PT POWER 

by Jim Aamodt

With the design experience of the Liberty World War I engines, and subsequent marine and aero Packard 6 cyl., 12 cyl., 16 cyl. and 24 cyl. engines, Packard was chosen as the supplier for the World War II "PT" boats. The Garwood Racing Team's development of the 1M-2500 V12 engine from 1928 eventually led to the 4M-2500 used in the PT boats.

Both Elco Co. and Higgins Marine built 76' and 78' PT boats. All were powered by 3 4M- 2500 engines of 1500 H.P. A few 1945 units had the 5M-2500 1800 H.P. units. Top speed was over 60 MPH for the PT's and half throttle or "cruise speed" produced a consumption of 100 octane gas at 110 gallons per hour per engine. A 2490 cubic inch, overhead cam, supercharged engine can be thirsty!

After the war, several hydroplane racing boats used 4M-2500s into the 1960's. The famous "Pardon Me" runabout (over 50') at the Clayton Museum is powered by a single 4M-2500. Packard's aero and marine engines of the 1930's not only led to the design of the 4M-2500, but to other famous engines. The Packard built British Merlin V12 aircraft engine, which powered the famous P51 Mustang, is considered the finest aero engine of World War II. 
The engine on display has been test run only, and is new as built in 1943, with some original shipping covering still intact. The engine was repainted sometime in the 1980's, as the original Packard green color is evident under the grey.