Keeping Electrics Dry
Bright Sparks Don't Get Feet Wet !
Part 1 - The Need
Imagine a garden hose, propped up on a brick aiming a jet at a bucket several metres away. Provided the pressure is right,
all the water will go in the bucket.
This pressure is like the 25,000 (or so) volts needed to fire the spark plugs, but before you go replacing the plug leads with garden hose, perhaps I had better explain.....
Electricity is like water in that it has to be carried to the point where it is needed, with sufficient pressure and without resistance or leaks, and then allowed to return to earth.
Just as water is carded under pressure in a pipe or hose, electricity has to travel through cables by the force of the atoms hitting against each other, transmitting pluses of energy to travel along the cable.
This brings us to the subject (have you guessed it yet?) of waterproofing, or more exactly how to get through water and still have an engine running on all pots.
Back to the hose - reducing the pressure in the hose by causing it to leak to the ground will result in less or no water hitting the bucket. The same with your spark. Not enough pressure to the hose will have the same result, so will a kink in the hose - or resistance in your leads. One problem will be magnified in the presence of one or more of the other problems. I was going to use the metaphor of a man standing at the urinal, not enough pressure in the stream and he will get wet feet, but the Editor would probably insert some bright remark like 'is that why women never get wet feet on Club Trips'
Back to the subject - not enough 'pressure' can be caused by a faulty coil, poor points maintenance, faulty ballast resistor. Worn leads, dirty spark plugs, wide or worn spark plug electrodes or corrosion build up will cause resistance (the kinking of the hose) whilst leaks to earth through inadequate insulation will result in loss of pressure. '
Electricity will flow through a variety of mediums including water, so mud and porous or spongy items that hold water will conduct very high voltages. The classic 'belt" off a plug lead involves fingers via arm, body, legs, shoes, ground, lyres, wheel bearings and finally back to the chassis (earth). All those items would normally be considered good insulators, but if enough force is applied to the atoms they will still transmit electricity - all that rather than jump an air gap of only 0.4mm.
Resistance down the line will cause a build up of pressure so that the spark will find other ways of getting to earth (the equivalent of a hose bursting or leaking under pressure).
Prevention - two requirements:
1. The pressure - good coil output, good leads, good plugs, good connections.
2. Prevention of leaks - waterproof grommets on coil, cap and leads keeping water out of the distributor cap, and of course preventing or minimising entry of water splash by premium driving techniques (or failing that a good radiator blind!)
Two other points are:
1. lonisation, electrical sparks cause the air around the spark to ionise, which builds up resistance of sparking (you've heard of lightning not striking twice, etc) spark plugs have a constant charge of air so no problem but the distributor cap if sealed will cause ionising of the trapped inside thus preventing sparks crossing the points and also at the rotor arm to pick up gaps - result excessive burning of contacts likewise sealing leads into coils is tricky because of trapped air around a push-fit connection.
2. Crossfire is when the spark takes the line of lease resistance through a neighbouring lead, or causes induction current through a parallel lead, causing interferences with optimum electron flow - parallel leads look pretty but should be avoided, likewise leads that cross each other should be separated - preferably by air rather than metal or plastic clips.
PART 2 - TIPS & CURES
Part A
If all your ignition components are working property, the chance of drowning is minimised. There is quite a lot of reserve power in the high tension system (spark dept) to allow a little to be lost so don't go out and replace everything - yet.
The coil - is a sealed unit that does not wear out, but it can break down with excessive vibration or heat Keeping it cool, clean, solidly mounted and vertical are the main requirements.
Leads - have a carbon impregnated string through them. Carbon does not produce as much radio interference as copper but is harder to make good joints (lead ends) and can be stressed by stretching - they do build up resistance so it is a good idea to replace them every couple of years - but replace the full set (5) to keep the resistances equal.
Points - if you have them, require regular maintenance. Poor points equal poor spark, equals less reserve power.
Condenser - is like coil - same rules apply. Tranny ignition requires no maintenance other than to keep it clean. All the components above can be tested on a 'vane'type diagnostic machine and is part of a responsible tune up.
Distributor Cap - is a weak spot in the chain as the HT current has to jump the contacts between the rotor arm and the cap contacts. Moisture and corrosion quickly reduce free flow so keep the cap clean and dry (inside and out) and the contacts clean and smooth, but do not use sandpaper - an ink eraser does a good job cleaning the brass surfaces while a microscopic amount of Vaseline on the centre contact minimises wear.
Spark Plugs - are where the action happens (or doesn't happen) they are blasted with combustion, coated with fuel impurities (particularly lead - which is a great conductor) and expected to provide a smooth surface for the spark to jump across - the correct grade or heat range is critical, however cleaning is becoming less necessary on the newer models, but the correct gap is vitally important.
