[TR] Triumphs Digest, Vol 16, Issue 39

JOSEPH MATO joemato at sbcglobal.net
Tue Mar 21 04:56:13 MDT 2023 

Hi. John Esposito is the best LBC mechanic in CT and he has a shop in Oxford, CT called Quantum Mechanics. He is a math nut and works with the MG club and does the rebuilding work for TRF. He was making TR main shafts after he found no saleable units.
Joe Mato62 Wood RoadRedding, CT 06896917 232 1555 

    On Monday, March 20, 2023 at 02:49:34 PM EDT, triumphs-request at autox.team.net <triumphs-request at autox.team.net> wrote:  
 
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Today's Topics:

  1. Calling anyone with transmission rebuilding experience -
      second attempt, part 1 (aribert neumann)
  2. Calling anyone with transmission rebuilding experience - 2nd
      attempt, part2 (aribert neumann)
  3. Re: Calling anyone with transmission rebuilding experience -
      second attempt, part 1 (DAVID MASSEY)
  4. Re: Calling anyone with transmission rebuilding experience -
      2nd attempt, part2 (DAVID MASSEY)


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Message: 1
Date: Sun, 19 Mar 2023 19:46:53 -0400
From: aribert neumann <aribertn at gmail.com>
To: triumphs at autox.team.net
Subject: [TR] Calling anyone with transmission rebuilding experience -
    second attempt, part 1
Message-ID:
    <CAGkVM28WONnczb-ObP54A8pB0O4nMs-6QzVN_432Y8LqZ=Zq4A at mail.gmail.com>
Content-Type: text/plain; charset="utf-8"

I tried to send this message yesterday but it has not appeared yet so I am
resending it - guessing that I may have had too many (or too large of)
images.  I'll splint it into two messages and reduce the image file sizes
- hopefully this message will go thru.

I'll start off with a quick comment - as I started to type the e-mail
address, up popped suggestions that started with TR.  Third on the list
was "TR3driver" - the late Randall (Young, I think).  I sincerely hope
someone will "fill his shoes" with respect to my questions.  I'm not on
any other Triumph related groups - you are all I've got for input.

I am in the process of reassembling (or trying to) my GT6 transmission -
please don't tune out, conceptually the trans is similar to the big
Triumphs.  On dismantling my trans, I observed that the split collars had
spun on the main shaft, wearing a relief in the collars and raising an edge
on the main shaft.  What keeps the collars from rotating when 1st gear is
in motion?  I am focused on preventing this problem in the future.  When I
rotate first gear on the shaft, the split washers rotate with the shaft.  I
am wondering if the tolerance stack up of the 2nd & 3rd gear bushings,
spacers, etc (from the circlip to the split collars) was too large allowing
first gear to push the split collars forward on the shaft.  What else could
cause this rotation/wear?

Images as follows - old mainshaft with raised edge from the spinning split
washers, good & worn split washers, good split washers nested in the first
gear pocket.    Off in digest mode preparing part 2 of this message.
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Message: 2
Date: Sun, 19 Mar 2023 19:52:24 -0400
From: aribert neumann <aribertn at gmail.com>
To: triumphs at autox.team.net
Subject: [TR] Calling anyone with transmission rebuilding experience -
    2nd attempt, part2
Message-ID:
    <CAGkVM2_qddwDt8R2M5Wx1mGzUgXgX1kQH6noupRw_yA7JqY-BQ at mail.gmail.com>
Content-Type: text/plain; charset="utf-8"

Next question - my (new) replacement main shaft is oversize in a couple of
places.  The diameter under the 2nd & 3rd gear bushings (I have opened up
the bushings to only have a light interference fit).  Worst is the diameter
under the rear bearing.  I can install the bearing but I have to hammer it
***hard*** to get it to fit on the shaft - can't be good for the bearing -
guessing I might change the inner race diameter a miniscule amount.  I'm
thinking of sending this main shaft back to Spitbits and reusing my old
main shaft.  I have cleaned up the groove for the split collars on my
lathe.  The other damage on the shaft is on the nose where the cage bearing
rides in the input shaft - this damage is only on one side of the shaft and
only on half of the bearing surface (fore/aft).  I am already going to
replace the cage bearing with a bearing bronze bushing since the surface
inside the input shaft pocket is showing wear also.  The max amount of
surface missing on the nose of the old main shaft is 0.003 in diameter.
 Images:  exploded view from Bentley  manual, nose of the old, worn
mainshaft

Your thoughts and suggestions please - off in digest mode awaiting your
responses.  Trying to formulate a new plan of attack for Monday morning.
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Message: 3
Date: Mon, 20 Mar 2023 12:39:48 +0000 (UTC)
From: DAVID MASSEY <dave1massey at cs.com>
To: "aribertn at gmail.com" <aribertn at gmail.com>,
    "triumphs at autox.team.net" <triumphs at autox.team.net>
Subject: Re: [TR] Calling anyone with transmission rebuilding
    experience - second attempt, part 1
Message-ID: <2090616878.2487776.1679315988251 at mail.yahoo.com>
Content-Type: text/plain; charset="utf-8"

