LPG conversion

[Joe Harding]

For insertion into technical articles for LPG forum and 300 series forum. Detailed article with photos which I will supply shortly.

Volvo 340 Conversion to LPG fuel; September 2012

Background: This is the second car I have converted to LPG, the previous one we ran for about 70,000 miles with few major problems. Liquid Petroleum Gas (LPG) which currently retails for about half the price of diesel and when our current car popped up on ebay with barely 15,000 on the clock and virtually immaculate, it made sense to do it again . Concurrently the number of forecourts supplying LPG has increased, maintaining in our area a supply in major residential areas. Satnavs can be programmed to sniff out the suppliers, so availability should not be an issue. As the system described in this article is piggy-backed on to an existing petrol fuel system, it is merely a matter of switching over when LPG is running low.

Before taking the plunge on this though, please consider the following factors:

Is the vehicle worth the effort? Yes, I know it is a Volvo, and it has a place in your affections above the family, home and favourite pet but what is the mileage? How likely is it to survive the next MOT? Will garages be happy to weld bodywork with LPG on board?

Is the car running well? Don’t start until you are sure that the existing fuel delivery systems are running at optimum. Check plugs are well-tanned and HT leads, coil, distributor etc. are up together.

Is your car suitable? Notwithstanding the above, ask yourself; ‘is this within my capability?’ It is one thing to be able to maintain the car, but does underbonnet space allow room for more major components? We purchased a 340 for two reasons: firstly it is an easy car to maintain. Solidly built and reliable. No frills, (unless you count heated seats!) and my preference has always been the 1.4 B14E engine. OK it is underpowered, but it goes well. And the plus point leads me to my second reason for buying this type of car: there is loads of room under the bonnet.

Our other car is a V70 diesel. Magnificent, but I dread the day it throws a major wobbly. It would probably cost more to repair than the 340 cost to buy.

The 340 fits most of the above criteria. We got ours from ebay. Take a look - there are very many low (and I mean low 10-20k) mileage vehicles emerging blinking into daylight as grandparents pass away and relatives are forced to dispose of their “pootle-mobile.”

It runs sweetly on petrol, the carburettor is functioning well, and most deterioration expected from a twenty-year old car has been dealt with. It is used as a run-around, which is another factor making it an ideal candidate for conversion- the LPG tank fits in the boot, taking up the space of a large suitcase. In other words the luggage for a family of six, even supposing we could all fit in there, is no longer an option. But running around is where most of our miles go, so again the sensible thing is to convert it. At the time of conversion it had clocked up 16,000 miles. So barely off the starting block!

As an aside, the system installation does not interfere with the running on petrol. At any time during the conversion the car could be up and running on petrol in twenty minutes so it could be done if a 340 is your only car. Not only that, but conceivably the installation could be stripped out if you decide to dispose of the car. (Unlikely, I know, but I had to say it…)

Before going on, where do you get these kits from? There must be other suppliers, but we plumped for Tinley Tech (www.tinleytech.co.uk) as they seemed to have been doing it for a while, and Land Rover forums (a major user of LPG I understand) seem to quote their name without question. They supply kits for carburettor and injection vehicles.

And so to the system itself. Essentially there is nothing complicated about what we installed. It is an alternative fuel delivery arrangement. Actually the term ‘gas’ is a misnomer - what is delivered is a vapour. The system divides into two - a high pressure storage and delivery element, then a pressure reducer/vaporiser part which delivers low pressure high flow vapour to the carburettor. The final part delivers the vapour proportionately over both barrels of the carburettor. It should be said that although Solex carbs are sometimes fitted, as far as my experience goes the Weber 32DIR carb is the one I know. Anyway the type of carb is specified when ordering the LPG conversion kit.

With this division of the system in mind, the work becomes apparent: install the high pressure elements, check they are sound and leak-free, then install the low pressure parts. In fact the order doesn’t matter - some parts of the job are just sheer hard work but low brain effort - running the pipework under the car for example. If you have access to a pit or hoist, a cinch. If not, then the best part of an afternoon’s work. As I was sceptical about almost everything to do with the project, I opted to carry out the tasks that would do very little damage to the bodywork - namely installing the tank, vaporiser and mixer before installing the filler port.

