Frequently asked questions ...

1. Will the sensors on my engine work with ETB gauges?

Unfortunately, the short answer is: probably not!

Temperature Gauges:
You will need our own temperature sensor in order for the ETB temperature gauge to read correctly.

Oil Pressure Gauges:
Most engines do not have an oil pressure sensor to supply an oil pressure gauge. Instead an engine usually has a low oil pressure switch mounted on the side of the engine block. This is a simple switch that illuminates a dashboard mounted warning light should oil pressure drop below a certain level. It is not able to supply an oil pressure gauge with a suitable signal. Therefore you will require an ETB oil pressure sensor to match our gauge. ETB pressure sensors have a warning light switch built in, so the oil pressure sensor is mounted in place of the old pressure switch.

Speedometer Sensors:
Many OEM gearbox speedometer sensors will work well with an ETB electronic programmable speedometer provided that it is not also supplying an engine management system (where fitted) with a speed signal. The only sensor we know of that we can cannot match is a Renault 25/30 gearbox sensor. For further information please see the section concerning speedometer sensor set-up

Fuel Level Gauges:
ETB manufactures 3 types of fuel gauges.

The first type is matched to our standard, 6-hole, top-mount float-arm sensor. This sensor is calibrated to provide an electrical resistance of 260 Ohms at empty and 20 Ohms at full. This calibration range is similar to early Smith's type fuel level senders, as well as some Ford fuel senders (most commonly 1982-1986 Ford Sierra hatchback / saloon).

The best way to check whether your existing fuel level sender will work with an ETB fuel gauge is to measure the resistance range of the sender unit. To do this, you need to disconnect any wires connected to the sender unit and remove the sender from the fuel tank (taking great care if there is any fuel left in the tank). Using a multimeter that can measure resistance in Ohms (Ω), connect one probe to earth and the other to the connector on the fuel sender and note the resistance reading with the float at empty (lowest position) and at full (highest position).
If the reading is approximately 260 Ohms at empty and 20 Ohms at full, it will work reasonably well with an ETB fuel gauge.

BUT!!!

These sensors were not designed to work with the modern ETB air-core movements, but with old bi-metallic strip gauge movements. Therefore, although empty and full will be correctly indicated on the gauge, mid-range indication will read incorrectly. This is because ETB gauges expect a relatively linear change in resistance as fuel level changes, whereas the older Smith's type / Ford type are not linear - this basically means that fuel will appear to decrease very rapidly from reading full for the first two-thirds of gauge pointer movement and then slow considerably when the pointer nears empty.

The second type of ETB Fuel gauge has a range of 3 Ohms at empty to 180 Ohms at full. This type will match certain VDO lever-arm type fuel senders.

The third type of ETB fuel gauge has a range of between 60 & 90 ohms at empty to 0.5 Ohms at full. These are made specifically to match VDO dip-pipe fuel senders.

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2. Will ETB sensors match the threads on my engine?

All ETB sensors (temperature and oil pressure) unless otherwise stated have a 1/8"NPTF (27) tapered thread. ETB holds stock of a great variety of brass thread adapters in order to match the vast majority of engines in existence.

We make our sensors to match this thread type because it is: a) small and it is easiest to increase in thread size to fit a larger hole rather than reducing size, and b) the most common thread size.

If you tell us the make, model and year of the donor vehicle when placing your order, we can tell you what thread adapters you might need.

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3. Will the tachometer work with my vehicle's ECU (Electronic Control Unit)?

Our standard tachometers normally work by taking a signal from the negative side of the Ignition Coil. Some ECU's or Ignition systems have their own output wire dedicated for a tachometer. Unfortunately, there is no "standard" signal output from ECU's and they can vary greatly from manufacturer to manufacturer.

ETB can often match an ECU output or specialist ignition system as long as you tell ETB when placing your order what type you are using.

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4. Will the fuel sender fit my fuel tank?

Yes, if you are prepared to cut a 40mm diameter hole in the top of your tank and drill 6 mounting holes!  ETB's standard 6-hole, top-mount fuel sender is 290mm from the top of the tank to the bottom of the float unit. It is a simple float -arm sender that can be shortened to length as required.

Alternative sensors are available including Capacitive tube-type fuel senders that are manufactured to length. Please contact ETB for further information.

Please note that ETB fuel senders do not incorporate fuel feed or return pipes.

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5. If I order a mechanical speedometer, will it pass the SVA test?

