Toro groundsmaster 455-D - Page 68

8. Check the protrusion of the swirl chambers
(Fig. 68, A).
Protrusion: 0 to 0.03 mm
Achieve this dimension by machining faces (a) and (b).
9. Check the valve recess (B).
Exhaust: 0.9 to 1.45 mm
Inlet: 0.5 to 1.05 mm
Achieve this dimension by machining the valve seats.
10. Lap in the valves.
11. Re-install the valves.
IMPORTANT: If the cyl ind er head has been
m
achined, fit compensating washers under the
valve springs. (See Identification and Specifications
section.)
12. Install the shims as removed in step 2. If replacing
c
ylinder head or if cylinder head has been machined,
install a basic shim (Fig. 69, Item 6) (2.425 mm thick) to
each valve stem and check that each shim is higher than
the spring cup (Item c). If a shim is not higher than the
cup, grind the top of the cup (Item c).
13. Re-install the tappets.
14. Oil the camshaft bearings.
15. Install the camshaft, with the DI
ST mark at the timing
gear end.
16. Progressively tighten the bearing caps to a torque
of 17.5 Nm (13 ft-lb). The bearing caps have cast-in
markings for correct installation.
Figure 68
c
Figure 69
Figure 70
Engine Page 3 - 50
Rev
. B
Groundsmaster 455-D