Which Stern Gland Packing

[Kaiser]

Reaching out to knowledgeable members as to which is the best gland packing to replace on my cruiser. I have removed the existing which has been in service for 21 years - (6 rings) which looks like PTFE which has gone quite hard. Has anyone had experience of PTFE and silicone, (seems to be a new kid on the block) compared to PTFE flax Sturntite or Graphite cotton. My stern gland is water lubricated/cooled - not greased. BTW, the stuffing gland is bronze with 2 clamping/tightening bolts. Appreciate any guidance on the wear, heating and longevity.   

[Vaughan]

Gland packing comes in square profile of different sizes, such as quarter inch.  Available at places such as Peachment or Brian Ward.

Make sure all old gland packing is removed.  With the nuts undone and the front of the gland drawn forward, wrap a length around the shaft and cut it so that it forms as tight a butt joint as possible.  Push this into the stuffing box with a screwdriver.  Add further pieces until you have filled the stuffing box.  Three will usually be enough.  Angle the cut joints in different positions, so they don't end up in line with each other.  Slide the front part back in and do up one nut on each thread, to squeeze it all together, but not much more than finger tight.

Run the engine in ahead gear at about 1500 revs for at least 10 minutes and feel the gland with your hand. If it is warm to the touch, that is normal but if it gets too hot to touch, ease the nuts off a turn. When you have found the best position, put on and tighten the lock nuts.  One drip every couple of minutes when the engine is stopped, is normal.

In all honesty, this is a job I would prefer to see done by a boatyard.

[OldBerkshireBoy]

When refurbishing gland packed commercial water pumps we found that the shaft was often damaged because people overtightened the packing causing friction and damage which meant removing the shaft and metal spraying and machining the shaft back to size because new packing alone would still leak so worth checking the shaft for deep scores first.

If you cant measure the old packing for size then measure between the outside of the shaft and the inner wall of the packing box for an idea of what size you need (imperial not metric) Sorry but cant advise on type of packing required.

As Vaughan said postion the butts at different places, ie 12 o`clock > 2 o`clock > 4 o`clock and so on, and if you can, an angled joint (see attachment) works better than a straight butt joint and start loose and gradually tighten the packing plate to control leakage. 

[dnks34]

Not wanting to contradict anyone but we once had our shaft repacked by a reputable boatyard in Horning and we could never get it adjusted just right.  After putting up with it for a number of years we repacked it again ourselves when we had the boat out over a winter and found 3 and a half rings in the gland.  This was a head scratcher as the boatyard had also supposedly had the shaft out before they repacked it. 

We used 3 rings, cut at an angle and spaced the joints and it was absolutely perfect from then on.  We got the packing from ASAP in Beccles as it was our nearest place.

[OldBerkshireBoy]

3 and a half rings! What did they think the half ring would do for crying out loud?

I have found all the rings cut in half before, remember asking technical if they knew something I didn`t  Another was a bent shaft, quite how it became bent we never did figure out.

[Smoggy]

I've heard of folk complaining of overheating with the ptfe packing, I nearly went for it myself but plumped for graphite after hearing about issues, also talk of ptfe welding itself to the shaft.

[Guest]

6 hours ago, Vaughan said:

feel the gland with your hand. If it is warm to the touch, that is normal but if it gets too hot to touch, ease the nuts off a turn.

Had to check there, thought I was on Pornhub for a minute 🥴

[MauriceMynah]

What's "Pornhub"?

[Guest]

9 minutes ago, MauriceMynah said:

What's "Pornhub"?

Fancy wheel trims for cars 😉 

[BroadAmbition]

We have PTFE glad packing onboard 'B.A' - Fitted it mysen, from memory four rings (But it might be three) we use ZX1 grease - Never had any issues.  I repacked it a few years ago when we changed the cutlass bearings

Griff