Return to the home page...

Go Back   Moyer Marine Atomic 4 Community - Home of the Afourians > Discussion Topics > Reversing Gear

Reply
 
Thread Tools Display Modes
  #1   IP: 68.129.90.42
Old 07-05-2020, 07:11 PM
nesdon's Avatar
nesdon nesdon is online now
Senior Member
 
Join Date: Aug 2019
Posts: 10
Thanks: 0
Thanked 1 Time in 1 Post
Forward vibration after rear thrust bearing replacement

I have a 1972 Tartan 30 with an A4 which growled in gear and leaked oil through the rear seal. I replaced the seal and bearing and sleeved the flange.

Growl and oil leak solved, but today (first extended run) I noticed a vibration in forward. Very smooth in neutral and I didn't notice it in reverse, though I didn't do much reversing. It has a bit of a banging sound at around 1000 rpm, but smoothed out and became just a vibration at speed (1800). Felt like it might be something on the prop, but I checked and it's clear.

It might shift a little harder than before, but I wonder if I could have damaged or dislodged something when installing the flange. I bought the OilSeal video, and Don mentions that the pilot bearing has some fragile aspect. What would the symptoms be if I had damaged it, and how might I check.
Reply With Quote
  #2   IP: 24.53.89.131
Old 07-05-2020, 07:18 PM
Peter's Avatar
Peter Peter is online now
Senior Member
 
Join Date: Jul 2016
Location: Nova Scotia, Canada
Posts: 262
Thanks: 112
Thanked 117 Times in 84 Posts
Nesdon,

Exact same thing happened to me - growl and leak fixed by seal and bearing replacement.

Vibration when I put it all back together. Re-did engine alignment and it went away.

Also check to make sure the prop shaft flange is fully seated on the output coupling.

Hope that helps.

Peter
Reply With Quote
  #3   IP: 32.211.28.40
Old 07-05-2020, 08:11 PM
Al Schober's Avatar
Al Schober Al Schober is offline
Afourian MVP
 
Join Date: Jul 2009
Location: Uncasville, CT
Posts: 1,779
Thanks: 11
Thanked 377 Times in 281 Posts
First, I'd check shaft alignment. Loosen the shaft coupling and check clearances. Still thinking on how to check the pilot bearing..
Reply With Quote
  #4   IP: 68.129.90.42
Old 07-05-2020, 10:28 PM
nesdon's Avatar
nesdon nesdon is online now
Senior Member
 
Join Date: Aug 2019
Posts: 10
Thanks: 0
Thanked 1 Time in 1 Post
Funny, that was my first thought as I just put new mounts and flanges in my boat club's Old Port 26 launch under a Yanmar HJ4 to solve a vibration after having had the trans rebuilt last year, so I thought I had just had shaft alignment on the brain and ignored it.

While I didn't put any feelers in there on my A4, it slid in so well and seemed like nothing I had done should have changed it, so I just tightened it up. The previous owner did install a pillow bushing (somewhat sloppily) about mid shaft, and the cap was off as I was working on it so that might be involved.

One of the nice things about this Tartan is that the engine is midship so that you can easily see and touch almost every surface of it!
Reply With Quote
  #5   IP: 32.211.28.40
Old 07-05-2020, 10:52 PM
Al Schober's Avatar
Al Schober Al Schober is offline
Afourian MVP
 
Join Date: Jul 2009
Location: Uncasville, CT
Posts: 1,779
Thanks: 11
Thanked 377 Times in 281 Posts
That 'pillow bearing' was probably original. My T30 (#173) had one. The pre-purchase survey said it needed grease, which I did. Not long after, I noticed the prop bearing was loose and pulled the shaft to replace it. That steady bearing along with its block fell into the bilge! Bond had failed.
Examination of the shaft at this time showed corrosion in way of the rubber bearing, so the shaft was replaced with Aquamet 22. Never did replace the steady bearing.
Still have the old shaft. It's great for digging rocks out of the garden.
Reply With Quote
  #6   IP: 172.58.228.108
Old 03-11-2021, 01:49 PM
nesdon's Avatar
nesdon nesdon is online now
Senior Member
 
Join Date: Aug 2019
Posts: 10
Thanks: 0
Thanked 1 Time in 1 Post
Replace pilot bearing

I’ve done some investigating and am pretty certain my vibration is the pilot bearing. The flanges are perfectly parallel, and when I pry on the output flange I see a bit of movement of the gear assembly.

Also when I was winterizing on the hard I ran it in gear up to 3000 rpm, and though with no load the vibration was hard to detect, it did suddenly make the distinctive noise of a worn-bearing harmonic I have heard many times in failing power tools.

