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A well running engine requires a well adjusted compression ratio. You should never risk overheating or a hole in the piston, needless to say you should also not give up performance. It is important that the compression ratio is optimal in modified motors. Air cooled motors cannot handle compressions as high as liquid cooled engines can. Also the squeeze gap must not be too small, otherwise you risk the piston crashing the cylinder head.

geometric compression
We are working with the geometric compression. If adjustments are necessary we modify the cylinder head and put special attention to the correct dimension of the squeeze gap (a minimum of 0.80mm in smaller engines and 1.2mm in larger engines).

To be able to perform these adjustments the engine housing, crankshaft and piston that are going to be used with this cylinder and head have to be provided.

On the diagram below you can see that the gains of horsepower at a geometric compression ratio over 17:1 are very small.

Typically the following geometric compressions are recommended:

Air cooled standard cylinder: 9 to 10

Air cooled modified cylinder: 10 to 12

Liquid cooled cylinder: 12 to 14

Extremely modified liquid cooled cylinder: 14 to 17

Optimize compression including spindling head - from 40 EURO

head spindling
We spindle your head like your specification.

spindel head - 25 EURO

Thermodynamic effectiveness: