Daimler Straight-Eight engines

From Wikipedia, the free encyclopedia
Twenty-Five
3¾-litres V 26 engine
Overview
Manufacturer The Daimler Company Limited
Production early 1934 to September 1935
Combustion chamber
Configuration 8-cylinder in-line[1]
Displacement 3,746 cc (228.6 cu in)[2]
Cylinder bore 72 mm (2.8 in)[2]
Piston stroke 115 mm (4.5 in)[2]
Cylinder block alloy aluminium alloy. 9-bearing crankshaft with vibration damper[1]
Cylinder head alloy one-piece detachable
Valvetrain OHV worked by pushrods from a nine-bearing camshaft-in-block,
timing is mounted at the back of the block[3]
Compression ratio 5.5:1[3]
Combustion
Fuel system Stromberg twin downdraught carburettor with cleaner and silencer, mixture thermostatically controlled (automatic choke). The induction system is split; four central cylinders are fed by one section, outer pairs by the other section.[1]
Fuel type petrol supplied by mechanical pump[3]
Cooling system water, pump and fan, thermostatically controlled[3]
Output
Power output 90 bhp (67 kW; 91 PS) @3,600 rpm (claimed)
Tax rating 25.7 hp[3]
Chronology
Predecessor 3.7-litre Double-Six 30
Successor Thirty-Two V 4½

The Daimler Straight-Eight poppet-valve eight-cylinders in-line petrol engine was announced by The Daimler Company Limited on 1 May 1934 with its first vehicle, Daimler's new Twenty-Five saloon and limousine. The new engine was the first of a series intended to replace Daimer's outmoded large sleeve-valve six-cylinder and twelve-cylinder engines. The sleeve-valve engines with silence and great low-speed torque were unable to spin fast enough to make full use of new combustion technology and remain reliable.[4] These new engines were intended to run comfortably at 4,000 rpm.[3]

The general aim with the engine was "to give the greatest luxury in travel as expressed by quietness, smoothness, flexibility, and general ease and safety of control rather than great speed".[4]

While a great deal of useful experience must have been acquired by Daimler from Lanchester, who were still building their overhead camshaft straight-eight when they were purchased in 1931, the Daimler Straight-Eight is not a copy.[3]

Twenty-Five V 26

In the Daimler Twenty-Five the straight-eight was mounted using their Daimler-patented bi-axial design by which flexible support is given to the engine at five points. The gearbox was also held with rubber at three points and one underneath.[4]

The one-piece cylinder-head had the spark plugs sunk into it at an angle along the nearside. The make and break and the distributor were set almost vertically at the side of the block. Alongside was the coil with a spare mounted beside it. The generator on the offside shares a triple belt drive with the water pump and the radiator cooling fan.[4]

The crankshaft was fully counterbalanced mounted in nine main bearings and was fitted with a vibration damper. The valves like other poppet valve Daimlers had exceptionally wide clearances. They were overhead and driven by pushrods from a chain driven camshaft taking power from the rear end of the crankshaft.[3]

Increased engine size

In September 1935 it was announced that the cylinder bore was now increased to 80mm increasing the engine's capacity from 3.746 to 4.624 litres following the 25% reduction in horsepower tax which took effect on 1 January 1935. intended to provide improved performance but more important lighter running for the engines and a consequent extension of silent and comfortable service. The tax horsepower rating is now 31.74.[5]

Thirty-Two V 4½

Thirty-Two
4½-litre V 4½ engine
Overview
Manufacturer The Daimler Company Limited
Production December 1935-[3]
Combustion chamber
Configuration 8-cylinder in-line[3]
Displacement 4,624 cc (282.2 cu in)[3]
Cylinder bore 80 mm (3.1 in)[3]
Piston stroke 115 mm (4.5 in)[3]
Valvetrain OHV worked by pushrods from a nine-bearing camshaft-in-block[3]
Compression ratio 6:1[3]
Combustion
Fuel system Stromberg twin downdraught carburettor with cleaner and silencer, mixture thermostatically controlled (automatic choke).[3]
Fuel type petrol
Cooling system water, thermostatically controlled[3]
Output
Power output Tax rating 31.74 hp[3]
Chronology
Predecessor Twenty-Five V 26
Successor Thirty-Six DE 36

