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4Wd Gearbox Conversion


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#1 Moke Spider

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Posted 10 December 2014 - 08:51 AM

Well, I should kick off by say this is not for me! This is actually the repair of a Gearbox for a Moke known as Quadra. suffered a major failure at an outing a few years back now. I undertook this re-design / repair back in early 2012.

 

It was originally made by an aquantance, Max Kinsmore, back in the late 70's. The Bevel Gears used in this one are actually from a Prototype that was Made by our local Leyland Factory as they were considering putting these in to production - another story for another time!   I digress - This Leyland Prototype design is actually based upon the Leyland ST Mini, which in turn was based on one of Issigonis's Prototype Single Engine, 4WD Mokes of the early 60's.

 

A Friend of mine now owns the Moke, which is not a factory car, but does have a few factory parts in it.

This was the gearcase from it, after I'd stripped most of it

SDC12054-1.jpg


When it was stripped down, the diff pinion was found in a hundred pieces. Not the first one I've seen like this

SDC12062-1.jpg

but closer inspection of the gearcase show a LOT of other problems, most of them old, but signs that this design was not up to the task

SDC12058.jpg

the case and the diff cap were fund FULL of cracks and other damage from previous failures. The diff cap hardly even lined up, so no wonder it leaked oil.

It was off to the drawing board for a few weeks. I came up with a solution and design to overcome all it problems and (hopefully!) make it un-breakable.

So, next thing was to start making all the bits

First was the diff hemispehere. The stock 2 sun gear designs are hopeless, so I made a 4 sun gear, X-pin type

SDC11376.jpg

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I had to make a special tool to cut the thrust faces for the sun gears

SDC11427.jpg

trial fit to check it's shape - perfect!

SDC11439.jpg

now to cut them for real

SDC11446.jpg

starting to take shape

SDC11638.jpg

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next, I had to machine up a crown wheel, this is another weak point in the stock mokes and this one is no exception

SDC11648.jpg

then fit the bevel gear to it

SDC11649.jpg

then the next major problem part, the diff cap. We got a new gearcase and I had to measure up super-accurately the existing diff cap

SDC11660.jpg

I machined up a new one from a soild billet. Here, I'm just starting to face it, to get it 100% square and flat

SDC11661.jpg

then next was the bearing tunnel. to get this perfectly round and on size, I had to bolt it up to another piece the same. This is the start of something BIG

SDC11682.jpg

back in the lathe

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boring it

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perfect!

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pitch out and drill all the holes. This needed to be super-accurate (I was working to +/- 0.005 mm!)

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fits and lines up! Bonus!

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next, some relieving of the gearcase as the new diff is bigger

SDC11701.jpg

trail fitting the diff

SDC11703.jpg

yippie!

next, I had to measure exatly where the output pinion needed to be for the RWD part

SDC11707.jpg

then, I could machine out the guts of the cap

SDC11719.jpg

look it fits!

SDC11721.jpg

then face back the cap to get it all lined up with the gearcase

SDC11730.jpg

planing the back of the diff cap at an angle, to get the output pinion facing the right way

SDC11740.jpg

boring the hole for the pinion

SDC11744.jpg

just about there!

SDC11748.jpg

there, all major machining done!

SDC11752.jpg

all that's left now is the big clean up and assembly!

 

To be continued.

 



#2 Moke Spider

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Posted 10 December 2014 - 08:54 AM

Here's some pics of the original proto-type Crownwheel

SDC11764.jpg

There's the part number. Anyone got a reference to it?

SDC11765.jpg

You can see that this one is missing teeth, but also, that it has the bearing mount. Oddly, there are only 3 bolt holes for the hemisphere, I have no idea what the score was on that.

The ratio of the bevel gearset is 2.1:1 so way too tall to be a diff from any other vehicle that I know of. I am in no doubt that these are genuine Moke ones.

SDC11762.jpg

On the Left is the new Crownwheel and the one that was fitted on the right (I have machined the bevel gear out of it). I think the new one will be considerably stronger!

SDC11763.jpg

And the new Pinion too (on the left).

Some pics of the diff cap that was on it

SDC11768.jpg

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This was a Remote Shift cap on a Rod Shift Box!!!!  I doubt that this was done by the factory, I think this was some of Max's handywork. The alignment was unbelievably poor. I have no idea how it held oil. You can see some cracks and gouges from previous learning experiences.

