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Conversion from Cooper S 8TR to 4TR reproduction NCB148
https://ausmini.com/forums/viewtopic.php?f=2&t=101068		 Page 1 of 1
Author:  68Rusty [ Fri Jul 23, 2021 1:30 pm ]
Post subject:  Conversion from Cooper S 8TR to 4TR reproduction NCB148
Hi there,

I am all but ready for a blue slip check but the regulator is no good :(

I have bought a 4TR reproduction and changed the (F) and (-) connectors to suit, I now have an ignition light, but it is on when all the time and turns off when ignition is on, I haven't tried starting the car to see if the alternator is now charging.

The alternator has been check by the auto elects and it is fine.

Do I need to swap the (+) and blank (B+)? terminal connectors?

Has anyone had experience with this conversion/update?

Attachment:
8TR orig.jpg


Attachment:
4TR repo.jpg
Author:  winabbey [ Fri Jul 23, 2021 4:12 pm ]
Post subject:  Re: Conversion from Cooper S 8TR to 4TR reproduction NCB148
My MK II S came with a 4TR fitted and 15AC alternator. Apparently there are a few different versions of the 4TR so you need to get the correct one. Unfortunately my car is off in storage otherwise I could've checked the part number and also get a pic of the wiring for you.

Perhaps make contact with Tony at Auto Electrics on Wheels in QLD (contact in the Suppliers folder). Maybe he can help.

Are you on the Cooper S Facebook Group? I'd ask there as well.

https://www.facebook.com/groups/222100815049219
Author:  Steam [ Fri Jul 23, 2021 4:51 pm ]
Post subject:  Re: Conversion from Cooper S 8TR to 4TR reproduction NCB148
The 4TR is not a direct replacement for the 8TR. It needs a 6ra relay to make it similar to the 8TR.
It will all depend on what alternator you have. If you have a 15ac with the large black plastic end cover then ingram do a direct replacement regulator.
Author:  winabbey [ Fri Jul 23, 2021 6:16 pm ]
Post subject:  Re: Conversion from Cooper S 8TR to 4TR reproduction NCB148
Steam wrote:
The 4TR is not a direct replacement for the 8TR. It needs a 6ra relay to make it similar to the 8TR.

Are you sure? My car has a 4TR and doesn't have a relay, and the wiring harness doesn't appear to have been messed with.

Is it possible that there is a version of the 4TR that needs the relay and another that doesn't?
Author:  gtogreen1969 [ Fri Jul 23, 2021 7:04 pm ]
Post subject:  Re: Conversion from Cooper S 8TR to 4TR reproduction NCB148
You need the 4TR with B+ + F -.

You have the + - F which will need rewiring. I think it suits a Jag.
Author:  drmini in aust [ Fri Jul 23, 2021 7:20 pm ]
Post subject:  Re: Conversion from Cooper S 8TR to 4TR reproduction NCB148
gtogreen1969 wrote:
You need the 4TR with B+ + F -.

You have the + - F which will need rewiring. I think it suits a Jag.


I agree, I went through this many years ago. The Jag one isn't a direct replacement.
Author:  Steam [ Fri Jul 23, 2021 7:53 pm ]
Post subject:  Re: Conversion from Cooper S 8TR to 4TR reproduction NCB148
The 4TR has no way of disconnecting the field winding from the battery which is why the 6RA is needed.
Ther may well be different 4TR units that are different but technically it is no longer a 4TR. We all know that Lucas did some strange things, the 16AC which is really an ACR, and the Aussie wiper motors.
As has been said by others battery sensing unit with 4 connections is required.
Hope this is clearer.
Author:  winabbey [ Fri Jul 23, 2021 10:35 pm ]
Post subject:  Re: Conversion from Cooper S 8TR to 4TR reproduction NCB148
This is an extract from the Lucas Alternator manual for Australian cars. The left side lists various BMC models, incl Mini and Moke, that use the 15AC alternator. These are the corresponding regulator part numbers.

Attachment:
AM 1_72 p3 Regulator.jpg


I see there's a NOS one for sale in the USA.

https://www.ebay.com.au/itm/NOS-Lucas-3 ... 4405587699

There's a nice description of the 4TR in this document (although they misspell it 4TH in a few spots). It lists the 4TR part number for different applications.

http://repair-manuals.blogspot.com/2013 ... 63-74.html

Here's a Lucas workshop instruction for the 4TR.

Attachment:
Lucas 4TR Manual_4.jpg
Author:  Steam [ Sat Jul 24, 2021 8:38 am ]
Post subject:  Re: Conversion from Cooper S 8TR to 4TR reproduction NCB148
Going back to the original post from 68Rusty, if you have a 15AC Alternator then you can switch the Brown and Brown/yellow as you suggested, the alternator should charge but it will be machine sensed rather than battery sensed which will reduce the charging capacity somewhat, but it will charge.
This is assuming the 4TR is standard and not recomfigured internally.
Author:  winabbey [ Sat Jul 24, 2021 10:15 am ]
Post subject:  Re: Conversion from Cooper S 8TR to 4TR reproduction NCB148
Steam wrote:
The 4TR is not a direct replacement for the 8TR. It needs a 6ra relay to make it similar to the 8TR.

Steam - the Workshop Instruction I posted above mentions the relay as you pointed out. It seems it applied to an earlier version of the 4TR.
Author:  68Rusty [ Sat Jul 24, 2021 11:02 am ]
Post subject:  Re: Conversion from Cooper S 8TR to 4TR reproduction NCB148
Hi all,
Thanks very much for the help and advice. Just checked resistance ohms on + and blank pin, nothing! It appears they have taken a 3 pin 4tr and essentially just made it into a fake 4tr with a piggy backed terminal pin from +.

Will be sending it back and advising not to sell or at least change description as advertised.

After hours of searching the net, there were many accounts of confusion regarding this product across various English base cars.

This 4pin 4tr regulator is essentially a 3 pin 4tr reproduction regulator.
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