The 6PS is a solid little compressor motor, capable of raising 250 psi to cold start the older Ruston and other diesels. Most larger RB cable excavators had a 6PS plumbed into the main engine cooling system, and for a very cold start, with luck you could get the compressor running long enough to warm the main engine for an easy start. However, usual trick was to be sure the air tank valve sealed well, then start the compressor and run up full pressure at the end of the day's work and 250 psi was usually enough for a cold start and one or two warm starts during the day.
Still have a 6PS that came with my Ruston 3VQ from a 19 ton shovel. Just need the space to plumb them together permanently.
Plough Book Sales list operator/parts manual for several variants of the 6PS depending on magneto type. They do need a good spark for easy starting, as they have no impulse device on them. Regards,
Combustor.
