Wednesday, January 8, 2025

J.A.Prestwich cutaway engine


The JAP 550 engine for sidecar work. Bore and stroke of this engine are 85x95 mm, low compression with heavy flywheels for slogging.
 

2 comments:

André Smit said...

correction, I think the 550 was a side valve engine from the 20's, this looks more like the early 30's speedway engine with the pushrods in line hence the off-set followers, the ribbed small crankcases, smaller diameter of flywheels and 80x99 bore and stroke? very nice and fast engines anyway!

André said...

ah apologize, correction needed, at looking closer, the pushrods are not in line, there are straight followers, also text on cover is different so will be speedway later model as used from '34 or so