FUEL CAMS, theory and design
Do you have a clever method of
measuring, and charting fuel cam curves for racing Lucas metering setups?
We are trying to collect and share fuel cam curves from known applications.
Please email with your ideas!
Fuel cams on Lucas race metering come in a variety of different
shapes and sizes. Each one unique to a particular engine and horsepower
range. How do you compare different cams, or design a new cam? We use a
simple degree wheel and a pair of calipers to measure and document cams.
Place the cam in the center of the degree
wheel with the throttle linkage hole centered on the "0"
line and carefully measure with calipers along various degree lines. If
your cam is used, it is sometimes easy to see a telltale mark showing
the range of use. Document the dimensions, trace the cam for quick
visual reference, and write down all important data associated with this
cam like shims, motor, car etc.
The Lucas manual "Notes
on Installation and Calibration - Racing Cars" has instructions
on cam control curve design.
These three fuel cams, Small block Chevy Can-Am, Big block
Chevy offshore boat, and a 4 cylinder SV, illustrate the range of
differences. (click to enlarge)
Printable degree wheel
for fuel cam measurement.