It was replaced in 1946 with the CoBra (for "Copper Brazed"), a overhead-cam four with a bore and stroke. That engine in turn was replaced in 1949 by the new and more reliable CIBA (Crosley Cast Iron Block Assembly) engine utilizing five main bearings. The CoBra (Copper Brazed, also known as "The Mighty Tin") was originally developed by Lloyd Taylor, of Taylor Engines in California, for military use aboard PT boats and B-17 Flying Fortress bombers. The engine was made from sheet metal rather than cast iron like most other engines. This was done to get a thin, uniform wall thickness and thus avoid the creation of hot spots around the combustion chamber that could ignite the fuel, causing pre-ignition (knocks), which in turn limited the compression ratio. These engines were used mainly to power generators, refrigeration compressors, etc., and were widely praised for their successes in the war effort. The engine was adopted for automobile use in 1946. It was a small, lightweight engine with single overhead camshaft driven by two sets of bevel gears and a vertical shaft at the front of the block. It was America's first overhead camshaft automobile engine to be produced in five-figure numbers, after Duesenberg built some 650 overhead cam Straight Eights from 1921–1926. The unitary block and cylinder head weighed only dry; complete with all accessories (including the flywheel) weighing only . The engine displaced and produced at 5,400 rpm and @ 1200 rpm. Because of its remarkable power to weight ratio, and super efficiency for its time, the CoBra engine has been compared to Ford's 1.0 litre inline-3 EcoBoost engine. Longevity was measured in hours and was strictly controlled by equipment maintenance schedules for the wartime duties, but corrosion became a problem for these engines in civilian service. This problem with these automotive powerplants had tarnished Crosley's reputation by 1948. The Crosley CIBA (Cast Iron Block Assembly) was a more traditional and more reliable engine utilizing a cast-iron block. Nevertheless it had a unique design. Instead of a removable cylinder head — the combustion chambers, valve seats, cam supports, ports and cylinders are one casting, and the crankcase is another. In both the early and later cast-iron engines, the crankcase is aluminum. The engine produced 26.5 HP @ 5,400 rpm and @ 3,000 rpm. When Crosley Motors, Inc. was sold, the engine was renamed "AeroJet" and production continued.