I've not contributed to this discussion as I've been waiting until I've
checked my facts. Actually, I've lost the original posting but I seem to
remember that the writer wanted to fit a variable valve gear to a Ruby.
The reason it won't work is that the Ruby (I am now reliably informed) has
zero lap valves - in fact it could not be reversed by changing from inside
to outside admission if there were any lap. This applies also to most
Pearse and Merlin locos. Roundhouse locos use slide valves with zero lap
and those operators who "notch up" the Johnson bar are merely altering the
valve opening and NOT the valve timing (in theory at least - the timing may
alter for the worse as wear sets in.)
Sorry, it may look impressive, but you're wasting your time.
Mike Chaney