The basic rule here is:-
NEVER ASSUME THAT A MECHANICAL SPEEDOMETER WILL PASS AN SVA TEST UNLESS IT HAS BEEN SPECIFICALLY CALIBRATED TO MATCH THE VEHICLE SPECIFICATION

ETB mechanical speedometers are calibrated as standard to 1000 revs of the speedometer cable to 1 mile traveled. This means that in order to read correctly when fitted to your vehicle, the speedometer cable must revolve 1000 times for each mile the car travels. (N.B. Once a speedometer is calibrated to a specific number of cable revolutions per mile, it is fixed and cannot be re-calibrated by the end user - it would have to be completely re-worked by ETB).

Because ETB manufactures gauges to customer order, should you provide ETB with the relevant information (see below) when placing your order, ETB will endeavour where possible to calibrate the speedometer to suit your vehicle during manufacture at no extra cost. However, please note should the required calibration be deemed by ETB to be an unusual specification we may have to charge a small fee for this service.
The number of cable revolutions in a distance of 1 mile is dependent on 3 factors (unless the cable is driven from a wheel hub, where it will be the tyre rolling circumference that is the most important factor). These are:-

  1. Tyre Size (rolling circumference) (e.g. 205/50 15")
  2. Differential / final drive ratio (e.g. 3.92:1)
  3. Speedometer cable worm and drive gear ratio inside the gearbox (e.g. 3.43:1)

Unless all of these factors are known, then the only failsafe method of calculating cable revolutions per mile is to carry out "the Cardboard Disc Test":-

The Cardboard Disc Test
You will need 2 to 3 people to help you carry out this test!

  1. Connect the speedometer cable to the vehicle gearbox.
  2. Cut-out a circular piece of cardboard, mark the centre point and draw the four points of the compass (i.e. North, South, East and West) near the edge of the disc. This will be used to count revolutions and portions of a turn, so the more markings indicating degrees of rotation the better).
  3. Put the car in neutral.
  4. Ensuring that the front wheels are securely chocked so that the vehicle cannot move during the test, jack-up one rear wheel (assuming the vehicle is rear wheel driven) and ensure that the other wheel is chocked and cannot rotate. (If you have a limited-slip differential, you will need to jack-up both rear wheels).
  5. Push the centre of the cardboard disc onto the inner part of the speedometer cable.
  6. Turn the rear wheel 100 complete turns (if you have a limited-slip differential, you will have to turn both rear wheels in the same direction 50 complete turns) and have someone counting the number of revolutions of the cardboard disc.
  7. Note down this information, including any portions of a turn (e.g. 56.2 turns per 100 turns of one rear wheel).
  8. If you doubt your first result, repeat the test again!
  9. Telephone ETB on (01702) 601055 with this information along with the tyre size that will be fitted to the vehicle, and we will be able to tell you if your speedometer matches your vehicle's specification.
  10. If not, then the speedometer will have to be re-calibrated at extra cost.

Please note that ETB Instruments Limited does not accept liability for vehicles failing an SVA test as a result of incorrect speedometer readings. The responsibility of ensuring your car passes on speedometer calibration lies with the end customer!

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6. Are ETB instruments SVA compliant?

YES. The outer bezels were specifically designed to pass SVA. Of course you must ensure that your speedometer is calibrated to match your vehicle.

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7. Will my speedometer cable fit an ETB mechanical speedometer?

All mechanical, cable driven speedometers supplied by ETB have a metric M18x1.5mm thread fitting. The inner cable is a 2.6mm (0.104") square drive. In order to ensure that the mechanical speedometer functions correctly, the speedometer cable must match this type of screw-on fitting. If it does not match, then you will either have to have a new cable made or the old one re-ended. ETB does not undertake this type of work, but recommends either Speedy Cables Limited on (01693) 732213, or Speedograph Richfield on (0115) 926 4235.

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8. I want to buy an electronic speedometer.
Will I need a sensor and what is the best / easiest sensor set-up?

You will need to provide the speedometer with a signal related to the vehicle's speed. Some OEM gearboxes have electronic sensors that can provide our speedometer with a suitable pulse signal. Please check with us before ordering to check if the gearbox (or ABS sensor) is compatible with our electronic speedometer.

