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Raised air Intakes
Roof-Racks have evolved from utilitarian galvanised steel frames with wooden slats to alloy silver, grey or black hammer-tone powder coating with matching slats. They look better, are lighter and more durable to corrosion. although alloy racks are lighter they are not as strong as steel and overloading an alloy roof-rack will cause failure long before a similar load would damage a steel rack. I have fitted roof racks to all ten 4x4s I have owned and so roof racks have become a part of my everyday life. I have had good ones, troublesome ones, noisy ones and ones that are just right. What follows are some insight into roof-racks which will hopefully enable you to select one right for your purposes.
One of the most important elements of roof-rack design are the feet. If the feet are too narrow it will cut through the vehicle’s roof gutters. With vehicles designed to twist, such as Land Rover Defenders, full-length feet can damage the roof. Despite the claims by rack manufacturers, this happens! If full-length feet are fitted, the rack must be designed to twist with the vehicle.
Particularly important are the feet fitted to gutter-less roofs. More and more vehicles are being produced with gutter-less roofs and this, at first, posed a problem for rack designers. Ask your dealer to show you how the rack will be mounted and make sure the mount a plate inside the roof onto the part of the roof designed by the vehicle manufacturer for the mounting of a rack. On some vehicles this means removing the interior roof lining, which is time consuming and while not the easy way, the only way. Some rack makers still use Riv-Nuts (a nut that is fixed in position like a blind or pop rivet), although they have been proved many times not to be strong enough!
There are several rack makers in South Africa. Outback and Front Runner are the two biggies. There are smaller manufacturers like Hannibal, Big Country and a few others, whose racks are less aesthetically-pleasing but sometimes stronger than both Outback and Front Runner’s. Britain has Predator and Patriot, two very high quality products. The bigger companies have been able to spend money on extrusions which in some ways have given them an advantage with their designs and has enabled them to create system designs, that means that clamps for Jerry cans, hi-lift jacks and spades can simply be bolted on. These systems are convenient and work well. But have they done this at the expense of strength? Sometimes I think so.
Weight and load limits
Vehicle manufacturers sometimes supply a recommended maximum weight permitted on the roof. This figure is based on two things: the strength of the roof supports and the liability of the suspension to keep the vehicle on its wheels in the event of a violent swerve. Once a raised suspension is fitted to a vehicle, the maximum permissible roof load IS REDUCED, not increased as some claim. Did you know that the maximum permissible roof load on a Land Rover Defender is just 75kgs? Some claim it is 150kgs. I am not sure which is correct, but given the Defender’s handling, I reckon it’s 75kgs. Most vehicles are around 100-150kgs. Vehicles with the highest roof loading specs of 200 kgs are Mercedes G-wagen, Toyota Land Cruiser 70 wagon and Nissan Safari. The result of overloading a roof rack begin with a cracked windscreen, maybe broken springs, bad handling due to too much weight on the front springs or even complete loss of vehicle control resulting in injury or death. An overloaded roof-rack has the potential to kill you! Mounts on gutterless racks are not as strong as those fitted to gutters, so operators of vehicles with gutterless roof-racks should compensate even more, keeping heavy items inside the vehicle. Roof-racks that extend beyond the windscreen are a recipe for disaster. The front roof pillars are weakest, so are the front springs. This kind of rack also seems to cause instability at speed.
Racks-Responsibility for breakages
If any rack maker ever claims that they have never had a failure of one of their racks, I believe they are lying. Potential law suites prevent me divulging details but one South African manufacturer makes this claim, adding that the feet they supply are,’not part of the rack’, even though they are sold with, supplied by and made in the same factory as the rack. When a breakage occurs, their standard response is, the client overloaded it’. Shop around because not all racks or add-on fittings are made alike.
Bush or bull bars are now commonplace on vehicles from minibus taxis to four-wheelers. They are made of aluminum, mild steel or stainless tubing are fitted either because the driver wants genuine protection from the possibility of hitting an animal at speed or to look macho around town. Either way, they are useful items when it comes to filling winches, spotlights and grille guards. In the past it was fashionable to fit overly heavy steel wrap-around tubes designed by frustrated civil engineers who, during their during their working lives always wanted to build suspension bridges. and most bull-bars sold are lighter and look better too.
