Thursday, 17 January 2013


My main task for the month is to finish the electrical work which I thought would be fairly easy, but it's going rather slower than I had expected, partly due to the large number of alterations and additions.
As mentioned in a previous post, I've replaced the Lucas dynamo with a Dynalite alternator which looks almost identical.  Producing 40 amps, it is a considerable improvement on the dynamo output of 25 amps and will also start charging at a much lower RPM.  However it still falls quite a good way short of a modern car alternator at 70 to 80 amps output.  This would not normally be an issue with a fifties car, but given the amount of junk I've added I need to be aware of it's limitations.
Take for example, theoretical power requirements on a very cold and wet night - Essentials first :

Head Lights - Halogen - 2 @ 65 Watt       11.0 Amps
Side Lights 4 @ 5 Watts                          1.7 Amps
Wipers                                                    3.3 Amps
Water Pump (Electric)                             10.0 Amps
Heater Blower (Max)                                8.0 Amps
Heater Matrix Pump (Max)                       1.3 Amps

Total circa 35 Amps based on 12 Volts (31 Amps at 13.5 Volts).

Add in 8 Amps for the radiator cooling fan (unlikely, but possible if stuck in traffic) and we are on, or possibly over the edge. With 80 amp hours of fully charged battery capacity and an 'off' switch for the heater fan, not really a worry, but not a good idea to turn on the spot lights, another 7.5 Amps.  The music system (at full whack a potentially massive 20 plus amps) is definitely out. Other odds and ends like phone charger, instrument and map reading lights (or sat-nav) are negligible, but it all adds up.

All of the push in type bullet connectors which are the source of endless problems after a year or two are being replaced with fully soldered joints.  Other terminations used are screw type terminal blocks in enclosures and modern high quality multi-way connectors to connect the dash-board, the small ancillary switch panel for indicators / spot light switches, and the switches and other bits hidden away in the central arm rest.  The plan to ensure none of the additions are visible seems likely to be realised.

Common but reliable termination block for lights and indicators.

With lid in place, enclosure is IP66 rated

Multi-way connectors make dashboard removal easy.

One wiring job I've not been looking forward to is the mess of cables and connections around the Voltage control box.  In addition to the very stiff and awkward original looms there are another twenty odd cables (immobiliser, indicators and new hidden fuse box feeds in and out, of varying gauge) which need to be terminated but all out of sight.  The key to a reliable termination for the RF95 control box and other screw down terminals is having unstressed cables which don't rely on the screw to hold them in place but sit naturally where they need to be.  It takes a good deal of time and some stripping back of the original looms outer cotton covering to achieve this. Even with the utmost time and care, I would have to say this is not a happy arrangement.

Only the original wiring on show
 Back in the early ninety's car theft in the North East of England was endemic, with joy riders stealing anything that was not reasonably protected from theft.  After-market car alarms and immobilisers were big business but their design and installation often left a great deal to be desired.  Trac Communications designed and manufactured one of the better products using a newly developed fob which transmitted a code into a receptor and then to a processor which in turn opened or closed a couple of relays usually feeding ignition and fuel pump circuits.  Certainly possible to work around by a clever lad with plenty of time and a good knowledge auto electrics,but sophisticated enough to stop 99.99% of half wit twoc'ers.  The product was picked up by the UK's biggest car security and  immobiliser company at that time.  Trac manufactured them on their behalf and did very well out of it.  Eventually it became the norm for manufacturers to fit their own devices to all new cars and production ceased, but a small stock of a few hundred were retained as spares / replacements but never used. Since then I've fitted one to every classic I have owned and given quite a few to other classic owners.  100% reliable, they will certainly stop an opportunist thief which is probably the most likely sort to nick your classic.  Needless to say, one is secreted within the innermost depths of the 120 with its confusingly identical mass of black unmarked cables.

Trac Immobiliser - at the cutting edge of theft prevention in the ninety's.

Slightly fanciful, but I came across this image by accident and couldn't help noticing the similarity in shape.

Next Post early February