Preparing your car - Rally Round


Winners prep their cars properly! Here Rally Round’s highly experienced mechanics share a few tricks of the trade

If you are engaging professional mechanics to prepare your car – and we recommend that you do – it’s vital that they understand the nature of the event you are undertaking (preferably from personal experience) and that the car is ready several weeks before the shipping date, so that you may test it thoroughly (over at least 600miles/1000km) and send it back for adjustments if necessary. All too often we see a car that was ‘finished’ just in time for shipping, with little or no testing, which is why our mechanical support teams rarely have to buy their own beer. Be aware that rally preparation is not the same as race or ‘fast road’ preparation. If you don’t know who to trust, check out the list of workshops on the Rally Round Recommends page of our website.

All Rally Round regulations (set out in each event brochure) specify a number of compulsory, safety-related modifications such as a securely mounted, hand-held fire extinguisher, mud-flaps, a laminated windscreen and full harness seat belts for cars in the Classic (post-war) category; strongly recommended modifications include roll-over bars and sealed bulkheads separating the cockpit from the engine and fuel tank. If you hope at some point to compete under MSA ‘Blue Book’ rules, or those of a different organizer, be aware that some of the items we recommend might well be mandatory. It is more cost-effective to have all such major work done at the outset, so make sure your chosen preparation workshop knows exactly what is required. Note that certain modifications are forbidden, so don’t splash out on unnecessary work that might disqualify your car from competition. Simplicity is usually more reliable than complexity.

Crew comfort is not a luxury – it’s essential. You will be spending long hours in the car, when a niggling irritant can become frustrating and ultimately tiring. If you are likely to be accompanied by different navigators, check that people of different sizes can get in and out without banging their head on the map light or skinning their knees on the tripmeter. Can the navigator reach everything he or she needs when the seatbelts are tightly fastened? Is there somewhere to store a navigator’s bag, pens, notes and other paperwork, not least the all-important Road Book and Time Card? Can you reach the spare wheel and jack, the fire extinguisher and the first-aid kit without having to un-pack and re-pack a lot of other cargo?

Good seats are vital for crew comfort – spending long days on uncomfortable perches is no fun at all, and it’s always better to spend a bit more money here than to suffer a bad back. Avoid bucket-type competition seats but choose something with good support, preferably adjustable. Try them for size if possible and remember to check the seat width if your car has a narrow cockpit.

Fit a clip on the dashboard that can hold notes, reminders or simple route instructions on straightforward road sections, allowing the driver to make progress whilst the navigator gets on with other things (or catches some sleep). An extra horn button on the navigator’s side can also be useful.

Where will you keep valuable items such as vehicle documents, passports, money, cameras and the like? Plastic security film on the side windows offers a defence against opportunist theft, but also prevents the glass from being broken in an emergency. It’s better to store valuables out of sight in a secret compartment, or install a lockable safe. You should also find a hidden exterior location for a spare set of keys.

Four-point harness seat belts are required in all Classic (post-war) cars and recommended for all others. Push-button release buckles are lighter, cheaper and easier to use than the old twist-release rotary type. Inertia-reel harness systems are also available, and allow more freedom of movement.


A car is not a rally car until it is fitted with a tripmeter. You cannot hope to succeed without one, as your car’s built-in odometer/trip is simply not accurate enough. There are many different types for different applications and requirements, but bear in mind that average-speed displays are not permitted on regularity (Time-Speed-Distance) rallies, or must be capable of being disabled.


Some of the most popular tripmeters – (left to right) the Halda Twinmaster, Brantz RetroTrip, Brantz International 2 and Monit Q-20


Classic mechanical tripmeters such as the Halda Twinmaster or single-readout Tripmaster are great and can be super-accurate if calibrated correctly but they can be temperamental. Good ones are now hard to find and can be eye-wateringly expensive; they must also be looked after and maintained regularly. Being relatively bulky they can be awkward to fit, and you will need to carry a range of internal gearwheels for calibration purposes (maybe three larger and three smaller) as well as spare drive cables. A third Halda type, the Speedpilot, is an average-speed indicator and therefore not suitable for regularity competition.