Here are some points to consider when selecting a bull-bar:
Running boards/Rock sliders
Side-steps are often the firsts items to get damaged on an off-road vehicle. there are two schools of thought: most after market side-steps, unless designed by people who actually go off road, are a hindrance to off-road driving because they lower the clearance. Some are so badly designed that they jut out from the vehicles side, smearing trousers with mud or dust and do not assist access to any degree. The other thought is that they are damaged first, protecting the more valuable bodywork. I guess both are good points. Rock sliders are purposely designed side steps that replace running boards. Not only do they not get easily damaged, they are (or should be) strong enough to enable the vehicle’s weight to rest on them.
Bumpers and Towing Equipment
Tow-bars, bull bars and bumpers frequently adversely affect the vehicle’s ability to traverse uneven ground. Fitment centres, enthusiasts and while less common these days, the manufacturers themselves make this mistake. keeping all such modifications as close to the bodywork and as high as possible to prevent degrading the departure and approach angles. when de-bogging a vehicle, use the vehicle’s towing eyes to attach cables and ropes in preference to apparatus which is not designed to withstand the loads that can be created by snatch straps or winches.
To make launching a boat easier, fit towing apparatus to the front of your vehicle. Positioning the tow-bar off-center to the left. This will allow the driver to see alongside the trailer which will improve directional control. Do not fit the tow bar close to the ground because if it is low, the stern of the boat will be higher, which means the vehicle will have to push the trailer further and the stern lower. in other words, the boat will float off the trailer in shallower water. And, a low-slung front towing apparatus gets in the way, in a big way, off-road.
Original equipment headlights are good for a lot of conditions and masters of none. If you intend to travel at night in the Third World where dogs, chickens, cattle and goats are a constant danger, fit good quality auxiliary lighting to your vehicle.
Driving lights supplement the vehicle’s own lighting, giving moderately broad spread illuminating the road sides and providing penetration ahead.
Fog lamps are not simply driving lights with an amber filter. What is crucial about a fog light is its spread, not its colour. Genuine fog lamps throw a very broad flat beam that stays low. This prevents glare as the light bounces off the airborne particles and is thrown back into the face of the driver. Amber permits further penetration through the fog, but its primary function is not to increase the drivers visibility but to make the vehicle more visible to others.
Long range / spot lamps
Long range lights penetrate ahead, the range of a typical quartz-halogen light being three kilometres. specialist lighting such as the metal halide 900 000 candle-power units made by KC-hilites are rated at over 18 kilometres. Long range lights are characterised by a prism-less lens. My own light are KC, and after using Cibies for years, thinking that they were cutting edge. I discovered that they under perform both IPF and KC by fair margin.
Metal halide technology
Metal halide is technology where a special bulb runs at very high voltage. A ballast powers each lamp and these lamps throw light brighter and whiter than than all the rest. there is a short delay as the system charges itself when switching on ,which with the newer systems is not more than a few seconds. They are pricey and systems that convert halogen or xenon lamps to metal halide are available. This is a more economical way of getting the benefits of the extreme brightness of metal-halide.
Quartz halogen became standard equipment in most motor vehicles by the end of the seventies, before which incandescent sealed beams were used. Normal wattage ratings range from 50/65 (50 watts dim/ 65 watts high beam) to 100/150. The difference in efficiency between these two extremes is vast and if you are dissatisfied with your vehicle’s lights, simply changing the bulb rating may be an economical and effective answer. If you do this make sure that the vehicle’s relay and switches can cope with the extra current, otherwise expensive burnout will occur.
Quartz LED is without doubt one day going to replace most of there light types mentioned above. LED’s only limitation seems to be heat,. for as fast as the developers manage to dissipate the heat, so LED lights get brighter and brighter. They use a fraction of the current of all the others, and are cheaper to make, and the ‘bulbs’ have an extremely long working lifespan.
Sealed beams are waterproof and very robust. Incandescent sealed beams are not as white as quartz-halogen and their other disadvantage is that when the filament fails or the lens is damaged, the entire reflector and lens units must be replaced. As a general rule these are no longer fitted to new vehicles.
Fitting auxiliary lights
Auxiliary driving lights must be fitted in conjunction with a relay directly linked to the high/low beam switch, so that they automatically switch off when the head lamps are switched to low beam. Poor performance and unreliability can be avoided with quality connectors and relays and multi-core copper wire with a core diameter of over 3mm.
light shields protect against flying stones and bushes. White ones that clip over lamps are a pain. Why, for decades have light makers made them white, so they have to be removed for the lights to be used? it seems so obvious that clear ones will do the job just as well. however, its important that the light guards can be removed easily for cleaning. hinged steel mesh guards are a good alternative but broad-spread slats are not effective against flying stones.
