Return to the home page...

Go Back   Moyer Marine Atomic 4 Community - Home of the Afourians > Discussion Topics > General Maintenance

Reply
 
Thread Tools Display Modes
  #1   IP: 173.73.74.93
Old 04-02-2009, 05:37 PM
doublec9 doublec9 is offline
Senior Member
 
Join Date: Jun 2008
Location: Mid-Ches Bay
Posts: 12
Thanks: 0
Thanked 0 Times in 0 Posts
Stuffing box packing

Hello all,

I have stuffing box curiosity. Is there a standard packing size for A4s? I ask because I just pulled the old packing out of my stuffing box for the first time and found way too much packing in it (count 'em, 8 rings!). Luckily, the shaft is not scored and is in good shape. Unfortunately, I pulled 3 different sizes (and I think 3 different types) of packing out of the stuffing box, so I'm left guessing the right replacement size. I'm hoping there is a standard A4 packing size so I don't have to buy three different sizes. Shaft is 3/4". Boat is a '79 Pearson 30. The attached picture shows what I discovered.

Thanks,
Carter
Attached Images
 

Last edited by Administrator; 04-03-2009 at 08:22 AM. Reason: Resize image...
Reply With Quote
  #2   IP: 65.160.16.85
Old 04-02-2009, 06:27 PM
roadnsky's Avatar
roadnsky roadnsky is offline
Afourian MVP
 
Join Date: Dec 2008
Location: Lake Mead, NV
Posts: 3,104
Thanks: 24
Thanked 467 Times in 309 Posts
Carter-
It looks like you're lucky not to have scoring.
This is the best explanation and description of the stuffing box re-packing procedure that I have found:
http://www.pbase.com/mainecruising/stuffing_box

There are also various other threads here regarding the procedure.
Search "Stuffing Box".

Also, just for future reference, watch your file sizes when you post pictures.
This site allows for some pretty high rez postings which cause the viewer quite a bit of scrolling.
Smaller images work best.
Reply With Quote
  #3   IP: 65.160.16.85
Old 04-02-2009, 06:37 PM
roadnsky's Avatar
roadnsky roadnsky is offline
Afourian MVP
 
Join Date: Dec 2008
Location: Lake Mead, NV
Posts: 3,104
Thanks: 24
Thanked 467 Times in 309 Posts
Oops. I didn't actually answer your original question about the packing size...

The size will be determined by your shaft diameter.
(Hmmm, can I say that on this site??!)
Reply With Quote
  #4   IP: 142.68.103.225
Old 04-03-2009, 05:36 AM
rigspelt's Avatar
rigspelt rigspelt is offline
Afourian MVP
 
Join Date: May 2008
Posts: 1,187
Thanks: 0
Thanked 19 Times in 17 Posts
I had to estimate this for the first time too. Don Casey: "measure the space between the shaft and the inside of the packing nut to determine the correct flax size" (http://www.boatus.com/boattech/Casey/StuffingBox.htm). So if I've got this right, then size of stuffing C = stuffing box gland inside diameter A minus shaft diameter B divided by 2, since there are two sides to the diameter. Someone said that since packing won't compress down but can expand up a bit, go with the smaller size if between two and the larger is greater than C. Hope that's right.
Attached Images
 
__________________
1974 C&C 27
Reply With Quote
  #5   IP: 72.93.200.164
Old 04-03-2009, 09:59 AM
jayw jayw is offline
Senior Member
 
Join Date: Feb 2007
Location: Plymouth, MA
Posts: 66
Thanks: 0
Thanked 0 Times in 0 Posts
When you install new packing it is very easy and very common to overtighten. New packing will compress down for a while after it's first put in and will require a few initial adjustments as it wears.
Best approach is to first tighten the packing nut until the water drip is slow (like about 1 drop per second or a little less) then run the engine for a few hours and re-tighten to the same drip rate as before. This type of packing is supposed to slowly drip water for its life as the water cools and lubricates. Overtightening to the point of no drip causes the packing to heat up and wear quickly and may score the shaft.
Reply With Quote
  #6   IP: 173.73.74.93
Old 04-03-2009, 02:38 PM
doublec9 doublec9 is offline
Senior Member
 
Join Date: Jun 2008
Location: Mid-Ches Bay
Posts: 12
Thanks: 0
Thanked 0 Times in 0 Posts
Thanks for the great replies. Sorry for the large photo...and thanks for resizing it for me. As soon as I uploaded it, I realized how large it actually was, but couldn't figure out how to resize it.