It looks like I have to pull the rear bearing holder and flange as well as the whole reversing gear housing. Any tips?
Reply With Quote
  #7   IP: 108.79.1.46
Old 03-11-2021, 04:29 PM
jbsoukup's Avatar
jbsoukup jbsoukup is offline
Afourian MVP
 
Join Date: Jan 2012
Location: chicago
Posts: 144
Thanks: 0
Thanked 9 Times in 8 Posts
i had the same symptoms and could not figure it out for a long time. eventually just by chance i loosened the set screw on the coupling, put it in forward so as to push the shaft in, (at the dock, of course, and i don't remember why i needed to do that) and behold! the vibration was gone. tightened the set screw and it came back?! turns out the coupling was the culprit all along; although i could see no damage and it seemed to fit the shaft fine. i suspect that after removing the coupling ( it was Not easy) it became slightly deformed?

so new coupling and smooth as silk.

also, by the way, i felt real weird about relying on just a couple set screws keeping my shaft secure in reverse so i drilled a shallow detent in the shaft for the set screw to set into.
__________________
john
'77 catalina 30 #783
Reply With Quote
The Following User Says Thank You to jbsoukup For This Useful Post:
Surcouf (03-11-2021)
  #8   IP: 134.41.100.227
Old 03-11-2021, 04:46 PM
Mo's Avatar
Mo Mo is offline
Afourian MVP
 
Join Date: Jun 2007
Location: Halifax NS,
Posts: 4,355
Thanks: 176
Thanked 275 Times in 193 Posts
Check anode and cutlass bearing. If they are OK check shaft for bend. Sounds like you did everything else right.
Anode: if loose you will feel it and be able to move it with you hand.
Cutlass: about 1/16 play...just enough to make a little sound...should not be sloppy. That, said, there is a fine line on that one.
Bent shaft: Put it in gear and get into the lazarette...hold something like a credit card next to the shaft as it spins...if you notice a wobble, shaft is bent.

That would be my start. I changed an engine last Sept and micro metered the mounts before re-installation...when it bolted up there wasn't the slightest of a shimmy.

EDIT: If you think your alignment might be out where it bolts up take a cigarette package down to the boat with you. Loose the 3 bolts, so that the paper from a cigarette package can fit in the flange as you turn it 360 degrees. Then do 1/8 turn on each bolt in a circular motion until they all come tight. Funny as that sounds, it has sorted out a number of vibrations. You have to start somewhere.
__________________
Mo

"Odyssey"
1976 C&C 30 MKI

The pessimist complains about the wind.
The optimist expects it to change.
The realist adjusts the sails.
...Sir William Arthur Ward.

Last edited by Mo; 03-11-2021 at 04:56 PM.
Reply With Quote
  #9   IP: 38.27.109.137
Old 03-11-2021, 05:20 PM
W2ET W2ET is offline
Former Admin
 
Join Date: Oct 2008
Posts: 76
Thanks: 65
Thanked 35 Times in 20 Posts
Quote:
I noticed a vibration in forward. Very smooth in neutral and I didn't notice it in reverse, though I didn't do much reversing.
This must point to some things (and eliminate some things), though I don't know what.

My limited expertise has more to do with questions than answers.

Bill
Reply With Quote
  #10   IP: 68.129.89.87
Old 03-11-2021, 06:19 PM
nesdon's Avatar
nesdon nesdon is online now
Senior Member
 
Join Date: Aug 2019
Posts: 10
Thanks: 0
Thanked 1 Time in 1 Post
I pulled the shaft to check the flange alignment and there was no gap at all. It also turns very easily, smoothly, and freely. I had a lovely Yanmar 3GM in another boat that was aligned by a boat yard, not realizing that on the hard, the weight on the keel deformed the hull enough that it was way out of parallel when floating. I could see it shift the engine on its mounts as I turned the shaft by hand.

I do have a pretty old two-bladed prop quite close to the keel, I half expected to see a chip out of it or a damaged zinc, but none of that has changed, and it ran smoothly before the bearing work, tho' I did not replace the flange, I just put a sealing sleeve on it.

The kicker for me condemning the forward support bearings was the loud whirring sound it suddenly made when spinning the prop in the air during my winterizing run. I shifted it to neutral, and the noise stopped, went back into gear and it was gone. Maybe this is normal and unrelated.

In the rev gear video (see attachment) I see what looks like a babbit bearing with a large retaining clip in the outer clutch drum that rides on the end of the crankshaft, as well as the tip of the tail shaft, but no instructions on removing either bearing, as well as no listing for that drum bearing in the catalogue.

My manual discusses disassembling the gear case to replace the disks etc. and there is instructions in the engine rebuild section about removing the rear housing and getting the gear case out, but also mention of an idler shaft and bearing that I can't identify.

