Starter Motor Questions

[RupertW]

Hello all, I have a few questions about a starter motor I'm trying to revive on my 1934 Box Saloon and would appreciate some pointers. 

Firstly, underneath the armature inspection cover there is some sort of gasket which has become extremely brittle and disintegrated on removal. Is the purpose of this simply to keep muck and rubbish out of the inner workings, and can I replace it with standard gasket paper? 

Secondly, in the workshop manual it says to grease the armature shaft splines, but not the 'quickthread'. I can't work out why I wouldn't grease the quickthread, and it appears to already be lightly oiled. 

Finally, I'm a bit concerned about why the starter motor originally failed. It was long enough ago that I only recall lots of smoke and rapidly disconnecting the battery, followed by the top lever being absolutely seized/melted in place. The copper contact button on top of the motor was absolutely filthy and has taken some cleaning, but I'm not sure if this would be a cause or a symptom?? I've ordered myself a battery isolator as a precaution should it happen again! 

Any help much appreciated as always!

[John Mason]

Hi Rupert, The cause of the smoke etc maybe because of a failed starter motor switch that has stuck in the on position causing heat in the switch and sort of welding the contacts together. Clean the contact on the top of the motor use jump leads one to the body and the other to touch the button on the top and see if it spins (hold the motor in a vice as when/if it spins it does it with some torque). As to the quick thread do no grease this as it only encourages dirt and dust from the clutch to stick to it and thus in time stops the starter gear moving down the shaft and engaging with the flywheel. I do not know what the paper gasket is for and cannot help with that.

Yours John Mason.

[Nick Turley]

Hi Rupert

The paper thing is simply not needed.
The Bendix thread should be dry and very clean oil - or grease will stop it working !

Good luck with it.

[Bob Culver]

The switch lever becomes worn on pivot pin, tilts, and shorts to the body. You can test the motor wih a a heavy lead but note that it reacts very violently and needs to be firmly held if off the car. Ideally wear eye protection for sparks.
The switch arm should not be able to be much waggled sideways.
When tinkering, the tension of the clip which captures the pinion is critical so do not be tmpted to alter.

[Jeff Taylor]

I agree with Nick, in 40 odd years of messing about with various 1930's Lucas starter motors I've never come across one with a gasket beneath the inspection cover band - they never had them from new. I've always used a light dusting of dry powdered graphite on an absolutely clean and dry Bendix quickthread - you can buy small puffer bottles for lubricating locks from good hardware stores / ebay / amazon etc.

Personally I'd fit a new starter switch if you haven't already done so - The Seven Workshop have them in stock AE0334 for £33.60

[RupertW]

Thanks all, hopefully there's a picture below showing what the gasket looks like. As mentioned it's extremely brittle and fell apart on removal. 
My old pinion retaining spring was broken so I have new one - as far as I can see there's no adjustment for it and it just sits in place? 
I also have a new switch unit, as the old one was certainly beyond salvage! 


  IMG_20200828_180123RS.jpg (Size: 54.56 KB / Downloads: 157)

[dickie65]

The gasket is held on with the copper rivets, the gasket helps to keep oil out of the works.
I have had a few starter motors and dynamos which have had the original gasket on them.
I have been working on Austin Sevens since 1975 when bits were easy to find and mostly original.