In most respects a bored out version of the V26 which it replaced but with the compression ratio increased to 6 to 1. These engines were also fitted to a number of chassis made after 1936 which were fitted with a Lanchester radiator and nameplates.[3]

Light Straight-Eight E 3½ and E 4

Twenty-Six
3½-litre E 3½ engine
Overview
Manufacturer The Daimler Company Limited
Production 1936-1937[3]
Combustion chamber
Configuration 8-cylinder in-line[5]
Displacement 3,421 cc (208.8 cu in)[5]
Cylinder bore 72 mm (2.8 in)[5]
Piston stroke 105 mm (4.1 in)[5]
Cylinder head alloy non-detachable
Valvetrain OHV worked by pushrods from a nine-bearing camshaft-in-block[5]
Combustion
Fuel system Stromberg twin downdraught carburettor with cleaner and silencer, mixture thermostatically controlled (automatic choke). The induction system is split; four central cylinders are fed by one section, outer pairs by the other section.[5]
Cooling system water, thermostatically controlled[5]
Output
Power output Tax rating 25.7 hp[5]
Chronology
Successor Twenty-Seven DE 27

An entirely new engine to power a livelier car for the owner driver. During 1935 a 3½-litre Straight-Eight open car achieved a maximum timed speed at Brooklands of slightly in excess of 90 mph.[3]

Increased engine size

In August 1937 an increase of engine bore to 77.47 mm (3.050 in) took
cubic capacity to 3,960 cc (241.7 cu in)
output to 95 bhp (71 kW; 96 PS) @3,600 rpm,
Tax rating to 29.77 hp
and the engine was renamed E 4.[3]

4-litre Thirty 1939 example
for the Lord Mayor of London

Thirty-Six DE 36

Thirty-Six
5½-litre DE 36 engine
Overview
Manufacturer The Daimler Company Limited
Combustion chamber
Configuration 8-cylinder in-line[6]
Displacement 5,460 cc (333.2 cu in)[6]
Cylinder bore 85.1 mm (3.35 in)[6]
Piston stroke 120 mm (4.7 in)[6]
Valvetrain OHV worked by pushrods from a nine-bearing camshaft-in-block[6]
Compression ratio 6.3:1[6]
Combustion
Fuel system Twin SU downdraught carburettors with cleaner and silencer, mixture thermostatically controlled (automatic choke). The induction system is split; four central cylinders are fed by one section, outer pairs by the other section.[5]
Fuel type petrol, fuel pump AC mechanical[6]
Oil system Gear driven pump, Tecalemit full flow filter[6]
Cooling system water, thermostatically controlled[6]
Output
Power output 150 bhp (110 kW; 150 PS) @3,600 rpm,
Tax rating 35.92 hp[6]
Chronology
Predecessor Thirty-Two V 4½
Successor Regina DF400 and DK400
5½-litre Thirty-Six 1946 example
5½-litre Thirty-Six 1948 example
in royal livery
5½-litre Thirty-Six 1949 example

References

  1. 1.0 1.1 1.2 New Eight-Cylinder Daimler.The Times, Tuesday, May 01, 1934; pg. 9; Issue 46742.
  2. 2.0 2.1 2.2 Cars Of To-Day. The Times, Tuesday, May 29, 1934; pg. 19; Issue 46766
  3. 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 3.20 3.21 Brian E Smith, The Daimler Tradition Transport Bookman, Isleworth 1980 ISBN 085184 014 0
  4. 4.0 4.1 4.2 4.3 New Eight-Cylinder Daimler.The Times, Thursday, May 17, 1934; pg. 13; Issue 46756
  5. 5.0 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 Motor-Cars Of 1936. The Times, Saturday, Sep 28, 1935; pg. 6; Issue 47181
  6. 6.0 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 6.9 Road Test No. 15/47. The Motor, December 17, 1947
    (reprinted in Brian E Smith, The Daimler Tradition Transport Bookman, Isleworth 1980 ISBN 085184 014 0)

External links

This article is issued from Wikipedia. The text is available under the Creative Commons Attribution/Share Alike; additional terms may apply for the media files.