External cleanliness is important as water and solvents are quickly evaporated, therefore more power - sucking impurities are left deposited on the ceramic insulators than any other component in the ignition system. Speaking of reserve power - most ignition coils run on less than 12 volts through a resistor (resistor lead or ballast resistor) and this is by passed when the ignition key is turned to 'start' (starting puts greatest strain on spark requirement). A boost of power can be achieved by fitting a push button to the dash for those times when extra spark is required (don't use a switch as continuous 12 volts will damage the coil) - run it from battery '+'term to coil '+'the push button.
PART B
Minimise water entry - driving techniques determine how much water gets in. Compare photos A and B - it's the same spot, same day - no points for guessing which one had the wet ignition!
Pic A
Pic B 
Practice good 'bow wave' technique or carry several cans of WD40!! Radiator blinds work well, if a little time consuming, so is the practice of removing the fan belt to prevent the mechanical fan from spraying the motor. These measures need only be used for really deep water.
Radiator Blind - Slow & Steady Creates A "Bow Wave"
The electric fan can be cut off easily by fitting a dash switch. I use the 3 way type so that I can have off, auto and on positions.
Cut wire between fan switch and fan, extend the two wires to the dashboard # 1 position joins fan switch wire back together (auto) # 2 position joins fan to earth (on) # 3 position joins nothing (off). For electrical wizards, a buzzer that sounds in the off position would ensure you doni forget it and risk cooking the motor. Air conditioning should be switched off prior to water entry.
A simple trick is to spray WD40 before the wet bit as this will disperse water as it lands, but the effect only lasts for about 1/2 hour so needs prior warning of a dunking.
As mentioned in the October issue, keeping water out of connections is vital, provided that ionisation doesn't creep in, silicon is a very good insulator, but should not touch contacts. Vaseline is a very good insulator but melts, so if you carefully put a little Vaseline in the connector - displacing the air, the fitting can then be sealed with silicon.
Note:
White grease instead of Vaseline works ok, melts at higher temp.
Works for coil and distributor cap - don't do it to Plug caps, too much heat and hard to remove.
Sealing the distributor cap and breather makes inside water tight but causes ionisation. Suzuki has a trick of running a tiny air hose from the heater into the cap, and then a breather out (to the clutch bell housing, which is a double bonus). If you are clever with the Araldite try this one - it takes a bit of work but is incredibly successful. For obvious reasons, don't use metal pipe! Practice on an old cap. An easier trick is to copy the late Minis (front mounted distributor was prone to three spots of rain), after some success with a cover that looked like a rubber glove, they made a plastic shield to deflect water around the dizzy, I have seen a clever use of a soft drink bottle, upside down with a vertical slot - the bottle is slid over the dizzy with the slot at the rear (for the leads) while the neck is strapped to the base shaft with tie-fasts. Simple but effective. I have noticed that my 'L'Series takes longer to drown than the 'MY' because the distributor is at the back of the motor so less water hits it.
Not an electrical problem, but nevertheless important is to make sure the air intake cannot pick up water or spray - simply face it backward or remove the pipe to the exhaust (not needed in Qld) and turn the control to 'winter'. A wet air filter will make the carby run rich which requires more spark.
Exhaust Heat-Riser - Not Needed In Sunny Queensland!
PART C
Now to test. I mentioned before about testing the components, but to test how water proof your car is can be done simply.
Take a jumper cable (the ones used for jump-starting). Attach one end to the battery negative (earth). Clamp a large insulated screwdriver in the other end, then with the engine running and being careful not to dangle the lead into the fan, Wipe the tip of the driver along all the high tension bits (spark leads etc), if the motor misses or a spark is heard then this spot should be investigated. This trick becomes visual at night but more care needed with fan. Don't touch any connection with ordinary (12 volt) wires as you will short-circuit them. When you can do this with no problems, lightly spray the motor with water (a pump-pack bottle works well) and try again.
If you still have no problems, turn off the engine, and when cool, spray the garden hose on the motor (avoid air intake) and try again.
After the last test, leave the car for 1/2hour, then remove the distributor cap and check for condensation inside - wet means go back 3 spaces, if dry, sign up for the next Bribie Island run.
Is This Fun Or What ?
Nikko
Disclaimer: Technical information given or disclosed in this website is given with the best intent and is advisory only. No responsibility is taken by the the Subaru 4WDrive Club of Queensland or its members for any damage or injury caused by any vehicle modifications made, or by the use of any products or the adoption of any procedures mentioned in this website.