MSP LSD in a G-box

[SgtRauksauff]

Hmm. Wierd. I've been really busy with work lately, and haven't had time to check the forums, but I swear there was a thread regarding an MSP LSD in a G-box, that had some pictures in it, and ones that I posted at that.

I dunno WTF happened to that thread, does anyone know? Did it get deleted by those darned pesky intarweb gremlins? Anyway:

Gro mentioned that there was a spot that needed to be ground down in the tranny case, and he circled the area in his picture. In my case, I didn't have to do quite the same thing, I only had to grind down a tiny bit of the area where the speedo gear sensor comes in. Here is a picture of the ground area in my transmission: click for the full size picture.



And it was also mentioned that Eric Burmeister, the cool Mazda Rally guy, when driving his Protege, busted the MSP diff wide open, and a fix/reinforcement of that was to weld the ring gear to the carrier. The pictures of that are in a thread on SpecialStage.com. Here is a picture of the test weld I did tonight on an open diff that I broke doing a burnout. It's just a Lincoln 230V mig (sp175plus, if i remember correctly) using ArCO, and set fairly high on the scale of current and wirefeed speed. I didn't really bother protecting any of the diff from splatter, since it's a busted one basically, and I didn't clean up anything. I just let it cool down for a few hours, then took the picture. Again, click for the full size:




This is just a cool shot of the primary and secondary shafts meshing together, I like cool pictures of meshed gears and stuff.
[


Anyway, that's all for now...

--sarge

[Mazda_Powered]

sweet man let us know how the welds hold up if you try using it.

JACK

[BuGS]

Ya, I think the grinding is only needed for V6 boxes.

[Jho]

Badass Sarge!

[SgtRauksauff]

Well, tonight I actually welded my MSP LSD. I took a MAPP torch (I haven't got any useable tanks for Oxy-Acetylene right now) and heated up the carrier before each weld between the rivets, because the carrier looks cast to me, and if you weld cast too hard/fast, you can crack it. The welds look a LOT better on the LSD than they do on the open diff above.

Hopefully tomorrow will see me getting the tranny put back together, more pics taken of the process, and hopefully the current tranny out of the wagon, and the new one either in or ready to be in. I've gotta get it done, there's an autocross on Sunday.

I'll post more pictures as I get them.

--sarge

[ROB-80E]

I haven't had to mod my cases at all to take the diff. I've had the diff in two different G series boxes (one of them the crown had to be changed), and again, no case mods.

I've had this diff fully appart, and I see no need for the welds to be on there with the second revision diff (the one you'd get if you buy one now). I've removed the welds on mine because I had to, to get the crown wheel off, and I haven't had any issues with the diff. I've done many 1/4 mile runs, and I can assure you, there is enough power there and it gets used regually.

[BuGS]

What Shafts are you useing Rob???

[ROB-80E]

1 is standard, intermediate shaft is shortened and resplined and the other has a 28 spline end on it otherwise standard.

[SgtRauksauff]

just an FYI:

1992 Mazda MX-3 GS (1.8L V6), manual transmission, non-abs. This axle has the 28-spline inboard side to match the intermediate/jack shaft, and the 26-spline end to fit the standard Protege/Escort hub. I took a hub and the jackshaft in to make sure they fit, and they do. It's New In Box length is ~24", with non-stretched CV boots. The just-off-the-car EGT axle had a length of ~25.5", with an inner boot that was stretched a good amount.

Now I've just got to find a way to get the intermediate shaft bearing carrier bolted up to the block. Time to go buy some good cutting bits.

--sarge

[SgtRauksauff]

It's in and working. w00t!! I took some good pictures here and there, and will be getting them together in a good document pretty soon. If it's un-busy enough at work, hehe...


--sarge

[BuGS]

So you used a GS intermediate shaft and just stretched the boot on the stock outer CV??? I wonder why not just use the GS outer CV then... which did you use for the passenger side?

[bmikedaman]

You can't just modify the MX3 intermediate and use the EGT carrier? I was under the impression they worked the same way but that the MX3 piece was too long or something?

[SgtRauksauff]

No no, you misunderstand a little bit. Maybe I wasn't clear enough when I typed it, I was tired. Unless that's directed to Rob, in which case, I've got no idea how he did his, as he's so far away from me that even his toilet flushes in the wrong direction...

But, for my setup:

The driver side axle is a Hybrid one built by Raxles for Corksport. It's got the 26-spline hub end, and the MSP-splined center part. (I counted them, but I can't find where I wrote them down. Might be 28, not sure)

The intermediate shaft is a custom one machined somewhere (local, I think) for Corksport. It's got the MSP-splines on the inboard side, and 28-splines on the outboard side where it connects to the passenger side axle. It's a larger diameter than the Protege/Escort ones, also, by about 2mm.

So the passenger-side axle is the ony one that's a stock piece. It's for a '92 MX-3 GS with manual tranny, and no ABS. The measurement I did was in length. End-to-end, the MX-3 axle was 24" brand new, without the boots being stretched over time like was the case on the stock EGT axle I took out, which was 25.5" end-to-end.

I also had to modify the intermediate shaft bearing carrier where it bolts to the block. I'm going to talk to Corksport about it and see if they can revise their part to fit properly. I think it's from a different application, but works on ours.

A quick diagram, as seen previously around here somewhere, but I don't remember who posted it:

[hub]<==26..raxles DS..==>[MSP DIFF]<==..CS INTshaft..28==><==28..MX3GS PS..26==>[hub]


--sarge

[BuGS]

how much did the axles run you?

[SgtRauksauff]

well, the Corksport kit is right around a grand, that's the driver axle, the diff, and the intermediate shaft. the passenger side axle was 75 bucks plus a 50-dollar core.

Just like 92_2_Fast said in his posts, you have to do a little bit of modification to the intermediate shaft bearing carrier, because it won't quite line up to the holes on the block otherwise, but it's easy enough to do, took me about 20 minutes. Looking closely at it, if you've got a machine shop nearby, a slight modification of the carrier to move the bearing seat about 1/4" deper would eliminate that need completely.

--sarge