After removal of cylinder head, suction and exhaust valve must inspected thoroughly.
Checks/ Inspection of suction valve and exhaust valve
Following things must be checked:
- Both the valves must be checked for sulphuric acid corrosion and bend of the suction/ exhaust valve stem, and measure the dimensions.
- Check for high temperature corrosion of the valve poppet.
Why valve poppet tip or exhaust valve top should be checked/ measured?
Correct the valve poppet tip part upon carefully checking it because if it becomes too thin, it may be chipped and the pieces may enter the combustion chamber and turbocharger causing damage.
- Check the state of blow-by and carbon biting-in at the valve seat part, and according to the state, grind the seat face.
- Measure the dimensions of the valve seat part. If the dimensions have reached the usage limit value, replace it.
- Check for cracks and corrosion of valve springs.
Suction and exhaust valve must not be confused after overhaul. So, they must be marked and kept separately. There is marking also on the suction v/v and exhaust v/v to identify them.
How to identify inlet valve and exhaust valve of an AE ?
Take care not to confuse the suction and exhaust valves as they are of the same shape but made of different materials.
FIG.: Marking on suction and exhaust valve stem
In the fig., S represents suction valve and E represents exhaust valve.