Applicable scope: QSZ-C500, Dong Dong Kang Kang Dong Kang QSZ-G3, QSZ-G7, QSZ13-C380- II, Dong Dong Kang Kang, Kang Dong QSZ13-C400- II QSZ13-C450- II, QSZ13-C450- III, Kang Kang Dong Dong Dong Kang QSZ13-C475- II, QSZ13-C475- III, QSZ13-C500, Dong Dong Kang Kang Dong Kang QSZ13-C500- II, QSZ13-C500- III, QSZ13-C525- II, Kang Dong Dong Kang, Kang Dong QSZ13-C550- II QSZ13-C575- II, QSZ13-C575, Dong Kang Dong Kang QSZ13-G2, East QSZ13-G3, Kang Dong Kang, Kang Dong QSZ13-G5 QSZ13-G6, East QSZ13-G7, Kang Dong Kang Dong Kang 6ZTAA-C, 6ZTAA13-C480- II, 6ZTAA13-G2, Dong Dong Kang Kang, Kang 6ZTAA13-G4, 6ZTAA13-G3 Dong Dong Kang, Kang Dong 40, ISZ425 ISZ13-G2 Dong Kang Dong Kang ISZ450 40, ISZ450 41, ISZ480 40, Dong Dong Kang Kang Dong Kang ISZ480 41, ISZ520 41, ISZ525 40 Dong Kang related parts: working principle: rocker arm, valve rocker arm transmission pressure control Valve opening installation position: fault and analysis between rocker and valve: deformation and fracture reason analysis: extrusion and collision