Norton singles oil pump question

[esometisse]

Gentlemen, I need help on this one:
Norton used for their non-ohc singles (16H, 18, 19, ES2 etc.) an oil pump that looks somehow 'mirror-inverted' to the one used later in the twins. These 'singles' pumps have for example the feed bore near the 'top' of the oil pump body and the drive pinion on the 'left' side of the body.
Did Norton later switch to pumps in their singles that look like the ones used in the twins?
Or does this only apply to the ES2/M50 Mk2 that isn't a Norton at all but an AMC hybrid?
In short - are all real Norton singles oil pumps the same? I don't have a clue...

Thanks
Andy

[rogerwilko]

There is a dedicated Norton single site that would answer your question but i forget what it is called ? Something like pushrod Norton something...

[R]

All Norton singles used the single cylinder oil pump.
And the twins all used the twin cylinder pump.

Single cylinder needs low volume dribble feed, and the twins needed a bit more volume for pressure-fed big ends.
The actual mounting in the timing chest doesn't allow them to be switched - perhaps deliberately.

[R]

Whether all the singles oil pumps are the same inside is a trickier question.

The pumps for the twins were upgraded, several times.
Got wider gears = more oil.
And the Commando got a steel (iron ?) pump body.
And the drive gears were altered, to spin them faster.

Mr Pemberton may know the answer to that, for the singles.
Or a study of the parts books show if the p/n changed along the way.
The oil flow into the big end is restricted by a jet though, so the singles pump has more capacity than needed,
so the design/capacity may never have needed to be changed.

[rogerwilko]

Here it is.  http://www.pushrod-performance.co.uk/

[esometisse]

many thanks guys!