Considering a Liquid Petroleum Gas (LPG) conversion? Want to do the job yourself? Chris Perfect explains what's involved, and converts an EFi Range Rover
The increasing availability of LPG as a relatively cheap and environmentally sound fuel means that thirsty, large-engined Land Rovers can be run at the cost of a smaller petrol car, and with lower emissions.
This has resulted in an increasing number of firms offering to supply or install various systems, all of which they claim, rightly or wrongly, are safe.
The best LPG conversion companies will understand not just the LPG system requirements, equipment and regulations, but also the needs of your particular vehicle and its engine.
A bespoke system designed, manufactured and installed correctly should give many years of good, safe performance.
Many practical Land Rover owners want to do every job themselves, not only to save money, but to ensure the vehicle is exactly how they want it to be.
They are the competent DIY owners who will be painstaking and careful in any job they do, whether sorting out the brakes or steering, or fitting an LPG system.
They also want to gain the knowledge that will enable them to carry out their own regular safety checks and maintenance on the system.
As a result, DIY LPG systems that are specifically developed for Land Rover engines and backed up by full instructions and help, have filled a real need.
Safety and performance are paramount when considering an LPG installation. But let's put things in proportion.
Petrol is a familiar, though very hazardous fuel. A cupful has the explosive potential of a small bomb. A petrol tank containing liquid and vapourised petrol, connected by soft tubing to a hot engine needs treating with respect, especially when you consider that the petrol tank is plastic or thin, sheet metal.
An LPG fuel tank that has been designed and built to appropriate codes is of relatively heavy steel construction, 3-4mm thick, and will have been pressure-tested by the maker.
The LPG pressure is about 100-150psi (8-10bar). The tank should have a pressure relief valve installed and the tank's connection to the system should always be closed unless opened by a solenoid valve.
The fuel feed to the engine will be through plastic-covered copper piping secured with metal P-clips at the correct spacing, and with anti-vibration provision where you need it.
Under the bonnet, electrical solenoid valves that are held open only when the engine is running allow LPG to flow from the tank to the engine. The moment the engine stops, the valves isolate the system and the gas shuts off.
So, in many ways, LPG systems may be safer than petrol. Despite this designed-in system safety and its fail-safe characteristics, it is essential that components are installed correctly and that means following the installation instructions to the letter.
Last year, Trading Standards reported a high percentage of defects in a sample of LPG-converted vehicles. These included professional installations and various system types, so you should research it all carefully before going for a particular installation. Learn enough to be able to form a reasonable judgement, and also to be able to monitor and maintain the LPG system whenever you need to.
Older equipment and systems
Some existing LPG installations are now quite old. System components stamped to the earlier code of 67/00 and installed before August 2001 are still acceptable, but 67/00 (or uncoded) parts should not be used in systems installed after that date. New systems should use components with the current 67/01 code. Apart from possibly affecting system safety, the use of non-coded components may invalidate your insurance cover.
LPG components are now turning up at autojumbles and that's where you should avoid them: out of date, untested and secondhand parts are potentially dangerous. I have seen old tanks being offered for sale with unsatisfactory manual valving - or even with no valves at all.
LPG systems vary enormously and, whether they are for EFi or carburetted engines, there are big differences in power output, economy, reliability and convenience.
It's not a good idea to choose only on price. Although a very basic system may actually run the engine, it can cause serious problems if important factors are ignored. Inadequate components can lead to lean running, causing poor power and economy. They can also produce excessive cylinder temperatures and burnt pistons, and cause damage to components through backfire.
EFi systems can be badly affected if you take a shortcut to bypassing the petrol system, when switching the fuel to LPG. SU and Stromberg carburettors can deteriorate if the needles are not lifted when running on gas. Mixtures under light load are frequently too rich unless there is a means of controlling the mixture under both full- and light-load conditions.
If you intend buying an LPG kit, make sure that your supplier is familiar with your type of Land Rover and will provide evidence of performance, such as dynamometer tests results, plus any back-up service that you may need in order to look after the system in the future. Remember, the average garage will not know what to do with the system!
The picture sequence shows an Iwema LPG kit installed on a 1988 3.5-litre EFi Range Rover. This installation illustrates some of the points we've mentioned. For example: the 3.5 EFi engine (without catalytic converter) has the earlier flap-type air meter which is vulnerable to damage and also affects the air-flow when running on gas - that problem was solved by fitting a special L-jet opener.
Comment (By Teflon)
It's not a definitive 'How To', and I would SERIOUSLY not recommend that any-one attempt an LPG conversion armed with nothing more than this, and a bunch of bits procured of e-bay! Essence of the article is:
'get a kit - follow the instructions'
Which you have to take with a pinch of salt, baring in mind that the author sells LPG kits! However.... he is a recognised Land-Rover 'Authority', and his business is an off-shoot of his interest, rather than the other way around.
And to be honest, the advice is fairly 'sound', and the article does give a reasonable insight into the bits of an LPG system and what's involved in fitting one. Obviously it's no ten minute job, but its not too daunting or demanding either