Benz Bz.IV

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Benz BZ 4S 2.jpg
Benz Bz.IV
Type Inline piston engine
National origin Germany
Manufacturer Benz
First run c. 1916
Number built 6,400
Developed from Benz Bz.III
Developed into Benz Bz.IVa

The Benz Bz.IV was a German six-cylinder, water-cooled, inline engine developed for aircraft use. Deliveries began in 1916 and some 6,400 were produced.

Design and development[edit]

The Bz.IV was a dual-camshaft design, with two intake and two exhaust valves per cylinder. The cylinders were cast iron surrounded by a sheet metal cooling jacket. The crankcase was aluminium and pistons were initially steel but later versions had aluminium pistons. A high compression version of the engine (Bz IVü) was produced from 1917 onwards and can be recognised by the red bands painted on each cylinder. In February 1918, pistons from Bz.IV were the first captured aluminium pistons to be examined by the British Ministry of Munitions.[1]



Data from [2]

General characteristics

  • Type: 6-cylinder, water-cooled, inline aircraft piston engine
  • Bore: 145 mm (5.7 in)
  • Stroke: 190 mm (7.5 in)
  • Displacement: 18.825 l (1,148.8 cu in)
  • Length: 1,990 mm (78.3 in)
  • Width: 530 mm (20.9 in)
  • Height: 1,150 mm (45.3 in)
  • Dry weight: 370 kg (815.7 lb)


  • Valvetrain: Twin inlet and exhaust valves operated by pushrod actuated double rockers
  • Fuel system: Two Benz 2-jet carburettors feeding three cylinders each
  • Fuel type: Gasoline specific gravity 0.72
  • Oil system: Pressure feed at 0.2 MPa (28 psi): 50% Vacuum Heavy, 50% Sternol
  • Cooling system: Water-cooled


See also[edit]

Related lists


  1. ^ "Report on Aluminium Pistons from 230 HP Benz Engines". Flight. 4 July 1918. 
  2. ^ Grey, C.G. (1969). Jane's All the World's Aircraft 1919 (Facsimile ed.). David & Charles (Publishing) Limited. pp. 1b to 145b. ISBN 978-0-7153-4647-1.