From Classic Car to Rally Car

Whilst it’s totally acceptable to rally a completely standard car, the temptation to improve reliability, increase safety, add gadgets and improve performance is difficult to ignore.

However, this is an historic sport where we are trying to recreate the challenges and experiences of a by-gone era. Therefore, with the exception of certain safety aspects, only period modifications are allowed.

There are many things that can be done to a car, all needing far more detail that we can explain here, but here is an overview of the most common upgrades including those specific to the different rally disciplines:


To make a start in Historic events, very little additional equipment is needed apart from a suitable car, but the addition of a tripmeter which accurately measures total and interval distances travelled is a reassuring item to have for the novice navigator. When progressing to competitive events a tripmeter becomes essential as do at least two stop watches more usually referred to as ‘clocks’.


There are several manufacturers of tripmeters supplying models with varying facilities but for UK Historic events tripmeters must only display distance. Speed or average speed displays are not permitted. Neither are tripmeters that use GPS to calculate distances. Period historic tripmeters were mechanical devices driven from the speedometer cable. The Halda Tripmaster and Twinmaster were the most popular and although these are still ideal for today’s rallies, they are only available second hand at prices of around £1000 for a Twinmaster, plus a few hundred pounds for the extra cables, gearboxes and fitting costs. Most tripmeters in use today will be electronic with ether an LCD or LED display. The facilities are identical to the older mechanical tripmeters but being connected only by wires, they are easier to fit into the car. Popular types in the UK are those manufactured by Brantz, Terratrip and Monit with distance only models costing around £200. LCD displays tend to be better in bright sunlight with LEDs working well for night sections but it is very much a personnel choice.

In addition to an electrical supply from the car battery, tripmeters require a sensor to provide electrical pulses so that they can count distance travelled. Sensors are commonly fitted in the speedometer cable or on a wheel hub, and tripmeter manufacturers offer a wide choice of sensor types costing between £25- £40. Fitting will be specific to car model but all tripmeter manufacturers have web sites with helpful selection guides and troubleshooting advice on both sensors and tripmeters.


Clocks come in all shapes and sizes. Whilst a set of period analogue watches by Heuer or similar look very impressive on the dash, a cheap digital kitchen timer will provide more than adequate performance with an easy to read display and easy to operate controls. At the other end of the price range are clocks designed especially for rallying costing around £130. They do offer a range of extra facilities such as the ability to freeze displays whist the clock still runs in the background but advanced facilities are unlikely to be used whilst learning the art of navigation and timing. But whatever clock you choose, it should be as simple and foolproof in operation as possible, which is not always the case with ones that offer a wealth of facilities. Ease of use whilst sitting round the kitchen table is very different to operation in a rally car when things are not going according to plan. Remember that the most important aspect of historic rallying is the route. There is no point in being on time but in the wrong place!


Scenic Tours are a relaxed way of using your classic but that can quickly change if your car is not reliable. The MOT should have pointed to any potential mechanical problems but as the car is likely to be covering greater distances than it may have done for some time and occasionally over more challenging roads, reliability is very important.

Electrics and fuel

A well maintained classic car should be fine, but as the AA and RAC were always saying in period, the electrical system is usually the point of failure. The knowledge of how to “hot wire” your car so that the ignition is connected straight to the battery can be a very useful get-you-home fix. The battery itself is a vital part of the electrical system and a tired battery that just starts the car can have all sorts of electrical side effects, including rough engine running, so a good battery is a sound investment. The route on some tours may include traversing a ford, so using WD 40 or similar on electrics and having a can on board is good insurance.

The increasing Ethanol content in fuels will attack old rubber hose in the fuel system and cause it to disintegrate over time into small particles that will cause running problems as well as the possibility of a fuel leak, so consider replacing all of the flexible fuel hoses with Ethanol proof hose. It is also prudent to equip the car with a fire extinguisher as it must be extremely difficult to stand by helplessly and watch your pride and joy burn, but make sure it is a proper motorsport type with as big a capacity as you can fit, not one from a car accessory shop that is usually far too small to be effective.