I made some measurements when I extracted the packing, but my measurements didn't correspond to typical packing sizes. I measured between 5.5mm and 6mm as stuffing size "C," but that leaves me between 3/16" and 1/4". Of course, the problem could be the measurer, considering I was making the measurements at arms length.

Speaking of bad measuring, when I measured the shaft diameter, I got 15mm (roughly 5/8"). Does that sound like a normal shaft diameter or a bad measurement? I was expecting 3/4" or 1" diameter.

I'm probably safest buying 3/16" and 1/4" and doing a little trial-and-error experimentation.
Reply With Quote
  #7   IP: 207.210.5.64
Old 04-03-2009, 07:52 PM
Dromo's Avatar
Dromo Dromo is offline
Senior Member
 
Join Date: Mar 2008
Location: Canada
Posts: 193
Thanks: 0
Thanked 2 Times in 2 Posts
I used a caliper to measure the shaft on my 25ft boat.

I thought it would be 1'' or 1-1/8'' using a tape measure, but with a caliper I got 7/8''.

I'm thinking a 5/8'' prop. shaft sounds a little small for a 30hp inboard engine.

But I could be wrong.

Rick
Reply With Quote
  #8   IP: 151.199.53.169
Old 04-03-2009, 08:06 PM
smosher smosher is offline
Afourian MVP
 
Join Date: Jun 2006
Posts: 489
Thanks: 0
Thanked 35 Times in 34 Posts
I have a 74 P30 and its a 7/8 shaft and I used 3/16 packing, 4 rings
Reply With Quote
  #9   IP: 98.229.132.18
Old 04-03-2009, 09:33 PM
m_galligan's Avatar
m_galligan m_galligan is offline
Senior Member
 
Join Date: Jul 2006
Location: Carlisle, MA
Posts: 17
Thanks: 0
Thanked 0 Times in 0 Posts
Send a message via Yahoo to m_galligan
I have a Catalina 27, and I use 3/16" packing.
__________________
-Marty Galligan, Carlisle, MA
1976 Catalina 27 "Kookaburra" #2613
Reply With Quote
  #10   IP: 72.89.246.120
Old 04-03-2009, 09:44 PM
tenders tenders is offline
Afourian MVP
 
Join Date: May 2007
Location: Harlem YC, City Island, NY
Posts: 1,439
Thanks: 46
Thanked 259 Times in 170 Posts
Buy all the sizes that might be right and write the proper size down for next time. You don't wanna be in the situation where the boat's in the water and the shaft is leaking uncontrollably.

By the way it looks to me like you've pulled out 9 rings, not 8!
Reply With Quote
  #11   IP: 142.68.103.225
Old 04-04-2009, 05:14 AM
rigspelt's Avatar
rigspelt rigspelt is offline
Afourian MVP
 
Join Date: May 2008
Posts: 1,187
Thanks: 0
Thanked 19 Times in 17 Posts
Over or under size?

So, does slightly smaller packing expand up a bit as it is compacted by the packing nut? It makes sense to me that if one had to choose between a packing sized slightly less than C or larger than C, it would be risky to try to stuff the larger sized packing into C.

