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View Full Version : shimming the bmax diff


branstonpickle
20-02-2012, 01:45 AM
how many shims do people put on the diffs and the crown gear do u follow the kit settings or do people shim it a bit tighter thanks....

sosidge
20-02-2012, 11:43 AM
You should do it yourself, the mouldings will never be exactly the same from car to car.

A couple of things to bear in mind...

- The top and bottom gearcases are not necessarily identical so double check the shimming in both and again once assembled.

- Use shims on both the input shaft and the diff outdrives to get rid of any unwanted movement. Align the input gear so it is meshing fully with the diff gear and not rubbing on the edges.

- Shim the gears to have the BARE MINIMUM freedom in the mesh. Not fully tight, and certainly not loose. Get the finest shims you can find, 0.1mm or less. The kit ones are 0.2mm and too crude for the job.

I had loads of hassle getting my BMAX shimming right, but after a few stripped gears and one cooked motor I got it sorted by using the strategy above.

CODMAN
20-02-2012, 01:12 PM
As Sossdige says, it varies from car to car. Mine was spot on from the factory shimming and I've never stripped a single gear so far!

I personally would build it by the factory specifications, then see how it feels with your fingers. reshim as by Sossidges instructions if you feel it's necessary.

Mine felt tight when it was built (comprared to an AE car). There was NO binding, but the diff was not super easy to turn with my fingers.