Before you shrug and say, ‘oh well, I’ll get a professional installer to carry out the work consider this; the cost of a professional installation can vary from model and type, but a ballpark figure is about £1500-2000.

The cost price of the system kits from Tinley Tech varies from about £450- 1000+ for a top-notch multipoint system.

And so to the install. The tank comes separately, and following extensive measurements and considerable “um”ing and “ah”ing, I decided to opt for a 70 litre cylindrical tank. With the multipoint valve closing off the filling system at 80% (to allow for expansion) this gave a full tank of 56 litres of LPG. (It actually worked out spot on!) This tank fitted beautifully between the forward part of the boot space. A larger tank could be installed, but I knew this size would work - and it did.

Firstly fit the tank cradle, as snugly up against the rear seat as possible with the tank in situ. Bear in mind that the rear seat must latch into place to pass the MOT. Much squinting in the boot and under the rear gave me the options of fitting the cradle on two very secure mounting points- right through the chassis cross-members. These were in car terms the rearmost fittings (in other words, in the event of an accident, these would take the strain). Two M8 x 100mm bolts were used, with penny washers (to spread the load), shakeproof washers and lock nuts. As extra security threadlock was applied. From the picture you can see which pre-drilled holes in the cradle were used. These holes miss everything of importance in the rear of the car and go through one of the strongest mounting points in the area. As an extra tip, apply waterproof sealant (mastic bathroom stuff) to the penny washer to keep out moisture.

The remaining two holes were drilled through panels. Again, nothing vital was in the way, but as this was only a panel, the M8 x 100mm bolts were lock-nutted to the panel, then the cradle bolted to the secure fastening to avoid distorting the metal work. Spacers could be used, but don’t be tempted just to tighten the cradle directly to the floor of the boot. As with the other mountings, use mastic to seal the bodywork holes.

Now you have a cradle in place, hopefully central to the boot. You might as well fit the tank and the multivalve. The tank is simply strapped in place, (don’t forget to fit the rubber bumpers on the cradle.) and the multivalve installed by carefully tightening the six bolts; tighten them diagonally to avoid distorting the seating.


Much is said about getting the angle of the valve right. Try measuring it! Chalk marks and guesstimates abound, but in the end the option is simple: do you want to cut a hole in the parcel shelf, (knowing it will be the beginning of the end for this fragile item) so that the multivalve is set at exactly 30° from the horizontal; or would you prefer to have the multivalve probably a little lower than specified so that the parcel shelf closes over it? I chose the latter, and the cut-off point, determined by the angle of the float apparatus did work very well. So maybe try this first, but leave sufficient slack in the pipework to set it higher if necessary.

Stand back and survey the brooding, black monstrosity that now occupies just under half of your boot space. Reflect, it’s not that bad really; it is tucked away and there’s still plenty of room left. Down the sides will go all the junk and importantly the wheel jack tools from under the bonnet.

Now it just gets better. You need a fairly large hole to accommodate the corrugated outer casing down which the high pressure gas line to the engine compartment runs, (it acts as a fume vent.). In the boot well is a largish depression covered in rust proofing. Dig around and it turns out to be a large rubber grommet plugging a hole that is…no, it can’t be… well stone the crows! Exactly the right size for the bayonet that terminates the corrugated pipeline. Three small screws to secure the bayonet, plus more mastic, don’t worry if it doesn’t seem really rugged, the pipework will secure it in place.

The HP gas to filler pipe line can go through the boot to the best point available to fit the filler port. I say best point because unless I’m missing something, there just isn’t an ideal point. I considered the bumper, side panels, lower sills, etc. but they do recommend that you locate the filler somewhere where it won’t flex the bodywork too much. For the first conversion I did, I fitted the filler between the bumper wrap around and the fold in the side panel. It involved cutting into the bumper slightly but it’s mainly cosmetic at this point anyway. The current car has its mounting point above the horizontal bend where the metal is thinner and easier to cut, but the fitting does flex slightly when you apply the chunky filler bayonet to the filler port. It looks better and in fact you can cut the hole for the port using a rotary saw which would be difficult further down.

