Sure would! I can't even remember to look at my A/F meter towards the end of the run. Made three runs last Sunday and promised myself to watch it each time. Forgot each time, watching the tach and road after going into high gear. Been trying to figure out how to rig a cheap data logger, but need more than simple 0-5V input. I do have a multimeter that will data log to my android wirelessly, but its too slow. Need tach on engine and driveshaft in addition to 0-5V inputs and lots of data points to make it worthwhile doing.

 

Perhaps you could simply use a camera and video the gauges.
That could give some indication and you may be able to deduce some information from the phases of the race.

I guess a lot of time is spend at WOT

 

After first attempted run using trans brake on Sunday. Broke spider gears and blew out center of my Eaton Posi. Spool and c-clip eliminators on order. Think the ring/pinion and bearings are still OK. Driveshaft turns. Rear wheels don't. Looks like my truck is not going to make the S10 meet in Bowling Green this upcoming weekend.

 

Ouch - too bad.

So the trans-brake worked but the differential let go.
Has it blown a piece of the cover?

 

Yes, trans brake worked fine but cross shaft/spider gears just couldn't take the shock. It's like dropping a trans into gear, but under full power and about 3500 rpm for me.

When the guts from the center section slung out of the opening and the differential turned, it broke the magnet that was permanently glued to the inside of the cover, that's about all. But time for a new cover as well. Don't need the rest of the magnet coming off sometime and circulating through the gears.

With a full spool for the ring gear, then there will be no cross shaft or spider gears (or differential at all) to break - but have to get rid of the c-clip retention of the axles to use it. This means retaining the axles at the brake backing plates, and this takes some modification of the ends of the axle tubes and axles with some special parts and cutting off the place where the stock axle bearing fits. I will want to make sure everything will work as planned before cutting up the housing ends on my rear end. It's an original 8.65" (people still call it 8.5') housing with 30 spline axles and big carrier bearings out of a 2002 2WD Extreme Blazer with 5-speed. They are like hen's teeth! I thought the Eaton Posi differential I had installed in it would be strong. Guess it was not strong enough for a trans brake!

I really should be going to a 9" Ford rear, but can't justify the expense without first trying the spool. Especially since I just had a new $400 driveshaft made that will be specific to this rear end, and installed a $130 forged pinion yoke to change to the u-joints used in the new driveshaft. That would just be wasted going to a Ford Rear end. Really hope this trans brake will be worth it in the end.

Maybe my big problem is that I don't have a stutter box. These devices allow you to set the RPM the engine will go to when full throttle (and on the trans brake) by removing select ignition pulses to raise their engine to some RPM less than their true stall speed. I suppose that would soften up the initial hit on the drivetrain a lot. I just went full throttle against my torque converter and then let the button go.

 

We can only guess what torque goes to these parts at 3'500 rpm at full throttle.

That's racing and tuning. We venture into unknown territory.
I hope my Summit order will arrive this week. Got a couple days off next week and want to finalize the machining of my 4.3.

Good luck with the Mod of the rear end.

 

Well, housing is out of the vehicle, completely gutted, without backing plates, and sitting across a couple of jack stands waiting for washing out and then reassembly. I found the pinion had some dings on it from the breakage so bought a new ring/pinion, complete install kit with new bearings, and a pinion preload spacer with shims to replace the crush sleeve (in addition to the spool and c-clip eliminators already obtained). Because I needed a new cover anyway, I went ahead and bought a Strange Engineering Ultimate 10 rear cover which has the carrier bearing braces.

I don't have a pinion depth gauge, so plan to start with typical pinion shims for a 8.5 10 bolt and read pattern after setting pinion preload and then setting backlash to 0.008. From the pattern I should be able to easily tell whether I need to increase or decrease pinion and/or carrier bearing shims. To facilitate this repeated assembly/disassembly, last night I made setup bearings from my old pinion bearings (which happen to be exact same brand of my new ones). You hone them out enough so they will slide on/off the pinion without a press. Once you have the gear pattern that you want, you disassemble one more time and press the new bearings on the pinion. Hopefully the bearings were exactly the same size and all stays the same. Otherwise it's do more final adjustments while pressing bearing on/off pinion. At least that's my plan. I've never set up a rear before (but always wanted to learn), so who knows what trouble I will encounter. I have a guy who is mentoring me in this process (guy with the press who does race car fabrication for a living), so I can always fall back on him with any questions.

 

pinion and ring gears can be a PITA.

That is a very good idea to hone out a set of bearings. Lots easier to throw over the shaft to check for shimming.

After fumbling about two days with a Ferrari 365 to no avail we had a fixture made on which we could measure pinion depth. And alignment of the ring gear at the same time. Then using external shims we were finally able to put it back to factory standards. 4 - 5 hours now. The second one was going considerably faster.

Great thing having a mentor. I'm lucky in that too.