Rear flood lamps
It is also a good idea to have a small floodlight permanently attached to the rear of the vehicle.
Rear lighting is really useful when you:
Easily fitted to most 4x4s, these are the best way of increasing vehicle range in a safe, odor free way. But, some materi< als used in the construction of fuel tanks, even by reputable safari equipment
Stainless steel is brittle and is not the ideal material with which to build any tank, fuel or water, that is bolted to the chassis, Because every chassis is designed to flex, any tank bolted to it will flex to a degree. If it does not, it will damage the the chassis, if stainless steel flexes, it tends to crack! Don’t the makers of these tanks know this? The position of tanks will vary from vehicle to vehicle. possible locations are under the front wings, under the seats, in the loading bay as far forward as possible (pick-ups), headers above the existing tank, alongside the chassis rails between chassis and outer body near the doors and on the floor of the loading area. Never install a fuel tank in front of the engine-spillage or leakage can cause a disastrous fire. Switching from one tank to another can be made using either electronic solenoid valves or taps, the former being more expensive, or individual fuel pumps. Be aware that electric diesel pumps are notoriously unreliable. It is important to use proper fuel hose when fitting tanks as ordinary hose will soon become brittle and crack. To my horror I have seen ‘component’ 4×4 equipment fitters use ordinary plastic water piping in fuel tank installation. It lasts about a year before breaking up.Industrial hose suppliers sell fuel hose considerably cheaper than auto spares retailers.
Never Use ordinary plastic containers to carry fuel, as they are unreliable and after time the plastic can become brittle and slightly porous, causing fuel to seep out and create a fire risk. Bumping and jolting over rough terrain stresses plasic containers carrying liquid, and the risk of breakage when filled with fuel cannot be over-stressed. Steel jerrycans are therefore advised. When purchasing Jerry cans look closely at the seal clamp. Some cheap types leak and become a never ending frustration , so spend a little more and get good ones. Ex-Army Jerrycans, if in good condition, are cheap and can be repainted. (I advise not crossing the border if they are painted military drab. Diesel is less hazardous to transport than petrol, but if you are carrying diesel in Jerrycans once used for petrol, remember that as little as 2% mix will render it as volatile as pure petrol, so empty the cans completely.
Water tanks can be fitted to your vehicle by most safari vehicle supply workshops or can be installed by anyone with some DIY ability and welding skills. Water tanks must be very strong so they don’t crack under vibrations and flexing created when a vehicle moves over rough ground and corrugations. The selection of a position in which to fit a water tank will depend on your particular vehicle. The same positions recommended for fitting additional fuel tanks apply to water tanks. However, while fuel should never be carried in front of the engine because of the fire risk, water carried here aids weight distribution and is safe. however, if a large quantity of water is carried in front, it is advisable to strengthen the front springs. Tanks under the seat in Land Rovers, a position often used to fit fuel tanks, tend to get quite hot and make the water less pleasant to drink, but convenient for washing dishes. The tunnel behind the rear wheel arches in Land Rovers is an ideal position to fit a tank. For easy access, the tap can protrude out of the back of the vehicle and in this position the water can remain delightfully cool. In pickups, an obvious position is inside the loading bay as far forward as possible. Carrying water on the roof is not advised for a number of reasons. the tanks get warm, require some effort to fill if a running hose pipe is not available and severely compromise a vehicle’s center of gravity. Tanks fitted in the load bay of station-wagons can be semi-permanent with a tap fitted.
Consideration when piping from water tanks:
Secure all exterior water taps with small Padlocks to prevent theft.
I suggest wrapping rubber bands around the locks to prevent them being damaged.
By attaching a tyre valve to the top of a tank and pumping in air, the pressure will force water out of the pipe. Beware of over-pumping or you may split the tank.
This is a highly specialized field and not ever mastered by those that ‘dabble’, as some 4×4 equipment retailers and off-road trailer manufacturers do. Boy, have I heard some rubbish advice being shared by some 4×4 equipment retailers on this one! There are two types of battery applications that concern us: ‘Float’ and ‘Cyclic’. Typical of a float application is an ordinary car battery, where once the vehicle has started the current is replaced quickly as the vehicle drives. Cyclic on the other hand is when a battery is charged and then used with no or little charge being replaced. Such an application is common to the 4×4 scene when a vehicle arrives at a destination with its battery in an almost full state of charge. The fridge and lights run through the night and in the morning the battery has lost a significant amount of its charge, When selecting the type of battery, ask what is the application, float or cyclic? If a calcium battery (float application) is used in a cyclic application and the battery is not able to be recharged immediately, the battery will sulfate, causing irreparable damage to the plates. An apparent loss of capacity is noticed and after a short while total failure results. Should a battery designed for cyclic application be used in a float charge mode the result is stratification of electrolyte, mossing of the plates and a large amount of active material falling off the plates becoming sediment. This sediment eventually causes an internal battery short-circuit which cannot be reversed.
