[Fot] Fwd: Crown and pinion gear break in

John Styduhar johnstydo at gmail.com
Mon Sep 10 13:10:02 MDT 2018 

I looked at my TR3, TR4/4A, and TR250/6 shop manuals, and all of them show
the same factory tools to set the pinion depth measuring to the TOP of the
pinion head.  So why do the TR3 and 4 manuals have a rear axle illustration
that shows the critical measurement to the BACKSIDE of the pinion head??
Is the length of the gear on the pinion the same length regardless of
ratio?
[image: image.png][image: image.png]

On Mon, Sep 10, 2018 at 9:43 AM Bob Kramer <rkramer56 at gmail.com> wrote:

> Len Renkenberger wrote an article a long time ago for the 6-Pack
> newsletter showing how to do this without the factory tools, using polished
> bar stock to set up to measure pinion depth. I've used his techniques for
> years with great success.
>
> Bob Kramer
>
> On Sun, Sep 9, 2018 at 7:06 PM, John Styduhar via Fot <fot at autox.team.net>
> wrote:
>
>> Barry, when you are measuring TR pinion depth, where are you measuring
>> from and to?  The TR3 manual only has the dimension from the front face of
>> the pinion to the center of the ring gear which would be impossible to
>> measure directly with the pinion gear installed.
>>
>>
>>
>> On Sun, Sep 9, 2018 at 5:28 PM barry rosenberg <britcars at bellsouth.net>
>> wrote:
>>
>>> There is a factory set of tools that one uses to measure pinion depth
>>> before taking a diff apart. Then you set the new pinion at the same depth
>>> plus or minus the number on the gear.
>>>
>>> Barry
>>>
>>>
>>> ------------------------------
>>> *From:* John Styduhar via Fot <fot at autox.team.net>
>>> *To:* Greg Blake <gblake58tr3 at icloud.com>
>>> *Cc:* Triumph 'Friends of Triumph <fot at autox.team.net>
>>> *Sent:* Sunday, September 9, 2018 5:12 PM
>>> *Subject:* Re: [Fot] Fwd: Crown and pinion gear break in
>>>
>>> The "92" is the "matched set" number and should correspond with the set
>>> number on the ring gear.  The other number is the difference in pinion
>>> shimming from the "normal".    Haha, what is normal?
>>>
>>>
>>> On Sat, Sep 8, 2018 at 12:33 AM Greg Blake via Fot <fot at autox.team.net>
>>> wrote:
>>>
>>> Ok guys and gals.
>>>
>>> Here is a pic of the new pinion head. What do I do with the number on
>>> the pinion head?
>>> [image: image1.jpeg]
>>> Thanks.
>>>
>>>
>>> Sent from my iPhone
>>>
>>> On Sep 7, 2018, at 1:07 PM, Bob Kramer <rkramer56 at gmail.com> wrote:
>>>
>>> I have a 4.88 ring and pinion in a box. My Triumph club is running the
>>> VTR National near Austin next year and I've been volunteered to head up the
>>> autocross. I think I'll build a diff with it and put it in the Beandito,
>>> and sell tickets!
>>>
>>> Bob Kramer
>>>
>>> On Fri, Sep 7, 2018 at 8:37 AM, barry rosenberg via Fot <
>>> fot at autox.team.net> wrote:
>>>
>>> Wasn't this the new set of gears? If so, they were new old stock from
>>> England. They once belonged to Jim Ealy, who owned a black, 1966 TR4A race
>>> car. I bought his junk yard to get his race car and the gears were new in
>>> the box. I knew him since 1973 and he had the gears then. I had them until
>>> recently. I would not think that back then there were cheap reproduction
>>> gears available. He had 4:11, the 4:55 and 4:88 (great fun but useless).
>>> The 4:11 went in the car when I sold it, the 4:88 were put in a locked diff
>>> and played with on the street; the 4:55 sat on a shelf for all those years.
>>> If the diff still had fluid in it, then it has to be improper set up,
>>> unfortunately.
>>>
>>> Barry
>>>
>>>
>>> ------------------------------
>>> *From:* Greg Blake via Fot <fot at autox.team.net>
>>> *To:* Fot <fot at autox.team.net>
>>> *Cc:* fot <fot at autox.team.net>
>>> *Sent:* Friday, September 7, 2018 6:14 AM
>>> *Subject:* Re: [Fot] Fwd: Crown and pinion gear break in
>>>
>>> Thanks guys for all the feedback.