Gas pipe runs are easy. The stuff comes coiled up. It has a thick plastic sheath and uncoils easily. Practise with the 8mm internal dia. (thicker) filler pipe from the filler to the multivalve. As long as you bend it gently and smoothly, it should not kink or degrade. When you have established a sensible route, carefully trim back the outer sheath taking care not to cut the copper pipe, allowing sufficient exposed pipe to fit the glands and olives to make the connection. Cut the pipe using a pipe cutter. It is simply not worth the hassle of using a saw compared to the price of one of these items. Call me cautious, but I used PTFE tape on all threads, and I suffered only minor leaks. Also ensure that the section of pipe entering the filler port and valve section is straight, otherwise the glands become skewed. Fit the olive using a soft mallet if gentle persuasion is needed and push it up about 5mm along the pipe. Try to avoid scratching the olive.

Before finally connecting both ends, work the corrugated plastic outer pipe along the route, making sure both ends are well tightened. The kit comes with something like a sardine tin strap to hold it in place. (You’ll know what I mean when you see it!) For the life of me, I never worked out how to use these things, not even second time around. Best use heavy duty tie-wraps.

With experience gained from fitting the 8mm pipe; now run the 6mm pipe from the multivalve output port to the front of the car, to come up on the passenger side of the engine bay adjacent the brake pipes. This single sentence encompasses hours of grunting, rolling underneath the car and back out again. If possible, get help. Someone to pay out the pipe and make tea etc.

Jack up the car. This is another ideal use for a companion; someone to whom you can murmur your last words to as the car rolls off the ramps and crushes you. In other words don’t do a thing until you are 100% sure that the car is secure. What I did was to use ramps set opposite each other on one side only. The car was reversed up the rear ramp, then jacked up on to the front ramp, so that if the car moved, it wouldn’t descend. Whatever you do, take time to check it is secure.

The best direction to feed the pipe from is front to back. I took it along the passenger side enclosed box section. Then where it diverts towards the middle of the underside, I cut an angled hole and fed the pipe down the middle for the last few centimetres. Where it emerges, bend it upwards to hug the floor, avoiding exhaust as far as possible. Continue laying it flat to the floor except for where the rear axle gets in the way. Loop it over the axle and it should then be within sight of the convenient hole in the boot. Bring it up through this hole, and dress it tidily along the other pipe run to the multivalve, and fit the second corrugated sleeve along this as before.

Fit the pipe to the multivalve observing precautions when cutting pipe outlined earlier. To be on the safe side, leave enough so that if it becomes necessary to adjust the angle of the tank, you have sufficient slack pipe to facilitate this.
Then clamp the pipe to the car; 60mm between clips is recommended. There should be sufficient pipe and clips, although you won’t have much left over. I also took great care where the pipe goes through the chassis member to fit a collar around it to curtail chafing, and sealed the hole with…you guessed it…mastic.
Whilst you are in the mood for straining your stomach muscles and filling your eyes with dirt, run the cables supplied with the multivalve solenoid and the tank sender along the same route. I used tie wraps to secure these to the pipe. If this job is done well, you should not need to go back under the car. The rest of the work is more pleasant.

The first item in line is the second LPG cut-off solenoid valve. The instructions recommend installing an anti-vibration loop. Please note, at no time should the HP components be fitted to engine components, it seems obvious, but the vibration would cause rapid failure.
I installed a second loop ‘cos it looked nice, between the solenoid and the reducer. As the photographs show, the reducer was fitted above the passenger side wheel arch. In this location, you will have to relocate the jack and tools, but you can keep the spare wheel in its place of honour.

Fit the glands and olives (plus PTFE tape) to all HP joints and that part of the installation is finished.
I pressure tested at this point (and many other times) using an airline to pressurize the tank and professional anti-leak liquid (called SNOOP, it is used in anaesthetic trolley testing). Soap and water will do. Flex the joints, check for even the slightest bubbles. Check by activating the solenoids that pressure appears at the reducer but gets no further. If possible leave the system pressurized and check next day that it is still at pressure. Be satisfied with your work before proceeding.

