Crossley with 12" cylinder

Crossley 'HR' series engines had 10 1/2" bore, I think the stroke was around 12". They had (have, there are still a number in service around the world) a scavenge pump which took the form of an extra, much bigger, cylinder in front of the others. Starting, and reversing, was by compressed air direct into the cylinders. I thought the smallest they built was a 3-cylinder though I may be wrong. They were built from the 1940s or maybe late 30s until the 1970s. I think there was an earlier series of direct reversing scavenge pump engines, but know next to nothing about them.
Tim

13.5" stroke. The CRL series was 14.5" bore with 19" stroke although the smallest was a 4.
Tom