Bob Wilson asked:

What are the USA part number equivalents to British part numbers for light bulbs, primarily the turn signal lamps? Help!

Tiger Tom replied:

Bob, I am not aware of any interchange list. I’ve seen some references in years past of a lamp or two but I a not aware of a list of popular lamp types.

by Paul Dierschow & Tom Ehrhart

Originally Printed 6/87

Shown below is a wiring diagram for a Mk I Tiger with the tachometer circuit highlighted. Although the harnesses are different for Tigers and Alpines, the principle of that circuit is exactly the same. This is also true of most other British cars with electric tachometers from the 1960′s through the early 1970′s.

In Figure 1, the tachometer circuit has been removed from the factory wiring diagram and rearranged, showing the simple concept of this design. Several items are important to remember in understanding this circuit:

1. The ignition coil receives its power via the tachometer loop wire (white).
2. The tachometer must also receive constant switched power (green) and must have the housing grounded (black).
3. The tachometer is simply a voltmeter that measures the voltage generated by an internal printed circuit corresponding to the number of pulses produced by the coil in the low-tension circuit.
4. The counting of these pulses is affected by variation in dwell angle or point gap, especially with dual point and after-market distributors.
5. The inductive loop of wire on the back of the tachometer must be properly oriented for the system to function.

Tachometer Wire Hook-Up

This impulse tachometer cable installation is for negative ground; reverse A & B for a positive ground system. The ground wire must be attached under one of two knurled mounting posts. The other end of the wire must be connected to the car chassis.

As shown, Wire A goes to SW terminal on the coil or to the 12 volt terminal of coil. When using a ballast resistor, this lead must be the input lead to the resistor with the resistor output lead going to the coil.

Wire B goes to No. 2 terminal of ignition switch, or to a 12 volt source that is turned off with the ignition switch.

Interchangeability

Since the tachometer is simply a pulse counter, all tachometers of this type are basically the same, differing only in calibration, type of ground, and face design. It is therefore, possible to use the unit from an Alpine or an MG, change the face and recalibrate it to have a suitable replacement for a defective Tiger tachometer. To replace the face, remove the bezel, glass and glare ring. Remove the needle with its hub from the tiny shaft by very carefully prying both sides gently and evenly at the same time. Then, the two small black screws are all that hold the face to the body. Since the unit is simple to recalibrate, it is also possible to put in a unit with a higher range of reading to accommodate the capabilities of a high performance engine. A tachometer without any indicator jewels on the face would be preferable, since light from the face illumination bulb would show through unless it is covered. A Series V Alpine has a 7000 RPM tachometer with the proper face style to match a Mk II Tiger.

Calibration

Recalibration procedure is as follows:

1. With the tachometer removed from the car, remove the chrome bezel, glass and glare ring by turning and aligning the tabs with the gaps in the housing. It may be necessary to bend up the tabs slightly to be able to loosen the bezel enough to turn.
2. Remove the two screws from the back of the housing that hold the assembly to the can. Look carefully as two other screws do not release the guts but are part of the internal assembly.
3. Now a 5/8 ” diameter black (or yellow) plastic variable resistor is exposed. It has a narrow screw slot in it that is easily turned slightly for exact calibration. It can be turned enough to change from a four to eight cylinder reading.
4. The tachometer can now be rewired temporarily in the car and adjusted while it runs parallel to a good quality dwell tachometer and matched to that reading. The tachometer calibration will ensure accuracy over a small range around the point of calibration. For example, if adjusting the tachometer to 3000 rpm it will likely be accurate from at least 2000 to 4000 rpm. Although possible, in most instances, do not expect your tachometer to be accurate at 1000 and 6000 rpm if it was calibrated at 3000 rpm. the required calibration by a professional instrument re-builder.
5. If necessary, for future adjustments, you can drill a hole in the proper location on the back of the housing to make recalibration easy without removal from the car. Use the following template:

Changing Grounds

It is easy to convert your tachometer should you want to use a positive ground tachometer or change your Series IV Alpine from positive to negative ground. The procedure is:

