Re: Monobloc 12
Posted by West Peterson On 2010/7/18 10:05:28
The engine was developed early in 1929 and was installed in a "standard" Dietrich-bodied convertible victoria. The body was pushed back on its chassis approximately 11 inches, but with its hood lengthened by seven inches, its cowl another four, and the firewall pushed back about six inches beyond the back of the hood, there was roughly 13 inches of space added under the hood with no lengthening of the 145-inch wheelbase.
It has been theorized that the bore x stroke of this engine was 3.5 x 5 inches, which would have given it a displacement of 577.2 cubic inches. Early testing revealed output to be 150hp at 3,000rpm with 373 lb-ft of torque at 800-900rpm. Horsepower is estimated to have improved to 160 after a split exhaust manifold was installed.
Development of the monoblock 12 was canceled in March 1929, but there is plenty of evidence that the project led to the development of Packard's 734 speedster of 1930, truly a factory-produced hot rod. Packard engineers created the same amount of horsepower as the 12 with a modified eight-cylinder engine using a single dual-throat Detroit Lubricator carburetor, larger exhaust valves, 45-degree exhaust manifold and a secondary fuel pump that made it the second most powerful eight-cylinder car offered in 1930, right behind the Duesenberg Model J (which has been argued to have been between 200-250hp in non-blown guise).
While Packard wasn't in real competition with Duesenberg, it was with cross-town rival Cadillac, which took the wind out of Packard's sails with the introduction of its 452cid/175hp V-16 powerplant. Some believe that Packard had intended to take the speedster to Le Mans, but no evidence of this has materialized.
The Packard monoblock 12 could be considered semi-successful, with a finished car being tested several times with vibration problems only noted at certain speeds. The orange and silver car was seen around Detroit in the hands of Warren Packard, but after his death in August of '29 the car was returned to the factory and its whereabouts today is unknown. The engine was supposedly scrapped.
Note the twin Johnson "R" updraft carburetors in the picture. Johnson "R" carburetors were installed on production 1929 Packard Eights, but the thin-wall die-cast bowls quickly developed cracks and Packard instructed its dealers to retrofit all of them with single-throat Detroit Lubricators free of charge. A pair of Detroits were also installed on the monoblock 12 sometime after the photo was taken.
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It has been theorized that the bore x stroke of this engine was 3.5 x 5 inches, which would have given it a displacement of 577.2 cubic inches. Early testing revealed output to be 150hp at 3,000rpm with 373 lb-ft of torque at 800-900rpm. Horsepower is estimated to have improved to 160 after a split exhaust manifold was installed.
Development of the monoblock 12 was canceled in March 1929, but there is plenty of evidence that the project led to the development of Packard's 734 speedster of 1930, truly a factory-produced hot rod. Packard engineers created the same amount of horsepower as the 12 with a modified eight-cylinder engine using a single dual-throat Detroit Lubricator carburetor, larger exhaust valves, 45-degree exhaust manifold and a secondary fuel pump that made it the second most powerful eight-cylinder car offered in 1930, right behind the Duesenberg Model J (which has been argued to have been between 200-250hp in non-blown guise).
While Packard wasn't in real competition with Duesenberg, it was with cross-town rival Cadillac, which took the wind out of Packard's sails with the introduction of its 452cid/175hp V-16 powerplant. Some believe that Packard had intended to take the speedster to Le Mans, but no evidence of this has materialized.
The Packard monoblock 12 could be considered semi-successful, with a finished car being tested several times with vibration problems only noted at certain speeds. The orange and silver car was seen around Detroit in the hands of Warren Packard, but after his death in August of '29 the car was returned to the factory and its whereabouts today is unknown. The engine was supposedly scrapped.
Note the twin Johnson "R" updraft carburetors in the picture. Johnson "R" carburetors were installed on production 1929 Packard Eights, but the thin-wall die-cast bowls quickly developed cracks and Packard instructed its dealers to retrofit all of them with single-throat Detroit Lubricators free of charge. A pair of Detroits were also installed on the monoblock 12 sometime after the photo was taken.
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