Electronic units are ultra-reliable (if properly fitted) and generally easy to use; manufacturers such as Monit, Brantz, Terratrip and GaugePilot offer a range of different types and functions. If you are very short of space, the Monit is the smallest. If you want a period look, consider the Brantz Retrotrip (albeit rather noisy) or the GaugePilot, a digital recreation of the old Halda Speedpilot that offers additional engine monitoring systems; crucially, the average-speed display may be disabled for the duration of a regularity event. Whichever unit you choose, it’s vitally important that the electromagnetic sensors are fitted correctly to minimize the possibility of failure. A professional installation by a recognized rally preparation workshop is always a good idea, as they know what’s required for robust fitment.

The tripmeter should be mounted within easy reach of the navigator (with seatbelts tightly fastened) and also visible to the driver, but not where the navigator’s knees might accidentally touch any calibration buttons. Before you travel to an event the trip should be accurately set up; rallies outside the UK (or USA) are usually measured in kilometres, and with the help of an eagle-eyed passenger you can obtain a good measurement using the 100-metre marker posts alongside a motorway; you cannot legally stop on the hard shoulder to do this but measuring a distance of several km will minimize error. Calibrating an electronic unit is a simple matter of pressing a few buttons, but mechanical devices require a change of internal cog wheels.

You will be given details of a short calibration route at Signing On, so you can fine-tune your tripmeter to match the distances given in the road book. This is very important, as even a small discrepancy can lead to a major navigational error. Carry calibration instructions with you if you don’t know the procedure off by heart.


They aren’t required on Rally Round events, but if your chosen rally involves map navigation you might wish to install a compass. Novelty car compasses are useless, so fit a boat type that can be adjusted to compensate for the massive lump of iron under the bonnet. Illuminated types can be useful at night, but require a 12V power supply.


There is no substitute for cubic inches. But whatever its size, resist the temptation to tune the reliability out of your engine. Extra horsepower is usually very expensive and offers no useful advantage on a regularity (TSD) event.

A healthy, well maintained and serviced engine is essential, but a freshly built motor that has not been properly run-in can cause serious trouble, as can newly fitted and untested components. Ensure everything has settled down, then have the engine thoroughly checked before you leave.

Head gaskets always seem to blow at the worst possible moment, so this pre-event inspection should include a compression test to highlight any potential weakness.

The oil pressure should also be checked, but don’t assume that your existing oil pressure gauge is accurate. Many old ones aren’t, and any error might be compounded by an oil pressure sender that isn’t working properly, whether it’s an old capillary tube or an electronic unit. Tubes can become blocked or damaged, and aftermarket electronic sensors are often variable – different batch numbers may deliver different readings. If you don’t want to spoil the look of your old dashboard with a new gauge, you could fit a GaugePilot tripmeter, which offers an oil pressure monitoring function.

Engine mountings need to be good and strong – they get very hot and covered in oil, so they can soften or even break. It is worth putting extra straps on the mountings and caps above them to restrict how far the rubber can stretch if you hit a bump.

Starter motors (including solenoids) must be in good shape too – we quite often see them fail on events if they have not been replaced or overhauled. Having to ask for a push or tow start several times a day is extremely tiresome.

Other worthwhile minor modifications include a bracket on which to mount a spare ignition coil and retention chains on the oil and radiator caps, so they don’t get lost even if you forget to tighten them. The same goes for the fuel filler cap.

Oil is your engine’s most critical component. Always take advice from your preparer or engine builder as to what oil has been used and what is required for topping up, as some older engines don’t like modern synthetic oils. These days it’s hard enough to find your preferred lube on a UK forecourt, let alone in the rural backwoods of a distant land, so it’s vital to know what your engine likes, how much it is likely to use on an event and what it will tolerate if your normal oil cannot be found. Do some research on what might be available en route. You can carry your own supply of course, but it’s heavy.

This is very often the Achilles’ heel of vintage or classic cars, and modern ones too for that matter.

The radiator needs to be in tip-top condition. Get your preparer to have it inspected and pressure tested before going any further. It might just need cleaning and flushing but it might require a new core, which is an opportunity to increase the cooling capacity by fitting extra rows. Good strong mountings are also very important, with plenty of rubber to absorb vibration.

