc. and ask them first.

BTW it's not graphite. It's a solid carbon ring against SS.

It's carbon graphite......straight off the PYI. website.

James L

[delmarrey]

Originally Posted by propellanttech

It's carbon graphite......straight off the PYI. website.

James L

I don't want to get in a pissing contest but graphite is one of the most common allotropes (products) of carbon. Allotropes of carbon - Wikipedia, the free encyclopedia

[propellanttech]

Originally Posted by delmarrey

I don't want to get in a pissing contest but graphite is one of the most common allotropes (products) of carbon. Allotropes of carbon - Wikipedia, the free encyclopedia

Not a pissing match at all. I said, "carbon graphite" was directly off the PYI website. You can't argue with what the manufacturer states. Unless you want to call them and argue the issue.

I've had people in the past argue, "it's not graphite, its carbon." Well, actually they are one of the same.

James L

[Khagan1227]

I confess, I didn't read all (most) of the pervious posts, but let me throw out a couple of things.

Dripless seals are only "dripless" as long as the carbon ring stays smooth. Once they start to leak, they only get worse. With packing, you can snug it up until it is time to repack. If a complete repack isn't possible, you can replace the first ring to buy you a bit of time until you are in a position to do the job correctly.

Also, the cabon ring and stainless steel collar should only be touched when wearing clean cotton gloves. Oils from your skin can etch the face of the carbon ring, which in turn will leak.

Personally, I like a dripless seal, but I wish they'd make them with an option for a couple of rings of emergency packing as a back up.

[sailorboy1]

One thing that has been jumping out to me is just how inexpensive the shaft seals for boats are compared to their use. Being an ex-pump guy and comparing boat seals to pump seals it just seems a better product would be available.

[Khagan1227]

Originally Posted by Don Lucas

One thing that has been jumping out to me is just how inexpensive the shaft seals for boats are compared to their use. Being an ex-pump guy and comparing boat seals to pump seals it just seems a better product would be available.

I agree, the seawater pumps I've dealt with and US Navy shaft seals are MUCH superior to the stuff for small boys. It might not be cost effective to produce something better.

Perhaps a business opportunity exists, at least for someone else to spend many hours on.

[mlydon]

take a look at the Norscot shaft seal
it looks like a traditional stuffing box, uses regular exhaust hose like one, but uses a lip seal,just like on your engine. i had one on my last boat, am putting one on my new one this winter.

my one beef with the face seal ones is the bellows - make it hard to alight the engine, tends to go catastrophicaly, have to do the 'burping' thing, etc

[Hudson Force]

Originally Posted by mlydon

................my one beef with the face seal ones is the bellows - make it hard to alight the engine, tends to go catastrophicaly, have to do the 'burping' thing, etc

That's intended to be "align" the engine right? I hadn't recognized the problem with aligning, but I do know that the "burping" need is easily eliminated with a vent hose open to the centerline well above the waterline. Please describe to me the problems that you would anticipate with alignment. 'curious, thanks

[Sailmonkey]

Originally Posted by mlydon

my one beef with the face seal ones is the bellows - make it hard to alight the engine, tends to go catastrophicaly, have to do the 'burping' thing, etc

I would also like to know how the bellows make alignment difficult......I've done it several times and never noticed it being more or less difficult by the type of shaft seal.

[mlydon]

sorry to take so long replying - it IS the holiday weekend.....

alignment woes with a pss.....

the pss depends on pressure from the bellows pressing the face up to the stainless disk you clamp on the shaft, right?

alignment is NOT a problem if you have a stock ridgid coupling, however, if you
have a plastic flex coupler, you have to remove the coupler to allow the shaft flange to contact the transmission output flange. this allows the shaft to move forward from its regular postion, releasing the sealing pressure, and you have a major flood while you're trying to perform your alignment. also, depending on your configuration, you have to move the shaft aft somewhat to pull the flex disk out from between the flanges. you only get so much travel possible with the bellows. the flex disk i had for my CD28, which had a volvo md2b in it, was aproximately an inch thick, and required a total of 2+ inches of clearance to install ( you have to bolt the disk onto the transmission with bolts long enough to pass through the disk AND grab thread on the tranny flange). In the end, i wasn't able to use the coupling on my dory as i had insufficient clearance between the tranny and stern tube to allow for that needed 'slide back'.

I happen to have a federal coupling on my new boat - a hunk of metal the size of a shaft coupling, with spider bolts holding rubber balls bolted into an inner sleeve, which is attached to the shaft, and an outer housing which contains the rubber and bolts to the tranny. alignment witn one of those calls for removing the coupling altogether, replacing it with a ridgid flange for the alignment, then swapping in the flex coupling to finish the job.

doing either type of coupling removal requires that you slid the propshaft aft 2-3 inches.....NOT happening with a pss, but easy with a stock packing gland, norscott, or other LIP SEAL type gland i might not have heard of. Well, you COULD do it, but you would need to loosen the stainless disk, flood like crazy while you're doing it, peform the coupling removal, retighten, align, loosen, flood, coupling install, then retighten it (with NEW set screws as spec'ed by pss, of couse).

Much hassle, thus my original remarks



matt

[sailorboy1]

Well I found a good deal on a Lasdrop Gen II and the seal has some design items that addressed my concerns. It doesn't have a bellows and uses a tube just a packing box would. It is a cartridge type seal with a spring to maintain pressure instead of using a belows and a couple of set screws.

Hamilton Marine had them on a closeout deal so the price was about the same as what I would have spend to install packing box.

So I got one and will hope it works out.

PS - looking at the faces of my old PSS seal I think it got overheated sometime in its' past. The SS rotating ring had a lot of crap on it.

[delmarrey]

Originally Posted by Don L

Well I found a good deal on a Lasdrop Gen II and the seal has some design items that addressed my concerns. It doesn't have a bellows and uses a tube just a packing box would. It is a cartridge type seal with a spring to maintain pressure instead of using a belows and a couple of set screws.

Hamilton Marine had them on a closeout deal so the price was about the same as what I would have spend to install packing box.

So I got one and will hope it works out.

PS - looking at the faces of my old PSS seal I think it got overheated sometime in its' past. The SS rotating ring had a lot of crap on it.

The spring does the same thing as a bellows.

All the PSS's now use the hose fitting. If one gets air in the bellows w/o bleeding it out, it will over heat. The old days they recommended burping the air out before getting underway. That didn't go over too well.

The other thing too that I discovered on all packless seals, is they need to be rotated once in awhile to get oxygen back in, so the SS ring doesn't start pitting.