I measured C at 4.5/16" = halfway between 1/4" and 5/16", so bought 1/4" Teflon-impregnated packing, which is only 1/32" smaller than C. Would it be better to drop even smaller and start with 3/16",which is 3/32"" smaller than C?
__________________
1974 C&C 27
Reply With Quote
  #12   IP: 64.231.81.11
Old 04-04-2009, 09:33 PM
67c&ccorv's Avatar
67c&ccorv 67c&ccorv is offline
Afourian MVP
 
Join Date: Dec 2008
Location: London, ON
Posts: 1,559
Thanks: 4
Thanked 9 Times in 9 Posts
Oh boy, just looking at this job gives me the willys! You should the tiny little work area I have to somehow squeeze into (probably with my wife holding on to my bootstraps) in order to redo the packing gland on the Corvette!
Reply With Quote
  #13   IP: 173.73.99.167
Old 04-20-2009, 09:35 PM
doublec9 doublec9 is offline
Senior Member
 
Join Date: Jun 2008
Location: Mid-Ches Bay
Posts: 12
Thanks: 0
Thanked 0 Times in 0 Posts
Just wanted to send a follow-up. Successfully repacked the stuffing box this weekend. Started the job with a pack of 1/4" and a pack of 3/16" GTU packing. The four loops of 3/16" fit the bill perfectly.

By the way, remeasure the shaft at 1-3/16". Now I need new zincs and am guessing I should go with 30 mm: West Marine carries 1-1/8" and 1-1/4" anodes, and also a 30 mm.
Reply With Quote
  #14   IP: 207.107.4.230
Old 04-21-2009, 05:30 AM
rigspelt's Avatar
rigspelt rigspelt is offline
Afourian MVP
 
Join Date: May 2008
Posts: 1,187
Thanks: 0
Thanked 19 Times in 17 Posts
Quote:
Originally Posted by doublec9 View Post
Just wanted to send a follow-up. Successfully repacked the stuffing box this weekend. Started the job with a pack of 1/4" and a pack of 3/16" GTU packing. The four loops of 3/16" fit the bill perfectly.
What happened when you tried 1/4"? Just would not fit in? Just interested in learning more about this procedure, since I'm about to do it for the first time.
__________________
1974 C&C 27
Reply With Quote
  #15   IP: 76.126.149.144
Old 04-21-2009, 01:07 PM
tartansailboat tartansailboat is offline
Senior Member
 
Join Date: Mar 2009
Posts: 100
Thanks: 0
Thanked 2 Times in 2 Posts
packing gland

When I first tried to replace the packing material, measurements indicated that 1/4 inch material was correct. After installation I found that I could not get any dripping even with the nut backed way off and after running for a minute, the shaft was very hot. I redid the packing using 3/16 material and the shaft ran cool. All boats are different but I suspect you want the smallest diameter packing that still does the job, to prevent scoring of the shaft.
Reply With Quote
  #16   IP: 173.73.99.167
Old 04-21-2009, 07:01 PM
doublec9 doublec9 is offline
Senior Member
 
Join Date: Jun 2008
Location: Mid-Ches Bay
Posts: 12
Thanks: 0
Thanked 0 Times in 0 Posts
Yep, I agree with tartansailboat. I could have squeezed the 1/4" into the packing nut, but it would have been very tight and I doubt the shaft would have gotten the needed lubrication. The 3/16" fit like a glove...just a tad bit loose, but will compress when tightened to be just right.
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Sealing stuffing box hose connection? rigspelt Drive Train / Propellers 7 08-07-2008 06:09 AM
Need to replace my stuffing box Overspendin' Drive Train / Propellers 1 06-02-2008 11:24 AM
Rebuild of Atomic 4 and Dripless Packing John B Overhaul 9 04-16-2008 11:06 AM
High RPM under Load oly sailor Drive Train / Propellers 7 01-09-2008 09:09 PM
Packing box OCsails Drive Train / Propellers 4 06-12-2006 09:26 AM


All times are GMT -4. The time now is 10:56 AM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2024, vBulletin Solutions, Inc.


Universal® is a registered trademark of Westerbeke Corporation

Copyright © 2004-2024 Moyer Marine Inc.

All Rights Reserved