Diff Narrowing

[mklotz70]

Morrisun and I were a bit undecided about whether to post this up as we go or wait until it was finished. I tend to like to post as I go.....in case something happens along the way, at least some of the info gets out there. Plus, I don't have a huge post to make at the end. :)

 

So.....this is our attempt to narrow the rearend from an RX7(year?) to fit under Morrisun's 1200(Smurf-n-ator). I'll send him a link to this thread so he can add details about the year and such.

 

This rearend had the small axles/bearings. He had pieces from a large bearing axle.....so while we're at it, we're going to put the large bearing stuff onto this housing. Hopefully, he can chime in and explain why. He told me..I understand why.....it's just that my part of this is the metal work....his part is the idea and details. :)

 

Morrisun had the housing nearly cleaned of brackets. He'll finish that up before our next mtg. We started off with cleaning up the bearing holders on the lathe. We cut the ends off the housing. I started modifying an open diff carrier to make it lighter and so that it will allow us to see what's going on in the middle.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[fisch]

Woah, lots of work here Mike! Look forward to watching the experiment develop!

[datzenmike]

Mike, you're an honorary Auzzi for that mad mod stuff.

[]2eDeYe]

Cut away man! This is the stuff. :cool:

[mklotz70]

Thanks guys :)

 

After I mill down the carrier, I'll get on the lathe and start making the alignment discs to go on the polished 1.25" rod we have for aligning it all :) I'm hoping to make some more progress this weekend.

[Zeusimo]

QUESTION!

When Welding The Ends Back Together Do You Butt Them Up Or Leave A 1/2" Like When Welding Pipe To A Slip-On Flange? :huh:

 

BTW Nice Work :thumbup:

[mklotz70]

A lot of places will simply butt weld them. The reason for the lathe work on the axle bearing holders is so that we can push them over the end of the housing....for about a 1/2" slip on. Then, we can fillet weld the two together.

 

 

....and Thanks! :)

[ggzilla]

why have you cut the gear carrier in half?

[mklotz70]

Partly because I can, partly because we want to see inside, partly to make it lighter, party to make putting the alignment rod in easier. :)

[Morrisun]

So a little background on this project. 79-83.5 had smaller axle bearings and 24 spline axles. The 83.5 to 85 rear ends out of 1.1L cars are the same as early cars but, came with rear drums or disc- all had 4X110mm axle bolt patterns and used lug bolts to hold the wheels on. The rear end housing axle tubes are about 2 1/8 in diameter.

 

The 1.3L cars came with disc brakes on the rear, either solid or vented. Axles were larger bearing and 26 splines. Axles had bolt pattern of 4X114.3 and used studs instead of bolts to hold the wheels on. These axle tubes are the same size has the others so welding the larger bearing ends on gives me the correct bolt pattern.

 

Both 1.1L and 1.3L cars were available with LSD, however side gears in the carrier have different number of splines and the gear ratios are a bit different, 24 spline 3.933 and the larger axles with 26 splines have ratio of 4.076. I posted this info so anyone looking to use Mazda RX7 rear ends knows what came in which car. This one will use larger bearings and axle setup, with solid rotors disc and stock calipers as they are compact and have built in E brakes.

 

All of this just to put LSD in a Datsun 1200! I had taken LSD and large bearings off of a damaged housing and was going to weld them on to a Mazda B2000 truck axle housing which has almost 3" tubes. And no I don't know if the truck axle splines fit RX7 LSD carriers, but the 3rd member pumpkins bolt right up, and trucks do have 6 lug wheels, I wonder...

[ggzilla]

Why not just use the A10 Datsun 510 (newer 510) rear? You can buy a new LSD from TRD.

But that's $1300, is the RX LSD any cheaper?

[Morrisun]

Price depends on what you want. The larger bearing rear end with 4X114.3 axle bolt pattern are the most sought after. I have $350.00 in to this rear end set-up that includes the LSD and calipers. I will replace the rotors so more $$ and rebuild the calipers. To have 2 axles shortened at Dutchman in Portland Oregon is $95 for the pair. $20.00 ( cost of studs)to replace the axle wheel studs to 1.25X12mm. The rest in materials to narrow the rear end. Hoping to keep the cost around $600.00 total.

[mklotz70]

It finally worked out for us to work on this some more. We started making the slugs that will hold the end pieces. Still need to so the final cutting to the diameter and bore the center hole, but at least it's progress :)

 

 

 

 

 

 

[Laecaon]

This makes me happy. This is the diff I want for my Goon.

[mklotz70]

you being local means it might be an option. I don't see me shipping diffs around the country! :)

[Laecaon]

you being local means it might be an option. I don't see me shipping diffs around the country! :)

 

I know what you mean, and thinking behind my comment was that maybe one day you could help with this job now that you have/will have a jig for it.

[mklotz70]

We'll see how this one comes out first. I wouldn't get your hopes up that it will be free, but I'm pretty affordable :)

[hang_510]

cant wait to see this installed!

 

I don't see me shipping diffs around the country! :)

id drag my rear end up there and get one!

[Laecaon]

We'll see how this one comes out first. I wouldn't get your hopes up that it will be free, but I'm pretty affordable :)

 

I dont expect free. Good work is worth something. And to be honest I dont know how soon I will get around to this.

[mklotz70]

I don't think I'll be doing any more before Canby....I keep getting sidetracked!! LOL!! :)

 

 

Here's how the end pieces turned out. I need to turn the two for the carrier and we can do the final measure, cut, weld :)

 

The piece sticking out in the first pic is a piece I cut off the 1.25" shaft to test the fit of the center bore.

 

 

 

 

 

[mklotz70]

Put in a bit more time on this tonight...got the inner adapters done. The pic of the drill bit is the twist I put in it be overfeeding the bit. A big chunk broke off...had to hand sharpen it enough to get the 1" hole finished so the boring bar would fit. The fit of the parts came out great!! Next week, we should be fitting/measuring/cutting/welding!! :)

 

Big thanks to A100addict for the idea to weld the short piece of stock to the C channel so I could cut it!!! :)

 

 

 

 

 

 

 

 

 

 

 

 

[Zeusimo]

:w00t:

[freaky510]

your not a fabricator, your artist !!!!!

 

I mean that with the utmost respect!!

[]2eDeYe]

Wow Mike, this is going well :cool:

[Charlie69]

Mike this is a work of art. When I saw you cutting the bell off the housing I said to myself what is Mike up to now. It is really great that you are this tallented and willing to machine all these parts to attempt to do repiars & mods that most people would not even consider. Mike you really think outside the box. :cool: