CYLINDER HEAD—E.5
Fig. E.7. Press Tool for Valve Seat Inserts.
Inlet
Exhaust
A— 1/16 in (1,59 mm) at 45 A— 1/16 in at 45
B— 3/4 in (19,05 mm)
B— 3/4 in
C— 0.250 in (6.35 mm)
C— 0.3125 in (7,29 mm)
D— 3 in (76.20 mm)
D— 3 In
E— 1.582 1.583 in
E— 1.248/1.249 in
(40,18:40,21 mm)
31,70/31,72 mm)
F— 2.009'2.019 in
F— 1.670/1.680 in
(51,03/51,28 mm)
(43,32/43,76 mm)
G— 1/32 in (0,79 mm) radius G— 1/32 in radius
H— 1/16 in (1.59 mm) radius H— 1/16 in radius
J— 1/16 in (1,59 mm) at 45 J— 1/16 in at 45
K— 0.372:0.373 in
K— 0.372/0.373 in
(9,45i/9,47 mm)
7.
Re-cut the valve seat at an included angle of 900
as in normal procedure, so that the valve head
depth below the cylinder head face is within the
production limits given on Page B.7.
NOTE
If the cylinder head face has been
skimmed since the fitting of valve
seat inserts, then the following action
is permitted :
(a)
If the insert is in a serviceable condition,
machine to the dimensions given in Fig. E.8
and continue as in stages 6 and 7.
(b)
If the insert is damaged or unserviceable
through wear, remove the insert and replace
with a new one, but before fitting, the back of
the insert should be surface ground, removing
the equivalent depth of material to that
removed by the skimming of the cylinder head
face. Do not forget to re-chamfer the insert as
it was prior to grinding, i.e. 0.020/0.030 in
(0,508/0,762 mm) at 450. Then proceed as
in stages 3 — 7.
Valve Springs
Valve springs deteriorate because of fatigue resulting
from the combined effect of heat and the normal working
of the springs. After a period the spring becomes weak
and is then prone to failure. This, of course, applies to
all types of engines.
A new set of springs should be fitted whenever the
engine undergoes a major overhaul.
Fig. E.8.
Showing Flare to be cut at 30°.
A-0.100 to 0.105 in (inlet), 0.094 to 0.099 in (exhaust).
