Preparing Your Car
Rally Round’s highly experienced mechanics share a few tricks of the trade
There are few experiences more disappointing than setting out on a great driving adventure only to fall by the wayside with a broken car. This often happens because the owner has neglected a few basic preparation issues whilst spending an awful lot of money on stuff that doesn’t really matter.
So, to keep you on the road, we offer the following advice in the hope that it proves useful, whatever type of rally you do. Some of it is written with long-distance events in mind and will be less relevant to shorter rallies closer to home. Some of it will be old-hat to seasoned veterans, some of it might seem too technical for novices. You might not agree with all of it. But it has taken many years, plenty of mistakes, lots of grazed knuckles and countless Anglo Saxon oaths to get here, so if you take just one useful tip from it we’ll be happy.
First things first
If you are engaging a professional to prepare your car, it is vital that he understands the nature of the event you are undertaking, and that the car is fully prepared several weeks before the shipping date, so that you can test it thoroughly (over at least 600miles/100km) and return it for adjustments if necessary. All too often we see a car that was ‘finished’ just in time for shipping, with little or no testing. The predictable result is that your dream drive is punctuated with dastardly thoughts of revenge as time and again you head off bearing bottles of cold beer to find the rally mechanics, who suck air through their teeth whilst asking: “Remind us – again – which idiot prepared your car?”
Rally preparation is not the same as race or ‘fast road’ preparation. If you don’t know who to trust, check out the workshops on our Rally Round Recommends page (click here).
A car is not a rally car until it is fitted with a tripmeter. You cannot take part in an event without one. You need a device that measures both intermediate and total distances, but average-speed displays are not allowed. The unit should be mounted on the dashboard within easy reach of the navigator, but not where it is subject to accidental knocks.
Some of the most popular tripmeters are pictured below – (left to right) the Halda Twinmaster, Brantz RetroTrip, Brantz International 2 and Monit Q-20.
The Halda Twinmaster is the classic old-school option, a purely mechanical device driven by a cable from the speedometer and calibrated by swapping internal gearwheels. Unfortunately, as they stopped making them in the early 1970s, Twinmasters are now hard to find and eye-wateringly expensive (the smaller, single-readout Tripmaster model slightly less so) but similar mechanical units are today made by Belmog, and cost rather less. Having set up the unit in advance, you will need to carry a range of different-size gearwheels (maybe three smaller and theee larger) to match any discrepancy in the rally organisers’ tripmeter, on which the Road Book distances are based. You also have to change gearwheels if you fit new rear tyres with a different circumference. Don’t forget that different gearwheel sets are required for miles and kilometres, and that mechanical tripmeteras require occasional servicing.
Another popular Halda product of old was the Speedpilot, a mechanical unit with a single trip readout and two dials which indicated how closely you were keeping to a pre-set average speed. This is not permitted on regularity rallies. However, the Speedpilot has now been recreated in digital form as the GaugePilot. It looks very similar but offers an impressive range of functions, from temperature gauges to service interval reminders and datalogging. Crucially, the average speed function may be disabled for a set period of time – the duration of an event, for example – so the GaugePilot might be an attractive option for gadget lovers, albeit a relatively expensive one.
Brantz and Monit produce simpler, electrically operated tripmeters with digital displays, usually driven (like the GaugePilot) by an electromagnetic sensor on the wheel or propshaft. Most digital tripmeter problems can be traced to the power supply or to the sensor, which may be vulnerable to dirt, vibration, knocks and chassis flexing on rough surfaces. Sensor misalignment will cause a malfunction, so make sure it is mounted securely, out of harm’s way, but can be reached easily if necessary (carry a spare). Calibrating a digital unit is a simple matter of pressing a few buttons, but carry instructions if you don’t know the procedure off by heart.
If you are short of space, the Monit is a good option, as it is the smallest (it has an LCD display). The Halda Twinmaster is the largest. Brantz units have switches and calibration buttons on the underside, so must be mounted where they can’t accidentally be touched by the navigator’s knees.
Before the car is shipped, you should set the tripmeter to be as accurate as possible over a measured distance (several kilometes or a couple of miles, as appropriate for the coming event). You can easily do this on a motorway, where numbered distance marker posts are set at 100m intervals. You will be given details of a calibration route at Signing On, so you can fine-tune your tripmeter to match the Road Book before the start of the rally.
Cooling vintage cars
Even well-built old radiators can fail due to solder becoming work hardened and crystallising over time. To prevent joints cracking on rough roads, it’s a good idea to have the tanks, pipes and necks removed and re-soldered. You should give the radiator a proper clean out at the same time.