Cooling system and brakes

Because you may get stuck in traffic or there could be a long uphill section on the tour, the cooling system must be in good condition. It is not necessary to fit an electric fan as the original engine driven fan should be adequate but the condition of the radiator is very important. Radiator cores tend to become blocked with age and it can be very difficult to unblock them and even more difficult to see if all the cores are clear. A new replacement or reconditioned radiator with a new core is a sound investment.

Going up hill is one thing but coming down can be just as difficult. Most modern cars require a brake fluid change every two years and this is a very sound piece of maintenance advice for a car of any age. Brake fluid absorbs water from the atmosphere and, as well as causing corrosion to brake system components, more importantly, it reduces the boiling point of the fluid. The effect of this may be felt on long down hill sections when the brakes heat up, boil the water in the hydraulic fluid and the brake pedal goes to the floor, and all braking action disappears. And don’t forget, if you negotiate a ford make sure you dry out your brakes after going through deep water to ensure you’re not in for a nasty shock in the next few hundred metres!


Crews who move on to road rallies from Scenic Tours usually start with novice level UK events and the advice on car preparation in Scenic Tours is equally applicable to novice level road rallies. Initially, reliability is more important than car performance as “To finish first, first you have to finish” and crew performance is likely to be the determining factor.


But before embarking on any modifications to the car, it is important to know what is and is not allowed within the Motorsport UK/HRCR regulations. Apart from safety equipment, which is defined in the ‘Blue Book’, a wise starting point is to purchase a set of Homologation Papers for your car from the Motorsport UK. These show what modifications were homologated in period and are therefore allowed today. Anything else can be a matter for discussion with the Eligibility Scrutineer and that is best carried out before arriving at an event. Reading through the web site at is also highly recommended. Whilst the regulations can at times seem very restrictive, the aim is always to provide a level playing field for everyone, keep costs at an affordable level and keep the cars as they were rallied in period.

The cockpit

The role of the navigator is critical for success at any level and for a navigator to do their job a good working environment is necessary. This may mean fitting competition fixed-back seats and a full harness, but if you do start out using the original seats then the backs must be secured so that they no longer tilt forward. The navigator will probably require a foot rest so that they can brace themselves when using a map board and, if night events are being planned, a power supply for an illuminated magnifying Poti and an additional light that enables Ordnance Survey map colours to be seen correctly. In addition to a tripmeter that does not display speed or average speed, clocks and timers will be required and the normal set up is two for the navigator and one for the driver. Digital stopwatches are allowed on most events and all sorts of types are in use from cheap kitchen timers to expensive rally timers designed for road rallies. There is a large amount of paper involved in rallying and additional storage for maps, speed tables, road books, time cards, pens and pencils will be required but these are best manufactured and fitted as you develop the car with the navigator.

Under body protection

Some rallies use rough, or very rough, roads and additional under body protection becomes essential. Often the most vulnerable item is the exhaust system and where there is no option to fit it closer to the body or re-route it, simple welded skid plates on the leading edge of silencer boxes can provide a lot of protection. The replacement of bolted joints with ones held together with springs helps to prevent damage if the worst should happen and the system falls off, with the springs allowing easy reassembly. Do not modify the exhaust in any way that will reduce its silencing efficiency, as a lot of classic exhaust systems only just make the Motorsport UK noise limits in their original form.

Fuel tanks and engine sumps are also vulnerable to attack by hidden rocks but can be protected by the addition of alloy sheet guards bolted to the body. Unfortunately, the fitting of an engine sump guard can also require the fitting of an oil cooler due to shielding of cooling air over the sump by the guard.

Interior protection

As you become more experienced and move up to more demanding rallies then it may be desirable to fit a roll cage. This is best left to professional installation but the fitting requirements are detailed in the Blue Book. At the same time additional protection for brake and fuel lines may be advisable and these can be run inside the passenger compartment although UK Historic regulations require the retention of significant portions of interior trim including the rear seat.

Moving the fuel tank to the boot for added protection is a common modification on some cars but will require the bulkhead between the boot and passenger compartment to be made fire proof.


