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[Diamond Black Geezer]

Reading up on Limited Slip Diffs (apologies to hard drugs users who were expecting a different tread) found the below article, with an interesting discussion on diffs, and they also mention the Omega, with reference to diff wear...

http://www.pistonheads.com/features/ph-features-tech/born-slippy-all-about-limited-slip-differentials/25275

[KSR]

Good reading... 

[Diamond Black Geezer]

Though in retrospect it's obvious any diff will wear it sounds like an Omega with as low as 60k km(or 37k miles) is potentially pretty knackered; or at least working effectively only as well as a brand new standard 'slippy' diff. If I've read that right. Amazed they should become ineffectual after so few miles.

If someone offered me an old Carlton GSi/ex plod Omega LSD diff with only 50k on the clock I'd be snatching their hand off thinking I was buying an 'as new' diff. Now I learn that in actuality there may be close to no point whatsoever in it.

Think I'm going to try and spend my money trying to get my mpg up a bit. New plugs, replacing the filters and find where my air leak is are on the cards... 

[Varche]

Think of the Omega one as being like a clutch. They don't last forever and need new friction material.

You could get a secondhand one rebuilt. Might need machining as well.

[Diamond Black Geezer]

Ahh, that makes more sense, thank you  Sadly we didn't delve into the proper, hard engineering as much as I'd have liked on the course. Unfortunately it was enough to know the difference between front, rear or all-wheel drive, and the approximate dimensions/packaging constraints that each option posed.

I can imagine building my own refurbed diff being a bit of a mini-money pit, for no appreciable gains on day-to-day driving. Rally interesting to see actual experts asked about such detailed things, rather than yet another clarkson-wannabe motoring journalist's opinion on why car a) is 'pants' because it gets to 60 0.1second slower than car b) without appreciating the other hundred thousand things that goes into designing and creating a car.

Will re-read when I get home. Really enjoyable read. 

[Mr Gav]

I remember a guy on ABS who took three  Carlton LSD`s to be rebuilt with new friction plates and all came back without being re-built as they had excessive wear and would need far too much spending on them to be worth while, all under 100k on them so you would assume them to be relatively ok but the engineer said differently.

The fact is though that all three still worked as they should do so even though he was told they were scrap due to the cost of the crown wheel that had the most wear and other parts needing replacement, they were still a working diff much as any LSD fitted to a Omega will probably not be worth a re-build but will probably work as it should for a few more years to come.

[zirk]

Assuming the Omega LSD type diffs aren't ragged around a Track or doing Donuts around a McBurger car park all its life they will last a lot longer than 60k.

[ted_one]

I've just had a quote for the two ex plods at £600 each,this particular company has an excellent reputation amongst the classic car clubs and although both cars are still on the lowish side in regard to mileage 74k and 90k I think the units have undoubtedly had a bit of a ragging so I'm happy to get them refurbed,also the Elite will be done first as it's starting to whine very slightly due to the high mileage at 230k

[Diamond Black Geezer]

Ah, ok 

Can anyone clarify what is meant when the engineers say " In one direction it was 18 per cent and in the other direction it was 13 per cent. Even an open differential, a new one which is a little bit sticky, has similar figures to this."
by the turn of phrase 'direction' that suggests if the diff is actually spun forwards, efficiency was 18%, then in reverse efficiency was 13% but this doesn't make much sense. Surely determining the wear on a LSD would be measuring the torque, or the slip between shafts as a ratio? Or literally 'how much does the NS shaft slip when the OS is braked'. A bit like a dyno test, but on an output shaft.

I'm sure I've probably slipped (no pun intended) on the theory a little here, though. 

[Marks DTM Calib]

That's why its important to keep the fiction modifiers in good order on a clutch based LSD.

The one on my ex-plod had circa90k miles on it and still worked well, and even better with new LSD oil.