Fitting alternator

[Peted7202]

I've completely stripped my 58 1000 and currently restoring it. It is postive earth. When I rebuild I want to install an alternator. It currently has points setup.

1. What is the alternator spec?
2. What is the rebuild procedure?

I am aware of the battery rotation and no need for the control box. Is it as simple as installing and wiring the alternator without affecting any other components?

[svenedin]

I don't have an alternator and I've kept to positive earth and dynamo but I do know you can buy a kit from ESM that includes the alternator, a mounting bracket and a loom to make installation straightforward.

The alternator contains its own charge regulator which is why the RB106 becomes redundant.

If your fuel pump and distributor are still points then nothing is affected by a switch to negative earth except certain (not all) heater fan motors will run backwards and need the wires swapped over (some heater fan motors have both field coils and rotor coils whereas others use a permanent magnet for the field)

If you have an electronic ignition system or an electronic fuel pump these will not work if the car's polarity is changed.

A professionally rebuilt Lucas dynamo (not a Far East copy) and a genuine Lucas RB106 (or an RB106 with electronic internals) will give excellent service and I really see no need to ruin the original appearance of the engine bay with an alternator! The copy RB106 units from overseas are total rubbish and I think they give dynamos a bad name, not the dynamos themselves.

Stephen

[geoberni]

Basically get a kit which will have hopefully appropriate instructions and parts, including mountings.

Depending on the age of your fuel pump, assuming an SU Points one, it may or may not be dual polarity.
Note: Electronic ones are always polarity sensitive and cannot be changed, without changing the circuit board inside it. SU do provide conversion kits, no need to replace whole pump.

Traditionally, SU tinkered with different arc suppression devices across the pump points, some of which are polarity sensitive. The simple thing to do is take the cap off and see what's under it. The early attempts, of fitting a Capacitor or Zener Diode didn't have much of a noticeable effect so quite honestly, if you find one under the cap, you can remove it. I've serviced 2 pumps recently, I won't bore you with why, they were both post 1985 pumps, but neither had any arc suppression device fitted.
More recent versions include a special type of Zener Diode which is NOT polarity sensitive and that is what is in their latest overhaul kits.
See this link, the special 2 way diode is the blue thing with the connecting terminations.
https://sucarb.co.uk/su-fuel-pumps-spar ... -1985.html

I assume there are no additional Positive Earth items, such as vintage 1960/70s radio. If there is, and you're lucky, it could have a switch on the back somewhere to change the polarity. Check the labels.

Stephen has covered the rest.
But like him, I would just say don't fit an alternator because you feel you have to, or it's the 'done thing to do'.
Do you need the extra power?
If you do, then that's fine, but don't change it just because your existing system hasn't been maintained or adjusted for many years, and it perhaps isn't giving everything it could.

[geoberni]

A professionally rebuilt Lucas dynamo (not a Far East copy) and a genuine Lucas RB106 (or an RB106 with electronic internals) will give excellent service and I really see no need to ruin the original appearance of the engine bay with an alternator! The copy RB106 units from overseas are total rubbish and I think they give dynamos a bad name, not the dynamos themselves.

Stephen

I think with many people the 'Bad Name' comes from the recent, slightly younger, owner who is of the 'replace it rather than maintain it' generation.
They don't understand the maintenance requirements of a mid last century vehicle, being too used to the drive until it breaks designs of 1980s onwards.
How many people go for alternator conversion without carrying out any checks of the system, or replace an original RB106 that just needs cleaning and resetting with a cheap copy and then slag off their dynamo system.....

Yes there are times an alternator is necessary; I considered it myself when I got my car and found it fitted with Halogen Headlamps, but replacing them with LEDs dramatically reduced the current draw of driving with lights on

[svenedin]

I totally agree Geoberni. I have had several dynamos rebuilt over the last 34 years of Morris ownership. Most recently by a wonderful old company called Robson and Francis rewinds in Streatham, London. I was lucky enough to be given a tour of their workshops to see everything from giant motors for cranes to Lucas dynamos and even pre-war magnetos being carefully rebuilt. The chap who showed me round was of the opinion that a well maintained dynamo will outlast an alternator. They really give very little trouble and as you say, LED headlights greatly reduce the load. The RB106 is a different matter and those far more expert than me have argued that the 2 bobbin design is something of a compromise and it can be somewhat cruel to the battery. I replaced the innards of my RB106 with electronics and it works beautifully. The appearance is original even if the insides are not. I have of course retained a NOS RB106 should it be essential to return my car to original spec.

