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MG Midget and Sprite Technical - MGOC 3.7 Diff

Hi all,
just thought you might like to know about the MGOC 3.7 diff I received a few days ago. This was reconditioned with new CWP costing £466 inc vat including a £60 surcharge against return of old unit.

The interesting thing is the CWP is 37/10 not the original 41/11. Confusingly, it has been rebuilt into a case marked 39/10 so it will be interesting if I ever come to sell it.

I don't plan to return the old unit to get my £60 back, judging by the prices they achieve on eBay!!!!

Rob
Rob aka MG Moneypit

As an aside I had a new 3.55 shipped from Bastuck in Germany and had it built up to replace the old 3.9. Total cost to about £270.
Fergus Pollock

Yes, the 3.7's now are indeed 3.7 not 3.727 as they were originally.
I hope you have better success than I did with one of those units, it was very noisy. Checked the tooth contact and it was well out. Cost me a bundle by the time the customer was happy.
Then when I ordered a 3.7 CW&P for another job, it came with instructions to use the original pinion head spacer and simply adjust the backlash. Hey-ho, so all those different pinion head spacers and all that bit in the book about setting the pinion head position were all a waste of time then! Somehow I don't think so ...
Paul Walbran

I had a 3.7 from Hardy Engineering that came complete with a little howl. I took it back, and after driving round the block, the man gave me another diff.

It was a 41/11, though.
Nick and Cherry Scoop

It's a little harder, slower and much more expensive to return from here :-(
Paul Walbran

How accurate can you get just relying on the contact patch indication? I ask as last year I helped my neighbour rebuild the final drive in his Morgan with a new CW&P from a Morgan specialist. I provided some technical knowledge and slip gauges etc for checking the set-up and my neighbour is fairly handy and has quite a bit of measuring equipment as he makes small locos. At one point the Morgan "specialist", who normally builds the final drives for customers said that he didn't use the figures marked on the pinion and crown wheel for set-up at all but just went by the contact patch. His argument apparently was that the pinion offset figure and crown wheel backlash only pertained to a theoretically perfectly machined final drive housing which you would never find. That flagged up to me that the Morgan "specialist" didn't understand the use of the figures or the reason for them and various measuring procedures to get the CW&P in the correct position for correct running. When set-up according to the specs my neighbours final drive did run sweet. BTW the Morgan axle as fitted to my neighbours car was also used on Winget dump trucks and the rebuild procedures for those can/could be found online. The Morgan specialist did have a guy that dealt with gearboxes and final drives but he retired but apparently showed the main guy what to do before going, how he built them I don't know.
David Billington

So am I a mg midget specialists.

What are the qualification to achive the title

Prop
Prop and the Blackhole Midget

Fergus,
Could you tell me the contact to get one of those 3.55 crownwheel and pinion sets? I assume that if the total cost was 270 pounds then the CW&P would have been considerably less? I don't mind if it is a good s/h unit or new. I don't need the complete diff because I can set them up myself and a whole diff would be harder to ship to Australia.

Bob Schapel South Australia
R L Schapel

I still have a new-old-stock 3.7 diff.
Previous owners dad owned a britisch car dealership/garage in the 60/70ties.
tried it in my 1500 before going 5speed.
Ofcourse Im not selling it. ;)
A de Best

Bob the CW&P was new from Bastuck and cost 246 Euros with shipping to Blighty about another 15.
http://www.bastuck.de/content.php?&id=743&lang=en
I ordered over the phone and the CW&P arrived within 5 days.All very painless and easy.
Fergus Pollock

Hi

These newly manufactured diffs from Bastuck sound good. Do they make any other high quality replacement parts?

They are a new name to me. Someone making good bits with good QA (and European made?) sounds refreshing. UK companies should note!

Cheers
Mike
M Wood

Thanks Fergus,
Before your post I was unaware of their existence. I have now found their website and they have some useful stuff! I run spridget diffs in my MG TC s/c historic race car. 4.2 for most circuits and 3.7 for Phillip Island. A 3.55 would be handy to have if I ever run at Bathurst because of the long downhill straight.

Bob Schapel
R L Schapel

This thread was discussed between 19/08/2014 and 31/08/2014

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.