Fitting new type camshafts. The special inlet cam No. 024534 first intro-
duced in 1960 can be fitted to earlier type engines providing the crank-
case alongside the timing side bush is machined for clearance, as the valve
lift is higher. The inlet tappet guide should also be reduced in length
(inside the timing cover) to the extent of 8", also use inlet valve guide
026030.
G80 R Models. Engines for this model use the inlet cam 024534 and a
special exhaust cam marked CE Part No. 024535, the exhaust valve opens
83° b.b.d.c. and closes 60° a.t.d.c.
The valve lift is .445" (use No. 1 mark). This combination is best suited
where high r.p.m. is required for short circuit events, or in drag events
providing the engine is taken up to 3,500 r.p.m. before take off. Where
good torque is needed at comparatively low r.p.m. the 1960 set up is the
best arrangement.
Valve springs. These springs (which are shot blasted after manufacture)
must be free from bruises or blemishes, which can cause a spring break-
age. The free length (unassembled) taken between the wire centre for the
spring leg and the portion which engages with the valve spring collar is
1A".
Valve spring collets. Must be free from burrs and a good tight taper fit
in the valve spring collar. Loose fitting collets can cause a valve breakage.
1962 Engines. An improved type of valve operating mechanism is used
on these engines, comprising the following parts:
(1) Long push rods
(2) Short tappets
(3) Tappet guides
(4) Inlet rocker
(5) Inlet camshaft
(6) Exhaust camshaft
2 off 028185
„ 028182
„ 028184
1 off 042043
„ 028191
„ 028193
The new type parts can be used on earlier type engines.
1964 Model GS5 CS; G80 CS; 350 c.c. and 500 c.c.
Standard Models
Lubrication. A gear type oil pump driven by the worm gear on the timing
side axle is retained by two studs, and secured by two nuts. A conical
shaped heat resisting rubber seal is attached to the pump body, where it
abuts against a drilling in the timing cover.
From here oil is fed to the big end via a steel quill, which enters the
timing side axle, lubricating the big end assembly. A by-pass from the
main feed, taken from the timing cover conveys oil to positively lubricate
the rocker gear. The oil supply is regulated in a manner described for the
earlier type engines.
The oil seal. It is important that the oil seal is under light pressure when
the timing cover is fitted, for a reason that is self evident. When both
valves are closed and the timing cover fitted, the pressure of the seal
should move the cover outwards, making a gap of about .010". If pressure
does not exist, use packing shims, provided for this purpose, between the
seal and the pump body. Conversly too much pressure can mutilate the
seal and cause oil leakage.
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