Inside a Kaaz Differential VW 020, and 02A, preload?

Bump for a bit more info on the Kaaz diff for VW 02A and 02J gearboxes which is different and not interchangeable with the 020 gearbox.

Part number: DBV1820
The Kaaz diff uses a 114mm crownwheel ID which I understand is the size used in all 02A and early 02J boxes up till around 2003, whereupon they changed the crownwheel ID and rivet / crownwheel bolt sizes to try to overcome rivet failure. (you would have thought VW would have had that issue licked by then seeing as the earlier 020 was plagued with rivet and diff pin issues!)

The Kaaz diff uses the "bolt in" type output flanges rather than the "push in" type. This is a more straightforward setup to build than the Kaaz diff for the 020 box which is a little fiddly to put together correctly due to asymmetry because of the packaging constraints of the smaller 020 box.
The pics show the basic layout of how the parts fit together:
I have included in the pics the 02A 100mm inner CV joint bolt in output flanges (later 02J boxes came with both 100 and 108mm inner CV sizes), their retaining bolts, and the two "threaded buttons", all of which need to be supplied from the donor box.
The spacer that sits in-between these two buttons is supplied with the Kaaz diff, as are the crownwheel bolts, and 2 litres of fancy oil making it good value seeing as other manufactureser require an expensive crownwheel bolt kit to be bought that is not included with their diffs.
There is a pic showing the ramp angles which is important to fit the two parts the correct way to ensure proper operation of the diff.
There is a pic of one side's clutch plates showing the 2 driving, two driven and a Belleville thrust spring washer which sit on either side of the planet a sun gears. This makes 8 clutch plates overall. These can be swapped in position to change the locking effect characteristics of the diff.
There are also two small thin shims that are not pictured as they happily stuck inside each of the diff casings with oil, these sit in the outer extremes of the internal cavity of the diff housings.
It is important when reassembling the two halves to ensure all parts are sitting correctly and aligned. It is easy for the Belleville washer or a clutch plate to slip out of position and this will prevent the two halves tightening back together with the 4x M6 countersunk Allen headed countersunk screws that sit under the crownwheel. It is possible to damage components if something is out of place and the two halves are attempted to be forced back together.







Also for info TranX have been bought over by Quaife and now there is a plate diff option for the 02A and 02J boxes marketed by them alongside Quaife's original gear type ATB diff. Their new plate diff comes with a wide range of ramp angle choices, but also comes as std with two setting options as there are two sets of ramps cut into the housing.

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Disappointingly not yet a Jackass



Edited 1 time(s). Last edit at 01/04/2013 03:27PM by danster.

So with all these expensive diffs needing a lot of expensive work, why not run a locked diff on a FWD car? I'm asking this is all seriousness, so please edumacate me.

Good info Tom. I hadn't heard about the Tranex diff. Are you going to try one?

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Robert.

"You are way too normal to be on Rally Anarchy." Eddie Fiorelli.

A word about dealing with Kaaz USA. The guy who answers the phone will lie to you rather than give you bad news. You must assume that all orders will come from Japan and take eight weeks. Plan accordingly and keep the pressure on them.

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Robert.

"You are way too normal to be on Rally Anarchy." Eddie Fiorelli.

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Robert Culbertson
So with all these expensive diffs needing a lot of expensive work, why not run a locked diff on a FWD car? I'm asking this is all seriousness, so please edumacate me.

In a VW, a locked center diff exposes weaknesses in the case and CV joints.

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fliz

In a VW, a locked center diff exposes weaknesses in the case and CV joints.

I know that VW already have CV issues, so how much more of a risk does a locked differential pose? How many people have broken CVs with open, LSD, and locked? To me it seems like a locked differential would guarantee the ability to drive out of a stage, allowing you to change a CV in service. Though the rate of service might increase (but by how much?), the rate of DNFing an event might go down .

The CV failures stem from too much torque at high steering angles. VWMS solved this in part by installing 8mm thick stops on the steering rack.

The key is to undetstand that mk2s don't like big power. Your money needs to be put into a final drive and gearset.

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Robert.

"You are way too normal to be on Rally Anarchy." Eddie Fiorelli.

I reckon the ability to drive out a stage with a broken shaft is over-rated. Possibly it stems from live axle RWD cars where limited damage can occur.
I was speaking to a mate that serviced for the works mk3 Golfs and when the drivers chose to continue with a busted shaft it caused immense damage to the car with the shaft flapping around. On occasion destroying the gearbox casing, taking out the brake lines and beating the bulkhead to bits. Manage to fix all that at service?
Fine for a works team maybe but possibly not so for a lesser funded car.
I also know folk that can change a busted driveshaft on stage quicker than some can change a flat tyre.

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Disappointingly not yet a Jackass

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danster
I reckon the ability to drive out a stage with a broken shaft is over-rated. Possibly it stems from live axle RWD cars where limited damage can occur.
I was speaking to a mate that serviced for the works mk3 Golfs and when the drivers chose to continue with a busted shaft it caused immense damage to the car with the shaft flapping around. On occasion destroying the gearbox casing, taking out the brake lines and beating the bulkhead to bits. Manage to fix all that at service?
Fine for a works team maybe but possibly not so for a lesser funded car.


-->I also know folk that can change a busted driveshaft on stage quicker than some can change a flat tyre.

