Illustration: Z 18 Xe
- 1. Cylinder head height
- 2. Installation height of valve guide
- 3. Installation height of valve
- 4. Valve seat width in cylinder head
- 5. Valve seat angle in cylinder head
- 6. Valve stem diameter
- 7. Valve seat angle at valve
- 8. Valve length
- 9. Valve head – diameter
| Engine | | Z 18 XE |
| Cylinder head height 1) | mm | 135.85 - 136.0 |
| Valve seat width in cylinder head | | |
| Intake valve | mm | 1.0 - 1.4 |
| Exhaust valve | mm | 1.4 - 1.8 |
| Valve seat angle in cylinder head | | 90° 30' |
| Valve guide inside diameter | | |
| Standard size | mm | 5,000 - 5,012 |
| Oversize (0.075) | mm | 5,075 - 5,087 |
| Oversize (0.150) | mm | 5,150 - 5,162 |
| Length of valve guide | | |
| Intake valve | mm | 38.7 - 39.3 |
| Exhaust valve | mm | 38.7 - 39.3 |
| Installation height of valve guide | | |
| Intake valve | mm | 10.7 - 11.0 |
| Exhaust valve | mm | 10.7 - 11.0 |
| Installation height of valves | | |
| Standard size | mm | 38.5 - 39.2 |
| Oversize (0.075) | mm | 38.1 - 39.6 |
| Oversize (0.150) | mm | 38.1 - 39.6 |
| Engine | | Z 18 XE |
| Valve length | | |
| Standard size | | |
| | Intake valve (GM) | mm | 101.2 - 101.6 |
| | Exhaust valve (GM) | mm | 100.56 - 100.96 |
| Oversize (0.075) | | |
| | Intake valve (GM K1) | mm | 100.8 - 101.2 |
| | Exhaust valve (GM K1) | mm | 100.16 - 100.56 |
| Oversize (0.150) | | |
| | Intake valve (GM K2) | mm | 100.8 - 101.2 |
| | Exhaust valve (GM K2) | mm | 100.16 - 100.56 |
| Ø Valve stem | | |
| Standard size | | |
| | Intake valve (GM) | mm | 4,955 - 4,970 |
| | Exhaust valve (GM) | mm | 4,935 - 4,950 |
| Oversize (0.075) | | |
| | Intake valve (GM K1) | mm | 5,030 - 5,045 |
| | Exhaust valve (GM K1) | mm | 5,010 - 5,025 |
| Oversize (0.150) | | |
| | Intake valve (GM K2) | mm | 5,105 - 5,120 |
| | Exhaust valve (GM K2) | mm | 5,085 - 5,100 |
| Engine | | Z 18 XE |
| Valve stem play | | |
| Intake valve | mm | 0.030 - 0.057 |
| Exhaust valve | mm | 0.050 - 0.077 |
| Perm. runout of the valve stem | mm | 0.03 |
| Ø Valve head | | |
| Intake valve | mm | 31.1 - 31.3 |
| Exhaust valve | mm | 27.4 - 27.6 |
| Valve seat angle at valve head | mm | 90° 40 ' |
| Valve rotator | | |
| Intake valve | | none |
| Exhaust valve | | none |
| Engine | | Z 18 XE |
| Camshaft | | |
| Valve lift | | |
| | Intake | mm | 8.50 |
| | Exhaust | mm | 8.00 |
) Resurfacing of the cylinder head is not permitted.