I can only see the 8TR in brochures, roadtests or period photos for the MK2 S, Mini K, Clubman GT, Clubman Van. I checked my collection of MK2S photos and the unrestored cars have the 8TR as well. This subject had been discussed before and I got the impression that the factory fitted the 8TR and the 4TR was a replacement spare part. I cant confirm the 4TR was ever factory fitted.

John Smidt has a few good comments here - viewtopic.php?f=2&t=48686&p=583443

Yes, confirming what you said in the post I mentioned earlier - viewtopic.php?f=2&t=101068

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ex-NSW Police 1970 MK II Cooper S
VMCI #43

Lacking photos confirming factory fitment I can only go by the parts books for the round-nose and Clubman I posted earlier that list the 4TR - 37527.

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ex-NSW Police 1970 MK II Cooper S
VMCI #43

A couple more things I stumbled across that might be of interest.

Minisport list a 4TR but it only has three connectors, not four. I wonder if it's incorrectly listed, being the Jag type instead, or maybe the image is the wrong one.

https://minisport.com.au/4tr-alternator ... -regulator

Here's the BMC engineering drawing for the 8TR. Can't find the equivalent for the 4TR at the moment.

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ex-NSW Police 1970 MK II Cooper S
VMCI #43

Warning sticker points to it being a replacement

8TR at the bottom of photo is 6/71

I would like to know whether 'Steam' has any information on another 4TR (4 pin) control box with Lucas number 37586. It is listed with 37527,suggesting they are interchangeable.

https://www.bing.com/images/search?view ... ajaxserp=0

I bought a 37586 years ago in case I needed one and would like to know if it is useful.

Bill, I have no info on that model number however if the terminals are in the correct place it will work as it should.
I am using an aftermarket 2 pin regulator on a 15ac, as long as the field gets the correct voltage level with regard to battery charge level it will work.
The 3 pin 4tr will also work if wired correctly, the 4 pin was to acheive battery sensing.

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Cheers Dave.

I replaced the 4TR Voltage Regulator with a 8TR Voltage Regulator after asking about the factory fitted unit.
Was very lucky to find one with the correct date period and in working condition.
Thanks to everyone who supplied information and details to make it happen.

Perfect result.

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Cheers Dave.

Thanks Steam.
From my checking online, it seems that the 4TR (black plastic box with 4 terminals) was used in various Triumph and MG models that used the early UK made 15AC alternator; 8TR was made in Australia to go with the Australian-made 15AC alternator used in mini K, Mk2 S and later models running alternators without internal control units.
So some parts for these units might be available for this combination through Triumph and MG specialists in UK and Nth America.