>>>
>>> So far I have only put the car in the air and pulled the cover. There is
>>> ample evidence of excessive heat so something went wrong with my setup.
>>>
>>> I might get the chance to pull it all out of the car and take some
>>> measurements on Sunday. Once I do, I’ll share my original setup notes and
>>> what I measure upon disassembly.
>>>
>>> On a related note. I ordered a new gear set from Rimmer on Monday and it
>>> arrived in Austin today, standard shipping. Amazing. Way faster than some
>>> of our domestic suppliers.
>>>
>>> This new gear set was supplied by Bastuck. Hopefully lasts a little
>>> longer.
>>>
>>> Sent from my iPhone
>>>
>>> On Sep 6, 2018, at 7:41 AM, Rick Parent via Fot <fot at autox.team.net>
>>> wrote:
>>>
>>> Looks like the pinion was way to deep.
>>>
>>>
>>> On Thursday, September 6, 2018 6:38 AM, Bill via Fot <fot at autox.team.net>
>>> wrote:
>>>
>>>
>>> I doubt if a break-in procedure could have prevented failure, but as
>>> Marcel says, checking the temperature of the diff could have stopped the
>>> damage. The likely culprits are incorrect engagement or bad parts, but
>>> anything that heats the gears enough to cook the oil off the parts will
>>> kill the gears. I had a close call with one of the gear sets I use.
>>> Apparently I screwed up somewhere in checking fit—when I pulled the rear
>>> end to assess the problem there was no backlash. I have a huge finned
>>> differential cover so checking temperature doesn’t help, but I could feel
>>> the car slowing quickly between shifts. Fortunately I wasn’t doing my usual
>>> clutchless shifts and noticed the sudden deceleration every time I
>>> disengaged the clutch. The gear teeth were slightly blued and the oil
>>> smelled like a cesspool, but the gears were still usable once I did the
>>> setup properly.
>>>
>>> Bill
>>>
>>> > On Sep 5, 2018, at 1:48 AM, van.mulders.marcel--- via Fot <
>>> fot at autox.team.net> wrote:
>>> >
>>> >
>>> >
>>> > ----- Doorgestuurd bericht -----
>>> > Van: "van mulders marcel" <van.mulders.marcel at telenet.be>
>>> > Aan: "Greg Blake" <gblake58tr3 at icloud.com>
>>> > Verzonden: Woensdag 5 september 2018 10:47:59
>>> > Onderwerp: Re: [Fot] Crown and pinion gear break in
>>> >
>>> > I think it is good measure to check the heat of the differential
>>> casing after a few laps when the pinion and crownwheel are freshly mounted
>>> : when the casing gets very hot, something is wrong : or the parts are bad
>>> or they are mounted not correctly
>>> > There are at least 2 manufactures of the TR parts, I forgot about the
>>> names. As far as I know, used original parts are running cooler than some
>>> of the aftermarked parts. How was the noise of the diff? Did you notice the
>>> smell during the first laps?
>>> > Marcel
>>> >
>>> > ----- Oorspronkelijk bericht -----
>>> > Van: "fot" <fot at autox.team.net>
>>> > Aan: "fot" <fot at autox.team.net>
>>> > Verzonden: Woensdag 5 september 2018 03:25:39
>>> > Onderwerp: [Fot] Crown and pinion gear break in
>>> >
>>> > I would love to here the FOT experience in breaking in new
>>> differential gears. What has worked well for you in the past?
>>> >
>>> > Last weekend, I was running the TR3 at Hallett with a brand new 4.55
>>> gear set and it failed. I probably got 30 laps total in 4 sessions on
>>> track. I did not think to follow any set break in procedure with the gears
>>> and I am wondering if that is why they failed.
>>> >
>>> > I am interested in the lists experience with brand new or new old
>>> stock ring and pinion break in.
>>> >
>>> > Here is a pic of the failed set.
>>> >
>>> >
>>> >
>>> > [image/jpeg:image1.jpeg]
>>> >
>>> >
>>> >
>>> > Sent from my iPhone
>>> > _______________________________________________
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>
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