 It has been many years (< 25, I think) but I once rebuilt a TR6 transmission with a used mainshaft that had similar wear on a shoulder like that.? There was a thrust washer that fitted up against shoulder.? A few years later I was rebuilding it again.? The thrust washer had broken into parts.? My solution was to buy a new mainshaft (that is a story in itself) along with some other parts.? 25 years later that part is still soldering on.? (I had to rebuild again for layshaft issues but that's unrelated)
I would be very reluctant to reuse that mainshaft.? The raised ridge is not what worries me it is the fact that the edge of the grove is not square and the thrust applied by the helical gears will point load the split collars and they will fail again.? The TR6 transmission si probably different but the basic design is similar and the force loading is also similar.? Helical gears are sued to keep tooth noise down but the fact that they are wound in a helical manner around the axis means the forces applied to the gears is at an angle to that axis.? Part of that force is used to rotate the shaft but the other is applied to the bearings at either end of the transmission meaning the split collars in your case will take up that force as an interface between the shaft and the bearing inner race.? I don't have enough experience to say whether the transmission will last a week, month, year or 10 years with that shaft but I would have much more confidence in a new, quality shaft.
 
Dave 


 
 
-----Original Message-----
From: aribert neumann <aribertn at gmail.com>
To: triumphs at autox.team.net
Sent: Sun, Mar 19, 2023 6:46 pm
Subject: [TR] Calling anyone with transmission rebuilding experience - second attempt, part 1

I tried to send this message yesterday but it has not appeared yet so I am resending it - guessing that I may have had too many (or too large of) images.? ?I'll splint it into two messages and reduce the image file sizes - hopefully this message will go thru.
I'll start off with a quick comment - as I started to type the e-mail address, up popped suggestions that started with TR.? ?Third on the list was "TR3driver" - the late Randall (Young, I think).? ?I sincerely hope someone will "fill his shoes" with respect to my questions.? ?I'm not on any other Triumph related groups - you are all I've got for input.
I am in the process of reassembling (or trying to) my GT6 transmission - please don't tune out, conceptually the trans is similar to the big Triumphs.? ?On dismantling my trans, I observed that the split collars had spun on the main shaft, wearing a relief in the collars and raising an edge on the main shaft.? What keeps the collars from rotating when 1st gear is in motion?? I am focused on preventing this problem in the future.? When I rotate first gear on the shaft, the split washers rotate with the shaft.? I am wondering if the tolerance stack up of the 2nd & 3rd gear bushings, spacers, etc (from the circlip to the split collars) was too large allowing first gear to push the split collars forward on the shaft.? What else could cause this rotation/wear???
Images as follows - old mainshaft with raised edge from the spinning split washers, good & worn split washers, good split washers nested in the first gear pocket.? ? Off in digest mode preparing part 2 of this message.


** triumphs at autox.team.net **

Donate: http://www.team.net/donate.html
Archive: http://www.team.net/pipermail/triumphs? http://www.team.net/archive

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Message: 4
Date: Mon, 20 Mar 2023 13:30:54 +0000 (UTC)
From: DAVID MASSEY <dave1massey at cs.com>
To: "aribertn at gmail.com" <aribertn at gmail.com>,
    "triumphs at autox.team.net" <triumphs at autox.team.net>
Subject: Re: [TR] Calling anyone with transmission rebuilding
    experience - 2nd attempt, part2
Message-ID: <583075131.2506945.1679319054463 at mail.yahoo.com>
Content-Type: text/plain; charset="utf-8"

 That looks like the heat treated, hardened? surface is starting to break up.? That is what happened to my layshaft.? Another reason to abandon that mainshaft.? If you have an alternate bearing combination that doesn't relay on that surface for the bearing rollers then the hardened surface is no longer critical.? But this is above my pay grade.

BTW, I misinterpreted one of your previous photos.? The split washers transfer the lateral forces from the synchro hub to the mainshaft but the end result is the same, with a compromised groove surface like that the split collars will fail prematurely.?? If you open the grove to clean up the shoulder will the split washers stay in place?? If they fall out you have serious problems.? Even if they stay in place will it increase backlash?? Can you get oversized split collars?? Make shims?? All this is above my pay grade.
 
Dave 


 
 
-----Original Message-----
From: aribert neumann <aribertn at gmail.com>
To: triumphs at autox.team.net
Sent: Sun, Mar 19, 2023 6:52 pm
Subject: [TR] Calling anyone with transmission rebuilding experience - 2nd attempt, part2

Next question - my (new) replacement main shaft is oversize in a couple of places.? ?The diameter under the 2nd & 3rd gear bushings (I have opened up the bushings to only have a light interference fit).? Worst is the diameter under the rear bearing.? I can install the bearing but I have to hammer it ***hard*** to get it to fit on the shaft - can't be good for the bearing - guessing I might change the inner race diameter a miniscule amount.? I'm thinking of sending this main shaft back to Spitbits and reusing my old main shaft.? I have cleaned up the groove for the split collars on my lathe.? The other damage on the shaft is on the nose where the cage bearing rides in the input shaft - this damage is only on one side of the shaft and only on half of the bearing surface (fore/aft).? I am already going to replace the cage bearing with a bearing bronze bushing since the surface inside the input shaft pocket is showing wear also.? The max amount of surface missing on the nose of the old m
 ain shaft is 0.003 in diameter.? ?Images:? exploded view from Bentley? manual, nose of the old, worn mainshaft

Your thoughts and suggestions please - off in digest mode awaiting your responses.? Trying to formulate a new plan of attack for Monday morning.

** triumphs at autox.team.net **

Donate: http://www.team.net/donate.html
Archive: http://www.team.net/pipermail/triumphs? http://www.team.net/archive

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End of Triumphs Digest, Vol 16, Issue 39
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