MPM 1/72 Fokker G.I Mercury

A sectioned Pegasus engine showing interesting details such as the twin pushrods running in an oval-section tube, the valve operating mechanism, the reduction gears, and the exhaust pipes at the front side. The function of the small-diameter pipes running from the base of each cilinder to the cilinder head is unknown to me.

Photo from 'British piston aero-engines and their aircraft' by Alec Lumsden.