ON INSTALLATION AND CALIBRATION
(a) Mounting and Driving the Metering Distributor
The position chosen for the metering distributor must be such
that sufficient space is available for fitting, connecting up,
etc., and that the unit is not close to an exhaust pipe or
The metering distributor can be mounted at any angle between
horizontal and vertical. It is essential, however, that the
running petrol seal on the drive shaft should be kept wet with fuel,
so that if the unit is mounted horizontal, the leakage fuel tube
on the drive end flange must be positioned above horizontal.
A half-engine speed drive is necessary for the metering distributor
rotor, the torque required being on the order of 0.5 Lbf ft. The
drive is transmitted to the rotor through an Oldham-type
Suggested methods of driving the metering
distributor are either:-
( i ) by a cogged belt drive.
( ii ) by an angled
drive from the ignition distributor drive shaft.
( iii ) by direct camshaft drive, although in this instance
some special intermediate coupling may be necessary
to offset the effects of torsional oscillation.
For racing applications, which are frequently "one-off"
method ( i ) is preferred, since it does not necessitate special castings
or machining of major engine components. It is necessary, however,
to employ an adaptor which incorporates a bearing and petrol seal,
details of which will be provided be the Lucas P.I. Design Office.
rubber cogged belt. 0.5 in (12.7 mm) wide and 0.375 in (9.37 mm)
pitch, will be found to give successful results.
The best manifold arrangement for high-performance racing engines is
undoubtedly one having separate intake ducts for each cylinder, with
a slide-type throttle valve situated conveniently close to the cylinder
head (see illustration
LSK487). It is appreciated that a slide-type
throttle mechanism of this nature necessitates precision engineering
with its accompanying cost, and a less expensive alternative frequently
adopted is the use of individual butterfly valves in the intake ducts.