Do I I need a new starter?

[19Fordy]

20 Years ago I converted my 8BA to 12V but kept using
the 1940 6V starter. Today I pressed the starter button and engine didn't crank over on the first tap of the starter button like it always. Tried again and all I get is a "whirring sound" like an electric motor is running. Engine doesn't crank over.
Does this mean I need a new starter Bendix/spring?
Are the new high torque starters worth the money or should I
convert the old starter to 12V like Fordbarner Ed Pitts did in this thread?
All ideas welcome.
http://www.fordbarn.com/forum/showth...2+volt+starter