Low Pressure components

The reducer/vaporiser does as it says on the tin: it reduces the high volatile liquid petroleum pressure and mixes air into the flow to produce a vapour. To achieve this efficiently it needs to be hot. The suggested location over the wheel arch allows easy connection to the primary car cooling system. The kit supplies two Tee pieces, jubilee clips and heating hose to enable this adaptation. It is self explanatory, suffice it to say that I connected into the cabin heating circuit and it worked excellently. (Tip: use clamps to save losing too much coolant along the way.)

Check the vaporiser gets lovely and hot- it should be hot to touch after the engine is warmed up.
Word of warning:- where I drilled the holes for the vaporiser bracket, I was careless enough to drill into a wire loom. The horn went berserk and an hour was wasted unpicking the loom and rejoining the wires. Not easy and best avoided!

The next bit is important to do well. The placing of the mixer over the carburettor is crucial to the stability of the final performance. So time spent here getting it right is time well spent. No gasket was supplied with my kit, so I suspect they don’t come with a gasket. Essentially the aluminium body of the mixer just fits over the mouth of the carb, held in place by the pressure of a spring against the lid of the air intake. Which means that when you go to change your air filter, ‘boing!’ the lid leaps off and flies over the fence.

Sceptical of the likelihood of this contrivance remaining securely in place (after all, you can’t see what happens to it when the lid is fitted,) I opted to manufacture a clamp, visible there on the RH corner. I found another nut to tighten the air intake to the carb, then used the nylock nut to hold the clamp in place. I kept the spring, but its function is less crucial now.
Now for the gasket: Using the mixer as a template, I drew my own, taking care to include the centre bridge section as well. You will notice the bottom LH side the gasket has been cut flush to the mixer. This is to stop it fouling the carb linkage. The same applies to the choke butterflies; ensure they do not come into contact with the gasket.
Once the gasket has been fabricated, I used a gasket compound to glue it in place. (Very small amounts!)
Having a second carburettor in the workshop gave me the opportunity to measure the gasket and offer it up properly. But I repeat- get this bit right!

With the benefit of second time around, I can relate that I didn’t use a gasket. After all, any leaks in vapour are headed only one way, and that is towards the inlet manifold. At time of writing no ill effects but I include this bit about the gasket for completeness’ sake.

Satisfied with the mixer gasket, the twin hoses need to be connected to the “power valve”. This impressively-named unit is basically a top-flow regulator. An explanation helps here:

The system is open-loop. In other words gas flows into the engine largely regardless of need. To avoid unnecessary wastage the flow is capped at maximum power needed; a y-piece splitter directs gas to both mouths of the carb. Both arms have variable restrictors on them. In the instructions you basically set the engine at 3000rpm and set the restriction so that it starts to affect the engine, then back it off slightly. [* see end of article] With the first car conversion I bought an improvement on this: where the flow through the single vapour pipe is varied by a stepper motor responding to the oxygen concentration in the exhaust gases. For the second conversion I didn’t bother as it didn’t seem to contribute much added economy.

So from the mixer, two pipes go through the bottom of the frying pan air filter and converge at the power valve; then one pipe goes on to the vaporiser.

Your next problem is immediately apparent. But what the heck- you’ve had it easy so far! Time to scratch your head and wish you’d let somebody else do this.
A plastic moulding from the frying pan forms into a gutter which overhangs the mouth of one of the carb barrels. It connects via a pipe to the rocker box breather outlet, and through a tee-piece to the bottom of the carburettor. Quite why two pipes are needed, I don’t know, but simply put, it sucks oily fumes from the crankcase and vents them into the inlet manifold, there to be burnt in the engine. The problem is twofold: 1) the plastic ‘gutter’ is right in the way of the mixer block and 2) the instructions stress that no air should enter the carburettor AFTER the mixer. In other words the lower breather pipe should be clamped off. What I did was to install a solenoid valve that opened the lower pipe when the car was running on petrol, and closes it when on gas.

