Duesenberg straight-8 engine

This article is about straight-eight engines made by Duesenberg. For the automobile marketed and sold under the name "Duesenberg Straight Eight" from 1921 to 1926, see Duesenberg Model A.

The Duesenberg straight-8 engine was produced from 1921 to 1937 and sold in Duesenberg automobiles. Fred and August Duesenberg got their start building experimental racing engines which achieved a great deal of success. Among their accomplishments are wins at the Indianapolis 500, the 1921 French Grand Prix and speed records at the Bonneville Salt Flats. They used the expertise they had gained to start building production engines and cars which were renowned for their performance and luxury.

Duesenberg straight 8
Overview
Manufacturer	Duesenberg/Lycoming
Production	1921–1937
Layout
Configuration	Overhead cam multivalve overhead valve straight-8 engine

Among the novel design features (for a pre-1940 production engine) seen on various Duesenberg engines are single- and double-overhead camshafts, three- and four-valve heads, superchargers and aluminum castings.

Production engines

Main articles: Duesenberg Model A and Duesenberg Model J

Duesenberg Model J engine[1]
Overview
Manufacturer	Duesenberg
Production	1928-1937
Layout
Configuration	Straight-eight engine
Displacement	420 cu in (6,900 cc)
Cylinder bore	3.74 in (95 mm)
Piston stroke	4.76 in (121 mm)
Cylinder block material	cast iron
Cylinder head material	cast iron
Valvetrain	DOHC, 4 valves per cylinder
Compression ratio	5.7:1
Combustion
Supercharger	Duesenberg centrifugal (optional from 1932)
Fuel system	Single updraft Schleber carburetor
Fuel type	gasoline
Cooling system	water-cooled
Output
Power output	265 hp (198 kW) at 4,250 rpm (normal) 320 hp (240 kW) at 4,200 rpm (supercharged)
Chronology
Predecessor	Duesenberg Model A engine

Production	Engine	Displacement	Bore x stroke	Cam and valve	Model
1921–1927	260	259.7 cu in (4,256 cc)[2]	2.8750" X 5.0000" (72.16 x 125.50 mm)	SOHC 2v	A,X
1928–1937	420	419.7 cu in (6,878 cc)	3.7500" X 4.7500" (94.12 x 119.23 mm)	DOHC 4v	J,SJ,SSJ

Competition engines

The engines listed below were designed by Duesenberg for the Indianapolis 500. Some engines of the 122 CID and 91 CID design were bored/stroked to larger displacements for other races classes, after the 1930 rules change at Indianapolis.

Production	Engine	Displacement	Bore x stroke	Cam and valve
1919–1921[3]	300	296.9 cu in (4,865 cc)	3.0000" X 4.7500" (75.30 x 131.78 mm)	SOHC 3v
1921-1923[3]	183	183.0 cu in (2,999 cc)	2.5000" X 4.6600" (62.75 x 116.97 mm)	SOHC 3v
1923-1925[3]	122	121.3 cu in (1,988 cc)	2.3750" X 3.4220" (59.61 x 85.89 mm)	DOHC 4v / DOHC 2v (supercharged)[4]
1926–1929[3]	91	90.3 cu in (1,480 cc)	2.2860" X 2.7500" (57.38 x 69.03 mm)	DOHC 4v
1930–1932[5]	244	244 cu in (4,000 cc)	unk	SOHC desmodromic

See also

• Duesenberg
• Lycoming Engines
• Multivalve
• OHC
• Overhead valve
• Straight-8