The fuel pumps that were designed for an arc suppression device have a hump in the cap to accommodate this but the only way to tell for sure is to take the cap off as you say.

IMG_9158.jpeg (1.41 MiB) Viewed 1936 times

[geoberni]

The fuel pumps that were designed for an arc suppression device have a hump in the cap to accommodate this but the only way to tell for sure is to take the cap off as you say.

IMG_9158.jpeg

Actually, one of my pumps, the one that was originally on my car, had a hump, but no Capacitor, it was probably left out at a previous rebuild.
It was an awful 'hammerite' silver all over...

The hump was intended for the Capacitor as it was so large, but the latter attempt as the Zener Diode solution does not need all that space so fits under the regular cap.

There's a good recent write up here on the MGT Society website: https://ttypes.org/the-su-pump-revisited/
For example the author even explained the difference between an AUA66 and an AUA25...

[oliver90owner]

Does the fuel gauge meter require connection reversal on that model?

Anyone mentioned the ignition coil connections?

An alternator is so much better for output at low engine speed giving full output (for maintaining the battery in a full state of charge) - particularly important for short trips in dark, wet, cold stop-start driving or with screen heaters. Modern batteries do not tolerate partial discharge (like the earlier battery technology of the mid to late 20th century) - they have a reduced number of (equivalent) charge-discharge cycles while having a much improved CCA rating compared to earlier years.

[geoberni]

Does the fuel gauge meter require connection reversal on that model?

Anyone mentioned the ignition coil connections?

An alternator is so much better for output at low engine speed giving full output (for maintaining the battery in a full state of charge) - particularly important for short trips in dark, wet, cold stop-start driving or with screen heaters. Modern batteries do not tolerate partial discharge (like the earlier battery technology of the mid to late 20th century) - they have a reduced number of (equivalent) charge-discharge cycles while having a much improved CCA rating compared to earlier years.

I agree that alternators are better at low revs, such as idling, that's one reason why they were often the required fit for Police vehicles. Not particularly relevant with the typical Police Minor, but in the early days of Motorway patrols, iconic cars such as Ford Zephyrs were initially found to be inadequate at accident locations, because idling with Blue Lights running killed the battery. An alternator fit soon fixed the problem.

I would fit an alternator if I had the need for the extra amperage, or operational needs, like sitting there at night in traffic with the car idling, but I don't. My car is a pleasure drive, not a daily commute.

I'm not aware of any issues with fuel gauges, either in instructions for alternator fitting nor with people complaining afterwards in forums such as this, and as I mentioned

Basically get a kit which will have hopefully appropriate instructions and parts, including mountings.

changing the Coil connections is usually part of the standard instructions

[Tinasminor]

While looking to replace my faulty neg earth dynamo I've seen a brand new one for sale at ESM for £63 and a brand new alternator for £53, I have also asked my local auto electric place if they could repair/service my original one which they can but the cost will be between £90 - £110. So it seems a no brainer to me that if my dynamo is unservicable I.e after fitting new brushes etc i will buy the alternator kit.
Steve.

[Jim McCrae]

I replaced my noisy dynamo with an alternator as this was significantly cheaper than a new dynamo. The instructions supplied with the alternator were quite clear and fitting it was straightforward. There are few changes required to the wiring and the control box can be retained (if you wish) as a connect to house the new connections.

I would strongly advise you to change the battery for one with the terminals in the correct orientation. Simply turning the battery around puts the terminals very close to the retaining bar and risks shorting out the battery.

Jim

[geoberni]

I would strongly advise you to change the battery for one with the terminals in the correct orientation. Simply turning the battery around puts the terminals very close to the retaining bar and risks shorting out the battery.

Jim

IMHO, replacing a perfectly good battery is an unnecessary cost; just wait until in needs doing.
My Basil had the terminals to the front when I got him, I decided I'd just add some insulating tape to the edge of the bar.
The only period of 'risk' is when removing or refitting the bar.
I've seen some cars with the retaining bar slightly 'relieved' on the edge to give extra clearance, but a bit of tape does the job just as well.

If you've got an original painted bar, so long as the paint is in good condition, that will insulate it just fine; Basil's isn't an original bar unfortunately.