Battery charge and temperature
A battery charge is also affective by temperature. A rule of thumb for this follows: A battery is rated at 25°C; for every degree below 25° the battery will lose one percent of its capacity. Its life however will be increased (before failure). Also for every one degree above 25°C the battery will gain one percent of its capacity but its life will be reduced.
Dual Battery split-charging systems/ Battery isolators
When a freezer or lighting is powered from the vehicle’s primary battery, there is a risk that it will be flattened overnight or during an extended stay. Should this happen in the bush the vehicle may have no way of being started. Duel battery split-charge systems solve this problem by enabling a second battery to run the fridge and lighting while the vehicles primary battery remains unaffected. This second battery must be able to cope with the cyclic nature of the application. Deep-cycle and high-cycle are designed to cope with the larger discharge and recharge cycles than normal vehicle batteries.
Current draw and recharge
If you are choosing between a number of popular makes of freezers and judging them by current draw then I would suggest you buy any one and focus on the real issue: How is the current going to be put back and how long is it going to take? This is the big question as there are always difficulties experienced with recharging deeply discharged batteries, and there seems to be no cure, just bad , good and better solutions.
Charging Deep-cycle batteries
Lead-acid batteries, be they float or deep-cycle types, have recharging characteristics that can frustrate the user. Because deep cycle types are used in many off-road applications, I will deal with these alone. When a deep-cycle battery’s charge drops below about 11.8 volts it resists accepting a charge. No matter how much current is fed into such a battery it can appear to be lifeless. The reason appears to be associated with voltage. Ordinary car alternators produce between 13.8 (e.g. Bosch-English & German vehicle) and 14.6 volts (e.g. Nipon Denso- Many Japanese vehicles.) it is not enough! This is because when the battery voltage is low, when the charge is initialized, unless the charge voltage above 14.6 volts, only a small amount of current is accepted by the battery. After some hours or charging, the battery voltage slowly increases, and in doing so, Once the battery is in a state of about three-quarters full, its voltage is enough to-receive all the current it needs. One such battery recharge system is under development.
Take a look at the following typical scenario: A battery is used cross country all day. It reaches a point when the engine is shut down for the night and the fridge and some lights are turned on. The following day the vehicle remains stationary. By the morning of the second day, by the morning of the second day, two nights and a day have gone by. The daytime temperatures are high and the fridge has been running about 70% of the time. The operator knows that the battery charge must be getting low but he or she is not too worried because there is a duel battery split-charge system fitted. He or She decides to take the vehicle for a short run, mainly to charge the auxiliary battery. The battery voltage although high enough to keep the freezer working has dropped off the high current accepting plateau, ±11,8 volts’. The vehicle is driven for a two hour game drive; plenty of time so the driver thinks, to recover the battery with the 100-amp alternator fitted. But, over this two hour period the deep-cycle battery has accepted half an amp for the first hour, one amp for 30minutes and 20 amps for the last 30 minutes- a total charge of 10 and a bit amps. However, the operator is under the false impression that he has fully or almost fully-charged battery. Night falls and on goes the electric lights while the freezer continues to keep its contents frozen. By twelve that night the freezer low-voltage cut-out activates and in the morning everything has thawed. The operator is baffled and curses the battery supplier because he thinks he has been sold a bad battery.
Time required for a flat battery to accept a measurable charge
On-charge voltage Hours
16 volts : Up to 4 hours -check every half hour
14-15,9 volts : Up to 8 hours -check every half hour
13,9 volts: Up to 16 hours -check every half hour
The table above indicates the time required for deep-cycle Delco battery to receive a measurable current and the usable power of two models of the Delco voyager. For standard use, discharge is from 100% down to 50% charge. In emergency use, the table indicates usable power from 100% to 0%. A second battery wired in parallel will double the value. (excluding reductions due to battery mismatch.)
