18 ENGINE
18.4.29 Checking valve spring seat
304679-10
18.4.30 Checking the cylinder head
304680-10
304681-10
216
Exhaust minimum length 40. 7 mm (1 .602 in)
(without valve spring
seat)
If the measured value does not meet specifications:
- Change the valve spring.
- Check the valve spring seat for breakage and wear (visual
check).
If the valve spring seat is broken or worn:
- Change the valve spring seat.
- Measure the thickness of the valve spring seat.
Valve spring
Valve spring seat
1.8 mm (0.071 in)
If the measured value does not meet specifications:
- Change the valve spring seat.
- Check exhaust valve guides
O
using the special tool.
I Limit plug gauge (77029026000) (
!ill
p. 360)
If the special tool is easy to insert in the valve guide:
- Change the valve guide and valve.
- Check intake valve guides
8
using the special tool.
I Limit plug gauge (59029026006) (
!ill
p. 357)
If the special tool is easy to insert in the valve guide:
- Change the valve guide and valve.
- Check the sealing area of the spark plug thread and the valve
seats from damage and cracking.
If there is damage or cracking:
- Change the cylinder head.
- Using a straightedge and the special tool, check the sealing
area of the cylinder for distortion.
I Feeler gauge (59029041100) (
!ill
p. 357)
Cylinder/cylinder head
sealing area distortion
� 0.10 mm (� 0.0039 in)
If the measured value does not meet specifications:
- Change the cylinder head.