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Oi! Unlike the subject may falsly imply, this is not about various illegal substances
Got a couple of questions to those in the know about drive couplings and limited slip differentials!

I am in the process of restoring my '72 Spaghetti Cooper 1300 to all original condition, except for period engine- and suspension upgrades.
Where I am prepared to compromise is the LSD, there I am tempted to go for a Swiftune Quaife ATB.
My original base engine is a 12H610 (similar to Morris 1300) with remote gear change. I intend to keep the 3.44 final drive as well as the hardy spicer joints.

In the light of the above - is the Quaife ATB a sensible choice for road and occasional gravel rallying? I too need to consider I haven't got the pot-joints, hence will require HS-adapters, which makes the assembly more expensive.

Secondly: what is actually better on a 80-90hp engine - Hardy Spicers or pot-joints - given the fact I could change to the pot joints at this opportunity?

BTW: I am also on a tight restoration budget.

I would appreciate your thoughts (and maybe prayers - for me winning the lottery ) and experiences on the above.

Cheers
Marcus

... my recommendations if you are on a tight budget: leave the LSD out! On road cars absolutely unnecessary!

r.tec wrote: ↑Mon Aug 10, 2020 10:42 am ... my recommendations if you are on a tight budget: leave the LSD out! On road cars absolutely unnecessary!

Hmm - sorry r.tec, that does't answer my questions at all - if I may quote myself:

blabla...road and occasional gravel rallying?

The posi you have picked would be fine IMO for street and gravel rally use. I'd think if you have HS parts they would go a ways toward paying for a pair of pot joints the matching axles and side covers. Should help with exhaust clearance as well. A properly set up cross pin diff. with HS or Pot would be almost as good and save a pile of money. Steve (CTR)

I'm running a Quaife atb with 'knock on' hardy spicer output flanges from a late hardy spicer jointed auto mini, these still require the use of cooper S gearbox side plates due to the use of the larger diameter S bush.
The Quaife is a very nice diff on the road, you don't know it's there under normal driving but seems to pull the front end in tighter though corners with power applied and seems to reduce lock up under braking. It doesn't have any negatives in my opinion other than price.
Personally I'd use hardy spices given the choice, I think the swiftune/MED output flanges use standard mini gearbox side plates. So much easier for engine or driveshaft removal and you don't need to drain the engine oil if you leave the output flange in place.
Don't know what it's like on gravel, obviously nothing like as effective as a plate diff.

Hardies vs Pot Joints - technically, either will easily do the job here, the down side though to Hardie Spicer joints these days is some of the parts can be quite expensive. If you have all the Hardie Spicer parts, save for the knock on drive flanges, then run with them, but if you find yourself up for a complete sliding joint, then I feel a swap to Pots would be sensible.

I run ATBs in nearly all my cars. The ATB is nothing in the world like an LSD and IMO, perfectly suited to Rally work. I find them much safer in a road car than an open diff and having tried an LSD long ago, they are quite dreadful and even dangerous in the hands of someone who doesn't know how to drive with them or is caught off guard.

After a few years rallying with the Quaife diff I'd say that it would be great for road and track use but where it falls down is on tight bends and loose or very slippery surfaces - it doesn't lock it just biases the torque better than an open diff - up to a point.
I've just switched to a plate diff and, in the tight bends, it's much, much better.

As Spider says though, a plate diff is a different animal.
My first plate diff was set at 60-70lbft pre-load and made the car horrible to drive. At low speeds you needed the arms of Schwarzenegger to turn the wheel and the music of Motorhead to drown out all the clunking and banging.
The current fitment is set at about 20lbft and seems to be a good compromise.

Do you mean 'road rallying' and occasional gravel rallying or 'normal road use' and occasion gravel rallying?
I initially thought I could use my rally car for multiple uses - stage rallies and shows, trackdays, tours etc. but soon learned that a well-developed competition car isn't an ideal road tool!

Pot joints are constant velocity so, in theory, better than HS but don't look 'period correct' on older cars.
They fit straight on to the Quaife without adapters but need different driveshafts.
The adapters are useful for keeping the oil in when you remove the engine but that means loosening the fiddly nuts on each HS.
It's quicker to drop the oil and then pop the adapters out in the same manner as pot joints.
If the engine is coming out for work then you'd surely need the oil to be drained anyway?

Andy

There was/are two versions of the atb, one for pot joints and takes all the standard later cwp combos and 1 for HS, which takes the lsd crownwheels, I had the later in my 3 sync remote gearbox with minispares 3.47 cwp - C-BTA1250EVO, but take notice of the instructions, it does need fettling to fit the quaife.
I love the atb in mine as a fast road car, and we've fitted them to all our 8 ports.

The later type pot joint Quaife that take standard type crown wheels is a direct swap, no fettling required.

Thanks for all your feedback that shall enable me to come to a decision. I definitly keep the Hardy Spicers, which are OE on the first series of Inno Cooper 1300s.
Ta
Marcus

I would always again choose the Swiftune ATB.

It virtually eats the bends. And it's well spend money.

A other advantage is that you have Lifetime guarantee as Quaife say...

I first had the pot joints but then changed to hardy's because the LCB was to near of the inner gaiter and burned it in no time...

Hope this helps...

Grüsse aus der Schweiz