Battery split-charge/ recharge solutions:
Auto-relay split-charging systems
These systems, by far the most complicated, charge all batteries in the circuit and with a monitor unit fitted, tell the user the state of each battery. those that read just the voltage are pointless and need to read in increments of one-tenth of a volt. these systems do not change the voltage so do not solve the recharge problems discussed. they are fully automated, which is a plus. their efficiency varies and some are very inefficient. for example one of the better unit work like this: Input voltage in this case is 14,1-volts from a Toyota Nipon Denso alternator, one of the most efficient. Voltage through transistors and other components drop 0,3 volts. loss through wiring and connectors, another 0,5 volts. Voltage to the battery is 13,3 volts. Not even close! Result: the battery is never fully charged and this is a best case scenario! even the most highly inefficient systems only deliver about 13,2 volts to the battery. The battery doesn’t stand a chance of delivering at rated current or being able to accept current at the rate a vehicle alternator can deliver it.
High-current manual switches
Marine switches are switches able to carry the heavy charging currents produced by alternators running at full revs, sometimes over 100 amps. They connect the batteries in parallel so when the alternator charges the one, the auxiliary battery gets the same charge. There is little voltage drop, as long as the cables are thick enough and the connectors good. On the down side, if one of the two batteries is bad, it will discharge the other and if the operator forgets to switch the main battery off at night when the freezer is running, there is the risk of flattening both batteries.
Constant voltage chargers
The idea behind a 12-volt to 12-volt charger is that no matter what the engine speed, the charge voltage remains constant. A constant range of charge is very good for the battery and the battery’s life is extended. Their downfall is that when the alternator is running at full charge and the battery is in a position to accept such a charge, it will only accept the pre-set current.
Diode-based battery isolators
A diode is a component in a circuit that permits current to flow in one direction only. between two batteries it permits one battery to charge but not discharged. This sounds ideal but for inefficiencies of diodes. The voltage drop across a high-< current diode is often over a volt. They also tend to permit other current loss, although I am not sure how and why. All I know is not to trust them.
Tips to better battery charging:
Keep it simple
Because this is a complex subject, and few understand it completely, when selecting a system, my advice is to keep it simple.
Deep-Cycle and High-Cycle Batteries
Because Delco is the most popular auxiliary battery found in 4x4s, here is some advice for their use.
Delco Voyager is of flooded cell construction, fully sealed and requires no topping up. The only maintenance required is cleaning and greasing of the connectors. The built-in hydrometer allows an easy check of the state of charge. The battery is often not suitable for use as a regular vehicle battery as its cold-cranking current is often not high enough to start big diesel engines.
Normal charging requirements
Optimum battery life will be obtained if a green hydrometer condition can be maintained and batteries should never be left in a deeply discharged state. If the state of charge has reacted 100% charging should only be continued for long periods at a reduced rate to prevent long-term electrolyte loss. On-charge voltage should be 13,5-13,8 volts.
Care of batteries
Batteries do not store well. When operating a low mileage vehicle or a vehicle that stands for long periods, make sure that the battery is kept in a good state of charge, otherwise it will deteriorate rapidly. Check and top up the electrolyte and recharge every three months- leaving it longer will damage the cells. If necessary store batteries indoors to prevent the electrolyte from freezing as in most cases this destroys the battery. Batteries must be fully charged beforehand and must be disconnected from all loads, however small.
Inverting current from 12-volt DC to 220-volt AC is done with an inverter. new technology has made these devices very compact and virtually indestructible. Overload them and they simply shut down or wire them up incorrectly and they simply refuse to work. for one year I used a solar panel to charge a battery which by means of a 200-watt inverter ran an Apple Mac and printer in ambient temperatures over 40°C. Much of the work on the first edition of this book was done at this time. The inverter became so hot that it could not be touched, yet it operated faultlessly. Current draw reached 10-amps at 12-volts(120-watts). Quasi-sin-wave inverters are suitable for computers, printers, televisions and hi-fis etc. Sin-wave inverters are required for scientific equipment but are unnecessary for most applications.
Despised by all those who work hard to get into the bush, away from noise and stress, portable generators are an unforgivable annoyance. Because they can be easily replaced by alternative power sources that are silent, more ecologically friendly and cost no more, I see no reason why these are used, except in cases where life support systems require high electric current. Running a TV is no excuse: why not then stay at home? As a result, I see no place for portable generators in this site.
Monitoring engine performance while traveling far from home is a good idea. Twice I learned the hard way. the first occasion was when my oil pump failed in central Botswana on the return leg after two weeks in the bush; and the second was a blocked air filter when a gauge monitoring the exhaust gas temperatures would have prevented a damaged turbo.