A traditional brass radiator is best. Aluminium alloy should be avoided as it is almost impossible to repair in the middle of nowhere.

Electric cooling fans can be a good idea, if they will fit, but they need to be of good quality so they don’t break, well mounted and correctly wired. It’s not always a good idea to remove an original cooling fan and rely on electric fans alone – some engines don’t like this.

Always carry a spare fan belt that has been previously test-fitted and checked – all too often the spare turns out to be the wrong size.

Under-bonnet heat can cause all sorts of running issues so keep this in mind. A heatshield between the exhaust manifold and the carburettors might help a little but it’s very often better to concentrate on getting the heat out and away from the engine bay.

In water-cooled engines, antifreeze should always be used regardless of where you are going. You might be embarking on a summer event but most rallies will take you up a mountain at some point, so think about altitude – for every metre you climb, the boiling point of water falls.

That said, at altitude engines using waterless coolant often outperform engines using water and antifreeze. Waterless coolant is a wonderful thing, as it allows engines to run at the temperature they like. Water starts to boil just below 100 degrees Celsius and in normal conditions many engines will run happily at this temperature; indeed such warm running can actually be more efficient, producing slightly more power. Waterless coolant boils closer to 180 degrees Celsius and consequently there will be no pressure in the system, saving hoses and head gaskets too. There’s no need to worry about springing a leak as waterless coolant may be topped up with water if need be; the only effect is a slightly lower boiling point.

Altitude not only affects engine cooling, as discussed above, but fuelling too. At sea level, an engine needs 14.7 parts of air to burn one part of petrol. The amount of oxygen in the air decreases with altitude, so it follows that as you go higher you need correspondingly less fuel, in other words to ‘weaken the mixture’. If you don’t, the car will belch out more and more black smoke as you lose power and eventually grind to a halt.

With SU carburettors, weakening the mixture is easy: you just raise the jet. Fixed-jet carbs are more troublesome, as you have to change the jets. The rule of thumb is to drop one jet size for every 2,000 feet of altitude.

Tanks should be clean and free from rust, likewise pipes and fittings. A new tank and pipes are invariably better than old ones full of dirt that comes loose when shaken about on a rally.

Consider your fuel tank capacity, especially on long-distance events – that small village fuel station in the road book might not have enough fuel for everybody! Organizers will often tell you what range you need for a particular event, but 400km (250 miles) should be sufficient in most cases (assuming you don’t stray too far off route). If you need a longer range, you will have to carry an extra jerrycan. Always ensure that it is securely mounted, leak-proof and easy to use, Collapsible jerrycans are a good idea, as you can stow them empty when not required.

Small fuel tank leaks may be sealed with soap, topped with a healthy dollop of body filler – it sounds wrong but it works! Carry both in your spares kit. Opal Fruits (now Starburst) sweets may be used instead of soap, if you haven’t already eaten them all.

A good inline fuel filter is a must for any rally car – even in developed countries you may find fuel contaminated with dirt or water, or even a wrongly labelled pump that dispenses diesel instead of gasoline. Install good quality filters that are easy to maintain and clean, even disposable ones if they are a better fit, and carry plenty of spares. If you would rather not fill up with contaminated fuel in the first place, use a funnel with a dirt and water filter, such as Mr Funnel.

Use a good filter to protect yourself against potential contaminated fuel problems

Older fuel pumps with serviceable contact breaker points may be cleaned and adjusted if they stop working, but it’s wise to carry a spare. If your pump has solid-state electronics then you should carry at least one spare. Check that electric pumps deliver enough fuel when needed but not too much – a good engine tuner can advise on the correct fuel pressure. Fit a fuel regulator if necessary.

When we rallied through Brazil on the 2013 Great South American Challenge, there was some concern that fuel containing ethanol would act as a cleaning agent, releasing old fuel-system deposits that would then bung everything up. We also worried that it might rot rubber pipes and seals. Such problems have been debated at length; the extent of any damage might depend on the proportion of ethanol in the fuel, or the duration of exposure, but rubber inevitably decays over time and old components should be replaced as a matter of course.

