DO NOT DO THIS BY JACKING UP THE

WHEEL AS THIS GIVES COMPLETELY

FALSE RESULTS

Put a chalk mark at the bottom of the measured wheel and then push the car straight forward (with gear in neutral), counting exactly 6 revolutions of the wheel, whilst a partner counts the number of times that the arrow on the cable revolves.

(1) Take the measurement from the centre of the hub of a drive wheel to the ground, with the tyre pumped to normal pressure.

ANSWER:(1)__________ distance in Inches.

(2) Put a chalk mark at the bottom of the measured wheel also marking on the ground          where it meets. Push the vehicle forward one revolution of the chalk mark and record  the distance travelled.

ANSWER:(2) __________ distance in Inches

(3) Now disconnect the speedometer and place a cardboard arrow on the end of the protruding inner speedometer cable as shown in the diagram on the right.  >>>

ANSWER:(3)__________ number of turns of the cable. (N.B. include parts of a turn e.g. seven and a quarter turns).

Now send us the values  recorded for ANSWER:(1)  ANSWER:(2) and ANSWER:(3) above

To ensure that your speedometer reads accurately when fitted to your particular vehicle, we will need to calculate the required "revolutions per mile" >>>>

For calibration of a new instrument, or re-calibration of an existing instrument, we will need you to provide the following information from your vehicle...

Print calibration information only. Write in your results and send it to us. (Prints as one A4 sheet)

Ensure the connections on the speedometer match the connections on the speedometer cable. There are three possible connections on the reverse of the speedometer:

• (1) A trigger/snap-on connector (as featured on the 100mm Smiths Classic Speedometer)
• (2) An SAE cable connection (as featured on the 80mm Smiths Classic and AC Cobra Speedometers)
• (3) A mini thread connection.

Connections are not interchangeable. It is far easier and cheaper to change your Speedo cable to match the back of the instrument than the other way round. We can have new Speedo cables made up for you at a competitive price.

 INSTALLATION

Speedometers cannot just be changed from one vehicle to another. They only read accurately when used on the unmodified vehicle for which they were originally calibrated.

Even when used on the original vehicle, any changes that may have been made to the wheels, tyres, gearbox or other related parts can seriously affect the speedometer readings to the extent that the vehicle will fail to pass an IVA test or may result in a speeding fine. In this case, the speedometer will need to be re-calibrated.

CALIBRATION

The instrument is fitted with a connection known as a gas pipe fitting. In order to transmit oil pressure to the instrument you will require an oil pressure pipe with end fittings (see catalogue for part number HF22000etc.). In some instances you may require to operate an oil pressure warning light in addition to your mechanical oil gauge. In this case, you will require a tee piece, which screws into the engine block and enables the fitting of a pressure switch on one branch of the tee and the oil pressure pipe on the other. We have many more tee pieces than catalogued and can usually sort you out. Providing us with as much detail as you can about the engine is a big help.

Minor electrical gauges have either bi-metal (will require a voltage stabiliser) or air-core (voltage stabiliser not required) movements and require dedicated sensor units. Adapters may be required to go between the thread on the engine block and he thread on the end of the sensor unit. We have many more adaptors than we had the time to catalogue. Call stating threads or the engine and we will try to help you.

Mechanical Temperature Gauge

Some minor electrical gauges (prefixed with a "B" e.g. BT2240-00C) require a regulated voltage supply and at least one voltage regulator is required per three gauges. The voltage regulator must be earthed.