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None of Them! ( Long )

Posted by Joseph Scheil on Thu Nov 01, 2001 05:12:12 PM

In reply top PT Boat Engines posted by Glenn Wegman on Thu Nov 01, 2001 12:57:29 PM

: Which boats used Packard/RR V-1650 series engines?

A. None of them! As the war surplus Merlins were used in hydroplane racing, along with the Griffon, and the Boats were Packard powered, it was always assumed by most that they must have been Merlins. Boat racing used up and perhaps preserved the Merlin for posterity, but hundreds were destroyed racing.
Packard Motor Car Company was by the 1920's beginning to advertise Land, Sea and Air supremacy and had produced engines and winning records on all fronts. Packard began its marine engines for defense in 1939 with a redesign of the famous Gar Wood engine they had raced so successfully earlier. It was called the 2M, the 1M reserved for the racing mill, but was still too much of a racing design. The next was the 3M-1500 of 800hp. (1500 cid) a successful design. It grew to the 4M-2500 a 1200hp engine powering the 85' and 104' boats from Elco, Higgins and Vosper. This became the standard marine PT engine and grew to 1800hp by wars end.
This prolific engine was a pure Packard design and was considered "the most perfect marine engine of its type" in official communication to Packard. The 4M 2500 was built in 17 different configurations but the standards are below...

60 degree V-12, 100 octane gas, rt hand rotation 6 3/8 x 6 1/2 inch bore and stroke 2600 fpm piston speed displacing 2490ci weighing 2950lbs with 4 valve DOHC heads. As you can see, larger that the Griffon and heavy! There was also a Packard 16, the 1M 3300, and had 2500 hp. A few went to Navy training craft postwar. All subsequent development for surface ships was aimed torward diesels as the 100 octane gas was considered too dangerous by 1950.

Packard was a precision racing engine builder and this allowed them to consider building the Merlin in late 1940. On may 28 1940 Packard agreed to produce the Merlin XX. The V-1650-1 was a fully interchangeable two piece block design while the RR factory was still producing the one piece Model 28 block. The company regretted taking the job on as all the British threads, measures and tooling had to be copied in house to assure interchangability. However they began to love the best liquid cooled engine as their own. Packard refined the engine in concert with RR and reduced moving parts, cost and increased horsepower. The supercharger on the 1650-5 was a Packard refinement and was called two speed, but was in a sense an overdrive, and approved by RR. Testing began in August of 1941 and at the end Packard constructed 55,523 Merlins.
As for the PT's there were 808 ordered, 774 delivered, 70 losses, 219 to Russia, and 481 surplused or scrapped.

A long post, but a subject dear to my heart. Interestingly the Brits were worried of their dependance on Packard at wars end and were also leary of the high octane fuel required for these boats. The result was the incomparable NAPIER DELTIC, a diesel 3 crankshaft 18 cyl, 54 piston engine with tremendous power and operational use. See the Napier Deltic Tech page or the ptfnasty page. The ultimate PT?

Cheers Boys,
Joe Scheil


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