[Fot] Fwd: Crown and pinion gear break in

Fri Sep 7 12:07:39 MDT 2018

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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