I did look long and hard at welding a flange to the back of the shock Rod Shift Cap, but there is next to no meat in it. All the stock one really has to do is keep oil in, this one does a little more  wink.gif

This is the Factory proto-type hemisphere

SDC11766.jpg

You can see the chatter marks from the bevel gear teeth! This was because the whole assembly was parting company (from the stripping threads) and effectively bending. I have a black and white pic of the factory units I'll throw up a little latter (when I dig it out!).


Edited by Moke Spider, 10 December 2014 - 08:57 AM.


#3 Moke Spider

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Posted 10 December 2014 - 08:56 AM

Some progress

The Gear Shifter set up had something missing! It had no steady on it and so when accellerating or decellerating it was prone to jumping out of gear

SDC11789.jpg

So, I had to nut out a steady. Not having the car here made it had to make decisions as I didn't know what was where and what clearances I'd have.

So I brazed a bracket to the output pinion bearing carrier

SDC11792.jpg

Then bent up a suitable rod

SDC11795.jpg

I've also made up some spacers and so now ALL machining and fabrication is done!

Yipppeeee - it felt like a marathon!

So this afternoon, I tubbed everything up

SDC11797.jpg

Does anyone know where all this stuff goes  shocked.gif

SDC11799.jpg

I've started on the assembly. More to come  wink.gif


Edited by Moke Spider, 10 December 2014 - 09:17 AM.


#4 Moke Spider

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Posted 10 December 2014 - 09:00 AM

Really taking some shape here

SDC11804.jpg

Hopefully I'll have it fully assembled today. I've also now got the front Subframe here, so I can trial fit it and check that it actually fits - that could be embarrassing!

 

Here's a couple of shots of the subframe

SDC11805.jpg

SDC11808.jpg

The spacers on top measure a total of 31 mm. I'm not entirely sure why these are needed, but it maybe to get enough room between the tunnel in the floor pan and the output rear facing drive. The pics of have of the factory ones didn't seem to need any spacing. I might get a better idea later today when I trail fit them together.

 

Tada - it's FINISHED  grin.gif (much to my good wife's relief)

SDC11798.jpg

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#5 Moke Spider

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Posted 10 December 2014 - 09:03 AM

Following this repair / rebuild, the owner of the car in to which it belongs undertook a full restoration of the whole car, it's now been on the road for about a year now, he's commented that for the first time in his ownership it doesn't leak oil (funny about that!) and it's surprisingly so much quieter than it's ever been, all he hears now are the tyres and some exhaust note!



#6 steve m

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Posted 10 December 2014 - 09:10 AM

Can,t see any pictures



#7 Moke Spider

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Posted 10 December 2014 - 09:24 AM

Hmm,,,,, they are on photobucket, sometimes they are slow to load, just give it a few moments, if they don't pop up, I'll re-insert the images.



#8 Carlos W

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Posted 10 December 2014 - 09:25 AM

Phenomenal work.



#9 Carlos W

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Posted 10 December 2014 - 09:25 AM

Hmm,,,,, they are on photobucket, sometimes they are slow to load, just give it a few moments, if they don't pop up, I'll re-insert the images.

 

I couldn't see them at first, but can now



#10 Guess-Works.com

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Posted 10 December 2014 - 09:27 AM

Fantastic !



#11 cal844

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Posted 10 December 2014 - 09:55 AM

Epic and expensive work!!

#12 BritishRacingGreen

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Posted 10 December 2014 - 09:58 AM

Unbelievable... You didn't make two did you? 😜

#13 brownspeed

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Posted 10 December 2014 - 10:13 AM

Bloody Hell! I bet that was a busy couple of days!! ;D

love that workshop facility



#14 Tahiti Joe

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Posted 10 December 2014 - 11:45 AM

Fantastic work, I've dreamt about this sorta thing for mine for a while now. Would make the low traction situations I regularly find myself in a lot easier to maneuver out of...! If you'd ever be interested in making another id be seriously interested.

#15 coopdog

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Posted 10 December 2014 - 12:19 PM

That is amazing work

Never better than making something from scratch and watching it take shape!




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