View Full Version : Replaced shaft packing with the goretex...but now...?
07-22-2009, 02:48 PM
I don't have any dripping that I can see. The guys at Discount Inboard Marine says that is common, as the goretex are virtually dripless...yet it is scaring me. How 'hot' should the packing gland get? Should the shaft also get hot? It was so hot that I could not touch it without burning myself. I loosened the gland some and still no water, but no great improvement in temp control either? Any advice out there?
07-23-2009, 05:19 PM
Anybody know if I'm okay or need to worry about the 'heat'?
By observing a drip every now and then you know that you are getting water to the seal to cool it off and to lubricate it. In the real world of packing it is a fact that inboards leak and it is normal which at times is hard for people to understand unless you have a dripless seal. I would back off of it until I saw a drip if it was my boat. Or even return to the marina and purchase the 100year old technology packing that seems to work fine for most inboards of all types.
You need about +1500deg F to melt stainless steel so you wont hurt the shaft but not sure what you are doing to the packing or any surface treatment the shaft might have.
07-24-2009, 03:12 AM
I would back off on the gland nut to get the usual drip process and check the temps. Your cord can go to 550 degrees F but reducing the heat buildup is necessary to prolong cord life and reduce energy losses. I use a graphite cord from Sepco that has a 500 degrees F rating and I have no heat issues, no dripping and no adjusting of the gland nut after five years. Wax packing is in the 212-265 degree F range and is more susceptable to heat damage.
07-24-2009, 08:43 AM
Thanks for replying guys. Zabooda...I did back it off and still no 'visible' dripping, although a little wetness does accumulate (its dark almost black)... but nothing near 'drop' size. When you say you have no 'heat' issues...does that mean that you could 'grab' onto the packing nut after running for awhile and it be fine to the touch?
Keep in mind that energy is not free, if you have a shaft that is getting up and over 200F then you have a friction loss. That is power that could be going to the prop. You would also have to wonder what the long term issue would be with this almost becoming a lathe with the wear issues on the shaft. I have had a prop shaft break on me, a 1.0" diameter 17-4ph stainless shaft and it cost me 500 dollars to replace with me doing the work! It took several years to get to that point but it wasn't fun sitting out in the middle of the lake at sundown.
Again the drip is a minor issue, why would you want to waste the horsepower that could get you out of the hole quicker?
07-24-2009, 03:42 PM
Thanks Zegm, are you simply saying that I should 'not' use the goretex packing then? It seems from all the discussions I've had that it is better? I'll probably take a piece out and see if that helps the issue at all...maybe 4 pieces of goretex is not equivalent to the 4 pieces of regular packing that was in there previously.
No I am not saying I wouldn't use it, but I am concerned because you are making so much heat. I would think that you should be able to loosen the nut enough to just make it leak and NOT create so much heat. I did have an old MasterCraft for over 20 years and only replaced the old parafin/wax packing maybe 2 times. I think it cost me less than 5 dollars. I would put it in, tighten it hand tight at first, then while watching it I would put the boat in gear to turn the driveshaft over a couple of times then shut it off and watch how bad it leaked and then tighthen it some more. I never had to really "tighten the crap out of it" to make it stop leaking, my goal was to have a small drip every couple of minutes. I am not really sure what the advantages of the goretex are supposed to be? Did this packing come with instructions? It is a balance between not having water coming pouring in vs. creating a situation where the friction is causing a lot of heat and you might damage something. Remember a couple of drops of water every five minutes is nothing to worry about. That MasterCraft SAT in the water ALL summer long and she did not sink once! :-D
07-27-2009, 12:55 AM
I don't think I did four wraps and you may want to check the recommended number of wraps for standard cord and go with that. With the nut loose, you should have a good water flow and the cord may be packed too tight.
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