If there is a bit more water coming in at the prop shaft than I would like since it ends up in the pan under the engine ever so often...such as after a couple months can i just tighten the nut to seal up the packing around the shaft?? IF SO, what is too much? :{
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Too tight
usually refers to a shaft that has bene tightened so that it doesn't allow any water to drip when running. tighten it a bit, run it it a bit, tighten a bit, run it a bit, until you slow the leak to where you want. If i'm not mistaken, you always want it to drip a tiny bit when spinning, and even a drip once in a while when sitting is acceptable
usually refers to a shaft that has bene tightened so that it doesn't allow any water to drip when running. tighten it a bit, run it it a bit, tighten a bit, run it a bit, until you slow the leak to where you want. If i'm not mistaken, you always want it to drip a tiny bit when spinning, and even a drip once in a while when sitting is acceptable
If you have no dripping..
If you have no dripping at all then it's too tight! Traditional stuffing must drip for lubrication or shaft damage will be done..
If you have no dripping at all then it's too tight! Traditional stuffing must drip for lubrication or shaft damage will be done..
School house answer
Spinning shaft should drip about 3ish drops per minute stopped shaft should not drip at all. As all packings wear you will have to occasionally re-tighten the packing nut. The "tighten a little run a little re-tighten" is the correct method. I tighten 1/6th turn (one face of the nut) at a time to prevent the over tightening of the packing. Over tightening is a non-recoverable situation so creep up on the correct tightness but don't over tighten. A few drips a day with the shaft stopped is better than a scour on your shaft from over tightening. A scoured shaft will never seal again and require replacement $$$$$$.
Spinning shaft should drip about 3ish drops per minute stopped shaft should not drip at all. As all packings wear you will have to occasionally re-tighten the packing nut. The "tighten a little run a little re-tighten" is the correct method. I tighten 1/6th turn (one face of the nut) at a time to prevent the over tightening of the packing. Over tightening is a non-recoverable situation so creep up on the correct tightness but don't over tighten. A few drips a day with the shaft stopped is better than a scour on your shaft from over tightening. A scoured shaft will never seal again and require replacement $$$$$$.
PSS Dripless shaft seal
I changed out to a PSS shaft seal (can be found in this site) last year. Not a drop since. You can't get traditional shaft packing to stop dripping. And if you do, you will overheat the shaft/seal. They need water to cool the surface.
I changed out to a PSS shaft seal (can be found in this site) last year. Not a drop since. You can't get traditional shaft packing to stop dripping. And if you do, you will overheat the shaft/seal. They need water to cool the surface.
If you want a dry bilge with a conventional
stuffing box, you can drill and tap for a grease fittong on the side of the tube, and pump it full of waterproof grease. Works great, and it won't sink your boat if it gets a little crud in it like the dripless seal.
stuffing box, you can drill and tap for a grease fittong on the side of the tube, and pump it full of waterproof grease. Works great, and it won't sink your boat if it gets a little crud in it like the dripless seal.
Sounds like a great idea
"If you want a dry bilge with a conventional stuffing box, you can drill and tap for a grease fittong on the side of the tube, and pump it full of waterproof grease. Works great, and it won't sink your boat if it gets a little crud in it like the dripless seal." How can you be sure the shaft will get sufficient cooling?
"If you want a dry bilge with a conventional stuffing box, you can drill and tap for a grease fittong on the side of the tube, and pump it full of waterproof grease. Works great, and it won't sink your boat if it gets a little crud in it like the dripless seal." How can you be sure the shaft will get sufficient cooling?
PPS
I second Alex - this stuff looks good. No drips. You tighten the nut to no drip, then check the temp after running. If the the nut is too hot to grap you are too tight. Mine runs cool to the touch. Another guy at my club is also happy with the results so far.