Exhaust Gas Thermometer (EGT)
Monitoring the temperature of the exhaust gases (EGT) is highly recommended for all turbo-diesel vehicles, especially pre 2005 models. When the exhaust gas temperature exceeds 700°C turbo damage results within a short time. causes of high EGT are: high fuel-air mixture, blocked air filter and pushing the turbo-diesel too hard. In this way the gauge indicates that damage is being done to the engine. It also indicates if the engine is being driven too hard, for example towing up a long hill on a hot day. without such a gauge the driver towing up a long hill on a hot day. Without such a gauge the driver would press on regardless, with the gauge warning, a lighter right foot could prevent engine damage. I highly recommend this gauge, especially if you use your turbo-diesel to low. I bet, in five out of ten cases, an EGT gauge will prevent a huge repair bill.
Oil pressure gauge
The signal is transmitted to the gauge via either an electrical sender unit or thin copper tubing that carries the oil to the gauge. in general, the latter type is more accurate and reacts faster to pressure changes. The electrical gauge is more common in newer vehicles.
Oil temperature Gauge
The signal is transmitted to the gauge via an electrical sender unit. This gauge is an essential item when traversing heavy sand or towing, Know the safe maximum oil temperature for your vehicle and never exceed it. 120°C is the maximum for most vehicles.
This gauge monitors the condition of the battery. Voltage measurements must be taken with the engine turned off and some electrical equipment switches on e.g. park lights. Only when the battery is working can voltmeter indicate how much more work the battery is capable of doing. This is because it is the voltage drop that determines the condition of a battery. For example, a battery with nothing switches on may indicate 13 volts. If, when lights are turned on, the voltage drops to 10 volts, this indicates a battery in a poor state or one that is old or damaged. If the voltage stays above 12-volts, this can be regarded as normal and the battery in good condition. The higher the load on the battery, the higher the voltage drop will be.
The ammeter measures the flow of current in and out of the battery. Vehicle ammeters have a central indicator that swings to either negative or positive. It is wired to enable a vehicle operator to determine if the load on the battery by electrical equipment is higher or lower than the amount of current the alternator in returning to the battery. For example: If the lights are turned on with no engine running, the indicator will swing to the left or negative. When the engine is started and the alternator engages, the indicator will swing to the right, or positive. If you find that you ammeter tends to run towards the negative when running electrical equipment, then you need a heavy-duty alternator.
If you intend to drive on long stretches of dusty roads or through deep water, an extension to the air intake is highly recommended. The most well known make is the Australian Safari Snorkel. They are available for almost all 4x4s and can either be fitted at home or by off-road outlets. The benefits are more than just protection from water and dust. The air is cleaner up high and therefore air filters last much longer. The air is also cooler than inside the engine compartment. This clean, cool air will improve engine performance. Fitting a snorkel does mean drilling holes into the body and this is a deterrent to some who want to ensure the resale value of their vehicle. However, engine damage caused by water ingestion is never cheap.
There is some contention as to the effectiveness of a snorkel in dusty conditions. In 2003, during a trip into the Richtersveld shooting one of my 4×4 DVD’s I did a simple test. Two vehicles, one a Colt and the other a Land Cruiser were used. The Cruiser was fitted with a Safari Snorkel, the Colt had its standard air intake behind a headlight, A common location on many vehicles. Both vehicles were new, with about 7000 Kms on both odometers. The drive through the river beds was particularly dusty. The idea was to compare the air cleaners on the final day of the trip. The results were startling. Each filter was knocked against the front wheel to release dust trapped in them above a white towel lying on the ground. The top three photos show the snorkel-equipped Land Cruiser. The filter was dusty but still good for thousands of kilometres. There were no stones or sand in the filter bowl. I would estimate the unprotected filter had fifty times more dust embedded in it than the filter protected by the snorkel.
Most modern 4×4’s are equipped with suspensions better suited to road conditions than off-road work. Modifications are often necessary to increase ground clearance and improve payload. Also, vehicles that excel off-road may need softening up for road use. trouble is not all spring and shock manufacturers make well-researched products and many a disappointed traveler has cursed a salesman. bilstein, koni, Old Man Emu and TJM all make high-quality systems but above all, make sure you purchase them from a competent professional who is able to select an appropriate spring/shock combination. Backyard mechanics with limited knowledge are a liability.
When coil springs are exchanged for higher rated units make your selection carefully. Light-duty units will feel similar to those that the manufacturer has fitted but will ensure longer life of the shock absorbers, especially if they are gas type. Medium rate springs will improve road holding, reduce body roll and improve payload by a small amount. Hard springs will improve road handling, on-road adhesion, reduce body roll and are recommended for vehicles with loaded roof-racks. They they improve heavy payload handling, stability and safety but may feel harsh on road. poorly selected springs often cause instability at speed.
