Ignition wiring

[Campbell Sutton]

Hi everybody,
I have a late 1928 A7 chummy, (first of the coil ignition) 
I am currently tidying up the wiring and I noticed the ignition feed has been wired off the bacon slicer starter switch. I took the starter switch out to inspect and it was covered in oil, which would explain the sluggish starter motor. My question is should the ignition be wired off the early baconslicer or directly back to the 6v battery? I know the later cars with foward facing starter were wired like this, however the switch was not exposed to oil etc from flywheel. My gut tells me oil on the ignition feed contact would add resistance and effect voltage output.

[stuartu]

It would appear that Longbridge's guts were aligned with yours. The answer can be found in one of the wiring diagrams here:

http://www.da7c.co.uk/technical_torque_a...Wiring.pdf

As a matter of almost equal interest, I wonder if the amount of oil on your starter switch is significant? Perhaps it has accumulated over aeons or perhaps it might bear further investigation in due course.

Regards,

Stuart

[goodwoodweirdo]

stuartu, many thanks for sharing the link / pdf

[Campbell Sutton]

Thanks Stuart, that makes good sense.

Regards 
Campbell Sutton

[k8207418]

Some info here
Wiring Info
https://www.austinsevenfriends.co.uk/for...o#pid86437

[John Cornforth]

Hi

If the ignition feed is taken from the battery side of the starter switch (as per early 30s onwards), the state of that switch won't affect the ignition but could of course affect the starter. Engine oil is a pretty good insulator, so it's no problem if it coats the outside of a terminal as long as it doesn't actually get between the contacts. This won't happen with a "nut and bolt" connection if it's bolted up properly.

Even battery terminal contact faces can be very lightly smeared with vaseline after they have been cleaned but before assembly. Even though its an insulator it gets squeezed into the gaps when you bolt it up and the microscopic high points still touch each other to give a good contact. The vaseline keeps out air and moisture, which reduces any tendency to corrode.