This may sound an odd question but could anyone tell me the internal diameter of a Mini ring gear, preferably pre-engaged starter type (although I would guess both inertia and pre-engaged are the same size, just different number of teeth).
Why odd? I'm building an in-line MG Midget engine and am considering swapping the old inertia starter to pre-engaged (Mini should bolt on) but I can't find out whether a Mini ring gear will actually fit on a Midget flywheel .. doesn't seem to be published anywhere.
I could go lightweight but I've heard a couple of tales where the new starter jammed on the Midget as it had the wrong no of teeth (suggesting they were sold a Mini starter) plus they are a lot more expensive! 