With leaf spring vehicles such as the old Hilux or Land Cruiser pickup, the change is even more impressive. The new springs smooth the on-road ride and at the same time increase the axle articulation due to spring lubrication between the leaves. this improves off-road traction especially over rocks and dune driving.
Spring assisters/Air Springs
Coil spring assisters come in the form of helper coil springs that fit inside the existing coils or rubber blocks squeezed between the coils of a spring to resist its collapse. Firestone make a highly effective inflated to suit load and conditions are another option. Once prone to failures the new models are earning a good reputation.
Problems caused by suspension mods
The most common problem caused when the vehicle’s ride height is increased is over-sensitive steering and most likely to occur with a suspension lift of 50mm or more on a solid front axle. this is caused by a change to the camber angle and must be corrected with replacement bushes. The angle at which the prop-shaft universal joints operate is also increased by a suspension lift, often resulting in accelerated wear or vibrations. Other items to check are the brake hoses. There must be ample length to cope with additional axle travel made possible by the new shock-absorbers. However, mismatching components: taking shocks from one manufacturer and springs from another, is a common cause of premature failure of after-market suspension components. The stretch of the shocks and the height of the springs must be matched properly and not by guesswork.
Gas shock absorbers
Few vehicles have gas shock absorbers fitted as standard equipment and for vehicles expected to work long hours off-road they are essential. In the past, few four-wheel drive manufacturers have paid enough attention to shocks absorbers.
Working 4×4’s need gas shocks. For example, my own Land Rover 110 went through two sets of standard shock absorbers within 30 000 kilometers. Once the second set had worn out, the first being replaced under guarantee, I replaced them with Bilstein shocks. When selling the vehicle after clocking up 130 000 kilometers the shocks were as firm as when I fitted them. Gas shocks often make the ride a little firmer but the real advantage comes when cornering or carrying a load. The difference in my case was a significant improvement in ride even when compared with brand new, standard shock absorbers.
Torsion bar suspension problem
When fitting gas shocks it is essential that the suspension setup is checked and adjusted if necessary. Not centralizing the suspension before fitting gas shocks can cause rapid destruction of the shock absorbers. the reason for this is when a suspension system, particularly independent wishbone types, are set in the ‘central’ position when the vehicle is at rest, the shock absorbers act as bump stops instead of the rubber bumps designed for the job. The internal components are literally hammered to pieces. Secondly, torsion bars set in increase clearance can cause problems when the shock absorbers central or neutral position is altered. in this position the shock absorbers cant work as they should. The resultant poor ride is then blamed on the shocks, when the real culprit is the backyard mechanic who thought he knew better than the vehicle manufacturer about how the torsion bar should be set. Thirdly, do not assume that if your vehicle is brand new that the suspension is correctly set up. Many imported vehicles stay lashed down to the pump-stops in crates for months and when they are delivered the suspension has ‘sagged’ and must be reset. torsion bar suspension is particularly prone to this.
A shock absorber, simply described, is a metal tube filled with oil through which a piston moves. on the piston is a valve which permits oil to pass through a limited rate. The tube is connected to the chassis and through at a limited rate. The tube is connected to the chassis and the piston is connected to the axle. The oil’s limited travel damps the movement of the piston and therefore the axle to which it is attached. This prevents oscillation that the springs would create if left undamped. as the piston moves in the cylinder heat is generated. Heat thins the oil and makes the shock less effective. What is worse, the oil in a hard working shock mixes with the air and bubbles are formed. The mixture of hot air and hot oil is able to pass through the valve easier than pure oil, which means that the shock will lose its effectiveness, to the point where the ride becomes uncomfortable and unpredictable. Gas shocks are different in that they are pumped with a small quantity of inert gas. This gas cannot mix with the oil and so the main reason why shock-absorbers become soft as they get hot is eliminated. Shock-absorbers on a heavy loaded 4×4 on a rough sand track work almost as hard as shocks on a competition rally car. I know of one Range Rover which after being called to rescue the survivors of an accident in Northern Botswana (that was me in 1987), ‘cooked’ a gas shock by racing to get to the accident scene. the shock was blackened by heat and destroyed. I have used three brands of shocks in eight 4x4s that I have owned I can highly recommend Bilstein. They are undoubtedly very robust and are my first choice.
