Chapter 3 Ventilation system Section 1 Valve train (2)Valve seat (3)Valve guide (4)Valve spring a) (b) Figure 3.6 Spring seat fixed form (a)cotter form (b)lockpin form Figure 3.7 Valve guide pipe and valve seat 业机械电子工程学膜 Automobile and Tractor Northwest A&F University Automobile and Tractor Northwest A&F University Chapter 3 Ventilation system (2) Valve seat (3) Valve guide (4) Valve spring Figure 3.6 Spring seat fixed form （a） cotter form （b） lockpin form Figure 3.7 Valve guide pipe and valve seat Section 1 Valve train