Boland V-8  The Boland V-8 was an aircraft engine that was developed by the Boland Brothers for use in their tailless aircraft. Between 1908 and 1914, 4 versions of this motor were produced ranging in power from to . The Boland motors all used an unusual concentric overhead valve. This arrangement positioned the intake valve in the middle of the exhaust valve. These were actuated by a single push rod and rocker arm.