[Richard Coutts-Smith]

Hi Richard,
Hmmm, I've never heard of the gas engine before.
Yes I have, just did some last minute reading
" B Series commercial engines were also developed to run on either natural gas or propane, and in this form were installed in standby generator sets.
These engines were identified by the inclusion of a "G" suffix, eg B81G"
(Pat ware, "In National service")

Never heard of anyone fitting a gas conversion either, which is surprising given their prodigious thirst. I have considered doing it to the Humber, but would like to see someone else do it first!
I think Doug Greville (on his website) has a copy of the letter from Rolls Royce cofirming the use of Unleaded fuel. I would have thought the B Series predated the use of leaded fuel, so that has never concerned me too much, most of the Champ guys over here run a fuel supplement just in case though.
Rich.