TR2/3/3A Generator and voltage regulator on a tr3

[sp53]

I have never understood the exact relationship between the Generator and voltage regulator on a tr3. My question is should I replace the regulator and generator as a unit if I suspect the generator is the problem. The generator light came on while I was driving, and perhaps I should have unplugged it as I drove home, but I did not. Anyway, I could hear a mild rattling noise coming from the generator, so I pulled it. Now as I am putting on a new generator the thought came to me should I replace the regulator also. My concern is what if the generator shorted out and that fried the regulator is that going to now toast this new generator. Thoughts?
steve

 

[Geo Hahn]

I know of no reason why a failure in one would damage the other. Still, it would be prudent to test both once you have the replacement dynamo installed.

The only control box failure I have experienced was when the points became severely pitted. Not sure what (other than age) was the cause of that but the solution was a replacement of the unit (so far as I know the points are not servicable).

 

[TR3driver]

It is a good thought, and sometimes is the case. Not so much that the generator failure damaged the control box (in my experience anyway), but rather that a control box problem is what caused the generator failure in the first place.

However, your rattling noise is likely a mechanical problem (bad bearings) and relatively unlikely to damage the control box, IMO. Still, I'd want to at least check the regulated voltage after installing the new generator (whether or not you change the control box). Even new ones are not always properly set.

The relationship is that the generator is a relatively fragile device and will readily put out enough current at higher rpm to overheat and damage itself, if the regulator does not limit the current.

 

[Member 10617]

Steve,

Remember that if you install a new control box (a.k.a. voltage regulator), you need to clean the points and adjust it to your generator. There are plenty of instructions on how to do this, but I found them difficult to follow and I didn't trust myself to get them right.

So... I purchased a pre-cleaned and pre-adjusted control box from Moss. For sure, the pre-adjusted box will not exactly match your generator or your situation, but I have found that the box does a good job and I haven't had any noticeable problems.

On the other hand, there are some very experienced guys on this forum who can lead you through the procedure of cleaning and adjusting the box yourself.

It's your choice.

 

[mgedit]

Cleaning and adjusting the box ... now there is one thing I missed. Will have to check out the manual and add it to my to do list. Cheers, Mike

 

[Member 10617]

Mike:

I don't intend to favor or push Moss products, but here's what Moss says about Regulators: "A growing number of customers expect these to be 'plug & play.' They never were. Shops buying original Lucas voltage regulators back in the 60s and 70s routinely will remember the 'Contacts to be cleaned prior to fitment on vehicle' sticker on the cover. Cleaning the contacts and adjusting them has always been part of the installation process. If they are simply installed, they will not work properly and the generator and wiring harness may be damaged."

The regular contacts and the cutout contacts are cleaned in different ways because they are made of different materials. Don't use fine grit sandpaper! The regular points are made of tungsten, but the cut-out points are made of silver. They require different cleaning materials.

Also, adjusting the contacts depends in some way on ambient temperature. This I found too complicated for me... So that is why I chose the pre-adjusted and pre-cleaned regulator.

Here is more from Moss: "The regulator relay should be adjusted so that the points open at 13 to 14 volts. The cut-out should be adjusted so that the points open at 10 to 12 volts. We realize that these are not the specifications in the workshop manuals for cars equipped with these regulators. They are more consdservative, and perfectly functional."

AGAIN, however, there are folks in this forum who can lead you through the process and who will have good advice for you regarding Regulators. Randall, especially, questions the Moss method and thinks the Lucas instructions are better.

 

[M_Pied_Lourd]

Not sure if it is relevant, but there are a couple of simple youtube videos on the Moss channel regarding generators and control boxes.

https://www.youtube.com/user/MossMotorsCom/videos?query=generator

Cheers,
Tush

 

[6TTR3A]

<span style="font-size: 11pt"><span style="color: #003300">Moss does OK for a lot of things, but I wasn't comfortable with their regulator "adjustment" method.
I followed the Lucas method some 20 odd years ago, and it took me HOURS to get it right.

.......I would recheck the numbers every 5 years or so and they never varied until last year.

.......I tried to clean and reset the regulator again with absolutely no success this time.

...... I'm not sure if was my old age or the regulators old age, so I shipped off to Wilton & had a solid state unit installed.

........Unless you pop the Lucas cover no one knows except me!!

FRank </span></span>

 

[TR3driver]

Also, adjusting the contacts depends in some way on ambient temperature.

To clarify a bit, the contact adjustment remains the same regardless of ambient temperature. It's the spring (voltage) adjustment on the back that varies slightly. The manual will have a table (or formula) that changes the target voltage depending on ambient temperature.

The steps are pretty coarse, so just guess at the current temperature and use that. 20C is 68F and there is no correction required if you are within 10C (18F) of that temperature.

So if the weather is between 50F and 86F, don't worry about the correction. If the weather is over 86F and not over 104F, you can subtract 0.3 volts from the given set point. If you are crazy enough to be working on the car when it's over 104F, knock off 0.6 volts

 

[TR3driver]

.......I tried to clean and reset the regulator again with absolutely no success this time.

...... I'm not sure if was my old age or the regulators old age,

IMO, if they were bad enough to keep the unit from working, then the only way to really service the points is to disassemble the relay so you can clean, burnish and inspect (under a magnifying glass) the points separately. If the contact surfaces are damaged so badly that you cannot get a smooth clean surface, they will have to be replaced. In extreme cases, it may be necessary to use a coarser abrasive to remove some of the contact, but then that must be followed by successively finer abrasives to get back to a microscopically smooth surface.