My rear bearing was really badly shot, so I've also presumed the forward bearing would be in similarly poor shape. The way I can imagine these forward bearings causing this vibration is if they are so worn that the gear case is able to shift off off its centerline.

I'd hate to tear it all down and replace the pilot bearing only to find I did not solve it, either because it was that drum bearing or something like a bent shaft or prop. Hmm?
Attached Images
 
Reply With Quote
  #11   IP: 134.41.100.227
Old 03-11-2021, 06:39 PM
Mo's Avatar
Mo Mo is offline
Afourian MVP
 
Join Date: Jun 2007
Location: Halifax NS,
Posts: 4,355
Thanks: 176
Thanked 275 Times in 193 Posts
I'm no expert on the reversing gear, however, I do remember a guy named Hanley Cifford dx a pilot issue by removing the cover and grabbing the drum and seeing if there was any play in it. Hanley was pretty good at these things...he was looking for any bearing play...might want to check with Ken or Don Moyer himself about that. I just don't know enough on it because I've not encountered the issue of a pilot bearing failure.

That said, not feeling the vibration in reverse really may not mean much because of the 1:1 ratio and prop design...the prop is meant to be fully efficient in forward.

Next, just because we bolt things up and it looks lovely doesn't mean the coupling is perfect. Many have had issues with flange alignment, although I have been fortunate with the ones I've worked on.
__________________
Mo

"Odyssey"
1976 C&C 30 MKI

The pessimist complains about the wind.
The optimist expects it to change.
The realist adjusts the sails.
...Sir William Arthur Ward.
Reply With Quote
The Following User Says Thank You to Mo For This Useful Post:
ronstory (03-12-2021)
  #12   IP: 68.129.89.87
Old 03-12-2021, 09:00 AM
nesdon's Avatar
nesdon nesdon is online now
Senior Member
 
Join Date: Aug 2019
Posts: 10
Thanks: 0
Thanked 1 Time in 1 Post
FWIW, I realized that the pilot bearing would only be in play when in neutral or reverse, so my comment about expecting it to wear similarly to the rear bearing is likely incorrect.

Still, the gear case does seem to have some play, though its hard with the shifting linkage in the way to get enough purchase on it to judge how much. Being able to see it rock a bit when I pry back on one side of the drive flange suggests that it is pretty bad.

The ironic thing here is that I am trying to sell this boat. But having had to confront a lot of poor repairs and neglected maintenance (finally have most of the oil out of the bilge from that bad rear seal!) by the previous owner, I am loathe to do the same to the next owner, so am trying to do right by the sweet old gal.
Reply With Quote
  #13   IP: 68.129.89.87
Old Yesterday, 10:16 PM
nesdon's Avatar
nesdon nesdon is online now
Senior Member
 
Join Date: Aug 2019
Posts: 10
Thanks: 0
Thanked 1 Time in 1 Post
Update

Bolted up the shaft and saw the engine wobble back and forth with each rev. as the prop was turning slowly as I ran it in neutral. I unbolted the shaft and put a dial indicator on both flanges and they are running true =/-.002", but that they now seemed pretty badly (2mm) misaligned.

I tried to tighten the nuts that hold the engine to the stringers, and realized that the hangar bolts had pulled loose. What I seem to have done when working on the rear bearing was to shift the engine causing the misalignment. So I glued a dowel into the old hole and reinstalled the hangar bolts, then tried to shift the engine around to realign the shaft.

What i discovered was the the starboard stringer on my T30, which is just to port of the centerline of the boat, was wobbling around badly, obviously broken free form the hull, with the wooden core likely rotten from rainwater and snow melt in the bilge likely.

It makes aligning it impossible, but I did it as well as I could. How much does the engine weigh? Anybody have any experience moving one to replace the stringers? Also, this set up, with the engine sitting directly on the stringers without mounts seems less than ideal.
Reply With Quote
Reply

Tags
oilseal, pilot, vibration

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
It started as a simple Cutless bearing replacement... cdhickey Drive Train / Propellers 8 05-02-2015 12:48 PM
Rear shaft oil seal replacement Gari Tartan 18 11-07-2013 02:59 PM
Forward and Reverse Gear Adjustment Issues CraigRun Reversing Gear 12 05-17-2012 09:15 PM
Thrust Bearing Replacement Peter S Reversing Gear 8 04-18-2011 12:13 PM


All times are GMT -4. The time now is 01:50 AM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2021, vBulletin Solutions, Inc.


Universal® is a registered trademark of Westerbeke Corporation

Copyright © 2004-2021 Moyer Marine Inc.

All Rights Reserved