How to calculate the correct rocker arm geometry



Start by measuring how high the valve stem protrudes above the gasket surface, or the surface on which the rocker arm stand stands.

We say it was 41mm

Then subtract 37.8mm

This corresponds to the height of the rocker arm stand where the shaft should rest and the radius of the shaft

41 minus 37.8 becomes 3.2

On camshafts with lifting up to 13mm, you then subtract 6

If you have a camshaft that lifts over 13mm, you subtract 6.5

We say that your camshaft lifts 12mm so then we will subtract by 6

Then you take 3.2 minus 6 this will then be 2.8mm

This means that the rocker arm brackets must be leveled approx. 2.8 mm in order for it to have the correct geometry





41-37.8 = 3.2

3.2-6 = 2.8mm