Yeah I was at a BTRDA event just North of Scarbourough---started at Robin Hood's Bay Hotel---beautiful setting just down the road from Whitby---and I saw a lot of the Vauxhaul FWD guys in the Astras and Nova with a half shaft zip tied to the rollcage so I ax-ed a couple and they said the same like "I bust one by Gawd I'm getting this thing on quick time"......

The failures that really hurt are when the spline bit that pokes thru the actual hub shears right off....really frustrating when its .7 into the first stage..
Your mate still around who worked on the MkIIIs? Was he working with SBD down in Daventry??? Ask him if you could who would know what they were doing with the works cars regarding outer front CVs...

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John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

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danster
I also know folk that can change a busted driveshaft on stage quicker than some can change a flat tyre.

Now that's a trick I'd like to learn. The fiddly 12-pt bolts take me forever to undo, mostly because I'm paranoid about stripping them.

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Self-righteous douche canoe

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john vanlandingham
Your mate still around who worked on the MkIIIs? Was he working with SBD down in Daventry??? Ask him if you could who would know what they were doing with the works cars regarding outer front CVs...

Yeah. I keep in touch with him, I'll ask how often he needed to change them.
I understand the kitcar uprights, CVs and shafts were all pretty bespoke with several incarnations. Outer CVs had bolts rather than nuts to tighten them to the drive flange. A bit like the later Audi road cars use now. Think this was to allow changing the shafts without splitting the ball joint, undo bolt, turn the steering and undo the inner CV which may have used only three bolts with 3 dowels. Shaft can be removed.
These various upright pics are from Chris Eyre who runs the http://www.vwmotorsport.info/ site and show the development from GrpA modified standard uprights to the later SBG uprights made in the UK.

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Disappointingly not yet a Jackass

Nice stuff. I have suggested that if'n we'ze wuz smrat, we'd gusset that long thing extended goose neck kind of making it somewhat like the middle fabricated sheetmetal upright..
And I suggest people lookat the nice fat 14mm studs in the bottom piccie, I like 14mm studs. 14 gooood.
Been using 14mm since way back in the 80s when I converted from 9/16" bolts..

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John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

Here is one of the VWM shafts. You can see the single large bolt used on the outer CV, and the 3 dowels on the inner.


And this pic showing a similar inner CV design using 3 bolts with 3 dowels.

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Disappointingly not yet a Jackass

I have moved this quote from the camber castor thread as it is more appropriate here I suppose.

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john vanlandingham
You looked at Gripper diffs? Look arf-fully nice to me and heard to many first hand tales of woe and intrigue with Kazz over here anyway.

The lad I know that helped out with the VWs at SBG has run the Gripper diffs in the various Peugeots he is involved with.
I understand the early Grippers sometimes required the gear casings of the Peugeots to be modified by cutting and welding to give clearance for the diff. He reckoned the early Grippers where machined up by different shops and it took a while for the designs to be standardised to fit in the many different gear casings. I can understand this as it is only when you get seriously involved with a particular make and model of gearbox you begin to notice all the subtle little changes that were made over time. To expect an aftermarket lsd maker to have all the data to hand when they create a part is a bit optimistic.
Even when I recently spoke to Quaife they were unaware of the different crownwheel IDs for the 02A and 02J gearboxes for their newly marketed TranX plate diff. The 02A and early 02J having 114mm, I have not stripped a later 02J box to be 100% on the other size yet.
I explained to the technical chap that it was similar to the 020 gearbox situation with their two crownwheel IDs of 109 and 111mm, where the larger size restricts FD ratio choice to 3.6, whilst the 3.6, 3.9, 4.2, 4.6 had the 109mm.

The gripper design is very similar to the TranX from what I have seen with the centre cross shafts scalloped out to lie over each other and form the cross. Whereas the Kaaz has a one piece part that looks like the centre cross of a Hardy Spicer propshaft joint.

Here is something you may like to comment on. The Kaaz has two sets of ramps either side of the cross to exert the locking action on the plates, however the TranX has the cross fully supported on one half and only a single ramp cut on the other side. So when discussing or comparing ramp angles it is important to consider how they are calculated.
This video clip shows what I am trying to explain and the components in question at 1.25, and also you can see the two choices of ramp angles you get with the TranX diff at 2.10.

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Disappointingly not yet a Jackass



Edited 2 time(s). Last edit at 01/07/2013 12:54PM by danster.

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danster
Here is one of the VWM shafts. You can see the single large bolt used on the outer CV, and the 3 dowels on the inner.


And this pic showing a similar inner CV design using 3 bolts with 3 dowels.

oooh... just saw this (slight delay ) - I may consider going this route with the regular inboard joints.
Currently I have converted to VR6 joints on the outside - it has saved me a ton of trouble. Did take a bit of fabrication and machining to turn the 5x100 VR6 hubs into 4x100 - but is well worth it.
But I do frankly HATE the mucking about with the 6 bolts on the inboard joints. 3 would make it a bit more less appalling .

Any pointers as to how it would make sense to convert a stock setup?
Should I stick with the regular 12.9 in hex bolts I have in now? And then what for dowels? Some "push in from the rear" jobbies? studs that screw in? What? I don't really have a clue

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Brgrds
Brian