Group 21 Service procedures - engine
29
Valve seats, grinding
Before grinding, check the valve guides and replace them if
the wear limits have been exceeded.
Grind the valve seat just enough to give correct form and an-
gle and to ensure good contact.
The seat should be replaced when distance ”A”, measured
with a new valve, exceeds 1.0 mm (0.0394”).
A new seat is ground until the measurement between the
cylinder head face and the upper area of the valve (A) is 0.0-
0.4 mm (0.0-0.0158") for both inlet and exhaust valves.
This angle is checked with a valve seat gauge after coating
the seat contact surface with a light layer of marking paint.
Valves, grinding
Valve sealing angles:
Inlet 29,5°
Exhaust 44,5°
The sealing surface should be ground as little as possible,
just enough to remove all signs of damage.
If there is an edge of less than 1.40 mm (0.0552")on inlet
valves and 1.55 mm (0.0610") on exhaust valves, the valve
must be replaced. This also applies if the valve stem is bent.
Intake valve
Check for leakage using marking paint.
If leakage is found, regrind the valve seat - not the valve -
and recheck for leakage.
Exhaust valve
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