FIA Kill Switch

I'd been meaning to fit a battery isolator for a while.  Partly as a safety feature for when the car is stored in the garage and partly in preparation for possibly taking part in formal motorsport events, e.g. sprints.

There are simple isolators available that just cut the positive connection to the battery.  They achieve the goal of isolating the battery, but if turned off whilst the engine is running, will very likely kill the circuit in the alternator, as the load has nowhere to go.  Also, if the ignition coil/ECU is not isolated from the alternator, it is possible for the engine to continue running even after isolating the battery.

The solution to both of these issue is to use the more advanced model of isolator switch.  As can be seen below, this not only breaks the supply to the coil/ECU, but also dumps the alternator load to a resistor for the short period after the isolation switch is activated and before the engine ceases to rotate.

The main challenges to fitting the switch to an Avon with the bodywork fitted was finding a suitable location for the switch as well as routing the wiring.  I had some bespoke cables made up by a seller on eBay.  These were 170 amp rated and had the appropriately sized ring connectors fitted on each end.

I decided to locate the kill switch in a hole that was used for a side mirror before I fitted the cage.  The one on the other side of the car still has as blanking bung.  This location for the switch should also comply with the MSA regulations, i.e. it can be activated by the driver whilst strapped in to the car, as well as a marshal from the outside of the car.

Alternator Problem Solved

I didn't have a charge indicator light for the dashboard (digital dash has a voltmeter and a low/high voltage light).  Without this in the circuit the rectifier in the alternator does not send a charge to the battery.

With the light connected the alternator worked perfectly.  It's nice when problems are fixed easily (and cheaply).

Here is another video of the car running.  Apologies for the terrible sound quality from the mobile phone.  It is much, much better in real life.

Engine Start

I finally ran out of excuses not to start the engine.  So with a full tank of fuel and a fire extinguisher ready it was time to turn the key.  Unfortunately the battery died before it properly fired.  There is not enough power in the small race battery for extended cranking, so an hour's top up battery charge was needed.

Attempt number two, and she started straight away!  Here is the video:

I had hoped for a longer recording, capturing me driving very slowly backwards and forwards, but the video camera battery died prematurely too!

You can see smoke coming off the exhaust headers.  This cleared after a minute or so.  The engine was run until the fan cut in, at about 84oC, on the lower setting.  I'll try it again later on the higher setting.

There a couple of issues to sort out:

1.  The alternator (new from Tiger) is not charging.  I'll need to investigate this one.
2.  The high temperature silicon sealant holding the silencer to the collector partly melted and exhaust gases were seen escaping.  Hopefully it is just settling into its rest position and a re-application should keep a good seal.

Overall though I am really pleased.  Now I can get on with finishing the bonnet fitment (joyless task) and then concentrate on fitting the interior trim and seats.

Battery Bracket

Spent a few spare minutes (hours) fabricating a bracket for the lightweight battery.  The first attempt was very good, but turned out to be too large - I'd allowed a bit too much metal for the bending of the angles.  Effort number two I would rather not talk about.  Third time lucky.  Will fix this to the battery tray later with wing nuts to allow the removal/refitting of the battery.