Starter Motor Issue

[Bob Culver]

In the 1960s the later C40 Lucas dynamos had a much harder grade of brush not to be used in the earlier C40s. Something anyone filing down bruhes to fit  Seven shoud be aware of.

[Dave Mann]

Steve is correct, my earlier posting quotes the dimensional error.

[Bob Olive]

At the risk of being a pain, can I re-open this thread?
Until recently the starter on my '33 AH tourer has always performed as it should. Until when I last took the car out on a local run just a few weeks ago, it started perfectly well. Post-lunch, it merely gently whirred and whizzed (simulating a jammed starter noise) but, it was not engaging. Fortunately the car started immediately on the handle.
Removed it for inspection and nothing apparently wrong - as far as I could tell. Brushes with plenty of meat on and well bedded in, commutator clean and bright, no debris or junk inside. Same symptoms when tested OFF the car, on the same battery (so no thoughts of dodgy earth connection), but still no satisfying 'clunk' as I would expect when it should 'throw out' and engage. Tried my spare (same good condition as the other) and same whirring/whizzing noise and the same languid spinning - once again all on the same battery...
Must therefore be battery I thought, but it registers about 6.1v (off load) and seems only to drop only about 0.5v when starter pulled.
Despite that reading, it MUST be battery, right? BTW my meter is a small - but modern - device which I think is accurate.
What have I missed?
Be grateful for any ideas, suggestions or thoughts.
Thanks in anticipation.

[Reckless Rat]

Sometimes the pinion retaining spring can be over enthusiastic and prevents the bendix from throwing the gear into mesh with the flywheel. I encountered this after a broken spring - the replacement was just a bit too tight and was causing this problem. It's an easy fix.

[Ivor Hawkins]

Have you oiled the bendix? If so, clean it all off with paraffin and watch the difference!

[Bob Kneale]

Also check the 'live' lead connection at the connector tag where it screws into the starter switch. If it's just crimped onto the cable it can get oil soaked with a dramatic loss of conductivity. It happened to me, and I now always solder the connection by dunking the end of the cable in a bath of solder to form a solid conductor that fits snugly into the tag which is sweated on - with lots of heat and flux!

[David Stepney]

I had a similar problem several weeks ago. Cleaned the thread on the bendix and all has been well since. Don't be tempted to oil it after cleaning! They are supposed to run dry.

[Jeff Taylor]

As mentioned above by Ivor and David, the bendix spiral thread should under no circumstances be oiled or greased. Having removed any traces of oil or grease it should however be lubricated with dry graphite powder - the stuff you're supposed to use to lubricate door locks - available from good hardware stores and Amazon - the bottle shown below can be sourced there.


  Screenshot 2022-06-13 at 22.54.27.png (Size: 219.28 KB / Downloads: 158)

[Bob Olive]

Thanks everyone, I'll look at all those issues and report back.

[Bob Olive]

OK - re my problem above stated, here's what happened. Stripped the whole Bendix gear down, cleaned throughly with brake cleaner, reassembled and refitted.
As forecast by several of you, seems like dirt/oil was the first part of the problem - never done that before... Turned engine over nicely - and released - without any trouble without ignition on... BUT, with ignition on, started and then failed to completely disengage. Couldn't see anything wrongly assembled, so tried spare - worked perfectly. So final conclusion is dirt/oil plus maybe Reckless' thoughts on dodgy pinion spring.

Will look at spring replacement and report further in due course. BTW I have ordered graphite powder as recommended to help things along.

Grateful thanks as ever to all and sundry, where would some of us less competent folk be without the forum?