By measuring actual operating temperature of exhaust valve body near the valve sealing surface
the corresponding relationship between valve operating temperature and exhaust gas temperature (EGT) at this engine was obtained
and the mechanism of symmetrical distribution of valve ablation point was analyzed in combination with the engine structural design and actual operating environment. Results showed that the valve deflection led to uneven circumferential symmetry distribution of valve sealing surface temperature and the high temperature of valve sealing surface due to excessive leaning in operation
bringing about exhaust valve symmetrical ablation. Based on this
solution of limiting the leaning range in operation with EGT as reference was put forward
and the 70 000 flight hours practical test showed that the fault has been completely solved.