Valve lash setting method and device for executing the method

Method for setting the valve lash to a desired value in a piston type I. C. engine by means of a power operated setting device including at least one co-axial double spindle (22), wherein each valve (11a,11b;111) is operated via a mechanism including an adjuster screw (18) and a lock nut (19), comprising the following consecutive steps:

• a) arrange the adjuster screw (18) in a position leaving a valve lash,
• b) apply the inner spindle (23) of said co-axial double spindle (22) to the adjuster screw (18) and the outer spindle (24) of said co-axial double spindle (22) to the lock nut (19), and tighten the lock nut (19) via said outer spindle (24) to a predetermined initial torque level,
• c) loosen the lock nut (19) through a predetermined first angle,
• d) tighten the adjuster screw (18) via said inner spindle (23) to a snug torque level (TS) and register the angular position (So) of the adjuster screw (18) when said snug torque level (Ts) is reached,
• e) open the valve (11a, 11b;111) by tightening the adjuster screw (18) through a predetermined second angle while checking the torque magnitude required therefor,
• f) reverse the adjuster screw (18) through a predetermined third angle exceeding said second angle,
• g) re-tighten the adjuster screw (18) to said snug torque level (Ts),
• h) reverse the adjuster screw (18) through a predetermined fourth angle corresponding to the desired valve lash, and
• i) hold the adjuster screw (18) stationary while tightening the lock nut (19) to a predetermined final torque level.