Ethanol is also hygroscopic – it absorbs moisture – which might cause an accumulation of water in the bottom of a tank or fuel station reservoir, as several competitors on our 2017 Odyssey Italia rally discovered – another good reason to use a good fuel filter.

You will come across different grades and types of fuel in foreign lands. Don’t get into a flap. A few rules and a little clear thinking will keep you on the right track:

The rules:

For lower octane fuel, retard the ignition; for higher octane, advance it.

High temperature, whether ambient or engine, restricts how far you can advance the ignition.

The more the load you put on the engine, the less you can advance the ignition.

Retarding the ignition raises exhaust temperature.

The thinking:

There is a range of ignition timing within which your engine will run. Retard it too much and it will run too hot, advance it too much and the fuel will detonate causing a ‘knock’. Both conditions can lead to engine failure. So the idea is to keep the ignition timing within these parameters (that’s the easy bit) whilst trying get the most power from the given fuel in the prevailing conditions. The changeable factors are octane, heat and altitude.

The conclusion:

Retard for lower octane.

Run hotter plugs and ease up on the workload for lower octane, higher ambient temperatures and higher altitude.

Always start an event with a strong and healthy exhaust system. Experience has shown that mild steel is better than stainless steel, simply because it’s much easier to work with. If possible, fit a good flexible joint so that any hefty knocks to the exhaust pipe don’t stress the manifold; that might well be made of cast iron, which is incapable of absorbing big impacts.

A healthy ignition system is vital. If your car has old-style points ignition then fit new points before an event and ensure that they are correctly adjusted and lubricated. They should be trouble free save the odd adjustment, but carry plenty of spares (points, rotor arms, condensers, spark plugs and a good set of HT leads too). Check in advance that they all fit and that they all work – a crack in the outer insulation of an HT lead can cause misfires, and a ‘brand new’ rotor arm might not work at all if it has a hairline crack that is almost invisible to the naked eye.

Aftermarket electronic ignition systems were commercially available in the 1960s so might qualify as a period modification, but check that they are permitted for your car by the event regulations. They should need no adjustment but cannot be repaired if they fail so carry a spare. Buy a good quality system such as Aldon or 123ignition (which replaces the entire distributor).

It is always wise to have two coils fitted next to each other in case one fails.

Magnetos are wonderfully simple and straightforward, which is why they are still used on light aircraft, but most are now very old and many don’t have sufficient ‘oomph’. If you are mag-dependent, even if you run two, a coil conversion kit that may be fitted in the field can be an event saver.

Dynamos can work well but they are not reliable and they don’t produce as much power as most cars demand these days. A simple upgrade to a modern alternator is an easy, sensible modification. Renew the main wiring while you’re at it and you can usually forget any charging issues. Alternators come in many sizes, styles and power outputs so seek professional advice; if you have a pre-war car the upgrade might be a bit more challenging but a good preparation workshop should be able to help. Do check the condition of an existing alternator – if it fails you will suffer a misfire as you drain the battery and ultimately come to a dead stop. You could carry a spare, but they are heavy.

Most of the electrical faults we find on rallies are down to poor wiring, often traced to connections where new items have been added. Have the entire system checked, and if your car still has its original wiring loom consider complete replacement if possible.

Make sure the battery is up to the job too, along with all its connections. If you are still using a 6-Volt system you should upgrade to 12V; finding a 6V battery is almost impossible in some countries.

Fit a map-reading light that will not distract the driver, and make sure you have enough spare 12V power outlets to charge phone(s) and other gadgets – you can buy fittings that convert 12V ‘cigar lighter’ sockets to USB outlets. Don’t forget a 12V supply for the tripmeter (and compass, if illuminated).

Fit new light bulbs and carry spares (still mandatory in some countries even though modern cars use sealed lamp units). An event might not officially include night driving but a lengthy breakdown can leave you having to complete the day’s route in darkness, a scary prospect in some unlit regions. High-output bulbs can transform the effectiveness of your headlights but make sure the wiring can handle any extra power – a good auto electrician can help.