If you do not have a gearbox sensor, you have several other options:-

i. Light Duty sensor and Magnet Combination
This involves mounting 2 magnets 180º apart on a prop-shaft, drive shaft coupling or wheel hub (in-fact anywhere that rotates in relation to vehicle speed). You need then need to make a bracket to hold the sensor in place such that it points at the magnets as the rotate on the shaft.
This is the easiest method to set-up.

ii. Heavy Duty Sensor and Disc Combination
This entails mounting our speedometer disc (150mm diameter with 15 holes on a 130mm P.C.D.) between the prop-shaft flange and differential flange (i.e. sandwiched between the two flanges). You must them fabricate a bracket to hold the sensor in place such that it points at the centre of these perimeter holes as the disc rotates. The sensor creates a pulse for the speedometer each time the metal between each hole passes in front of the sensor head.
More difficult to set-up than sensor and magnet combination, but more reliable than using bolt heads.

iii. Heavy duty sensor and bolt heads
You can also use the heavy duty sensor in conjunction with ferrous bolt heads. These could be bolt heads on a front hub or those connecting the prop-shaft to the differential for example. (Westfield for example sometimes use bolts on the driveshaft coupling). The bolt heads must be ferrous (i.e. have an iron content and attract a magnet), and have a flat surface. (The side wall of a allen-key bolt would do)
Again, you are required to make a bracket to hold the sensor in place. This set-up is reliable if undertaken correctly, but is more difficult than using the light duty sensor and magnet combination.

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9. Where do I fit my oil temperature sensor?

The easiest position is generally in place of the oil drain / sump plug by using an appropriate thread adapter.  If the plug is located on the bottom of the sump, or should ground clearance be a problem, you may need to find an alternative port on the engine block accessing the oil gallery to mount the sensor.

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10. What is best: Ammeter or Voltmeter?

Ammeters measure electrical current (in Amperes) flowing through a circuit and therefore are wired in series with the load. They are useful when using a dynamo based charging system, as they can warn the driver (for example) of negative charging conditions. However, because ammeters are connected in series with the circuit being measured, it requires that current flow (both positive and negative) passes through the ammeter itself. This means that heavy duty cables are required to connect to the ammeter in order to withstand the large electrical current being passed through it.

If using an alternator based electrical system, the electrical current flow tends to higher than that of a dynamo, and therefore the greater the current flow the larger the cables need to be. Modern alternators tend to be connected to an ignition warning light that illuminates should the charging current become too low and thus reducing the need to constantly monitor the charging current. However they are a useful, instant method of measuring current drain incurred from various loads (e.g. headlights).

Voltmeters measure electrical "pressure" and are connected across a circuit. This means that wiring is very simple and standard automotive wire required for the other gauges can be used. Voltmeters will provide you with the current status of the car battery, as well as indicating charging problems (by a gradual voltage drop indicated on the gauge).

In general, if you are concerned about electrical wiring, ETB would recommend a voltmeter rather than an ammeter.

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11. What size holes do I need to cut in my dashboard in order to fit ETB gauges?

The size of our gauges denotes the outside diameter of the main body or casing of the instrument. In other words, a 52mm gauge has a 52mm diameter casing. This means that the hole required in the dashboard needs to be a little bigger:-
52mm Gauges - 53 to 54mm diameter hole
80mm Gauges - 81 to 82mm diameter hole
100mm Gauges - 101 to 102mm diameter hole

The diameter of the outer bezel of each gauge is larger than the casing diameter. The overlap of this bezel is approximately as follows:-
52mm Gauges - Outer Bezel Diameter = 56.5mm
80mm Gauges - Outer Bezel Diameter = 85mm
100mm Gauges - Outer Bezel Diameter = 105mm

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12.  How do I wire up my gauges?

Please refer to the section under wiring diagrams listing appropriate PDF files for download.

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13. What colour instrument dials do you sell and what colour pointers can I have?

We currently manufacture black, white, yellow and magnolia background dials. The standard pointer colours are black, white or red. Special pointers colours are available at extra cost.

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14.  What outer bezels do you make?

We currently make black, chrome or polished brass bezels.

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15. How can I order and how do I pay?

You can order your instruments by either telephoning ETB Instruments on +44 (0) 1702 601055 or by faxing us on +44 (0)1702 601056.

We accept payment by cheque in advance (please telephone ETB in advance of sending a cheque in order to confirm total amount due) or by credit card:-

We accept the following cards:-
Visa, VISA Debit, MasterCard, Maestro (Switch), Solo or American Express.

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16.  What are the delivery charges?

Standard Charges for orders over £25 are as follows:-
Recorded Post up to 2 Kg - up to £7.50
UK Special Delivery Next Day before 1pm up to 2 Kg - £10.00
BUSINESS POST up to 20 Kg - £10.00 + VAT at 20%
For details of international shipments please call

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17. Do you repair or re-calibrate instruments in general?

No, only ETB Instruments' own range.

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