C39 dynamo replaced by C40

[ian.mcdougall]

Hi
Is it alright to replace a C39 dynamo with a C40 keeping the original screw terminal regulator
Ian

[bmcecosse]

Can't see any problem! Will be fine.

[PSL184]

Its fine - The C40 is just a higher output version so no need to worry...

[mike.perry]

A C40 will work fine but looks out of place, use it whilst you get your C39 overhauled. It may be worth investigating if you can get the C39 rewired to C40 spec.

[ian.mcdougall]

Hi mike
I was thinking of putting the back plate with the greaser/ oiler of the C39 ( with new bush ) on the c40 and then putting the brush cover plate of the c39 onto the body of the c40 so that it looks like the original c39
Ian

[mike.perry]

The mounting hole offset is different on the C39 to C40. Where are your fan blades, on the end of the dynamo? Make sure that you can get the pulleys off. Also note that C39 brushes are a different size.
Have you got any auto electricians in your area? All the old boys who could repair a dynamo with their eyes closed have retired and if you can't plug it into a diagnostics thing the current mechanics don't want to know.

All the auto electricians who haven't retired take one step forward!

[PSL184]

All the auto electricians who haven't retired take one step forward!

err.... here Gov'nr !!!

Apart from appearance no difference to the workings and really dynamo's don't need an expert to fix.....!

[mike.perry]

What is the difference that gives the C40 a higher output and can a C39 be uprated?

[bmcecosse]

I honestly think the difference in output is minimal. And only an 'anorak' will notice the difference in appearance! What's wrong with the old unit anyway ?

[ian.mcdougall]

Hi
Bmc;; The armature end spindle is slightly offset as in when turning the brushes are moving side to side this was noticed when replacing brushes and rear bush bearing last year and now this year the dynamo does not put out the ign lamp although it does show it is charging but not enough but it was OK last year.
Mike;; the pulley is off, taken off last year when replacing front bearing. the dynamo is on, no problem fitting what do you mean about the holes being offset, the body of the dynamo looks to be same dia and length just has no holes for brushes in rear of body. Does the C40 have more windings on field coils and armature ??? .

[mike.perry]

The mounting bolt holes are further from the body on the C39, so if you swap the back plates over the dynamo will be out of line. I will take some photos.