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I first heard of LPG (liquified petroleum gas) as a fuel back in the mid 90’s. Up till then I thought it was just a cylinder that I used for the stove in my caravan, and for powering a barbeque. The first systems were coming on the market, but at quite a premium price, and there were few outlets that could refuel a car. Got me interested though and I dug deeper into the subject. I found that many forklift trucks ran on LPG and that vaporisers were available for them, also cylinders that were designed to supply fuel in liquid form rather than as gas through a regulator. The biggest problem for LPG is that as it vaporises it drops considerably in temperature and will freeze. Not a big issue with the low flows used for barbeques etc, but I wanted to fit a system to a 3.5litre V8 Landrover. That beast did about 14mpg on gasoline on the road, and considerably less when playing offroad.

So I got experimenting with a secondhand vaporiser from the local fork lift repair place. It was kind of small for its new home, but by drilling out the jets I got it flowing enough gas. The next problem came up, insufficient hot water flow to stop it freezing up. Solved that by using microbore copper tubing wrapped around the outside of the unit and covering the whole thing in a layer of insulation to keep the heat inside. Split the flow of water that came from the heater hose through the unit as standard and let it flow through both circuits. Threw away the engine driven fan and put in a pair of electrically operated ones from a ford truck, that helped to keep the heat level in the engine up. The tank and supply problems were easy to solve, just use the cylinders supplied for forklifts. I built a cradle with retainer straps into the back of the Landie and plumbed in the copper tubing along the chassis to the vaporiser.

Feeding the gas into the airflow involved adding adaptors to the front end of the carburettors. Another part to either buy or make. I cut the flanges off a pair of worn out carburettors, ground the cut edges nice and flat, then drilled and tapped brass barbs into them for the gas hoses. Not as pretty as the commercial venturis, but they worked fine. Fitted electrically operated fuel cut off valves to both the gasoline supply and the LPG feed line, and a switch on the dashboard to operate them.

To change over from gasoline was as simple as flicking a switch. Start up on gasoline and then shut off both the valves, wait for the carburettors to empty and then switch on the LPG valve. Instant savings. It took a bit of fiddling around to get it all working, but was a fun experiment that saved me a pile over the couple of years I had that beast. Of course, being an honest law abiding citizen, I only used the LPG when driving on private land. With no road fuel duty being paid on the cylinders I would have been illegal if I used it when driving on the road. Still saved me a wad of cash though as I used to compete regularly in land rover trials back then. As a side benefit, the engine was extremely clean inside and even when in use on the road using gasoline I never had a problem with roadside emission checks.