GM LSD Underway

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BeefFajitas
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Post by BeefFajitas »

I would bet the spider gears and pinion shaft are.
-Nate
'85 Merk. Back together. Only thing stock is the head and block.
Ed Lijewski
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Post by Ed Lijewski »

MerkXRTurbo wrote:My machinest wanted me to double check to make sure that none of the pieces within the differential are heat treated. They wouldn't be in my wildest imagination, due to the fact that they're all bathed in gear oil and shouldn't see more heat than any kind of metal can withstand, but just to comply with his request I thought I would get a second opinion. Anybody???
Won't swear to it but I've always understood "heat treated" is a process that tempers/hardens--strengthens--metal and doesn't refer to the temperature/environment the item will operate in.

http://en.wikipedia.org/wiki/Heat_treatment

YMMV 8)
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MerkXRTurbo
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Post by MerkXRTurbo »

BeefFajitas wrote:I would bet the spider gears and pinion shaft are.
Alright, he wanted to make the spacers to the same standards as the rest of it, and I really don't think that's necessary. I'm gonna go with my gut and tell him just to make 'em outta whatever steel alloy he feels appropriate.
3" mandrel bent exhaust, Ported/Polished head, 1.89/1.57 valves, Gutted uppper/Knife edge lower intake, T3/T4, LA3, Big VAM, Cold air intake, 40bob header, Gillis valve, Forge BOV, Mustang SVO T5, Conquest intercooler, 20psi.
BeefFajitas
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Post by BeefFajitas »

I wouldn't think so either. It's not like they're going to be moving and rubbing up against stuff.
-Nate
'85 Merk. Back together. Only thing stock is the head and block.
MerkXRTurbo
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Post by MerkXRTurbo »

My machinist says he has the bearing race spacer done, and had bolts laying around for that (yay for replacing torx head bolts with allens!!!), and now he's just finishing the ring gear spacer and will need me to go source longer bolts for it. The spacer is 550 thousanths thick, and he has all the ring gear bolts. I'd rather be able to pick them up on my way there, rather than going there and getting one, then going to the store, then coming back with them.

Question is, anybody know what size the ring gear bolts are? I need thread pitch, length, and diameter please! 8)
3" mandrel bent exhaust, Ported/Polished head, 1.89/1.57 valves, Gutted uppper/Knife edge lower intake, T3/T4, LA3, Big VAM, Cold air intake, 40bob header, Gillis valve, Forge BOV, Mustang SVO T5, Conquest intercooler, 20psi.
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Post by MerkXRTurbo »

Sweet! Both of my spacers are done! The Ring gear spacer is .550" thick, and the bearing race spacer is .362" thick. The ring gear spacer is designed so that it presses onto the carrier where the ring gear originally did, and then it has a lip for the ring gear to press onto it to keep it hubcentric.

I bolted 'em both on, and had the carrier in the case and it fit like a glove, except for the fact that the pinion gear sticks quite a bit past the ring gear and rubs a slight amount on the carrier. We are removing some material from the end of the pinion gear with a milling machine and rebalancing it to solve this problem. It should hopefully be together with pics this evening.
3" mandrel bent exhaust, Ported/Polished head, 1.89/1.57 valves, Gutted uppper/Knife edge lower intake, T3/T4, LA3, Big VAM, Cold air intake, 40bob header, Gillis valve, Forge BOV, Mustang SVO T5, Conquest intercooler, 20psi.
DSPXR4ti
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Post by DSPXR4ti »

And how much is this costing you or how much would it cost for the regular person to have all this machining work done?

Ben
85 DSP XR4ti, 2009 Solo 2 National Champion, burns muffler, 3in exhaust, Mc2 Full suspension, 325 hps & 328tqr, GMR Intake, Wilwood brakes, Eaton LSD, stand alone ECU. Working on being SM National Champion.
MerkXRTurbo
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Post by MerkXRTurbo »

This machine work would not be cheap for most, as a lot of time has been spent drawing up the spacers for the CNC machine. I know the machinist and he and I do favors for each other (I'm really setting myself up for jokes with that statement :x), so this isn't costing me much.
3" mandrel bent exhaust, Ported/Polished head, 1.89/1.57 valves, Gutted uppper/Knife edge lower intake, T3/T4, LA3, Big VAM, Cold air intake, 40bob header, Gillis valve, Forge BOV, Mustang SVO T5, Conquest intercooler, 20psi.
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Post by MerkXRTurbo »

As of about midnight last night the LSD install is basically complete! I found out that my differing experience was all because the carrier is designed for 3.23 and down (numerically) ratios. It definitely isn't the easiest route to go (although it is a stronger carrier according to some GM guys), but I got the carrier as a gift from a friend and my machine work was free. The spacers were made from scrap metal around the shop, so the final cost of the project was $10 for longer ring gear bolts!

$10 LSD!!! Beat that!

There were a few obstacles to overcome, to properly get the carrier into the XR's case (besides the grinding of the case just to get the damn thing in there, as we are all familiar with to some extent).

- The biggest problem I've run into was that this carrier appears to be designed for a larger pinion gear, which puts the ring gear too far away from the XR's small pinion. This presented a number of problems. 1st of all, the .550" spacer had to be machined to get the ring over to mate with the pinion, which was an easy solution. The other issue with this is that the ring gear landing (I guess that's what you call the part that you bolt the ring onto?) is much closer to the driver's side carrier bearing. Due to this, the ring gear bolts end up rubbing the case and the cover and clearance had to be made. Enough clearance was required in the cover that we ground all the way through, and I have a couple of small pieces of aluminum made up waiting to be welded on in place. This is actually very minor and probably sounds like a much bigger pain than it actually is.

