stuffing boxes

[PascalG]

a few months ago I had done my stuffing boxes but I messed up the first one, probably cut the ring a little short... I used regular flax with the lubricant and didn't have the removal tool... spent over 2 hours digging, etc...

well tonight, I did it in about 20 minutes using the flax extractor tool, $15 from West, and GFO packing. GFO is much easier to install, no sticky lubricating grease, easier to cut, and easier to fit as it seems a little softer. the extracting tool, a corkscrew at the end of a flexible shaft, makes a huge difference...

I do have a question though... how many rings should there be (53MY) ? I originally found 3 when I did it the first time but it seems that there woudl be room for 4 ?

[Jackman]

I just did mine too. The owners manual said four but I had room for five. I'd feel more comfortable with four in your case. Think for a sec....if you put the packing in like they say....the seam of the ring you're putting in is 90deg from the last one you put in...after 4 rings you've covered a full 360degrees and every one is overlapped as lease once...if that makes sense. JUst make sure you have plenty of room to get the nuts over the bolts to put it all back together and compress the packing slightly.

[dshuman]

How do you know how tight you can turn the nuts on the stuffing boxes? Mine were leaking about 1 drop per second and when I tightened both nuts 1/2 turn, no improvement but at about 2 turns, it completely stopped leaks. Can you go too tight and create friction that will cause failure? Do you just tighten enough to stop leaks and when the nuts finally run out of threads, replace the stuffing?

[nick]

Not too tight, you will score the shaft. The packing should be tight enough to minimize leaking and not heat up the shaft. Generally no more than a drip or so every minute at the dock.

[PascalG]

you're supposed to get it tight enough so that it doesnt leak when the shaft doesn't turn. With regular flax, you are supposed to get a few drops a minute underway; GFO is supposed to be dripless.

overtightening it indeed results in heat build up and possible scoring of the shaft.

pascal
miami, FL
1970 53MY

[Finalee]

Looks like 3 years now since this thread started. Wondering how the GFO is working?

[Paul45c]

I goofed on my first install of GFO by overtightening before I saw all the cautions -- the follower got really hot and I had to crawl slowly back the short distance home for fear of really screwing something up.

Very recently I just repacked the box on my new boat and this time I was EXTRA careful -- I tightened to only a level where there were drips at rest of about 1 every 15 seconds or so. I planned on needing to tighten it in some after about 2 or 3 hours of high speed cruising, and surprisingly there was only about 1 drip a minute while running. The gland was cool to the touch, too.

I have 2 1/2" shafts and used 3 rings of the 1/2" size. Seems good. I think it might be a little more of an issue not to overpack with the Goretex since the heat is potentially a bigger issue if not tweaked perfectly right in the beginning -- and the very nature of the product is such that it doesn't allow much water at all through it to cool. It relies on the thermal transfer properties of the Goretex. If 3 seems to do the trick I think I'd stay with it. I plan to keep an eye on mine for a while and see how it breaks in.

[yachtsmanbill]

Hey Paul... hope all is well. I measured the depth of the 2" box today and it is
2-3/8" deep. Thats room for 4 rings of 1/2 and 3/8 for the gland to enter and not cock. If the goretex is working at 3 dont worry. 4 rings with flax or conventional graphite gives you more flexibility/reserve to pull up as needed. ws

[REBrueckner]

The number of flax rings is determined by the space available. Three is fine I prefer four...As noted, a little water drip acts as lubricant. Once the nut is snugged against the flax/GORTEX whatever, I tighten mine for the winter to stop any drip...Within a few runs in the next season the slow drip resumes and I leave it alone til the following winterizing....Instead of running out of thread for the tightening nut, one should add a ring of flax before you get down that far because most of the old flax has either worn out or got pressed out...

[MikeP]

FWIW - gore packing can be adjusted so that it doesn't drip at all while running without the stuffing box getting hot. It takes a bit of fiddling but you can do it. As mentioned, the biggest problem is installing it incorrectly and tightening it too much initially. It needs to be dripping when initially installed and then slowly worked with from there to the no-drip status.

When I first installed gore, I did the same thing that others mentioned - started it too tight and I could not get it to drip even with the nuts slackend completely off. So I got the opportunity to do both boxes over!

[Pascal]

fine... no problem... i might have tightened them once since...

[bobk]

If you have sainless shafts, don't you risk crevice corrosion if you don't have a drip at rest?

Bob

[MikeP]

Hmm - good question. I had never thought about that and I have seen the results of crevice corrosion on other SS parts in contact with salt water that was not "renewed" regularly...

Maybe the fact that I have my stuffing boxes/gore fine tuned so they don't drip under any circumstances (and the boxes stay "room temperature) could produce a much more serious problem than some water in the bilges...

Perhaps some research is in order...

[mike]

To avoid this issue, switched to PYI dripless and added a small fish-tank air pump to the water injection port, which is set up to cycle on and off a couple of times a day. Before, the orig packing shaft seal area was so corroded that I had to grind down the shaft and plasma weld it back to spec.