Viscodrive

[HFStuart]

There's been a few posts about LSDs for Betas and I suspect when my car comes back from mapping this might be something I look into.

That got me thinking. The Fiat Coupe 16VT  uses the same C503 gearbox as the Beta and reading around the subject it looks like the diff would fit the beta box. They came with a viscous coupling unit on the intermediate driveshaft. It's splined onto the driveshaft and has dogs that engage with the diff.

I wonder....

When I've got the car running I might just have a play with my spare gearbox and some bits of Fiat Coupe - IF it works it would be cheaper than a Colotti or modified Quaife and not as aggressive as a gripper.

[Duncan23]

The Dedra Turbo had a viscous diff too (though I suspect it would be easier to find a 16vt box). I don't remember any torque steer with either car (I've owned both), and I think the diff was the reason the Dedra was so good in the snow! :-)

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[rossocorsa]

Had a dedra turbo and a delta hpe turbo with viscodrive always found it worked well the beauty of it is that if I recall correctly it us all external to the main box, often wondered if it could fit on a beta.

[HFStuart]

I can get a 16VT box for £50 (less if I can find one that's gone bang!). The first step would be stripping that and seeing if the diff will swap. The coupling and driveshaft will be a bit more so I won't buy those until I know the diff fits.

You're quite right it is all external - though obviously you need the diff to match the dogs on one end of the unit.

[swedgamma]

Hi!

Just found this in my documents,cant see if there is one in the car (Delta HPE 2l turbo HF),its to crowded under the bonnet!Sounds like a terrific idea if it works in a Beta!

Greetings from Urban(swedgamma)

[archigraphe]

I will follow this interesting post.

[MattNoVAT]

Thema Turbo 16v Phase 3 had Viscodrive too


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[HFStuart]

Sadly not too many of them in the local scrappies!

Having got used to my car on the throttle bodies now I think this is going to become more urgent  - it's very easy to light up the front in the damp.

[HFStuart]

This is very much a step closer now.

I few days ago I managed to lay hands on a Fiat Coupe 16VT Gearbox and driveshaft with the viscodrive unit.

It was immediately obvious that though it's the same gearbox  I wouldn't be able to use the Fiat gearbox case, or bellhousing  / diff carrier because the Beta engine is laid back and the Fiat isn't.  Though it would fit,  the diff would be in the wrong place and the starter has been moved from the front to the back of the engine.

Nonetheless the gearboxes were clearly very similar so I took the diff covers off to see what they looked like:




The bolt pattern is the same and other than the crownwheel being thicker on the Fiat it all looked pretty promising. I then tried the Fiat diff cover on the studs of the Lancia box.



Bingo  - it went straight on the only difference being that it's 3mm narrower on the offside everything else matched including the bearing housing diameters. That's a good thing

So then I tried the fiat diff in the Lancia case



As you can see it's a pretty good match - it meshed with the output shaft OK as well. It may need shimming on the offside or I may be able to transfer the bearing - it's even got a mechanical drive for the speedo cable!

This is very good news. I'll strip the diffs this week but it looks very much as though like I can just change the crownwheel and NS flange over and it will drop in - the Fiat offside driveshaft seal is a perfect fit so no worries there. Once I've looked at the diffs I'll get my spare block and mock up the assembly to see how well the driveshaft fits. Fingers crossed.

[rossocorsa]

Good work! I always liked the viscodrive much better than the modern electrical control methods