Offered through Mike Eck's
After purchase, you will need to ship your clock to:
71 Hillcrest Road
Martinsville, NJ 08836
The tach-mounted Smiths clock was used on Jaguars
from the mid 30's to the mid 60's.
They worked well for a while, but they are all getting
old and in need of modernization. Since the electrical
contact is the weak area in these clocks, they never
seem to run long enough for anything else to wear out.
Actually, it's not surprising that the contacts fail,
when you consider what they are required to do.
Normally, the current for the coil passes directly
through the contacts, which close and open five times
per second. Each of these cycles causes a spark,
which is easily visible. At the rate of 5 per second,
this spark occurs 18,000 times per hour, 432,000 times a
day, and 157,680,000 times per year! It's no wonder they
fail so quickly.
Our upgrade uses the contacts as a trigger for an
integrated circuit (IC), which actually provides the
power pulse to the coil. The contacts are required to
pass much less current than they normally handle.
In addition, the circuit produces a constant width
electrical pulse to the coil, which gives the balance
wheel a solid kick, no matter how bouncy or dirty the
contacts are. The same idea is used in dwell-extender
electronic ignitions. We use a custom printed circuit
board that uses surface mount techniques to shrink the
circuit down to the size where it will fit inside the
clock. None of the original clock parts are removed,
so the installation is totally reversible,
in case you ever want a non-functional clock again!
We use a state-of-the-art electronic calibrator to
adjust your clock. The calibrator is a
microcontroller-based device which counts the number of
ten-millionths of a second in a single tick. To
fine-tune the adjustment, the calibrator also keeps
a running total of 10, 100, 1000, 10,000 and 100,000
ticks. This provides an average over time, integrating
variations in individual ticks, which allows us to
adjust it so it will perform accurately when installed
in your Jaguar. However, since the clock still uses a
balance-wheel, it will never be as accurate as a crystal
controlled digital wristwatch. But if we wanted modern
technology we wouldn't be driving classic cars!