Bill,
Sounds like you're managing OK - with the pinion bearings are you fitting
new ones or reusing old ones?new ones require preloading, old ones don't.
The backlash should be .004 - .006, if in doubt (and for racing) go a bit
bigger.
Don't worry too much about the tooth contact, you should aim to be virtually
in the middle of the tooth on the convex (drive) side as this is the
strongest. To alter it you have to change the pinion height shim under the
pinion head bearing, with abuse the tooth contact tends to go upwards or to
the outside, there is a risk of teeth off if it is too high up. Increase the
thickness of the pinion height shim to bring the contact point downwards
towards the centre.
John Kipping
----- Original Message -----
From: "Bill Babcock" <BillB@bnj.com>
To: "'Joe Curry'" <Spitlist@gte.net>
Cc: <Malaboge@aol.com>; <fot@autox.team.net>; <vintage-race@autox.team.net>
Sent: Wednesday, February 05, 2003 9:17 AM
Subject: Differentials and clearances
> That's actually the GOOD stuff. I mean mashed peas, sandwiches so dry and
> tasteless that you need at least two pints to wash them down (that's my
> excuse and I'm sticking to it). Spaghetti and meatballs with sauce that
> must be made from ketchup. I spent two weeks in London without a single
> meal that was memorable in a positive sense. The British Museum and all
> the car stuff more than made up for it.
>
> But enough non-tech.
>
> I'm sure there's some opinion herein about differentials. I'm sticking my
> Detroit Locker into Peyote and changing the drive ratio (from 4.10 to
> 3.70) at the same time. I don't have any of the special tools, so I'm
> improvising a bit. For the pinion bearing pre-load, I added shims until I
> got a tiny bit of end play, and then took out a .005" shim.
>
> I did the ring to pinion engagement in the same manner. I added shims
> until the roller bearings were tight enough so I could barely remove the
> ring and diff assembly from the housing, then I swapped shims between the
> two ends until I got no shake in the tightest segment of the gear
> engagement. For anyone who hasn't played with a diff, the ring gear gets
> tighter or looser as you rotate it because of manufacturing or wear
> irregularities. I found the tightest spot, and then used that as my worse
> case for setting tooth engagement. The depth of engagement is controlled
> by shims that push the ring gear to one side or the other.
>
> I do have a dial indicator that I could use to measure backlash as you
> would with most mechanisms like this, but I don't have any idea what the
> value should be for a Triumph diff since the manuals I have only cover
> assembly with special tools.
>
> Then I checked the engagement point with some Prussian blue on the teeth.
> It's hard to tell where the engagement really is--there's not a nicely
> defined spot like you'd expect. The pinion seems to be wiping along almost
> the entire tooth, but at least it looks like it's not just at the top or
> bottom.
>
> I suspect that all of this is not so critical on a race car diff, where
> you don't really care if it moans a bit. I might be wrong, perhaps this
> backyard approach is going to cost me fifty horsepower and boil my diff
> like a lobster.
>
> Opinions and advice please.
>
>
> -----Original Message-----
> From: Joe Curry [mailto:Spitlist@gte.net]
> Sent: Tuesday, February 04, 2003 10:42 AM
> To: Bill Babcock
> Cc: 'Malaboge@aol.com'; fot@autox.team.net; vintage-race@autox.team.net
> Subject: Re: Oz
>
>
>
>
> Bill Babcock wrote:
> > They celebrate it in the same perverse way that Brits celebrate the
> > hideous food they were forced to eat in boarding schools (Public
> > Schools, which aren't public).
>
> You mean stuff like Yorkshire pudding (which gives new meaning to the word
> "pudding") and Kidney Pie (internal organs should always be relegated to
> the rubbish heap)???
>
> Joe (C)
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