GFO question

Stu Jackson · Oct 24, 2009

Sure

Like backing off a lot of things, once you do that you've broken the "set". You may have to repack the box. The general idea is to pack, set the box and over time continue to tighten bit by bit, not back off.

Then, also, you have to run the engine in gear to check whether the box gets too warm or not, so simply using the drip rate is only half the resolution of the problem.

Stephen K · Oct 24, 2009

Follow up question...

Stu Jackson said:
....Then, also, you have to run the engine in gear to check whether the box gets too warm or not, so simply using the drip rate is only half the resolution of the problem.

Stu, on a related question, I just tightened my packing and have 1 drip per minute when in gear and my box is not getting warm. Is this setting to tight that I might be scoring my shaft?

P.S. I don't know what the type packing as I have nit changed it out from the previous owner.

Stu Jackson · Oct 24, 2009

Sounds good

Stephen, your "setting" sounds good. If it's not getting warm, you are not damaging your shaft. It's when it tarts to "smoke" that you have a problem!

When was the last time the packing was changed? If you don't know, add at least two years to whenever you bought the boat! I know it's trickier on your boat than mine, but people do it all the time.

Maine Sail has a superb writeup on his website, and I wrote this (before the advent or invention of GFO gortex e-marine packing, and just so noted in the text: http://www.c34.org/wiki/index.php?title=Stuffing_box_packing

Try our C34 Tech wiki for lots of other stuffing box information, too.

Stephen K · Oct 25, 2009

Re: Sounds good

Thanks Stu, I don't have any smoking, so I guess I am fine; but I will continue to check the box temperature and keep an open eye for a problem. I "guestimate" that the exisitng flax material is 4 - 5 years old. I still have a good amount of room on the shaft for future tightening....if it makes it to next Fall, I will replace it while hauled out for a bottom job...if not, I will do it one the water and will plan ahead. Thanks for your article and I also have Mainsail's instructions...

Stu Jackson · Oct 25, 2009

Ron said:
The question now is do I repack with the 3/16" or the 1/4 " ? Some of the archival reports mention not to force the 1/4" into the nut.
Your thoughts ?

There is only one correct size packing for your box. Period.

That said, most if not each and every single one, read ALL, one inch shaft Catalinas used 3/16. SOME, a handful, I have read about, used 1/4. I can only surmise that someone at the factory had a handful of different sized boxes that they used, could well have been for larger boats (i.e., shaft diameters). I just don't know. No one really does.

You can't go wrong smaller, you can score your shaft using larger.

What does your owners manual and Association website have to say?

And, finally, when all else comes to naught, measure your own blinkin' box using Maine Sail's instructions, or just eyeball it with a piece of cardboard and a tape measure. I realize access may be poor, difficult or impossible in some cases, but the measurement of the gap to properly size the flax is not rocket science.

Stu Jackson · Oct 25, 2009

Stephen K said:
I still have a good amount of room on the shaft for future tightening.....

How do you know that? Just because there are threads showing OUTSIDE does NOT mean you haven't bottomed out INSIDE. You can't possibly know from looking at the outside only.

Stephen K · Oct 26, 2009

Stu Jackson said:
Just because there are threads showing OUTSIDE does NOT mean you haven't bottomed out INSIDE. You can't possibly know from looking at the outside only.

I do have a good amount of external threads and that is what I based my (erroneous ?) judgement on..... are you saying that the "insides" (or packing) may be significantly compressed or close to being worn out?...if so, then that is something I did not consider (or look at) and thanks again to learning from others knowledge on this site.

From a practice standpoint, I'm not quite sure how the evaluate the inside other than backing completely off and seeing if there is packing... don't think it could be measured without removing and that would dictate replacement. Am I misssing something here?

Stu Jackson · Oct 26, 2009

Am I missing something here?

Nope.

Stephen K · Oct 26, 2009

class dismissed...thanks Stu

Maine Sail · Oct 27, 2009

Ron said:
I have looked through the old postings on GFO, but can't find an anwer to my question.
This past spring, I installed 3/16 GFO packing on the shaft of my 1994 320. This is the size stated in my Catalina manual. I did the breaking in period, as per the GFO instructions. All season the drip rate has been inconsistent. After one day, the bilge is nearly dry....after another day running in the same conditions, the bilge is almost full. When I try to snug the packing nut down by hand to reduce the dripping, I reach a point where the GFO seems to distort and allow a stream of water to get in. When I back it off, I still get more drops than I want. Anyone have this problem ?

Ron,

Sounds like and incorrect pack or a twist in the packing when it went in. A re-pack is probably in order. Tightening it should not result in a stream of water...

Can you please describe how you packed it, seated it and how many rings you got in there?

Stu Jackson · Oct 27, 2009

Tag, you're it! For 2019!

Ron said:
....until now.....none of them have had my particular problem.

Ron, you're right. It's rare that folks have "backed off" and perhaps my link to my long article in the C34 'site can be improved to mention that. Between Maine Sail's excellent photography and description and my old written one, they pretty much cover what BOTH he and I found lacking in other descriptions from books, which is why we wrote them. Mine is circa 1999, his is this year.

Looks like every ten years or so, so, Ron, "Tag, you're it! For 2019!"

The Catalina Manuals have a pretty good drawing of the packing gland/stuffing box, look on PDF pages 40 & 41, here: http://www.c34.org/manuals/1988/1988-C34-Owners.pdf

I just went back to my article, added the "don't back off" and linked Maine Sail's photos. That article is now in our C34 wiki and I can edit it.

For those with M25 engines, you may be interested in our wiki with lotsa engine info: http://www.c34.org/wiki/index.php?title=Diesel_Engine

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