Be particularly careful with radiators which have brackets connected to the chassis and bonnet assembly, as they are prone to damage caused by vibration and the flexing of the chassis.
Check that your beautifully shiny radiator grille isn’t blocking air at speed. Try running without it to see if there’s a significant improvement. If there is, fit an open mesh grille instead. Consider mesh stoneguards to protect your headlights too, particularly if they are valuable. They are available in a range of sizes from Holden Vintage & Classic – click here.
Cooling classic cars
Use a good, clean radiator, perhaps upgrade it with extra rows, or consider a larger unit. Check that the rubber mountings are still resilient. Make sure the hoses are sound and the hose clips are strong (so that you can give them an extra nip without stripping them) and don’t forget the heater hoses – they are part of the cooling system too. Finally, pressure test the radiator cap and the whole system to 1.5 times the cap’s break pressure. If there are no leaks it’s good to go. You’ll find a range of hoses, and joiners on the Holden website – click here. For heaters, electric fans and radiator caps, click here.
Waterless coolant is a good thing, and works wonders in older monoblock engines which may run at temperatures much higher than the boiling point of water and have no cylinder head to warp.
However, before using waterless coolant in a more modern car it is important to know and understand what temperature your engine can stand. A steaming radiator alerts you to the fact that something is wrong, but a coolant that doesn’t boil will give you no such warning and makes it much easier to do major damage that can’t be repaired on the rally.
‘Water wetter’ is available from agricultural merchants who sell chemicals for crop spraying; it is mixed with the chemical liquid to reduce its surface tension, so less spray is needed. If you use it in your cooling system, the water will make better contact with the radiator and the system will be more efficient. If you are determined to spend as much money as possible, you can also buy water wetter in very expensive bottles.
Antifreeze is not essential in warm climates, but it aids cooling and inhibits corrosion.
If you have to remove a pulley in order to fit a new fan belt, have a spare belt fitted behind the pulley if possible (secured out of harm’s way). You’ll find a range of fan belts here.
Try to avoid fancy oils that won’t mix with other oils. These days it’s hard enough to find your preferred lube on a UK forecourt, let alone in the rural backwoods of a country powered by ox-carts and Honda 90 mopeds. Know what your engine likes, what it will tolerate when its favourite tipple is nowhere to be found, and how much it is likely to use on an event. Also do some research on what might be available en route. You could carry your own supply of course (there’s a decent range here) but it’s heavy.
The re-soldering principle that applies to radiators also applies to fuel tanks in older cars, which were constructed in the same way.
Over time, due to condensation, water gradually accumulates at the bottom of the fuel tank, causing rust. Eventually, when enough water has been collected, it may be sucked into the fuel system, along with the rust, as you bounce down a bumpy road. This only ever happens when you are lost in a remote area with no mobile phone coverage and no sign of any mechanics. To avoid this, follow two simple rules:
- Make sure your fuel tank is clean and empty of water
- Don’t pour potentially contaminated fuel straight into the tank. Use a filter funnel such as Mr Funnel (www.mrfunnel.com)
More about fuel systems
Always carry spare fuel filters (to be fitted before the pump) and a spare pump or pump service kit. Electronic SU-type pumps do break down and are not very repairable, so you are better off with the older, points type.
If using a different fuel pump than was originally fitted, check the fuel pressure that the carburettors are designed for. If they don’t match, fit a pressure regulator to suit. Viton-tipped float valves are good.
If you need to increase your car’s range, consider a plastic marine tank. They come in various sizes and may be strapped to the boot floor. Nevertheless at some point you will probably have to refuel from a jerrycan. Make sure you have a suitable spout or funnel (see above), or a magical ‘jiggle syphon’.
Holden have a good range of fuel pumps, filters and other hardware – click here.
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.
Fuel, octane, temperature and timing
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.
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.
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.
Retard for lower octane.
Run hotter plugs and ease up on the workload for lower octane, higher ambient temperatures and higher altitude.
When we rallied through Brazil on the 2013 Great South American Challenge, there was some anxiety about fuel containing ethanol. The concern was that it 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. Such fears were based on internet searches that all led back to American boating forums, where folks described problems with leisure boats that were left with fuel in their tanks for long periods. Similar concerns have been expressed by classic car publications in the UK, as the amount of ethanol in fuel has been increased. In fact, we had no problems with ethanol in Brazil.