A dynamo based electrical system may be changed to an alternator based one and, if the electrical system is completely original, it should be overhauled, paying particular attention to fuse boxes which deteriorate over time, and earth bonding which tends to suffer from corrosion build up and can produce some very strange faults. Consideration should be given to relay switching of the larger electrical loads such as headlights along with additional fuses so that if one light fails it does not effect anything else. Electrical modifications of this type are best implemented by an additional wiring loom rather than attempting to adapt the existing one. Depending on the level of rally entered, a FIA cut-off switch which disconnects the battery and stops the engine may be required, but they are a sound investment from a safety aspect no matter what the level of event.

Do not ignore the serviceability of standard equipment such as windscreen wipers and washers. It does rain on competitive sections and you will need good visibility. Likewise, a working heater to demist and keep the navigator happy is a serious requirement.

Suspension and brakes

Tyre sizes and wheel widths are also controlled and the fitting of extra wide wheels of greater than 6’’ width is prohibited but in reality are not required anyway. Changes to suspension components, including shock absorbers and brakes, are also very tightly controlled and little change from the original specification is allowed.

Likewise, brakes cannot be modified from the original specification, except for pad and lining material and changing from single circuit to dual circuit hydraulics, so it is vital that all brake components are in good condition and working properly. That includes the handbrake which will be needed on tests for handbrake turns.

Engine mods

Allowable engine modifications are limited to those that have been homologated and for UK night rallies, cars with more than two choke carburettors are prohibited on the grounds of noise.


As the title suggests Endurance Rallying is all about endurance for the car and the crew. An endurance rally can last for a week and often several weeks and cover very long distances. Navigation is largely straightforward with well prepared road books and although there are usually some tests along the way the real challenges are keeping the car in one piece and the stamina of the crew.

Hands-on approach

Limited mechanical support is usually provided by the event organisers but crews are expected to be able to perform basic repairs and carry their own spares and tools on the car. This ability to perform basic repairs and preventative maintenance such as a complete spanner check after a rough section is desirable when the organiser’s maintenance teams can be fully stretched with a long wait for their help.

Whilst it might be thought that there is a small number of cars that are suitable for endurance events, a look down entry lists show an amazing variety of makes and models but quite often it is a pre war US car that triumphs. Simplicity and ruggedness are desirable and although a post war car can be very adequately modified and prepared, the more complex the car the more spares have to be carried.

Specialist preparation

Car preparation is usually best left to the handful of preparation companies that have a proven track record on endurance events. They know how to modify the cars, what are essential spares and those that would be nice to have. Additional storage will have to be manufactured to carry spares, tools and equipment and distributed around the car so that the balance is not upset and the car is not overloaded. There will usually be a secure discreet store for documents and valuables as well. Packing lists should be created, showing what is on board and where it is located. A larger fuel tank is usually required and engineering this can be a challenge. There will probably be poor fuel quality at some point so fuel filters and the knowledge of how to clean or change them is required. Strengthened and protected suspension, full underbody protection, modified exhaust system perhaps running down the side of the car and pull handles on the bodywork are all likely to be on the list. Work to prepare a car for an Endurance Rally should be expected to take several months and the experienced preparation shops are booked well in advance, so entry to an event also needs to be planned well in advance, which is one reason why entries are accepted a year or so before the event.

Crew essentials

Crew personal preparation is equally important and will often include medical requirements including vaccinations for the more adventurous events. There is likely to be very little space left in the car for clothes and, as on any rally, you do need to have a good relationship with your driver or co driver, particularly when the going gets tough and things start going wrong.


Hill climb and sprint circuits have been used as test venues on rallies for many years so for rally crews they are just another test. The difference in the HRCR Speed Series is that the events are run under Motorsport UK Sprint and Hill Climb regulations rather than rally regulations.


