The Aeromarine B-45 is an aircraft engine built by the Aeromarine Plane and Motor Company in 1915.

The B-45 shares the same bore, stroke and valve configuration as the B-90, except in a 45° Vee configuration.

The other primary difference are cast aluminum cylinders in place of the B-90's cast iron resulting in a 40 lb (18 kg) weight savings.

[1][2] Data from Airplane Engine Encyclopedia[2]