Specifications

ENGINE
opening conditions. The take-off position for
this system can be found on the inlet face of the
cylinder head below the inlet ports for cylinders
No.2 and 3. This hole must be blanked off, using
the alloy blanking plug provided. The hole in
the angled abutment on the camshaft housing
(camshaft case), for the standard breather system
should also be blanked off. Apply `studlock' or
si
milar product to give additional retention. The
photographs show the two finished conditions.
The standard valves must be retained. They
can be slightly modified behind the valve head to
i
mprove gas flow, and the stem heights above the
cylinder head face can be adjusted for optimum
performance, but these operations should only
be carried out by suitably qualified personnel,
AND with close reference to the homologated
dimensions.
Heavy duty valve springs, large diameter
l ower spring platforms (valve washers), modi-
fied top retainers (valve spring cups) and thrust
pads are provided and must be assembled in the
following sequence.
I NLET VALVE
Place large diameter lower spring platform over
valve guide boss. Fit appropriate valve through
guide and press valve stem oil seal into place.
Fit valve spring, followed by the modified top
retainer and secure with split collets (valve stem
keys).
EXHAUST VALVE
Place standard rotator platform over valve guide
boss. Finish off assembly as for inlet valve.
CAMSHAFT
The design data for the camshaft supplied is as
a direct result of extensive dynamometer testing
and competition experience with this power unit.
Camshaft lubricant is provided and must be
applied liberally to the lobes prior to assembly.
During the fitting of this camshaft to the housing
(camshaft case), take care not to damage the
oil seal with the lobes of the camshaft. The
standard timing marks should be used for final
assembly, and experience has shown that in the
majority of cases they represent almost optimum
ti ming for this cam. Again there is scope for
optimising the valve timing, as tolerances in the
engine block dimensions do have an effect on
the actual timing. The correct timing for this
camshaft is confirmed by measurement of the
I NLET valve lift at top dead centre, and this
should be 4.4mm. (0.1732ins.) when measured
with zero valve clearance.
The cylinder head is attached by heavy duty
cylinder head bolts and must be fitted along with
the heavy duty, competition gasket supplied.
Make sure that the head face is thoroughly clean
and dry, fit with dry gasket. No grease or sealants
to be used. Make sure that the head is properly
l ocated on the locating dowels before any attempt
is
made to secure. Ensure that the mating faces of
the camshaft housing and cylinder head are also
thoroughly clean, then apply recognised sealant
to both faces prior to final assembly. Lightly
lubricate the thread area of the bolts to minimise
thread friction during the tightening procedure.
The bolts should be tightened in three stages,
adopting a spiral pattern sequence from the
centre of the cylinder head.
1st.

stage: 3.5 kg/m. (25 Ib/ft.)
2nd. stage: 6.0 kg/m. (45 Ib/ft.)
Final stage:
9.0 kg/m. (65 Ib/ft.)
The three tightening stages should be carried
out operating the torque wrench in a CON-
TINUOUS angular movement until the required
torque figure has been reached. This will almost
eliminate the errors introduced by the friction
i n the threads and under the bolt head. The
gasket thickness when fully clamped is 1.2mm.
( 0.047in.) which is equivalent to a volume of
6.1 cc.
As the standard engine breather system has
been deleted, an external breather must be pro-
vided. Connected to the camshaft top cover this
pipe should then lead into an auxiliary catch
tank with a minimum capacity of 2 litres. This
container could be made out of plastic but if