I second Alex - this stuff looks good. No drips. You tighten the nut to no drip, then check the temp after running. If the the nut is too hot to grap you are too tight. Mine runs cool to the touch. Another guy at my club is also happy with the results so far.
jviss, You make sure the shaft gets sufficient
cooling the same way you do with no grease fitting; check it often after you have tightened the nut, and occaisionally after it seems stable. The grease will melt and lubricate the packing as it warms up. If the nut is really loose, you can get a bit of grease flung off the shaft, but that's only if the nut is very loose or the packing is gone. Also, the newer Teflon packing is, by all reports really good stuff. It will help to make a no drips at rest, slow drip while running situation, and with a grease fitting on the tube, you should be able to have safe and dripless. I have confirmed a couple of sinkings and have friends who nearly lost their boat from a bit of crud in the dripless seal type shaft seal. I don't think they're safe.
cooling the same way you do with no grease fitting; check it often after you have tightened the nut, and occaisionally after it seems stable. The grease will melt and lubricate the packing as it warms up. If the nut is really loose, you can get a bit of grease flung off the shaft, but that's only if the nut is very loose or the packing is gone. Also, the newer Teflon packing is, by all reports really good stuff. It will help to make a no drips at rest, slow drip while running situation, and with a grease fitting on the tube, you should be able to have safe and dripless. I have confirmed a couple of sinkings and have friends who nearly lost their boat from a bit of crud in the dripless seal type shaft seal. I don't think they're safe.
Heat in Stuffing Box
The temperature of a stuffing box will vary depending on the type of Packing used. Traditional flax packing may cause the box to run cool on the outside however this is due to the fact that flax acts as an insulator. Actually the flax generates considerable heat and friction at the surface of the shaft. In the heat the flax hardens and causes damage, scorring and wear. Newer packing materials like expanded ptfe impregnated with graphite are up to 5 times more thermally conductive. They reduce frictional heat however they are so thermally conductive that they transfer all the heat away from the shaft and out to the stuffing box which acts like a heat sink. This is actually a desirable effect as it protects the shaft from scorring and wear. What you don't want to do is loosen the gland when using expanded teflon packing with graphite...this is not necessary. As far as how hot is too hot on a stuffing box that depends on the installation of the box. If the box is directly installed to the stern tube then I would say anything under 200F would be acceptable. If it has a rubber hose in between then it depends on the heat rating for the hose. In fact GFO is rated to go up to 550F and a bronze box will only melt at aprrox. 700 degrees f. There are a couple of packing material available that offer these advantages. One is GFO, another is Duramax Marine Ultra-X.
The temperature of a stuffing box will vary depending on the type of Packing used. Traditional flax packing may cause the box to run cool on the outside however this is due to the fact that flax acts as an insulator. Actually the flax generates considerable heat and friction at the surface of the shaft. In the heat the flax hardens and causes damage, scorring and wear. Newer packing materials like expanded ptfe impregnated with graphite are up to 5 times more thermally conductive. They reduce frictional heat however they are so thermally conductive that they transfer all the heat away from the shaft and out to the stuffing box which acts like a heat sink. This is actually a desirable effect as it protects the shaft from scorring and wear. What you don't want to do is loosen the gland when using expanded teflon packing with graphite...this is not necessary. As far as how hot is too hot on a stuffing box that depends on the installation of the box. If the box is directly installed to the stern tube then I would say anything under 200F would be acceptable. If it has a rubber hose in between then it depends on the heat rating for the hose. In fact GFO is rated to go up to 550F and a bronze box will only melt at aprrox. 700 degrees f. There are a couple of packing material available that offer these advantages. One is GFO, another is Duramax Marine Ultra-X.
Gortex packing
I was wondering what temp is ok at the shafts with Gortex.When Mikemarine said not to back off the adjustment not needed I have to try to get a resonable temp,did I screw up the packing. Thanks, Bill
I was wondering what temp is ok at the shafts with Gortex.When Mikemarine said not to back off the adjustment not needed I have to try to get a resonable temp,did I screw up the packing. Thanks, Bill
Grease nipple in stuffing box
Fred, where exactly on a stuffing box does one install the grease nipple you're talking about?
Fred, where exactly on a stuffing box does one install the grease nipple you're talking about?
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