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LPGas Conversion into a Granada 2.8i Ghia X Estate

by Kev Cole
Granada Classics Car Club 01215300107

In the words of Val Doonican, “I wanna tell you a story…” What started this entire LPG lark off was a conversation with my brother about a diesel Isuzu trooper I was looking at buying. We were talking about cheap fuels and using neat vegetable oil or bio-diesel in it when the conversation turned to LPG. That then led to me buying what I really wanted, an old automatic V8 Range Rover, which was converted within a few weeks of ownership with a kit from a land rover magazine advert. Talk about learning curves!! But I must admit that it was pretty expensive compared to what I pay now for stuff, but it did exactly what it said on the tin, started first time, ran as sweet as a nut till the camshaft when awol, and came with very good instructions. And here was me thinking the Range Rover was a money pit….

Now I’m going to try to describe the installation on my granny, the only problem I can see coming for most of you is the basic principles of LPG, this I will try to cover first, but it’s not the main story here so I will do it quickly.

Parts Required:

• Tank, either cylinder or toroidal (doughnut) shaped, in various sizes depending on space available.
• Multivalve, fits on/in the tank and controls the filling, supplying and pressure control of the tank contents.
• Vaporiser or Reducer, controls the amount of LPG that is needed for the engines demands.
• Mixer, mixes the vaporised LPG with the incoming air from the air filter.
• Switch unit, switches to LPG or Petrol
• Solenoids, controls the switching of the fuel required.

That is the basic parts list required for the installation on any vehicle. Over simplified I know, but a start non-the less. How it all works?? Well the liquid gas is stored at pressure (around 800ish psi) inside the tank; this is then fed to the vaporiser (sometimes called a reducer) via some 6mm copper pipe that is clipped along the chassis underneath the vehicle. The vaporiser is taped into the water system of the vehicle to stop the unit from freezing when the liquid is vaporised to a gas (you may have noticed ice form on top a calor gas bottle when being used). The common misconception is that the unit need heat from the engine to work properly, but it is purely there to stop it freezing, ask the Swedish? They use an awful lot of LPG equipped vehicles in temperatures of around –40oC. The vaporiser is constantly adjusting the amount of fuel required from signals it monitors from the mixer. In essence, the LPG system is very basic, but the modern equipment used are very sensitive and highly advanced, with some units having only one adjustment screw for mixture control. Usually all this equipment is specific to the engine size of the vehicle in question. So there you have it, DIY LPG OK???, have a nice day……. Oh, you want more……sorry got carried away.

Tank installation:

The Multivalve is fitted onto the tank by means of 6 cap head screws that are torqued down to a specific figure (supplied in the fitting sheet) this is the unit that controls the gas in it’s liquid state. An 8mm copper pipe is used to supply LPG to the tank from the filler, and a 6mm copper pipe is used to supply LPG to the vaporiser in the engine compartment. You can see the expanding foam that the tank is sitting on; this aids sealing of the tank from the cabin. Along with the small length of plastic pipe that the copper pipes goes through. You can also see the contents gauge in this picture. This unit is a cheaper one that has small knurled thumbscrews to shut off the tank if required (while fixing a leak for example). This tank is called a single hole tank, with all it’s functions acting through guess what??? A single hole. You can get tanks with a four-hole configuration, one for each specific function, which are more expensive, but fill much more quickly.

You can see how much room I had to play with!!! Especially considering how big the bloody thing is. You can see the water hoses running to the vaporiser and back. You can also see the mixer and blowback device (the silver rings in the intake tubing). The blowback device is a simple flap that slams shut in the event of a blowback, protecting any delicate devices in the standard fuel injection metering unit. Talking of which, I failed to get mine started on LPG due to the metering flap inside the injection unit. You can get devices that open the flap automatically when switching to gas, but I failed to find one for this type of unit (K-Jetronic). I did find a universal one but without it in my hands I couldn’t see how I was going to make it fit inside the air filter box. So I improvised, and used a piece of strong fishing line looped through the metering flap and the rubber hose. This is pulled up tight when running on gas and left loose when not, and it works a treat. Now if you have a big enough tank, and feel confident enough, you can dump all the existing fuel system and stick to LPG only. It’s been done plenty of times, if you only make specific regular journeys then you can plan filling times to suit. This means the engine can be tuned to make use of the higher octane rating of LPG, the existing injection unit can be thrown away and a performance filter used, all aiding power (back to the size thing again girls…) now as I intend to use the space in my estate I opted for a small toroidal tank limiting me to around 180 miles ish (42litres of LPG=9.2Gallons @ 20MPG on a run).

