Hi ExMil109 & rob1miles, Thanks again for your thoughts. What I was thinking, with taking the +ve feed to the regulator from the alternator output, was that the regulator would then control the field coil to keep that point in the system at 14.4v. Then if there is a 0.4v loss in the system...

P.S. The voltage between regulator + and - (also under full load) is 14.4v. But still not sure what that means from the Lucas manual notes!

Hi, Rain stopped play for a day here in Cumbria! After much sanding of 50 year old contacts, I reduced the resistance between battery +ve and regulator + from 0.2 Ohms to 0.0. However voltage, fully loaded, still up at 14.8v. It is the same if I do the direct feed from the battery +ve...

Hi ExMil109, Thanks. 14.8v not a bad thing for my particular battery, but does indicate that possibly the 4TR is struggling to keep the voltage down, which can't be good in the long run. I will also try the direrct feed, as you suggest. Relay is a new one. I thought the Lucas manual was a...

Hi rob1miles, Thanks. I guess in my case it must be the permanent +ve feed, which ends up at + on the regulator. Comes from the the starter solenoid, along with the +ve alternator output lead, and then on to the +ve terminal of the battery. I will check it and the Lucas test out in the morning.

Hi rob1miles, It is possible! The Lucas guide (my earlier post today) says in the notes on Pg34: 3. A high reading indicates a faulty 4TR unit. A correct reading denotes a high resistance in the sensing circuit which must be located and remedied. Which is a bit confusing! But I think they...

Hi Blackburn, Good question. Exmil109 will know a lot more about this than I do. But here is what I do know. In terms of my particular battery (Odyssey Extreme AGM type deep cycle battery) 14.8v is good. Standard lead acid battery though, 14.4v is generally regarded as max, I think? The...

Hi rob1miles, This is my third regulator! I think the first one (original transistor type) could easily have got damaged while the wiring was still in a mess, hadn't discovered the earthing (jury style) of one of the field coil leads by that time. Second one (PCB type) I think was faulty - I...

Hi Exmil109 & rob1miles, Good news! The replacement 4TR (PCB type) turned up, and seems to be working. After warming up I ran it at about 2000rpm (engine) for 10 mins, and it was steady. 6.5A on the +ve alternator output 0.6A on the F-ve lead 0.35A on the F+ve lead 14.4v across the battery...

Hi Exmil109, I meant to thank you for the latest wiring diagram. I think my Japanese regulator was wired something like that. If all else fails I will revert to that, although I will have to find another Japanese one, mine is definitely shot. I had thought that they had earthed the F+ve lead...

Hi Exmil109, You could well be right about the previous change to the Land Cruiser regulator - the search for something more robust! Selling my Series 2A and buying an FJ45 is always an option! And of course the path 'mystery' has taken is also an option. But he has lost the original engine...

Hi mystery, You think 16ACRs are still made in Birmingham by Joseph Lucas?

Hi mystery, That is obviously what Land Rover decided shortly after they built mine! But nearly everyone else decided to buy a Toyota Land Cruiser instead! However, I quite like their experiment with the voltmeter, to simplify the system. And if the 11AC was good enough for the e-type, then it...

Hi mystery, This one talks about the alternative of using an oil pressure switch for the ignition light, rather than the AL connection and the 3AW. If it helps. https://forums.jag-lovers.com/t/3aw-ign-warning-light-control-wiring/355332/10

Hi all, Just to clarify, I don't have an ammeter. Also there is no connection to AL, or the relay, or the regulator which could feed a charge warning/measuring device. It seems I have a rare setup. And no wiring diagram exists for it! (wish I had an electro-mechanical regulator like the RF95...

Hi Exmil109, Thanks very much for your thoughts. There was a slight difference between the readings on the F+ and F- leads. Circa 0.2A lower on the F-. I also measured the resistance across the ends (disconnected from the regulator) of the F+ and F- leads and it was 7 Ohms. A bit more than...

Hi mystery, Thanks for that. I seem to have a system that Land Rover only tried for a few weeks, before switching to the 16ACR, where everything was integrated into the alternator!

Hi mystery, I did take a look, thanks. They seem to have a different issue? Ignition/charge light coming on. My ignition light is OK. Nice and bright when you turn the ignition on, then goes out straight away when the engine starts. Also my system is charging - it's just charging too much...

In case the detail is of any help: F is connected to -ve permanently now in the blown 4TR. The system is charging (overcharging - 16.5V). Current flowing in the field coil is 3A.

Hi rob1miles, Thanks for trying! It is very trying! I think these modern 4TRs are PCB, so it's shot. I will have to get another one in any case. Fingers crossed (or perhaps a revelation will happen in the meantime)!