[Fot] Differential setup

[Greg Blake]

The spreader was released prior to taking these readings. 

I checked the backlash at 4 locations roughly 90 degrees apart and I am within 0.0005” so I think the carrier flange is straight enough. 

I have tried the pinion depth from 0.735” to where it is in the pictures with 0.020” shim under the pinion race, at 0.715”. 

At 0.735” (no pinion shim) the drive side pattern was at the toe and the coast side was off of the heel. 

As I added pinion shim, moving the pinion toward the ring gear, to get to where it is now, the drive side pattern has moved toward the center position between the toe and heel with a little bias toward the toe. I think this is ok because as the gear is loaded, the pinion is pulled into the ring gear further therefore would tend to center the engagement on the driven side. 

My concern lies with the coast side. It also moved more central as I added pinion shim, but is still more biased toward the heel than I’d like to see. 

I can’t seem to get the two patterns to align more toward the center. 

For a race car, should I be concerned with this coast side pattern?

Thanks. 

Greg

Sent from my iPhone

> On Nov 12, 2018, at 9:13 AM, Bob Kramer <rkramer56 at gmail.com> wrote:
> 
> Is the spreader released? Not sure if that distorts anything but it is different one side to the other. Did you check the runout without the ring gear attached? 
> I would worry more about the driven side and raise the pinion depth to move that pattern to the middle,
> 
> 
> Bob Kramer
> 
> 
>> On Sun, Nov 11, 2018 at 8:10 PM Greg Blake via Fot <fot at autox.team.net> wrote:
>> Attached are pics of the gear mesh patterns on the drive and coast faces of the ring gear on the diff. These are new gears from Bastuck which are the Oerlikon type. I like the drive side pattern but the coast pattern looks a little high. 
>> 
>> The pinion is set at 0.715” depth and backlash is at 0.004”
>> 
>> I have moved the pinion 0.020” deeper in the housing at 0.005” increments and the drive side pattern just moved to the tow side. 
>> 
>> Should I be worried about the coast side or leave it alone?
>> 
>> Thanks. 
>> 
>> Sent from my iPhone_______________________________________________
>> fot at autox.team.net
>> 
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