In turnomat the exhaust valve spindle and upper spring carrier is supported by spring via a axial roller bearing. There is freewheeling mechanism( its like a ratchet mechanism) attached to the spindle via two roller bearings. So when valve opens freewheeling mechanism is in free running state,. when valve is closing free wheeling mechanism is in a engaged state and lower spring carrier will be rigidly attached to valve guide. the exhaust valve and upper spring carrier rotates on the axial roller bearing.
Since very small needle lift is obtained in the test equipment result in an unequal pressure distribution in the cut off shaft resulting in a hard contact in a small area along with high frequency oscillations, low lubricity of test oil will increase the chance of seizure. Full lift and high lubricity of heavy oil eliminates this risk of seizure during normal operation.( Always open and clean slide type valves before testing as cold sticky heavy oil along with small clearances can cause restriction in the movement of the spindle).
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