Now where did we get to ??? oh! Yeah, got the hardware installed, now we need something to control it. (Yes, the wife!!!!!!!!!!!!!!!!!!!)

Shown here is the injection switch used on real basic systems. It basically controls the solenoids in either the petrol or gas fuel mode. If you can install a stereo (I mean install…not twist wires together and pray!!!)Then this is Childs play. With more complex injection systems you will need what are called emulators, these trick the STD ecu into thinking the injectors are firing when the switch unit has isolated them so it can run on gas. You can also get a carb switch, which has a central off position to allow the float chamber on the carb to be drained before being run on gas.

You can probably just see the switch unit under the dash. Look just above the centre console to the right, its there honest!

Now this thing on the tow bar is the filler. There are all sorts of filler and adapters, and it depends on where you plan to fill up. Some have adapters with them, some don’t. Some use an ACME fitting some use a BAYONET fitting. I’ve only ever used or been filled with a bayonet type filler nozzle, so guess which filler type I always use……..not hard really is it?? Behind that that centre screw cap is a 10mm thread into which an adapter is screwed which takes the bayonet nozzle.

Setting up. This can take some time; I have had cars run without adjusting a thing (usually a sign of a good mixer/vaporiser match). Then had others that refused to start even when driven flat out on petrol then switched to gas at pretty high speed to keep momentum up…..not until I had got the screws in sort of the correct positions. Talking of which, there is usually only 2 screws to mess with, the power valve, which controls the maximum gas flow (and the mpg) and a mixture screw (basically). Here goes then….

Start off by getting say 10 litres of lpg from you friendly stockist. Then get home and check for leaks!!!

It’s dead easy, just a small paintbrush and some soapy water. If you have done the joint nice they won’t be over tight, so if there are any leaks you have some room to tighten them a touch. Once all tested go back and fill her up. It should take around an 80% fill. A few litres here and there are nothing to worry about; the bloke who fills mine up tells me that some of the taxi drivers can get a 100% fill!!!!!!scary!!!!!!

Now if for some reason you fail to get anywhere near 80%, then it could be because the tank is not positioned correctly (the hole flange must be at 30O) or the float on the Multivalve needs to be bent, as this controls when the valve shuts off. The Granada took 17litres the first time, I ran it dry then adjusted the float arm and got 30litres, ran it dry again, adjusted the float arm again then got 42litres on the third attempt. Close enough for a 50 litre tank.

So, leaks (there’s none of course…) sorted? Tank full of gas? Lets get it started then.

I start with the power valve set about half way closed (check before installing it in the hose), then with the mixture screw say 2 ½ turns out, they’re just a starting point. If the car is a carb model then start it on petrol (switch to the right, red LED on). Running ok??? Then switch the unit to the middle, off position and wait for the engine to die. Now switch to lpg (switch to the left position, green LED on) and try to start it. If it’s running then close the bonnet and drive off into the sunset………sorry, not a romance flick, the real world. If you have it running, cool, you can adjust the mixture screw until you get the maximum revs (this is the full rich setting) then adjust the screw until you get the engine at it’s slowest revs (this is the lean setting) and somewhere between is where you run it at. A bit of time and experience with the system soon has it spot on (see what I meant about being not for the mechanically minded). Now if it hasn’t started, boy are you in for some fun!! You will need to check you have gas at each point in the system? If the solenoids are wired correctly? Is the mixer installed the right way round? Is there power to the switch unit? Etc etc etc

If all that’s ok, then start with the mixture screw on the vaporiser, get a mate to turn the engine over on the key and you fiddle with the screw a bit at a time until it starts, same goes for the power valve although not so much, that comes into play when it’s running, you can alter that to get some power for climbing hills or economy for the long runs (close it down for the mpg and open it up for a bit of power) Right, that’s about it really. Simple isn’t it? A bit of a quick run through really but you all knew most of it anyway, didn’t you? Aye? What’s that? Go through which bit again? Bugger off! I’m off on me bike… c ya!!

This car is presently under a full restoration. The club had to bug Kev to take time off the restoration to write this article, its funny, winters here so it didn’t take much to convince him!

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