Bushes made from hard rubber are fitted in various locations in suspension systems to soften the vibrations generated by the wheels, engine and transmission. in Off-road vehicles these bushes are stressed more than in a normal road vehicle and as a result wear out and need periodic replacement. Bushes are located in various places, namely leaf spring shackles, steering dampers, control arms locating the axle, radius arms and steering control arms. The effects of worn bushes can be vague steering, a vehicle that steers itself when driving straight, instability, an uncomfortable ride on corrugations, clunks and bangs on rough terrain and clunks when reversing or braking. A worthwhile option when replacing bushes is to fit polyester units. polyester is replacing the rubber in bushes in industry from shipping to heavy machinery and vehicles are reaping the benefits of the research into new age plastics and graphite’s. The advantages of polyester are long life and stiffer suspension which aid stability and safety. A little more vibration is sometimes transmitted to the driver but this is rarely noticeable and they frequently cost less than genuine parts.
How many times have you heard, I would never take that big, beautiful vehicle into the bush to get scratched.” The reason not to take them into the bush has just vanished – Literally. An elastic, plastic sheeting called VPS (vehicle protection shield) is the answer. I tried it on my Land Cruiser and after numerous trips through the Kalahari, the bodywork is as pristine as it was when I bought the vehicle ,this remarkable product can be applied to any bodywork area: For a 4×4 used in conditions where stones may chip and thorn bushes are likely to scratch, I suggest paying particular attention to the front roof supports, front fender, doors and the leading edge of the bonnet. Once applied, it vanishes. It is clear, is guaranteed not to fade and dust falls off it faster than it does on nude paintwork, so the vehicle appears to stay cleaner for longer. It also protects against vandalism and careless shoppers in car parks. Not cheap, but will add considerably to a vehicle’s resale value. A really impressive and practical product. (www.vpsprotection.co.za) Beware of some copies: Many product are out there making the same narrow sheets, which looks terrible.
Radiator grille grass nets
When you travel over grassland, fit a protective net over the radiator grille, but know that most grass seeds find their way to the radiator from underneath, not straight ahead. A grille net should prevent grass seeds choking the radiator and the resultant overheating. This includes the inter cooler radiator. Fine plastic mesh used to make swimming pool scoops work well when layered double and shade cloth also works well. one-size-fits-all grille nets sold in 4×4 stores are sometimes not particularly effective because they do not go low enough. THIS IS VERY IMPORTANT: Because grille nets severely restrict the passage of air to the radiators inefficient air-conditioners, extreme under-bonnet temperatures, damage to batteries and engine damage result when a grille net hinders airflow when traveling at high speeds and high power settings. If the vehicle could run as efficiently with the restricted air-flow caused by a grille net, the manufacturers would have fitted smaller radiators and saved on costs. Your vehicle needs every bit of airflow it can get when moving. I recommend taking grille nets off at speeds over 60Kph, especially on hot days. Vehicles towing trailers in thick sand should only fit a grille net if absolutely necessary, even if speeds are low.
Seat covers and interior protection
The way I see it, seat covers are intended to perform two functions: Improve comfort and protect the seats. Comfort is 100% subjective, si I am not going to say another thing. But protection is not. I believe priorities in this regard are as follows: 1. They must be waterproof to be effective. Water-resistant is not enough. 2. they must be washable and must not shrink when machine washed. #. They must be tear-resistant and if they are cut, the tear should not easily spread and repair should be easy. 4. They should look nice and not attract dirt. There are several seat cover manufacturers in South Africa and I have experience with three of them: Takla, Melville and Moon and Escape. Of them the Takla canvas look-alike cover called CanTech fits all these priorities the best and I can highly recommend them.
Mud flaps both look good and protect the vehicle and trailer. Vehicle manufacturers, all of them , put horrible, feeble flaps that do not do a very good job. Mostly they are too small and when they are a reasonable size, like on a defender, they are made of material so thin < that the rushing air blows them out of the way. Making your own flaps is easy. use conveyor belting or heavy rubber matt about 1-1,5 cms thick. Cut it with a utility-knife and make some simple aluminum strips as mounts. Simple, effective, cheap.
Water tanks and jerrycans should be locked with small padlocks and chained to the roof-rack if a loaded safari equipped vehicle is to be left unattended-day or night. The padlocks should be removed from the Jerrycans when driving to prevent sand and vibration from wearing the paint and damaging the locks. External water taps should also be secured by a padlock or have a shut-off valve inside the vehicle, especially in desert regions.
Many insurance establishments will not cover vehicles that travel into Third World countries. Make sure that your vehicle is covered and don’t get a nasty surprise should something go wrong far from home.