Good work then - and good luck (that hopefully won't be needed)

 

I'll certainly take some luck! Thanks!

 

Well, rear is back in the truck with new gears, new bearings, a spool, and a LPW cover.

Unfortunately discovered some issues with mounting the Strange C-clip eliminators with tapered bearings (for factory 10-bolt housing ends). Turns out the 2002 S10 Extreme 8.625 ring gear housing (and all of the 2000+ 8.625 housings for that matter) only came with disc brakes and the step in the flange where the caliper is retained (called the backing plate register) turns out to be about 0.100" larger diameter than the same step in the flange for the backing plates on the original 8.5 rears in the 60's and 70's. Guy that built my rear put original 8.5" backing plates on the 2002 housing and then tightened the bolts incredibly tight, bending the center of the backing plates in this area. Figured this out recently. In other words the center hole in the backing plates was about 0.100" too small, and it would not seat against the housing ends for the width of the backing plate - bending the center hole outwards when it was bolted on.

I removed the backing plates, cut off the bearings, and ground down the housing to even with the backing plate register (which does appear to be the thickness of the backing plate). The Strange c-clip eliminators that I bought need to use this area of the backing plate and housing ends for a sealing surface to their aluminum bearing housing, and actually comes with gaskets for each side of the backing plate - so the old bent backing plates would not work. Only new backing plates for drum brakes I could find, that I supposed could fit were for the old 8.5 rears at $60 each. When I received them I figured everything out described above, but still had holes too small in the center of the backing plates to fit on my housing flanges. Now I'm waiting for my fabricator friend/aquaintance to bail me out and nicely cut the center holes in the backing plates to correct size on his equipment so I can finish this damn job!

Now I believe I see why the tech person at Strange e-mailed back that this kit wouldn't work on my late model converted-from-disk-brake housing. At the time I believed it was because he thought it had truck housing ends with different bolt pattern, but that may not have been the case. I'm sure that it will work in the end, but not quite so easily as I thought.

I did finally figure out a misconception that I had on breaking in a new rear end. Previously I thought that the drive and then let cool break-in scheme was to somehow heat treat the surface of the gears - I'm sure I read it somewhere on the internet. Turns out that the drive 5-10 miles and let cool break-in scheme is just to keep from overheating the gears/bearings before they are broken in (and loosen up so they don't get hot any more). If you're not driving far enough to get a brand new rear end hot (as in drag racing), the only thing you need to do is a few minute break-in forward and then reverse on jack stands - then you're good to go. At least according to Mark Williams, US Gear, and Richmond Gear.

We will see how I did on my first ever set of rear gears. They were a modern 2-cut performance set and inexpensive - Auburn. Bearings were Koyo. Spool was Motive. I made setup pinion bearings to slide on and off the pinion out of my old ones so I could look at the pattern after increasing pinion shims 0.002" through the normal shim thickness range, setting preload using old pinion nut without any sleeve or spacer while keeping the backlash constant at min spec - then chose the best pattern (which was never quite ideal, but as I understand it that happens). Had the new big pinion bearing pressed on with the shims for that pattern. After checking the pattern with the new bearing, I installed a spacer with shims (instead of crush washer) and the new small pinion bearing, changing shim thickness 0.002" at a time until preload reached 15 in.lbs. Doing things this way I didn't need to have a pinion depth gauge or anything to hold the pinion in place while being torqued to several hundred ft.lbs to crush a sleeve. Also checked the runout of the back of ring gear on the Motive spool without the pinion in place - it was less than 0.0015". At the end I installed a new pinion seal, switched to a new pinion nut, added RTV in the yoke/red loctite on the pinion nut threads, and did the final pinion nut crank-down with my 1/2" impact that would be lucky to do 250 ft.lbs. Called the pinion install good. For the carrier bearing preload I added 0.004 to each side, got the wife to hold one of the races (needed three hands for this one) so could get the bearing races started as straight as possible with the shims in place (kept a 0.100" thick shim next to the bearing races. Whacked it a half dozen times on each side (spool and ring gear - not bearing races) with a big dead blow hammer and the spool was in first try. I didn't have to try to tap shims in like everyone talks about!! This is a trick my fabricator guy told me. Torqued the bearing caps, checked the backlash and pattern one more time, checked torque to turn pinion with carrier bearing preload was now 25 in.lbs, and put the cover on.

I was amazed how much work and how many times you have to assemble/disassemble for trial fits while doing a rear end. Must have had the pinion/spool in/out in some form or another 10 times, and you have to change carrier bearing shims to keep backlash constant at different pinion depths. I suppose that with experience a pinion depth gauge gets you much closer to start with, and then using a crush sleeve there is no trial and error assembly/disassembly for pinion preload - only one time and simply tighten until you are there. But my way seemed to work OK - just a hell of a lot more work. Now I just hope it doesn't howl at 50mph like it did before. We will see.