I notice the packing gland nut was getting hot to the touch so I replaced the teflon packing 3/16 its drips about one drop every 30 seconds but the Gland nut still gets hot to the touch - any suggestions.
Packing gland nut getting hot.
- Thread starter Mistyseas1991
- Start date
When you say it drips, do you see the water dripping specifically from where the shaft exits the nut? It's possible, depending upon how you have the nut adjusted, for water to drip out the back side of the nut, run down the underside of the sloping shaft log, and then drop down. So you'd see drips, but they are not coming from the *front* of the packing nut, where the shaft exits the nut. That's where the moisture needs to be to cool the shaft. If that makes sense.
Basically, you want to see some water glistening at the interface where the shaft exits the nut. You don't need a ton of water, but it should be moist.
How hot is it getting? Did you check it with an infrared thermometer? Is it over 130-degrees?
Basically, you want to see some water glistening at the interface where the shaft exits the nut. You don't need a ton of water, but it should be moist.
How hot is it getting? Did you check it with an infrared thermometer? Is it over 130-degrees?
I don't have an infrared therm. but it gets hot enough not able to keep my hand on it maybe about 3 seconds. The drips are coming from the front of the packing gland nut
Then it stands to reason that it should be cooling the shaft. Just how hot is the getting?
Even without measuring it that does seem way too hot. If you are seeing actual drips between the shaft and the nut then I’m not sure what to tell you. Maybe someone else will know.
Check out Maine Sail’s how to site. He did a great write up on packing glands. I would guess the nut is too tight. It should be warm but not hot. On my first boat I replaced the packing with GFO using 3/16 and I over tightened to reduce the dripping and it got hot. Not as common but my gland was actually designed for1/4” packing. When I replaced it with 1/4” I able to reduce the drip to almost nothing and three or four while running and the nut was barely warm. Over tightening will wear a groove in your prop shaft.
https://marinehowto.com/re-packing-a-traditional-stuffing-box/
https://marinehowto.com/re-packing-a-traditional-stuffing-box/
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 23,139
Try changing the packing material. Remember these stuffing box "glands" were originally made for flax packing. Then along came the hybrid products "i.e. Teflon laced"
My “standard” stuffing box would run pretty warm…I used an infrared thermometer to check it. I don’t remember what the temp was, but it was warm if not hot to the touch. I used both regular waxed flax (I didn’t care for that) and teflon-impregnated GFO packing. I liked the GFO better and could almost run it dripless (but it did run warm).
I replaced it with a Volvo dripless rubber shaft log. Very simple design and so far (first season with it), I am a big fan. No drips, bilge is dry, and it runs cool.
it also saved a lot of space in the bilge behind the engine…
The Volvo seal is about $100, and very simple design (no moving parts, no bellows).
Greg
I replaced it with a Volvo dripless rubber shaft log. Very simple design and so far (first season with it), I am a big fan. No drips, bilge is dry, and it runs cool.
it also saved a lot of space in the bilge behind the engine…
The Volvo seal is about $100, and very simple design (no moving parts, no bellows).
Greg
I'm sure this is unhelpful, but our Hunter 306 has a 1" shaft, and uses 3/16" packing. It is never even warm to the touch, even if I'm only seeing one drip every 5-6 seconds. I have literally never felt it to be warm. So again: I don't know what to say. At least it's a data point.
I'd say if it's too hot to touch, it's too hot. Never mind the infrared thermometer.
I'd say if it's too hot to touch, it's too hot. Never mind the infrared thermometer.
That seems like a lot to me. The advice that I've seen is 2-3 drips per minute. Ours is dripping about every 45 seconds but the packing nut is still cool to the touch so I'm happy with that.
I'm probably mis-remembering. I put a chunk of sponge under the packing gland, and it has a small wet spot after motoring around for quite a while. It's a very slow drip rate (as set this season), but as I said, I've never sensed any heat in the packing nut whatsoever.
I'm getting at least one drip every 60 sec. I used PTFE FLAX 3/16" I removed 4 flax rings so I put 4 in the gland nut I'm thinking 3 maybe better? I'm leaving tomarrow for Santa Cruz Island "Pelican Bay" that's about a 6 hour Mtr sail so I'll be checking it. I purchases a Infrared heat gun she'll hit 130F.
I'd loosen it up a bit: you can afford more cooling water than that if you're having heat problems. You may be right about the 3 rings. I can't recall exactly, but my best memory is that I put only 3 in. Given that we're both Hunters near 30 ft, I'd guess the stuffing boxes on our boats are pretty similar.
Maybe let some water in when you loosen it to make sure you don't have a big bubble in the groove in the hull leading up to the shaft gland.
Winner, Winner chicken dinner!
It is not just the drip that counts. It is the what the packing is made of too. Teflon packing has a tendency to not absorb enough water to cool the shaft as it it rotating.
Speaking of water. If you had your boat out over the winter the packing may have dried out and may need some time to get some moisture back into it.
When was the last time the packing gland/stuffing box completely emptied and repacked? I ask because way back in my navy days before pumps had mechanical seals, We would find people would add a ring of packing every time the the leak off exceeded the design rate. What happens is the packing rings below it get glazed over and the stuffing box gets over filled. It is always better to remove 2 rings and then add to rings.
I found this to be a good read for USBoats
Repack A Stuffing Box
I will say one thing about the article above. If I was doing the work I would have replaced the hose too. I believe there are fatigue in the form of cracking.
This is the same packing removal tool we used in the Navy, basically a corkscrew on a flexible shaft.
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