This thread is now about rebuilditng a RX7 clutch type LSD for my miata.
Ok, so I bought a carrier w/LSD removed from an 87' RX7 for 150+ shipping. Ended up being 215 shipped I think. Turns out it has 4.10 gear in it, where my miata has 4.30's. So a little bit higher gearing will be nice as first gear is useless at 10 PSI. Yesterday I tore it down and measured all the drive disk, friction disk, cone springs, etc. Turns out almost everything is exactly in factory spec. So I don't really have to buy new clutches and shit as they all measure 1.99-2.00mm (factory spec is 2.00mm, service limit 1.90mm). So I cleaned everything up, measured the total thickness of the LSD vs. its' carrier and the clearance for the differential per the FSM, and then reassembled.
Next I wanted to test the break away torque of the LSD. Factory spec is 50 ft*lbs new, but they wear and usually measure less. But there was no easy way to hook a torque wrench to the thing to measure it. So, I built a RHMT preload testing tool.
Found a piece of plate. Drilled two holes in it, then drilled one in the middle 3/4 inch. Found a big fucking 3/4" lag bolt and cut it off, dropped it in the 3/4" hole, and welded it out. Took 30 minutes start to finish to make the tool.
First it measured 26 ft*lbs to slip. Weaksauce. So I cut a shim out of some .014 aluminum sheet metal scrap I had and stuck that in there. Now it's up to 46 ft*lbs. Then I remembered you're supposed to torque the ring gear before measuring it, as that causes the number to go up. But I knew it needed another shim anyways, so I cut another .014 thick shim and tried again, this time torquing the ring gear on. Now she don't slip till somewhere north of 150 ft*lbs. Probably 170-180 ft*lbs if I had to guess, as I can make it slip with a bit more force after the wrench clicks at 150.
So yeah, this maita is fixin'a have one badass LSD.
Gonna set up the rear end myself this weekend. Got a set of 6-12" micrometers, a magnetic base dial indicator, and GM gear marking compound.