Austin Champ, The Story of One Starter Motor

This is not a full treatise on starter motors but the story of one that didn't work and was got working.
Notes: in the manuals 'D.E.' stands for 'Driving end' and 'C.E.' for 'Cover End'.
The No. 1 starter motors were the original type fitted at the factory and sometimes referred to as, (C.E.) 'the flat top' type, as against later ones fitted as replacements that had a rounded end on the top at the rear and sometimes referred to as, 'the Ferret type'.

A No. 1, Mk 1 starter motor (shown below) would spin-up but not turn the engine and then spin down. (the illustration below is from EMER D572, June 1955, page 263 & EMER D574, page 27. Also, EMER, POWER S 522, page 57 refers).

B40, B60, B80 starter motor 1
B40, B60, B80 starter motor 1
The motor was removed and the rear cover (part 8 on above) and the small cover held by two nuts (shown arrowed on the above) taken off. The motor was refitted and tried and it could be seen that the main shaft did not go all the way in, also the main shaft could not be pushed in by hand. The motor was removed from the Champ.
Removing the small cover exposes a collar with a lock nut inside the collar on the end of the main shaft. The collar on this motor was loose and could be turned by hand. The adjustment for the collar is shown above as dimension 'A', which is 1.862-1.886" (47.3-47.9 mm) - a special tool (see below) had to be made to go inside the collar to tighten the lock nut. Next check: with the motor out the end of the shaft was pushed right in to make sure it was free, it was. Thinking the loose collar could have been the problem the motor was refitted but it was exactly the same.

Made up tool to set collar on Austin Champ B40, B60, B80 starter motor

Next check: the pin (part 20) releases the trigger (part 17) to allow the contacts to close when the main shaft goes forward. The shaft was pushed right in and the pin came up and released the trigger and the contact plate could be pushed forward, so that was OK.

The photo on the left shows the Switch trip gap,(arrowed red, which is adjustable, gap is 3 mm to 5 mm, this one was 4.5 mm. The small cover can be seen on the end of the main shaft.
The photo on the right shows the trigger (arrowed yellow) that needs to be checked both that it is free to move up and back down - it needs to be held up to check if the main shaft will push all the way in. This photo also shows the nut with the split pin to adjust the 3 to 5 mm adjustment.
Also check the contacts are clean at the 3 to 5 mm gap (switch trip-adjustment).
switch trip adjustment Austin Champ B40, B60, B80 starter motor Trigger position on Austin Champ B40, B60, B80 starter motor
The motor was refitted and was no better than when I started.
A guess was made that the fault on the starter motor was the pinion. The original pinion had some wear - I have seen worse that have worked - and there was no obvious damage, but thinking the pinion could be the problem, perhaps, the lead-in, the pinion was tidied up by hand-filing but that didn't work.
The pinion was changed for a known good one and the starter motor worked.
The pinion is very easy to change. Push down on the Retaining Plug (1) (in lower left photo, second part up) and push out the Pin but keeping control because the spring (seen near items 1 & 2 in main diagram) is under pressure. Remove the Pinion Key (3) through the pinion, pull out the spring and the pinion will slide off. Assembly is in reverse order but getting the slotted part over/lined up, with the key (3) can sometimes be awkward, see photo below right to see the key (3) with the slotted part.

If you have any thoughts on this page they would be most welcome.

Pinion parts Austin Champ B40, B60, B80 starter motor Pinion spring and key Austin Champ B40, B60, B80 starter motor