The B18/B20 Engine

The engine for the early Volvo 1800's is the 1780cc B18. In his book, Swedish Iron, Bill Webb describes how this engine was produced by taking Volvo's V-8 3560cc gasoline truck engine and cutting it in half to yield a straight 4 cylinder engine. Not only did this design path save Volvo money in development costs, but it produced an engine of legendary ruggedness. Since the crankshaft was intended for a V-8, it contains twice as must bearing surface area as any engine of similar displacement. The crankshaft sits on 5 bearings instead of the usual 3. When the Volvo 1800 first came out, the automotive press was disappointed at the relatively small size of the engine in this car. But they were curious about that 5 bearing crankshaft. And the B18 has lots of extra room around the cylinders for expansion. Surely Volvo was planning several displacement increases in the near future...

Only one size increase was performed, however.

The B18 was used on P1800 and 1800S models through 1968. The engine was enlarged to 1986cc in 1969 (the B20 engine). All models through 1969 featured dual carburetors. The 1970 and on 1800E/ES models utilized fuel injection.

Volvo felt that the car was fast enough at 106 mph. They also knew that the car would be driven harshly, and therefore the extra conservative design was necessary for durability and reliability.

The automotive press in the early days of the 1800 were impressed by the smoothness of the engine and it's ability to be pressed to it's limit without signs of fatigue. Usually not in the habit of making long term predictions, several magazines felt confident that the B18 would be one of the most durable engines ever put into a sports car. "100,000 miles should be the rule rather than the exception." (Road and Track - 1966).

The engine is smooth over a wide range of rpm. It is equally at home at either a lazy 2,500 rpm. or at it's recommended maximum of 6,000 rpm.

Volvo designed the 1800 for comfortable high speed touring, rather than for all out speed. From a dead stop, acceleration is embarrassingly slow, but, the car steadily picks up speed until, "as though by magic, everybody else seems to be diminishing rapidly in the rearview mirror." (Sports Car Graphic - 1961) This theme of unsuspecting speed crops up again and again in the car magazines of the day: "it's always traveling faster and accelerating stronger than its acoustics indicate." (Motor Life - 1961).

The car's relatively slow acceleration was matched with superior handling characteristics that allow the driver the luxury of never slowing down. "The almost ridiculously high average speed one can maintain with this car over any sort of road more than makes up for any momentary discomfiture at standing starts." (Sports Car Graphic - 1961)

"It's one of a scant half dozen cars we have tested over the years that we really hated to return." (Sports Car Graphic - 1961)

B18B - First letter stands for fuel type (B = Benzene - Gasoline)

B18B - Numbers stand for displacement (18 = 1.8L, 20 = 2.0L)

B18B - Last letter stands for fuel system (A = single carb, B = dual carb, E = high compression - fuel injection, F = low compression - fuel injection)

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