Starter motor Bendix

[Deaconbrody]

I Have a Morris Minor with a 1300cc Morris Marina engine fitted.

Recently the starter motor has been very sluggish and eventually gave up completely.

I removed the starter motor stripped it down and did manage to get it working again by really just cleaning it and pulling the brush springs out a bit as they seemed not to have much spring left in them! However as the whole unit looked as if it had seen better days I decided to renew it.

The unit was a Lucas 25148E with a 5 inch pitch flange and 10 tooth Bendix.

I managed to track down a new starter from a well known supplier. However when I received it it had a 9 tooth Bendix.

I contacted them and was informed my car should indeed have a 9 tooth Bendix.

I fitted the new starter motor and while doing so checked the starter ring which showed no signs of the teeth being chewed or damaged.

The new starter motor was tested in the car and operated satisfactorily with with no strange noises or crunches.

Any comments for my peace of mind would be greatly appreciated.

Ian

[bmcecosse]

Sounds good to me ... what,s the problem ?

[Deaconbrody]

Thanks for the reply BMC.

No problem really, just how can a 9 tooth Bendix or a 10 tooth Bendix work on the same starter ring.

Should they not be matched to mesh properly.

Just would like some reassurance that it is okay to use either a 9 or 10 tooth Bendix
on my engine.

Ian

[philthehill]

I have just checked a Minor starter motor bendix and it has 9 teeth.
The Marina has a much bigger starter ring and you may have the Marina starter motor fitted.
When this rain stops I will go and check the pitch of the teeth on the Marina flywheel I have and also see what the meshing is like with the Minor Bendix and report back.
The pitch on a Minor flywheel is 8mm measured at the tooth tip.
The pitch on a Minor 9 tooth Bendix is 10mm measured at the tooth tip. What is the pitch on your 10 tooth Bendix?
The Minor 9 tooth Bendix and starter ring gear mesh correctly when brought together and run around the ring gear.
Phil

[bmcecosse]

There are 9, 10 and 11 tooth Bendix - all will match. But as above - larger ring and smaller Bendix gives your starter more mechanical advantage to crank the larger engine, although possibly at a lower speed. But it works - so don't worry!

[Deaconbrody]

Hey thanks guys,

For all the tech info it is great to read the differences between the Morris Minor and Marina parts.

Phil the pitch between the teeth on the 10 tooth Bendix is 11mm.

BMC, thanks for the info on the 9, 10 and 11 tooth Bendix and the explanation.

Ian

[philthehill]

For completion - the pitch of the starter ring teeth on a Marina flywheel is 8mm at the tip.