Low valve engine - what is it characterized by?

From the article you will find out on which cars a low-valve engine was installed. You will also learn about its strengths and structure.

Low valve engine - brief characteristics

The low valve engine is a simple design, also known as a side valve engine. This is a piston engine in which the camshaft is most often located in the crankcase, and the valves in the cylinder block. This leads to the fact that this type of engine requires a different valve timing system than an overhead valve unit. 

The disadvantages outweigh the advantages

Unfortunately, a low-valve engine has more disadvantages than advantages. This is an archaic design currently only used for mower engines. In such a unit, the compression ratio is usually less than 8, which means that this type of timing belt can only be used in a spark ignition unit. 

The biggest disadvantages of an under-valve engine are, above all, the low engine effort. This means that, for example, one liter of displacement produces less power than in the case of overhead valve engines. Unfortunately, low engine power does not go hand in hand with low fuel consumption, and at the same time the engine is not dynamic, a delayed reaction to the addition of gas is clearly felt.

The low-valve engine had frequent cylinder failures, which deformed due to constant contact with the hot exhaust tract. The design of the motor did not allow the use of popular wet cylinder liners. A serious disadvantage was also the achievement of low compression ratios. This was due to the specific design of the head.

Benefits of an overhead valve engine

The under-valve engine is the simplest design of all four-stroke motorcycles and this is the main advantage of these powertrains. Due to its design, it was very readily installed on motorcycles, but it was often confused with a small capacitive unit. All thanks to the small heads that give a filigree look to the entire project. 

Third division - hybrid timing

You are probably used to dividing internal combustion engines into lower-valve and upper-valve. There are little-known designs that combine the solutions of both motors. They are called mixed cam engines and are identified by the symbol IOE. In the case of these units, the intake valves are located in the heads, and the exhaust valves in the engine block. This solution was a recipe for eliminating the thermal problem associated with the deformation of the cylinder liners. 

Low valve engine - is it worth choosing

If you were faced with the dilemma of buying a valve-operated car, it would prove your passion for museum cars. You need to know the cost of restoring a car that was over 50 years old.