1. Remove the guts of the tachometer from the housing as listed from above.
2. On the rear most board, find the large brown resistor that connects to the terminal for the large green wire (power) from the harness and the small green wire soldered to the silver button adjacent to it (ground).
3. Carefully unsolder these connections from the board.
4. Reverse these two connections and re-solder. You can cut the long lead from the resistor or bend it backwards to fit properly. CAUTION; Items 1,2,3 & 4 apply only to tachometers where the printed wiring board ([PWB) circuitry do not come in contact with the metal meter frame. Examine carefully. It will be necessary to modify the circuitry if it comes in contact with the meter frame.
5. Reassemble the unit.
6. If you are changing the car from positive to negative ground, you must also do the following:

• Mark and cut the white induction loop wire a couple of inches from the plastic block.
• Reverse the connections and re-solder and tape them. Don’t forget that this is your ignition lead, so be sure the connections are good.

Author Unknown
Originally printed 1/84

The battery should not only be disconnected for winter storage, but also removed entirely from the luggage compartment. We know of at least one damaged car (Note: maintenance free batteries are riot without fumes). The several minutes spent removing the battery may save headaches, frustration and dollars later.

Your battery should be fastened down properly at all times; don’t even test-drive the car without properly securing your battery. If the OEM tie down is not available, improvise. We recently repaired quarter panel that sustained damage from an electrical fire. The driver was lucky considering where the gas tanks are located. Again, a small investment of time and money saves one large headache later.

The venerable Joseph Lucas Ltd. has done it to us again. The infamous 4TR regulator used on the Series V Alpine has been changed from a three (3) terminal unit (Figure 1) to a newer four (4) terminal unit (Figure 2). Both units are electrically the same as far as use in the Series V is concerned. Just reconnect wires as shown in figure 4. DO NOT connect any wires to the + terminal of the four (4) terminal unit when using this unit in a Series V. As a safety precaution be sure power is off i.e., no voltage is present at the wires to be connected to the regulator. To be sure, you should disconnect the battery.

By Ron Fraser
First published in Rootes Review, April 2006

The primary wires of the ignition system are all the small diameter wires from the ignition switch to the inside of the distributor. All of these wires and connectors, especially from the ballast resistor to the distributor, need to be inspected for cracked insulation, contamination, corrosion or other problems. You want to eliminate any parts that might be leaking voltage or that might be creating high resistance.

Voltage = Resistance x Amperage

Bad wires, bad connections or corrosion = more resistance.

More resistance = less amperage, less voltage or both = less performance

Anywhere you can reduce the electrical resistance in the primary wires will help performance. Remember, in the run position your ignition is not running at 12v; it’s most likely 9v due to the ballast resistor. You need to keep as many electrons flowing inside the ignition system as possible.

Inside a typical Ford distributor

Many manufactures used fabric coated wires inside the distributor; these work fine until the fabric becomes contaminated and damp; they begin to short, giving poor performance. They can also short out resulting in no spark and no start. These same kinds of problems will happen with cracked plastic insulation or oil contaminated wires.

I have fixed several distributors by replacing those fabric coated wire with modern plastic coated wire and soldering the connectors to the wire. The distributors I fixed were mainly Japanese cars, 70′s Hondas and Datsuns. Each car responded with better performance and better fuel mileage.

The point is to check all the primary wires for any problems, and fix them by whatever means you think is appropriate. This is where your VOM meter is your friend, used to check resistance, or voltage drops if you like. It is also a good idea to check all the ignition ground paths; again good ground paths means less resistance which means better performance.

Now that I have said all that, the easiest way to eliminate problems inside the distributor is to install a Pertronix unit or similar to eliminate the points, but you should still check the rest the primary system for any resistance problems.

NUMBER: 68-18
DATE: 10-14-68
GROUP: Engine
SUBGROUP: Intake Manifold

MODELS: Alpine V
SUBJECT: Engine Vibration

THIS BULLETIN CANCELS AND SUPERSEDES BULLETIN 67-45 DATED 4-3-67.

When you receive complaints of engine vibration which. can normally be felt through the accelerator pedal especially at 3200 r.p.m,. it is recommended that a clamp is fitted to the intake manifold in accordance with the following instructions:

Remove center bolt from intake manifold.