The other problem is that my point burnishing tool is too thick to go between the contacts unless I back off the adjustable contact.

 

[Member 10617]

... which all goes to explain why I whimped out and installed a Moss pre-cleaned, pre-adjusted, and tested Regulator.

 

[TR3driver]

Which is fine, I guess, if you can afford to keep replacing parts instead of performing minor, routine maintenance

But TS13571L is still wearing it's original 1956 control box & generator; and I'm going to see how long I can keep it that way. When it does finally die, I'll install a 40 amp mini alternator and be done with it.

 

[Member 10617]

Randall,

Actually, I tried maintenance on the alternator and only succeeded in making the thing completely inoperable. That's one part I gladly leave to others to repair or provide.

I thought that you had already switched to an alternator... Those who have seem to think it was a smart move.

 

[TR3driver]

I thought that you had already switched to an alternator...

Well, I did, twice, on previous TRs. It is a clear improvement, in much the same way that a Miata is better than a TR. But, it is not a 50's British sports car (which were famous for dead batteries among other things).

Just about every single aspect of a TR3 could be "improved" in some fashion. But as I see it, whether and how much to "improve" is a personal decision that every owner must make for himself. As I get older, I find that my taste tends more towards "original". Within reason, of course :laugh:

"Moderation in all things ... Including moderation."

 

[Member 10617]

For almost everthing on the TR, I go for "stock" -- original -- if possible. I think it's important to keep the look and the feel of the original. But, sometimes, as you say, it's hard to pass up an improvment, especially if the car is going to be taken down the road and not just shown.

 

[Andrew Mace]

...TS13571L is still wearing it's original 1956 control box & generator; and I'm going to see how long I can keep it that way....

Similarly, GA41429LDL (Herald sedan) continues along with its original November 1961 generator (rebuilt and doing very well), and I managed to score, through a fellow Herald buddy, a November 1961 control box in good condition to go with it. Frankly, I'm not all that trusting of the "new" control box I had to put on a few years ago, but it seems to be holding its own!

 

[angelfj1]

I have never understood the exact relationship between the Generator and voltage regulator on a tr3. My question is should I replace the regulator and generator as a unit if I suspect the generator is the problem. The generator light came on while I was driving, and perhaps I should have unplugged it as I drove home, but I did not. Anyway, I could hear a mild rattling noise coming from the generator, so I pulled it. Now as I am putting on a new generator the thought came to me should I replace the regulator also. My concern is what if the generator shorted out and that fried the regulator is that going to now toast this new generator. Thoughts?
steve

Steve: During the TRA meet I realized that my LUCAS control box was not operating properly. Most of the time we were running on battery even though the generator was fine. At one point the battery voltage got so low that the ignition system was failing to fire the spark plugs. When we returned we attempted to adjust the two relays and clean up the contacts. This helped a little, but operation was not reliable. I ordered a new box from Moss. This was right off the shelf not tested, not cleaned. It worked right out of the box.

I question the practice of offering a tested and cleaned box at a premium price. First of all, each installation is unique and for optimum success the box should be tested with the generator in your car. Second, it takes approx. 1 minute to "clean" the contacts. Perhaps we were lucky that the box operated correctly, but I was satisfied.

<span style="font-weight: bold">Update:</span> As a retired electrical engineer, I knew that any electro-mechanical device like these control boxes will eventually require maintenance, contact cleaning, testing, etc. I was prepared to deal with this as a routine PM requirement and then I became aware of Wilton Auto Electric, in Wilton, NH. They have designed a solid state voltage regulator for DC generators. They have designs for most of the old cars originally equipped with DC generators, including Autolite, Bosch, Delco Remy and Lucas. Yes. Lucas.
Details here: https://wiltonae.com/home/index.aspx

So, I called WAE and spoke to Bob Jeffers. He said he had supplied units for hundreds of LBC's including all of the TR range. He gave me this link for and MGA conversion: https://mgaguru.com/mgtech/electric/et232.htm which provide some additional details and photos. All Bob needs is your donor box. It doesn't have to be functional. In fact, it can be empty. Bob removes the guts and mounts his solid state unit inside. From the outside of the box there is no indication that a modern solid state units is hiding inside. Bob charges $80 for the conversion plus $5 shipping.

I have been driving with this unit in place for 3 weeks and it works great!

<span style="font-weight: bold">BEFORE & AFTER</span>

<span style="font-weight: bold">CONVERTED CONTROL BOX WITH COVER IN PLACE</span>

 

[MGTF1250Dave]

Aloha All,

Like Frank, I have been using a solid state conversion in my TR3. I'm not sure if the Lucas "box" was original to the car, but the date of production by Lucas was around the time the car was assembled. When it failed I first replaced it with an after market voltage regulator. I decided to have the failed unit converted by Bob at Wilton Auto Electrics as a back up. However when I got the conversion I opted to use it in the car. That was about five years ago. As you can see in the photo of "Grey Lady", the the Lucas cover installed it looks original, but it is now maintenance free.

Before the conversion can be made you will need to know the maximum designed amperage output of the car's generator. The solid state circuitry is adjusted to make sure that the voltage regulator and generator work together without overloading one or the other.