Whilst this should not present a serious preparation problem to an average road rally car, the scrutineers will be applying the appropriate Motorsport UK Sprint and Hill Climb regulations for these events rather than Motorsport UK Historic Rally Regulations. A significant difference is that only the driver will be in the car and a full race suit and helmet are required. There are other detail requirements and the best place to start is with the Speed Series regulations available within this website in the Speed Series section. These regulations refer the reader to the detailed sections of the Motorsport UK ‘Blue Book’ which is available in downloadable form from the Motorsport UK website.

Technical differences

It is difficult to make general statements about car preparation for this championship as it depends on the age of the car and which road-going category it falls into. However, some obvious requirements which are unlikely to be on a rally car are an engine oil catch tank and a timing strut. The catch tank need be nothing more than an empty oil container secured within the engine bay and connected to the crankcase breather by a length of hose. The timing strut can be easily fabricated from sheet aluminium and dimensions are given in the Blue Book. Any undertrays, which for a rally car will mean a sump or transmission shield, must have drain holes. Also, clearly marked tow points must be available front and rear. Depending on the age of car, a roll cage may be required which is compliant with Motorsport UK regulations for the car class and type together with its installation. Seats will require a head restraint and standard seats should ideally be replaced by competition seats. Again depending on age, a full harness may be required together with a fire extinguisher which can be a hand held one. Engine, transmission, suspension and braking allowable modifications again depend on age but generally follow what is allowable on an historic road or stage rally car. There is much more detail and advice in the Blue Book where the appropriate sections must be understood and complied with to avoid scrutineering difficulties on the day.


Stage rallies are of two distinct types, Gravel or Tarmac, and unlike road rallying speed is all important, but whichever type of rally and however fast the car and driver, reliability is still very important.

Safety first

First of all there is the mandatory safety equipment. For the crew, a set of fireproof overalls with helmet, gloves and boots are required. The car will have to be fitted with competition seats, full harnesses, roll cage, plumbed in fire suppression and an electrical system cut off switch. The exact requirements are detailed in the MSA Blue Book and time spent reading the relevant sections will be worthwhile.

Weapon of choice

There are also the requirements of Historic car eligibility. These are also detailed in the Blue Book but a lot of very useful make and type specific information is given on the HRCT website. Inevitably car preparation costs for stage rallying will be greater than for road rallying and additional costs, such as trailering the car to and from events and a service crew with their own service vehicle, need to be taken into account although these may be a later addition. Whilst it is theoretically possible to stage rally any type of car clearly some are more suitable than others. On one hand there is no point in reinventing the wheel, so selecting a type that is already common on the stages has the advantage of using other people’s experience of modifications, of what works and what does not, and a wider choice of suppliers for parts and preparation services. Rallying something more unusual is of course always commendable and appreciated by spectators and fellow competitors alike, but invariably isn’t always the most convenient to compete.

The build

It is possible to prepare a stage rally car in the garage at home but fitting a welded or bolted in roll cage requires considerable welding and fabrication skills with the fitting of the mounting brackets not to mention the experience of having done the job before, so it is often best left to a professional preparation shop. The same goes for seat mounts which can be difficult to install. A preparation shop will be able to advise on all of this and the smaller but vital matters such as fuel tank and electrical modifications. Moving the fuel tank to a protected position in the boot is standard but a fire proof bulkhead is then required between boot and crew compartment. Underbody protection for all vulnerable components is necessary with all fuel and brake lines run inside the crew compartment.

Performance enhancing modifications to both the engine and suspension are allowed but very tightly regulated to what was done in period as detailed by the Homologation papers for the car. This is an area which can become very expensive very quickly and talking to owners and preparers of the type of car you are interested in, before spending your own money, can be time well spent.

Tyres will vary depending on the type of event, but you will certainly use several sets in a season’s rallying and a spare set of wheels and tyres will be needed by the service crew, ready for a quick wheel change. Tyres are limited to a list published by the MSA but must not be wider than 7’’ or have an increase in nominal width of more than 1’’. Brakes cannot be modified but servos can be removed and dual circuits added, but adjustable brake balance bars are not allowed and neither are hydraulic handbrakes.

Finally, as the car will be driven on public roads between stages, it has to be road legal so must have an MOT, tax and insurance, all of which will be checked at signing on and scrutineering.