M4R engine:
- intake valves: 45.59 - 45.96 mm;
- exhaust valves: 45.13 - 45.40 mm.
H4J engine:
- intake valves: 46.73 mm;
- exhaust valves: 54.3 mm.
Use a dynamometer to check the wear of the springs by measuring their length (X1).
M4R engine:
- intake valves: 35.30 mm under load 151 - 175 N;
- exhaust valves: 35.30 mm under load 140 - 162 N.
H4J engine:
- intake valves: 32.4 mm under load 145±9 N and 23.96 mm under load 257±15 N;
- exhaust valves: 32.4 mm under load 201±10 N and 26.10 mm under load 285±13 N.