Thinking about fuel and ignition systems
Your engine is a mechanical unit that converts small explosions (internal combustion) into rotary energy (torque and power). Its integrity should remain intact as long as you maintain the right water temperature and oil pressure.
Fuel and ignition are the two external inputs that make the engine work, and each has its own system: one regulating the fuel/air mixture and the other generating and timing a spark. Consider these systems to be separate from the engine, though integral to its operation.
Both systems use ‘service parts’, which means they wear out and need replacing at intervals. If they have been reliable for a long time, it might not be long before they let you down.
More about ignition
Only carry the best-quality spares – there is a lot of rubbish about. You need plugs, coil, points, condenser, leads, distributor cap and rotor arm, all of which are available from Holden Vintage & Classic – click here. Make sure everything fits, and that it works! A ‘brand new’ rotor arm may have an invisible hairline crack that renders it useless.
Old points are the best, as in ‘old stock’. They were better made with better materials and they become work hardened. If you already have a good old set, or you find some new old stock, hang on to them.
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.
You can have a dynamo, voltage regulator and battery that seem to be in good shape at home but fail to keep up when you fit extra lights and chargers for goodness knows how many electric gizmos. Also bear in mind that some countries demand that you drive with your lights on all the time. On magneto cars you may not notice that your battery is running flat until it suddenly goes dark and your lights don’t work, or you have to start the car in a place where you can’t manage a push.
A fit and forget solution is to fit a small (Nippon Denso or similar) 60amp alternator (check the output before buying as some smaller units are only 20amp). You can fit it under the car, driven from the gearbox output shaft, or between the engine and clutch, or in the engine bay. If you plan to drive it from an auxiliary shaft, remember to take into account the larger loads that alternators need in order to generate.
Have your car’s wiring exorcised of all scotch locks and crimp terminals in favour of soldered joints and terminals. The process may take a little time, but it will usefully reveal any rotten, corroded wires or bad earths. Most of the electrical faults we find on rallies are down to poor wiring. Again you can find a wide range of hardware on the Holden site – click here.
Make sure the battery, starter motor and charging system are up to the job as they are sure to be tested by mud, sand, heat, water and long running hours.
Suspension, steering, wheels and tyres
Beware the temptation to dive into a catalogue, buy lots of lovely shiny things and bolt them on to the car, along with a nice wide set of wheels, like they do on the ‘Pimp My Ride’ type TV shows on the Discovery Channel. If you really can’t resist this urge, remember to bring extra loot as well, for all the mechanics’ beer…
Firstly, most bolt-on mods are designed to give you a ‘sporty’ feel, and merely tighten up the suspension, which is certainly not what you want on countless kilometres of bumpy tarmac, much less broken or unsurfaced roads. Second, you need to appreciate that each part of the original suspension system was carefully designed to handle the loads exerted by all the other parts of the system. Thus if you fit uprated dampers (commonly called shock absorbers, a function that is actually peformed by the springs) they will put more pressure on mounting brackets, suspension joints, bushes and wheel bearings. The same is true of wider wheels. So any modifications to a perfectly good suspension system (assuming it’s all in good condition) need to be well thought out.
Likewise, think carefully before fitting new wheels. Unlike steel, alloy rims cannot be repaired. As for tyres, tall is better than wide. Ask yourself whether you will be able to source your chosen tyre size in the back of beyond. Van tyres are worth considering on poor terrain; the time you save in puncture repairs will far exceed any small performance losses. And if you are running with inner tubes, get the best.
Holden stock a range of Andre Hartford ‘shock absorbers’ (and parts) for vintage cars – click here.
Available from Holden, here. Steer clear of DOT5 fluid in older cars; it attacks some seals, particularly those of US origin. Bring a full set of hydraulic seals for brakes and clutch.
Gearboxes and axles
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.
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.
Towing eyes must be up to the job and able to cope with both push and pull, as we like to 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 screwed into a bumper mounting hole which is actually 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 a manual plus a handy quick-reference list: points gap, ignition timing, camshaft timing, cylinder head torque, in fact 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.
Rally 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 (click here) and of course tank tape (here, in several pretty colours) are 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 of our Advice pages (click here), which may be printed out and used as a preparation guide, a reminder of where eveything is stowed and/or 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.
Don’t forget to pack some Opal Fruits (now called Starburst) or soap, both of which can be useful for emergency repairs to fuel tanks (they don’t dissolve in petrol). On balance we prefer the Opal Fruits. They taste better than soap.
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 understand 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.
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!