Lucas Rebuilt Starter Motor M35G

[svenedin]

During my starter troubles yesterday (solenoid connections). I realised the starter motor on my car is rather elderly (1969) and original to the car. I have never touched it for maintenance in my 36 year tenure of ownership. It's fine but a bit noisy and given how long it's been in use I think it deserves a full rebuild and a rest for the time being. I don't want it to give up on me abroad for instance.

I wanted to buy a genuine Lucas M35G (or M35J) 5" starter so that it could go on the car and then I can get the other starter rebuilt at leisure. I was not prepared to buy a Far East copy.

I looked around and found MGOC spares were selling genuine Lucas M35G starters rebuilt in England and sold by Lucas Classic. These are outright sales with no exchange necessary. I ordered and it was delivered next day. It is now on the car and works beautifully.

If anybody needs a starter next day and wants a genuine Lucas unit this is worth considering though they are not cheap. They have a 2 year warranty as well. https://www.mgocspares.co.uk/product/gx ... 0/719/1920

M35G has a metal band that is clamped on and can be removed to access the brushes. M35J (later) has no band and the brushes must be accessed by removing the end plate. Tip: the clamp pinch bolt may foul the engine block. It can be loosened and the metal band rotated but make sure it is covering the windows in the housing.

Stephen

IMG_2657.jpeg (3.47 MiB) Viewed 53821 times

IMG_2659.jpeg (3.27 MiB) Viewed 53821 times

IMG_2660.jpeg (2.42 MiB) Viewed 53821 times

IMG_2661.jpeg (1.6 MiB) Viewed 53821 times

[geoberni]

M35G has a metal band that is clamped on and can be removed to access the brushes. M35J (later) has no band and the brushes must be accessed by removing the end plate. Tip: the clamp pinch bolt may foul the engine block. It can be loosened and the metal band rotated but make sure it is covering the windows in the housing.

Stephen

For anyone wondering why the M35J doesn't have a band to give easy access to the Commutator, it's because the 'conventional' commutator is around the armature with the rectangular/square brushes pressing in towards the spindle of the armature, just as with the typical Starter motor.

The M35J is a very different beast, with 'segment' shape brushes pressing on what is called a 'face type' commutator.

One reason to check which you have before deciding to buy replacement brushes

M35J.JPG (73.01 KiB) Viewed 53785 times

.
.

Incidentally, I asked Google AI when Lucas launched the M35J, my curiosity arising because I knew Stephen likes originality.. .
If your original is a 35G, it's probably one of the last to be so fitted.

Google M35J.JPG (75.56 KiB) Viewed 53778 times

[svenedin]

Thanks Berni. That's interesting.

The starter I have just fitted in my car is an M35G which is incidentally dated 1968 I think (I didn't take a photo of the date).

The starter I removed from the car is indeed an M35J and is dated 12/69. I don't think it can be the original after all because my car was built in March 1969. Nonetheless it is the same year.

I did some reading on Lucas starters. The M35G and M35J are 35 because the yoke is 3.5" in diameter. The M45 is 4.5" and the M418 is 4 1/8". Just a bit of trivia. Normally the M35G and M35J are known as 5" starters and they are marked as such on the end plate.

Stephen

IMG_2670.jpeg (2.42 MiB) Viewed 53764 times

IMG_2671.jpeg (1.38 MiB) Viewed 53762 times

[svenedin]

Berni,

Do you know why Lucas changed to the face-type commentator in the M35J? Does it have advantages?

In practical use the M35G and M35J types are interchangeable and it does not seem to make any difference in terms of starting the car.

For maintenance, the G type with the metal band is easier to service but perhaps it is slightly more vulnerable to getting wet internally. The starter is mounted very low on the engine and is prone to getting wet which may or may not have had something to do with my starting problems. About a week before the starting problems I had to drive through an area where the road was flooded. This wasn't very deep and I drove slowly but the engine bay floor did get very wet.

Reading various Lucas documents I learned that the pre-engaged type starter has been around for a very long time. I thought it was a more modern invention. Lucas calls the inertia type starters like the M35G and M35J "crash" starters because they crash into mesh like a crash gearbox.

Stephen

[geoberni]

Berni,

Do you know why Lucas changed to the face-type commentator in the M35J? Does it have advantages?

In practical use the M35G and M35J types are interchangeable and it does not seem to make any difference in terms of starting the car.

For maintenance, the G type with the metal band is easier to service but perhaps it is slightly more vulnerable to getting wet internally. The starter is mounted very low on the engine and is prone to getting wet which may or may not have had something to do with my starting problems. About a week before the starting problems I had to drive through an area where the road was flooded. This wasn't very deep and I drove slowly but the engine bay floor did get very wet.

Reading various Lucas documents I learned that the pre-engaged type starter has been around for a very long time. I thought it was a more modern invention. Lucas calls the inertia type starters like the M35G and M35J "crash" starters because they crash into mesh like a crash gearbox.

Stephen

Sorry for slow response, I'm currently away and busy plus poor WiFi service.
The early part of my RAF career was depot maintenance of motorised equipment and I never saw one used.
The only thing I can think of is it being an attempt to innovate a solution to some of the inherent shortcomings of brushed motors. A conventional commutator is not particularly efficient in electrical terms, with losses from arching etc.
Brush bedding to get a good fit of brushes to the curve of the commutator can take many hours.
We used fine grit paper between commutator and brush to shape the brushes and then they would be connected to power and run at slow speed for quite a few hours to get a good fit. Only then would motors or generators be run at normal operating speeds for actual testing.
The flat commutator should be easier to match the surfaces.

[svenedin]

Thanks Berni. That makes a lot of sense.

Stephen