Make sure the bearings aren’t worn and that the gears are still set up properly; when bearings wear, gears can move away from each other and fail to mesh properly, and that’s when things go wrong. A quick rebuild that involves setting things up again with maybe a new bearing or two isn’t expensive, but a failed gearbox or differential can signal the end of your rally.


The suspension and steering need to be perfect. Worn suspension will only get worse, so make sure all moving parts are adjusted and fully greased, or replaced if necessary.

Catch straps and bump stops are easily forgotten. Have someone who knows what they are doing measure the full travel of the suspension to make sure that everything is within tolerance and then add those all-important bump stops and check straps to protect your dampers (aka shock absorbers).


Dampers (commonly called shock absorbers, incorrectly) come in all shapes and sizes. Make sure that what is on the car is right for the car, taking advice from a recognized preparer or specialist. If you are upgrading them, don’t forget to upgrade the mounting points too.

Springs are often overlooked. Leaf or coil, they are the principal shock-absorbing component of the suspension system – and a car that normally languishes in a garage can indeed suffer quite a shock when it is suddenly expected to work hard for a week or more. Make sure the springs and their mountings are in tip-top condition. Aged transverse leaf springs can sag under the weight of spares and tools, so check your ride height with the car fully loaded and consider having the springs re-tempered if necessary.

Resist the temptation to fit fancy new wheels – the standard items are usually more than adequate although careful inspection is advisable as some wheels do suffer from stress cracks around the stud holes. Fitting very slightly wider wheels is fine, but nothing more, as greater width can increase stresses on the suspension, reduce grip on loose or slippery surfaces and make the steering heavier. You may well find that the event regulations limit wheel and tyre sizes in any case. Avoid alloy rims, as they are all but impossible to repair; a strong steel wheel can last much longer and may be hammered back into something resembling a circle if the worst does happen.

All wheel bearings should be checked and adjusted before a good packing of waterproof grease.

Make sure your wheels are in good shape

You’re looking for the perfect combination of strength, durability, compliance and grip in a size that that fits your wheels. High-profile tyres (with tall sidewalls) absorb road bumps and offer better feedback than low-profile tyres, which should be avoided; go for 75-profile a a minimum. As with wheels, the event regulations might permit only a small increase in width from standard but this is no bad thing as narrow tyres work better on slippery surfaces.

Commercial (van) tyres are hard-wearing but don’t offer the best grip, especially in the wet; a van tyre with a slightly softer Winter compound would be preferable, and a M+S (Mud and Snow) tread pattern will also help with loose surfaces. On predominantly tarmac events you won’t need such an aggressive tread pattern but the compound does affect the amount of grip you have; again Winter or All-Season types are most suitable in temperate regions such as Europe. Sticky tarmac tyres are great for racing, but hardly necessary on a regularity rally. Whatever you buy, do ensure that the tyre’s speed rating is appropriate for your car, and carry two spares if possible, plus inner tubes.

Running with inner tubes is highly recommended – buy the best you can afford (Michelin offer a super-strong reinforced type). Put these inside a durable cover and you have done as much as you can to prevent pesky punctures.

Avoid tubeless tyres; if you damage a wheel rim they might not seal properly. If you must use them carry some tyre sealant but don’t imagine that you can keep running on a punctured tubeless tyre by fitting an inner tube – it won’t last long.

It should go without saying that the entire braking system must be in excellent condition. Ensure all brake lines are in good order and, if exposed, protected from potential damage. Plastic fluid reservoirs (brake and clutch) are better than traditional alloy types, whose caps can bind and stick; plastic also allows you to check fluid levels at a glance.

Brake pads and linings should be checked and replaced before any event – especially if there will be mountains to descend! Make sure the brake fluid is fresh and clean and avoid mixing synthetic (DOT5) fluid with mineral (DOT4) fluid as they don’t agree with each other. Find out how to adjust the pads and bleed the system, just in case, and carry spare linings, seals, cylinders and hoses, all of which might be specific to the car.

On a ladder chassis, pay attention to the area between the spring shackles, looking for extra holes where alternative dampers were fitted. As this is often the weakest part of the chassis, consider adding cross bracing or triangulation. The same obviously applies to any other potential weak spots.

