diff pinion angle

[Ed]

Hi guys,

I've been putting in a new gear box and noticed my diff pinion angle is way out.

i need to shim the diff under the brackets using wedge shaped shims to bring the diff pinion angle up.

any ideas where to get such wedges??

Cheers

Ed

[FB_MAD]

G'day Ed,

Don't know if you can buy what you need but in the meantime I'd be having a go at making something up to do what you want.
Otherwise you might have to move the diff/spring locating mounts I guess and reweld in the position you need to get the correct pinion angle.


Terry.

[FATBOY]

hi ed try sydney competition wharehouse
cheers fat

[Ed]

Hey Terry,

The shims are alot easier than remounting the diff, however I dont have the equipment sophisticated enough to machine a 5 or 6 degree wedge.

the US seems to sell this stuff, I'm googling to see what I can find.

EDIT
good tip Fat, why didnt i think of that...


Cheers

Ed

[Ed]

Found some shims....

2 degreees or 4 degrees.

from Wholesale suspension Penrith.

may shop around for 6 to 8 degrees, now i know where to look.
Cheers

Ed

[sgo]

Doesn't 2 deg and 4 deg make 6 deg  

[Ed]

Hey George,

ur dead right, however if you stacked a diff on 2 angled wedges the middle one will spit out...

I thought about welding the wedges together however at 28 bucks a wedge, 4 wedges would wind up being pretty costly and perhaps maybe more worth my while just to cut the saddles off and re-weld.

Interestingly I had a "pro" set up the diff for me and the angle would be all wrong given any combo.

you live and learn...

Cheers

Ed

[JB]

Hey Ed, had the same problem, and I got them machined up here in sunny QLD   can't remember the price though. So maybe try an engineer.

Jas.  

[Ed]

hey Jas,

Ive been spending an awful lot of time rolling about on the freezing concrete floor, but ive found out some useful info on diff pinion angles.

using an angle finder i worked out my

driveshaft was at 5° (down at rear).
gearbox was then shimmed up to 6° down at rear.
so the angle of the shaft relative to gearbox is now 1°

the diff is at 0 degrees and with the driveshaft there is 5° pinion angle.
while this looks bad, my internet research tells me a leaf spring  car should have negative pinion angle between 5 - 7° while the car is at rest to allow for correct geometry under load.

so it seems the angles now should be fine as the relative pinion angle is indeed 5 - 7° less.

Of course I have my doubts about such a large angle so may bring it back to 3 - 5° using a 2° wedge.

have I over thought this?

Cheers

Ed

[Ed]

After speaking with the guys at Sydney Driveline Service, I was advised to try get the pinion and gearbox angles parallel (with the car at rest).

For a street car this is apparently what to aim for.

i managed to shim the box to 5.5 degrees and just ordered the 4° diff wedges so the resultant relative difference is only 1.5°. 

uni joints operate best when under 3°.

so.. one last question.

do i place the wedges under the rubber insulator pad on the leaf spring.
or above the insulator and in contact with the diff saddle??



Cheers

Ed

[JB]

Hey Ed,

My wedges are on top of the insulator in contact with the diff saddle.

Hope all this works mate...

Too much thnking me thinks... Get out there and drive the thing.

Cheers
Jason.

[Ed]

Cheers Jas,

definitely too much thinking... my head hurts

got my drive shaft sitting next to me and im impressed with it.. perhaps I should put it back in the car now?

in any case im looking forward to a smooth, vibration free ride!

just waiting for a couple of little things now.

Thanks for allowing me to thrill you all with the tedium of driveline alignment.


Cheers

Ed