Haynes Forums - Quaife ATB

So, during summer I've saved up and bought a Quaife LSD:

I also bought a Sierra diff I can put that into, so if I botch it up I have a working one. for the castellated diff nuts I fabricated a tool:

One side came off quite easily with this, another required three evenings or so. First I welded an M12 nut through the hole. Rather than moving the bearing casing nut, I broke the weld. Then in addition to the weld in the hole, I added two tacks on the sides. The bearing carrier moved a turn or so, then seized. The second welded nut broke off, too. In a couple more tries, I had a nut welded all around, the diff strapped to a thick plank with a ratchet belt, myself pushing with a 2 m pipe, and my brother holding the tool in place and pulling up on the opposite end. Finally the bearing carrier came out. The problem was that the o-ring has gone gooey, stuck to both parts and crumbled to pieces while removing the bearing carrier.

Then it took a couple of weeks to get the oil seals and o-rings. Then it turned out that getting the old bearings off the differential is impossible without a bearing remover that is just right, so I got new bearings, too.

Finally, I was ready to put everything together, but it turned out that the diff does not just fit, you need to file off a ~7-10 mm bevel on the inside of the differential casing to get the Quaife unit in. You can see it here:

Then came the tuning. I found the Ford service manual for Scorpio/Granada diffs, which are essentially the same. Since I did not move the pinion, I just had to adjust the position of the crown wheel. I did not have gear compound, so I tried a dry erase marker (did not work so well) and alkyd paint (better) to set the pattern. Then on LCB I found advice that zero lash at the highest point works best. So I went for that. I set zero backlash with
the bearings finger tight, then added equal amounts of preload from both sides (4 teeth total, per Ford manual), then adjusted by turning both nuts to get zero backlash again. I gauged backlash purely by sound, at some point the gearset stopped clacking when rocking back and forth. This "agricultural" tuning method seems to have worked -- the diff is silent in drive and whines just a bit in coast. And the CWP has not broken in ~200 miles.

Since the end of August, I did not have much chance to try it out, I was away on business for a couple of weeks, and I'm not a big fan of hooning on the streets. Finally, this Sunday I went to an autoslalom/autotest practice and let a friend who's really good on his MX-5 have a go. Here's the result:

http://youtu.be/Gcg2VqyPKIM

Wheeee!