|Topic Review (Newest First)|
|08-12-2010 03:16 PM|
|CaptainForce||As Vasco implies, the temperature of the water can be a factor; however, I am quite satisfied running my engine for a long term and feeling the stuffing box to be warm. I don't tighten it to the degree that would couse it to be uncomfortable when keeping my hand tight against it, but warm is acceptable and not an indicator of damage. Take care and joy, Aythya crew|
|08-12-2010 02:00 PM|
|Vasco||It should not be even warm to the touch. It should be the same temperature as the seawater. Up here on Lake Ontario my stuffing box is always cold to the touch.|
|08-12-2010 01:43 PM|
From Maine Sail's excellent article on re-packing a stuffing box:
|08-12-2010 01:39 PM|
Originally Posted by DrB View Post
When I first installed Gore GTU (or GFO, don't recall which) season before last, I was interested in getting the drip rate to as close to the once-every-20-seconds recommendation as humanly possible. It was at 1/10-secs. To make a long story short: Couldn't do it. It was either 1/10-secs. or so, or (nearly) none at all, and I'm talkin' just a slight >< change in packing gland nut tightness. In my experiments I once had a synapse lapse and, after having tightened the nut just one RCH, forgot to subsequently check the drip rate until after we'd been under way on the iron genny for quite some time. Remembered. Went down and checked. No drip at all! Felt the stuffing box. Not just warm, but HOT! Luckily there was a public seawall marina right there, so we quickly pulled her over, tied up and I addressed the situation.
When the packing gland was dripping again, it dripped gray.
Another time, when the drip rate was really slow, after one of these adjustments, like one every minute, the stuffing box was noticeably warm to the touch, but not hot.
When it's dripping at about one every 10 sec. or so, it's not even noticeably warm to the touch.
Fast-forward to this spring, when the stuffing box coupling hose was replaced by our yard. He made it slightly longer than the old one, so the packing material would be on a different part of the shaft, but he said it hadn't been necessary as the shaft was un-scored, and, he said, the packing material looked essentially brand new, so he re-used it.
That Gore stuff is remarkable.
|08-12-2010 01:19 PM|
Boundarys on Hot
Originally Posted by sailingdog View Post
Curious to as to what everyone believes is "heats up noticeably" when referring to a SB. Are we talking warm to the touch, hot to the touch, a few degrees above the water temp? My SB is pretty tight as in it doesn't let in water at all when at rest. I don't know what the drip rate is, maybe a drip or two every 1 to 2 minutes when running, but after the shaft has been turning for a several minutes, the SB area doesn't feel different than the shaft a few inches above it or the coupling. Not too concerned about my set-up, just curious on the "heats up noticeably" comment.
FWIW, I am running the West Marine GTU Gore Shaft Packing Material as my SB packing. 4 wraps.
|08-12-2010 11:59 AM|
Yes, but on many boats, the stuffing box will drip very slowly when the shaft is not turning. If the stuffing box heats up noticeably when you're motoring, then it isn't being lubricated sufficiently—and you must adjust the stuffing box for when it is turning—and if it drips when the shaft isn't rotating, you just have to live with it.
Originally Posted by remetau View Post
|08-12-2010 11:51 AM|
The packing material shouldn't be "tight," per se, but it should fill the gap between the outside of the shaft and the inside of the stuffing box. Otherwise: How could it possibly seal?
Main Sail, I think it is, recommends fabricating a "pusher" out of rigid PVC. I just pushed mine in, gently and carefully, with a large-ish flat-bladed screw driver.
Hope the new packing material has you fixed up, and I apologize for coming across poorly.
You might care to peruse Main Sail's Re-Packing A Traditional Stuffing Box. Very informative.
|08-12-2010 11:43 AM|
Ours does not drip when the shaft is not turning.
This is from Don Casey:
"Water is required to lubricate conventional packing, so a properly adjusted stuffing box can be watertight when the shaft is stopped, but it must drip when the shaft is turning."
|08-12-2010 11:38 AM|
|sailingdog||I'd point out that if you're using a traditional stuffing box, regardless of the packing material, and it isn't DRIPPING...then you've overtightened more likely than not and are probably scoring the shaft. A traditional stuffing box NEEDS WATER as a lubricant, and if it isn't dripping at least a little bit, especially when the shaft is turning—it is probably running DRY. Even the GFO Goretex packing material REQUIRES SOME WATER PASSING THROUGH IT.|
|08-12-2010 10:28 AM|
Thanks for the humility Jim. In case others read this, here's what we learned. We were told our boat uses 3/16. The last time marina serviced the packing they used 3/16. Another PSC owner used 3/16. So I bought 3/16. I also bought 1/4 just in case because I knew it was likely we would be unable to have access to supplies at times.
I was able to get to a dock lastnight and remove the old 3/16 packing. It looked in perfect shape and came off without any fraying I could find. (Not much water came in and I just wrapped a towel around the shaft so it would drip instead of spraying.)
Since the inspection of the packing looked good I hesitated putting in the 1/4. It was a tight fit but I was able to get it in using the side of a wrench. After each strip I tightened the nut up to push it in. I got three strips installed and hand tightened slightly. Today there is no water dripping but I'll recheck after break in. The shaft is not hot nor was it scored.
I'm still unclear what caused the bronze dust. Perhaps there was a small piece of thread caught on the shaft and turning in the nut.
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