| T O P I C R E V I E W |
| johnc |
Posted - 20 Aug 2010 : 19:04:45
Hi all,
My Series IV has been changed to negative earth with an alternator and the original RB106/2 control box has been retained.I see from my parts book that cars with alternators were fitted with a 4TR control box,a field isolator relay 6RA and a warning light simulator 3AW.I have a new 4TR control box which I propose to fit and have three questions;
1) are the field isolator and warning light simulator essential with a 4TR control box or would it function without them?
2) if they are essential can they still be obtained and where from?
3) does anyone have a copy of a suitable wiring diagram for the alternator with/without the aforementioned components.?
I already have the diagrams for early and late SIVs with dynamos.
Regards
Johnc |
| 7 L A T E S T R E P L I E S (Newest First) |
| johnc |
Posted - 18 Jan 2011 : 16:42:51
Thanks for all the info.
I have determined that the ammeter fitted for the dynamo system may well not function properly (mg website advice) and shall fit a voltmeter which I have in stock. |
| 1922 |
Posted - 15 Jan 2011 : 18:07:38
Just in case a Series IV has an ammeter I found this diagram. Note the difference in wiring so all the current from the alternator has to pass through the ammeter.
(This is an early 70s Sceptre with 16ACR).
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| johnc |
Posted - 14 Jan 2011 : 20:08:53
All is becoming more clear now,the mg site is really useful.I have also confirmed that the LRA101 and the 17ACR are indeed the same.
Thanks for the input and diagrams.
Regards
John |
| 1922 |
Posted - 14 Jan 2011 : 19:38:42
I can help to some extent with that one. I think the last time bought a 16ACR it came with "LRA100" or "LRA101" written on it - but it was a while ago!
The two large spade connectors are positive - one of these needs to be connected to the solenoid or battery.
The small connector is for the ignition lamp.
See below part of the earliest 'Hunter with 16ACR' diagram from the Hunter Workshop Manual:
On this diagram the white/red wire on the ignition switch is the starter/solenioid activation wire, the brown wires are the power to the switch and the white wires are the power out from the switch (for ignition, instruments, indicators etc).
I can find a diagram that includes an ammeter if required.
I've never done a conversion from dynamo to alternator and when I do the Minx I shall be creating a complete new loom from scratch - so I don't know what you should do with the existing wiring. However this job has been done many times by others - it's something I've seen covered in Practical Classics.
Heres a one I found on the internet that might help:
http://www.mgb-stuff.org.uk/electricstext1.htm#convert
Hope this helps. |
| johnc |
Posted - 14 Jan 2011 : 16:44:30
Thanks for that,
I do have a new Lucas LRA101 alternator rated at 34A,it has three connections,one small and two large.This would seem to fit the bill. If I fit this the original control box would be obsolete but I am in a quandry as to which wires fit to the alternator and what happens to those remaining from the control box.I am sure that this conversion must have been carried out before and if anyone has an idiot proof wiring diagram which they could let me have it could well save me from frying the alternator.
Cheers
John
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| 1922 |
Posted - 13 Jan 2011 : 22:53:50
The 4TR was also used on early 'Arrow' range cars. I found this diagram in the Hunter Workshop Manual that might help:
I'm pretty certain that a 4TR is of no use on it's own - you need all three.
But I strongly recommend switch to a slightly more modern type of alternator with an internal regulator as these only have 2 wires; 1 for the ignition lamp and one to supply power. This is a much easier job and as these were fitted to pretty much everything Rootes and British Leyland from the early 70's onwards they are easy to find and cheap. That way you don't need any of the external control units.
My '68 fastback has been modified to use one of these, and I have a Lucas 17ACR in the cupboard ready to go on to my '46 Minx (there's no way I'm putting up with a dynamo and control box!).
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| johnc |
Posted - 13 Jan 2011 : 20:19:16
Hi all,
I've been doing some serious head scratching over this.Whilst I have wiring diagrams for early and late SIVs I do not have one for a SV which I think would help.Does anyone have one they could e mail to me? I have found one for a SV Alpine on line but don't know if there is any similarity between Alpines and a Rapiers in this respect.Any ideas?
Regards
John |
