A day in the engine laboratory
12:30 AM | April 4 2016

A Volvo moment: a day in the engine laboratory

It is a normal working day in Volvo’s testing lab in the late 1920s. The foreman Johan Fingal, wearing high boots, is checking something under the bonnet. His colleagues are reading and noting key measurements.

The lab makes it possible to test engines and brakes and obtain information on things like fuel consumption. The front wheels of the test vehicle are completely blocked, while the rear wheels are placed on rollers sunk into the floor which allow them to spin even though the car is standing still. The big cooling fan is running at full speed to stop the engine from overheating. The exhaust gases are taken out of the purpose-built facility through a pipe that passes through the wall.

Today’s test vehicle is a PV651, the model with Volvo’s first six-cylinder engine. PV stands for Person Vagn (passenger car), and the numbers indicate the number of cylinders and seats and the fact that it belongs to the first series. The decision to develop a six-cylinder car had been taken as early as 1926, and the new model was launched on 23 April 1929. It was a completely new car with a brand-new chassis and a strong frame. In Sweden, the PV651 cost 6,900 kronor.

The side-valve engine had cast-iron pistons, but for an extra 50 kronor, customers could have aluminium pistons. The statically and dynamically balanced crankshaft was almost unique to Volvo; it had seven bearings and weighed a hefty 32 kg. The new crankshaft allowed the power to be transmitted at much higher engine speeds.

The engine was called the DB; its cylinder capacity was 3,010 cc and it produced 55 HP at 3,000 rpm. The equipment in the ‘rolling road’ laboratory was advanced for such a small manufacturer as Volvo. The work on the engine must have gone well, because the DB was to be the basis for Volvo’s six-cylinder units right up to 1958.