Remove the existing center bolt and replace with Imp cylinder head bolt, part #9003239 (3/8″ U.N.C. bolt).

Assemble washers, clamp, nut and spacers in order shown in figure 1, to bolt ‘F’.

Fit clamp assembly at position shown in illustration and tighten bolt ‘F’ to 20 ft. lbs. and then tighten nut ‘C’.
NOTE: ALWAYS TIGHTEN BOLT ‘F’ BEFORE NUT ‘C’.

DESCRIPTION – PART NUMBER – QUANTITY

Plain Washer ‘A’ – 9068016 – 3

Spacer – 9088193 – 2

Nut ‘C’ 3/8″ UNC – 9029168 – 1

Clamp ‘D’ – 1214539 – 1

Lock Washer ‘E’ – 9661241 – 1

Bolt ‘F’ – 9003239 – 1

J.J. Rivers
Service Manager

NUMBER: 68-13
DATE: 6-27-68
GROUP: Electrical
SUBGROUP: Gauges

MODELS: All Models Equipped With Alternators; Negative Ground Only
SUBJECT: Fluctuation of Ammeter Needle/Ignition Warning Light In Models Equipped With Negative Ground Alternators

On cars equipped with Lucas 10AC or 11AC alternators and having NEGATIVE ground systems, some owners may report a condition where the needle fluctuates or the ignition warning light flickers. This will only occur under light electrical load conditions (i.e. in daylight with no accessories in operation) and can be immediately overcome by applying an electrical load such as switching on the headlights.

This condition will only occur when the battery is in a full charged state and is in no way detrimental to the functioning of the alternator charging system. If, however, an owner is insistent on immediate action being taken, first be sure that there are no bad connections in the circuit between battery and CI terminal on the 4TR control and from negative on the 4TR control to ground. Refer to WSM 149, Section N, for diagram and location of snap connections, etc.

If the fluctuation continues after this service, then the 6RA relay should be replaced. Be sure that the new unit, part number 1800746, is date coded 1/67 or later.

J.J. Rivers
Service Manager

NUMBER: 67-15
DATE: Jan. 23, 1967
GROUP: Electrical
SUBGROUP: Fan Belt

MODELS: All Models Equipped With Alternators
SUBJECT: Fan Belt Adjustment

Whenever it is found necessary to adjust the fan belt on cars equipped with alternators, adjustment of the alternator must be carried out at the forward mounting flange in order to tension the belt.

In no case should the body or rear of the alternator be used when adjusting, otherwise severe bearing damage may occur.

Would you please bring this to the immediate attention of all Service Personnel.

T.H. Bullard
Mgr. Service & Parts

NUMBER: 67-14
DATE: Jan. 23, 1967
GROUP: Electrical
SUBGROUP: Test Fuses

MODELS: All Models
SUBJECT: 35 Amp, Production Test Fuses

While testing instruments and wiring circuits in Production, a 35 amp. fuse is fitted between the starter solenoid and the main feed wire. On completion of the checks, this fuse is removed at the Factory prior to release.

Should this fuse be inadvertently left in the system and the total electrical load exceed 35 amps., there will be total failure of all circuits, causing complete immobility of the car. On those vehicles fitted with alternators this can cause severe damage to the semi-conductors with subsequent failure of the unit.

You are requested to check all cars during new vehicle preparation to ensure that this fuse has been removed. If any are found still fitted the complete assembly should be removed and returned to the Service Department with details of the Chassis Number of the car.

T.H. Bullard
Mgr. Service & Parts

NUMBER: 67-2
DATE: Jan 23, 1967
GROUP: Electrical
SUBGROUP: Alternator Support Bracket

MODELS: Alpine V
SUBJECT: Alternator Support Bracket

A new support bracket and securing bolts have been introduced in production from chassis number B-395-002437.

The new bracket has tapped holes and will provide a more secure hold down for the alternator.

It is recommended that the new bracket part #1238066, securing bolt part #1950581 and plain 5/16″ washer under the head of the bolt be used in cases where the mounting bolts continually loosen.

T. H. Bullard
Manager – Service & Parts