BMW 340 - Technical

Technical

Power output from the 1971 cc straight-6 engine is 54 PS (40 kW).

Mechanically the 340 carried forward some of its predecessor’s advanced features. The four-speed gear box of the 326 reappeared in the 340: however, the cable linkage, which in use had proven damage prone, was replaced with a more robust rod linkage system.

A particularly intriguing component in the engine bay was a mechanical self-cleaning oil filter. Sited above the clutch pedal, the device employed a scraper attached to a ratchet which moved progressively, driven a little further with each successive operation of the clutch pedal.

The engine block was water-cooled using a radiator that most 21st-century car owners minded to lift the hood / bonnet would instantly recognised as such. But here, too, the approach was not entirely conventional. Possibly reflecting the colder winter temperatures routinely experienced in central and eastern Europe, the radiator was protected on its outer face by a blind which could be raised or lowered from the driver's seat, a device also employed on certain Russian automobiles. In cold weather the driver was able to minimise the quantity of cold air passing through the radiator by completely lowering the radiator-blind. This minimised the period during which the engine operated below its efficient operating speed. Informed by a facia-mounted engine temperature gauge, the driver was able to anticipate and avoid the risk of overheating by raising the radiator blind as the engine approached its efficient operating temperature of 80 °C (176 °F).

Cars sold from 1952 also featured a fuel-based passenger cabin heater. In order to ignite the heater it was necessary first to open a small tap in the engine bay, after which the flow of hot air could be regulated using a control in the footwell on the passenger's side.

In recognition that the 340 had been developed in haste, under sub-optimal conditions, several early ‘production prototype’ level cars were subjected to a 10,000-kilometer marathon test run. The successful conclusion of this testing constituted a public demonstration of the manufacturer's confidence that the car was ready for serial production, which commenced in 1949.