Starter Motor Refurb

[PhilM]

Although I've now had my 1937 two seater (not Opal) project at home for several weeks now, I'm still in the process of getting the garage space sorted out in order to start work on the major items. I have a large double garage but the A7 shares the space with the Midget, a lathe and a small Mill so space is at a premium. This probably means that anything like engine out or body off chassis work is now going to have to wait till the spring when I can bear to put the Midget outside under a decent cover.

However being an impatient sort I've started to remove bite sized bits and pieces which can be overhauled and refurbished on the bench, the latest of which is the starter motor.  
On disassembly of the motor I found a bit of a mess, everything is covered in what looks like thick copper grease, which I guess is dust from commutator / brushes. 





I would guess that this stuff is quite conductive so I'd like to remove as much of it as is possible.
Is there something I can safely wash the area around the field coils out with?
I'm reluctant to use any strong solvents in case it adversely affects the insulation.

Any observations will be gladly received.

Many thanks,    .... Phil.

[bob46320]

Damp won't matter for a short period, so I would wash with warm soapy water and a paint brush, and then dry it out gently in the house next to a radiator or log stove etc. The windings are "massive", its not like cleaning a cut-out bobin.

[Steve Jones]

When the internals of a starter or dynamo need cleaning I simply wash them out with brake cleaner worked into the corners with a small paint brush. The residue evaporates that quickly it's not going to do anything harmful to any insulation.

Looking at the photo, a new set of brushes won't do it any harm but I imagine you're aware of that.
Steve

[PhilM]

Many thanks to both of you for your suggestions, i'll see how hot water and soap work firstly as I don't have any brake cleaner to hand.
I may be looking for a new armature though, I've just set it up in the lathe to skim the commutator and found that the shaft has one heck of a bend in it, not sure how that would have happend but the runout at the far end where the pinion operates is nearly 5mm.

Thanks again,    .... Phil.

[bob46320]

Did you mount the armature between centres and still get 5mm run out ?

[PhilM]

Did you mount the armature between centres and still get 5mm run out ?

Yes, I've tried between centres, it would appear the whole armature is a bit banana shaped.
I've no idea how it would have ended up like that as the shaft seems rather hard, I certainly can't "coax" it any straighter.

..... Phil.

[squeak]

Although I've now had my 1937 two seater (not Opal) project at home for several weeks now, I'm still in the process of getting the garage space sorted out in order to start work on the major items. I have a large double garage but the A7 shares the space with the Midget, a lathe and a small Mill so space is at a premium. This probably means that anything like engine out or body off chassis work is now going to have to wait till the spring when I can bear to put the Midget outside under a decent cover.

However being an impatient sort I've started to remove bite sized bits and pieces which can be overhauled and refurbished on the bench, the latest of which is the starter motor.  
On disassembly of the motor I found a bit of a mess, everything is covered in what looks like thick copper grease, which I guess is dust from commutator / brushes. 





I would guess that this stuff is quite conductive so I'd like to remove as much of it as is possible.
Is there something I can safely wash the area around the field coils out with?
I'm reluctant to use any strong solvents in case it adversely affects the insulation.

Any observations will be gladly received.

Many thanks,    .... Phil.

there seems to be quite a lot of wear in the arm and spindle that holds the left brush

[PhilM]

there seems to be quite a lot of wear in the arm and spindle that holds the left brush

Yes, you're right, the carrier likes to jump off of the pin given a chance, not sure if I can replace or repair it at the moment, we'll see!

..... Phil.

[Jeff Taylor]

Phil,

The early 1935 - 1937 Morris 8 Lucas M35A starter motors have the same pivoting carrier arm / spindle arrangement and suffer similar serious wear problems after 80 + years. If you have a lathe, I'm sure the carrier arms could be bushed as you would with a grandfather clock mechanism. I would think the spindle wear could be slightly more difficult to address as the spindles are riveted from the outer side of the rear cover plate. I'd be interested to hear how you intend to overcome this problem.

[bob46320]

To 'straighten the motor shaft, you will need a press. Support the armature with 2 'V' blocks, one at the commutator end close to the commutator, and the other at the "bendix" end as near to the end as practical. A third large "V" block should go between the press ram and the armature windings at the bendix end.

A motor shaft is easily bent if the engine is seized / hydraulically locked due to a head gasket water leak - How do I know that !!