Daimler Straight-Eight engines
| 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 |
| Displacement | 3,746 cc (228.6 cu in) |
| Cylinder bore | 72 mm (2.8 in) |
| Piston stroke | 115 mm (4.5 in) |
| Cylinder block alloy | aluminium alloy. 9-bearing crankshaft with vibration damper |
| 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 |
| Compression ratio | 5.5:1 |
| 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. |
| Fuel type | petrol supplied by mechanical pump |
| Cooling system | water, pump and fan, thermostatically controlled |
| Output | |
| Power output | 90 bhp (67 kW; 91 PS) @3,600 rpm (claimed) Tax rating 25.7 hp |
| Chronology | |
| Predecessor | 3.7-litre Double-Six 30 |
| Successor | Thirty-Two V 4½ |
| Thirty-Two 4½-litre V 4½ engine |
|
|---|---|
| Overview | |
| Manufacturer | The Daimler Company Limited |
| Production | December 1935- |
| Combustion chamber | |
| Configuration | 8-cylinder in-line |
| Displacement | 4,624 cc (282.2 cu in) |
| Cylinder bore | 80 mm (3.1 in) |
| Piston stroke | 115 mm (4.5 in) |
| Valvetrain | OHV worked by pushrods from a nine-bearing camshaft-in-block |
| Compression ratio | 6:1 |
| Combustion | |
| Fuel system | Stromberg twin downdraught carburettor with cleaner and silencer, mixture thermostatically controlled (automatic choke). |
| Fuel type | petrol |
| Cooling system | water, thermostatically controlled |
| Output | |
| Power output | Tax rating 31.74 hp |
| Chronology | |
| Predecessor | Twenty-Five V 26 |
| Successor | Thirty-Six DE 36 |
| Twenty-Six 3½-litre E 3½ engine |
|
|---|---|
| Overview | |
| Manufacturer | The Daimler Company Limited |
| Production | 1936-1937 |
| Combustion chamber | |
| Configuration | 8-cylinder in-line |
| Displacement | 3,421 cc (208.8 cu in) |
| Cylinder bore | 72 mm (2.8 in) |
| Piston stroke | 105 mm (4.1 in) |
| Cylinder head alloy | non-detachable |
| Valvetrain | OHV worked by pushrods from a nine-bearing camshaft-in-block |
| 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. |
| Cooling system | water, thermostatically controlled |
| Output | |
| Power output | Tax rating 25.7 hp |
| Chronology | |
| Successor | Twenty-Seven DE 27 |
| Thirty-Six 5½-litre DE 36 engine |
|
|---|---|
| Overview | |
| Manufacturer | The Daimler Company Limited |
| Combustion chamber | |
| Configuration | 8-cylinder in-line |
| Displacement | 5,460 cc (333.2 cu in) |
| Cylinder bore | 85.1 mm (3.35 in) |
| Piston stroke | 120 mm (4.7 in) |
| Valvetrain | OHV worked by pushrods from a nine-bearing camshaft-in-block |
| Compression ratio | 6.3:1 |
| 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. |
| Fuel type | petrol, fuel pump AC mechanical |
| Oil system | Gear driven pump, Tecalemit full flow filter |
| Cooling system | water, thermostatically controlled |
| Output | |
| Power output | 150 bhp (110 kW; 150 PS) @3,600 rpm, Tax rating 35.92 hp |
| Chronology | |
| Predecessor | Thirty-Two V 4½ |
| Successor | Regina DF400 and DK400 |
Daimler Straight-Eight engines were eight-cylinder in-line petrol engines made by the Daimler Company to power the largest and most expensive cars in their range. The Straight-Eight engines replaced Daimler's earlier Double-Six V12 engines. Unlike the Double-Six engines, which used sleeve valves based on the Knight patents, the Straight-Eights used conventional poppet valves in the overhead valve configuration.
Three series of Straight-Eight engines were built between 1934 and the outbreak of the Second World War in 1939; another series, the DE36, was built after the war from 1946 to 1953.
The Straight-Eight 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 Daimler'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. These new engines were intended to run comfortably at 4,000 rpm.
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".
While a great deal of useful experience had 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.
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.
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.
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Wikipedia