This is my first conversation on the site. I am looking for historical information about Petter possibly making an experimental engine for Onan back in the late 70's / early 80's. The engine I acquired is a flat 4 cylinder air cooled boxer design, but it is a Diesel engine with a CAV rotary injection pump ( date code March 78 ) and electric start. The engine has many similarities of Petter parts being used. The engine tag states the oil capacity in liters, and the serial number is "EXP 687" ( experimental ? ). Model P74N-DA024/X06. If anybody has information to contribute it would be very welcomed. hopefully there is a Petter expert out there. Thank you