CYLINDER HEAD — Inspection (Cont'd) / Valve Seats / Replacing Valve Seat for Service Parts
EM-33prose procedureInspection (Cont'd)
Valve guide replacement (continued)
- 4Heat cylinder head to 110 to 120°C (230 to 248°F) and press service valve guide into cylinder head. Projection "L": 11.5 - 11.7 mm (0.453 - 0.461 in).
SEM159D - 5Ream valve guide. Finished size: Intake & Exhaust 5.500 - 5.518 mm (0.2165 - 0.2172 in).
SEM932C
| Specification | Value |
|---|---|
| Service valve guide press temperatureHeat cylinder head before pressing | 110 - 120 (230 - 248)°C (°F) |
| Service valve guide projection "L"After pressing into head | 11.5 - 11.7 (0.453 - 0.461)mm (in) |
| Reamed valve guide finished I.D. (Intake & Exhaust)Finished size | 5.500 - 5.518 (0.2165 - 0.2172)mm (in) |
Service valve guide press temperatureHeat cylinder head before pressing
110 - 120 (230 - 248)°C (°F)
Service valve guide projection "L"After pressing into head
11.5 - 11.7 (0.453 - 0.461)mm (in)
Reamed valve guide finished I.D. (Intake & Exhaust)Finished size
5.500 - 5.518 (0.2165 - 0.2172)mm (in)
VALVE SEATS
Check valve seats for any evidence of pitting at valve contact surface, and reset or replace if it has worn out excessively.
IMPORTANT
Before repairing valve seats, check valve and valve guide for wear. If they have worn, replace them. Then correct valve seat.
Cut with both hands to uniform the cutting surface.
Replacing valve seat for service parts
- 1Bore out old seat until it collapses. The machine depth stop should be set so that boring cannot continue beyond the bottom face of the seat recess in cylinder head.
- 2Ream cylinder head recess. Reaming bore for service valve seat, Oversize [0.5 mm (0.020 in)]: Intake 29.500 - 29.516 mm (1.1614 - 1.1620 in); Exhaust 25.500 - 25.516 mm (1.0039 - 1.0046 in). Reaming should be done in circles concentric to the valve guide center so that valve seat will have the correct fit.
SEM795A
Intake
Reaming bore for service valve seat — Oversize [0.5 mm (0.020 in)] mm (in)29.500 - 29.516 (1.1614 - 1.1620)
Exhaust
Reaming bore for service valve seat — Oversize [0.5 mm (0.020 in)] mm (in)25.500 - 25.516 (1.0039 - 1.0046)