At Rally Round we try to avoid car-breaking terrain, but you might encounter gravel, sand and moderately bumpy or broken surfaces so you should fit undershield(s) to protect vulnerable areas such the sump, exhaust, brake lines and fuel tank. Ensure that the shield doesn’t block airflow in and out of the engine bay (it might need ventilation holes) and if it runs close beneath the tank, fill the gap with foam to prevent sharp stones from lodging there and puncturing the tank if you hit a bump. Shields are a compromise between weight and protection; aluminium alloy is lighter than steel but more likely to deform, making removal and refitting difficult. The greater your ride height, the less protection you are likely to need.

You should fit mud-flaps to all four wheelarches. Also consider mesh stoneguards to protect your headlights, particularly if they are valuable.

Towing eyes must be up to the job and able to cope with both push and pull, as rescue vehicles may tow with a solid bar. It ought to go without saying that they must also be properly attached; it is no use having a huge eye-bolt that is merely attached to a thin closing plate on the end of a chassis leg.

Having a set of data for your car can be very helpful. You need an owner’s manual plus a handy quick-reference list: points gap, ignition timing, camshaft timing, cylinder head torque and so on – everything you would otherwise spend ages trying to find. Don’t forget the data for any non-original or modified components (camshafts etc).

It is also very useful to have the information right in front of you as you work, so consider putting guidance arrows on the carburettors (richer/weaker) and the distributor (advance/retard), identify the number-one plug lead and record the firing order where it can be easily seen. The same goes for engine and chassis numbers, if they are not immediately visible to border officials.

Even Rally Round mechanics cannot carry everything, so if your car requires very particular tools (eg a unique hub-puller or a special spanner) bring them, or arrange to share them if another crew has a similar car. Otherwise just bring the tools you would use for normal maintenance, along with useful items that don’t take up much space, such as a piece of plywood that you may lie on or place under a jack for stability. String, elastic bungee cords, straps and of course tank tape (available in several pretty colours, for unobtrusive body repairs) are all useful for lashing things up, as are items that have no specific use but, with imagination, could perform many functions.


You will find a useful Spares & Equipment Checklist on another page, which may be printed and used as a preparation guide, a reminder of where everything is stowed and a contents valuation list for Customs. However, before you load the car with spares, take them out of their boxes and test-fit or measure them to ensure that they are exactly what you need.

We have mixed feelings about modern modifications. The earliest races and rallies were completed in the cars of the day on the roads of the day, so we really shouldn’t have too much trouble with newer cars in much less demanding conditions. Unfortunately people tend to prefer to pursue new ideas rather than properly understand older technology. The truth is that if you know how an original old car works, then you can fix it with very few resources. An SU fuel pump with an electronic pulse conversion cannot be repaired by the side of the road if a transistor fails, whereas if it still had points it could probably be fixed quite easily. It’s worth remembering that in many of the places we visit, the locals are more accustomed to mending old technology than to buying new stuff that is deliberately designed to be discarded and replaced.

Before shipping your car you may wish to add the crew names to the wings or doors; online suppliers can make up vinyl stickers for you, but make sure you specify them small enough to fit your chosen location (remember to leave enough space for competition numbers). Nationality flags are optional, but resist any temptation to add blood groups – no medic will rely on such information in any case.

You will often receive your rally plates in advance of an event. These are traditionally made of aluminium alloy and should be secured to the front and rear of the car with brackets and bolts, plastic cable ties, Velcro or double-sided tape – anything strong enough to resist the wind or souvenir hunters. If you will be attaching your plates at Signing On, remember to carry the necessary fixings with you. Either way, take care not to obscure the vehicle’s registration plates or obstruct airflow into the radiator. For tips on applying self-adhesive competition numbers and other decals, see the Scrutineering section of the On the Event page

Any advertising you display should be discreet, preferably in a period style and approved by the rally organizers. Garish commercial slogans or colour schemes are the preserve of post-1967 racing cars.

We’re here to help

That’s it for now, but we shall add to this guide in due course, ever thankful that we never stop learning. In the meantime, if you would like to discuss your own car preparations, please contact the Rally Round office, or refer to one of the workshops listed on our Rally Round Recommends page (click here).

 See you on the road!