- Next, as I stated before, the axle stubs had to be turned down about .002" in order to fit into the GM carrier. This was a process that took just a couple of minutes on the lathe.

- The overall height of the GM carrier is not as tall as the factory XR's carrier, thus both bearings will not reach the bearing carriers on either side of the case without a spacer underneath the removable bearing race. The spacer that was machined was .362" thick, although since the bearing carriers are adjustable, anyone duplicating this project would not be required to stay exactly at this thickness.

- The carrier is a little big, and the tip of the pinion rubs it just a tiny tiny bit. To solve this the carrier was turned down a few thousandths just on the portion that the pinion rubbed. This sounds scary, but is really a simple and quite safe process.

Like I said, it got completed around midnight last night, so I didn't have a chance to take any pics. For those who doubt that the axle splines are the same, you're just gonna have to take my word for it. They are 100% identical. If it was a better fit, it wouldn't fit at all! A friend should be tigging the aluminum to reseal the cover today, and when I can get it back I will take pics.

The backlash was set a .0055, and the bearing carriers have been locked in place to hopefully never move again. The only obstacle left is how I'm going to hold the axles in. There is no way that the factory clips are going to be able to be put back in there, so I'm going to attempt to put on some external snap rings or something like that. Stay tuned!
3" mandrel bent exhaust, Ported/Polished head, 1.89/1.57 valves, Gutted uppper/Knife edge lower intake, T3/T4, LA3, Big VAM, Cold air intake, 40bob header, Gillis valve, Forge BOV, Mustang SVO T5, Conquest intercooler, 20psi.
anglin
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Post by anglin »

Luke, excellent follow up. I cannot wait until this car is on the road and you can report the results and long-term life. Did you get any pictures of any of the spacers which were made? It sounds like a lot of good work was done.
MerkXRTurbo
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Post by MerkXRTurbo »

No I wasn't able to get pics of the spacers while they weren't installed, as I spent so much time with greasy hands and my mind on trying to get the thing to fit correctly. Stopping to take pictures, unfortunately, is kind of a distraction when attempting to troubleshoot a problem if you know what I mean. I will, however, provide pics of the assembly with the cover removed later on though. :)
3" mandrel bent exhaust, Ported/Polished head, 1.89/1.57 valves, Gutted uppper/Knife edge lower intake, T3/T4, LA3, Big VAM, Cold air intake, 40bob header, Gillis valve, Forge BOV, Mustang SVO T5, Conquest intercooler, 20psi.
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DPDISXR4Ti
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Post by DPDISXR4Ti »

MerkXRTurbo wrote:I found out that my differing experience was all because the carrier is designed for 3.23 and down (numerically) ratios.
Okay, that makes sense. I couldn't figure out why you were needing to make such huge changes from what anyone else has done. Given the add'l work required, I can't see anyone bothering to go this route when the 3.23+ stuff is readily available at the same price as the 3.23 and under. Only way it would make sense is if the scenario was similar to yours - diff and machine work was free (or close to it).
Brad
MerkXRTurbo
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Post by MerkXRTurbo »

Well, it's done! Here's the pic:

Image

You can see the .550" ring gear spacer. The stripe in the middle of the carrier was where it had to be turned down in order to prevent the pinion from rubbing it. Underneath the right hand side bearing race is the .362" spacer to get it to fit the case!

There is no room to get clips onto the axles to keep 'em in, and Deathbypsi told me that he doesn't use any clips at all and he's had no problems, so I'm gonna give that a go! 8)
3" mandrel bent exhaust, Ported/Polished head, 1.89/1.57 valves, Gutted uppper/Knife edge lower intake, T3/T4, LA3, Big VAM, Cold air intake, 40bob header, Gillis valve, Forge BOV, Mustang SVO T5, Conquest intercooler, 20psi.
DSPXR4ti
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Post by DSPXR4ti »

WOWthat is some spacer, now that I see holy cow batman.

Ben [/i]
85 DSP XR4ti, 2009 Solo 2 National Champion, burns muffler, 3in exhaust, Mc2 Full suspension, 325 hps & 328tqr, GMR Intake, Wilwood brakes, Eaton LSD, stand alone ECU. Working on being SM National Champion.
DSPXR4ti
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Post by DSPXR4ti »

--------------------------------------------------------------------------------

Hello All,

Well the Eaton LSD is in and ooooohhhhhhh man what a Diff., yes it was a little harder expected but I work out all of the detail and the fit is great, as you all know I can not Mod anything that is a stock FORD part to make this fit, so it was some little things like shim wise to make it fit.

You will need a .150 ring gear shim
10 25 MM 100X10 ring gear bolts
.250 bearing race shim for the non ring gear side,
the Xr4ti bearing are a little smaller in thickness than the GM 7.5 so grind off the end of the Diff. where the bearings go to install the stock clips, the other thing about the bearings is you cannot install them before you put the LSD in the case, then you install the bearings, you also cannot install the ring gear intill you have put the LSD in the case, it was a little work but it works great now and looks great, I'm not sure about the springs in the Diff. right now because Eaton has three different springs for the lock up for this Diff. so I'll let you know how this works out.

Ben DSP XR4ti

This is the shims That I installed, no Pic's yet but I will building a spare.

Ben
85 DSP XR4ti, 2009 Solo 2 National Champion, burns muffler, 3in exhaust, Mc2 Full suspension, 325 hps & 328tqr, GMR Intake, Wilwood brakes, Eaton LSD, stand alone ECU. Working on being SM National Champion.
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