This still leaves the gutter. Cut it off flush. You can’t do it any other way. An alternative will be made later. Right now you need to get those rather broad pipes from the mixer, through holes in the bottom of the frying pan without them kinking along the way. It can be done, and I drilled small holes in the ribs of the floor of the body to fit tie wraps to secure the pipes in place. The whole unit is then adjusted so that the mixer sits squarely on the carb without being tugged in any direction.

The rest of the pipework is simple, make sure the power valve can be easily accessed for adjusting later. Also make sure no moving parts are snagged by the pipework. Making another ‘gutter’ for the fume breather system is not easy, but I found that using rigid plastic pipe (in fact the same type that goes from the inlet manifold to the brake servo) was ideal, as with the aid of a heat gun it could be bent and flattened into shape. Alternatively use a small section of gas pipe with the outer sheath stripped away.



Petrol Solenoid

The last vital component in the system is the petrol solenoid. Switching over to gas means that the petrol must be completely isolated from the carburettor. So in-line with the flow from petrol pump to carburettor, you install a solenoid valve.

After much thought, I manufactured a bracket from some perforated metal strip (from a building site skip!). Use cardboard to produce a template and cut the strip to facilitate mounting the valve as close to the carb as possible. (To reduce switch-over dual-fuelling condition.) In retrospect you could always use the anti-run on solenoid on the carburettor. (If it works!)

A word of warning. The solenoid supplied with the kit is not man enough to hold back the pressure produced by the diaphragm petrol pump. In time it will leak leading to dual-fuelling. This causes all manner of nasty running issues and should always be the first thing to check if problems arise with running at any time. Gas AND petrol being fed into an engine is a hopeless condition. After this occurred first time, and following many false leads, I diagnosed the leaky solenoid valve and fitted a much beefier article which worked beautifully thereafter. Rather than go through my learning curve, order the bigger petrol shut-off valve (from Tinley Tech) and use the smaller solenoid they supply with the kit to make the air shut off system described above.

When the pipe runs are complete and the solenoid(s) in situ, take care to ensure the frying pan doesn’t clobber the arrangement when it is bolted down. It might take a couple of goes, but it does fit.

Electrical installation

The only electronic item to be installed is the changeover switch, which is fitted inside the cabin. Preferably within easy reach of the driver as changing over is best done at cruising speed. It comes with a wire loom and a diagram. Most diagrams and explanations supplied with the individual components are in “Italish” so they have to read a few times before their meaning is clear. However there is nothing rocket-science about wiring up the system.
Three solenoids attach to one +12 volt supply (the blue wire in our case). They are the tank cut-off, the pipeline cut-off and the reducer solenoid. At a stroke the gas supply can be isolated at every point. (Better than most petrol safety lockouts!) The other solenoid supply is to the petrol isolator. This obviously operates inversely to the gas solenoids. The tank sender wires are linked up so that the tank gas level can be seen on the switch bargraph display and the brown wire is used to sense whether the engine is running or not. On the first system I installed, this wire is wrapped round the HT lead about 15 times and taped in place.

The second system I installed uses the tacho signals from the Renix ignition unit. There are two sensitivity settings on the control unit and it is worth playing around to get it right. The final outcome is obvious; a period when turning the ignition on allows a priming dose of gas into the carburettor (solenoids activate, then after a few seconds if the engine is not started, they will close again.) If the solenoids do not open, or open but do not subsequently reclose, get it sorted.

Finally the usual fused +12 volt supply and vehicle ground wires are fitted to a convenient place. The instructions recommend soldering the spade terminals to the wires. This I did and also soldered the gas solenoid common supply wires into one wire, which I then attached to the supply wire using a crimped connector. Numerous tie wraps and electrical insulation tape to form a loom; and the wiring was complete. It pays to take time with this- the vibrating engine can soon detach connections if the wires are not properly supported.


Commissioning

Chances are you have run around a bit trying things out as you go along. A good time to recheck all those gas joints for leaks. A sniff test is useful, but imagination runs wild; especially after the first fill of liquid napalm. A van driver remarked; “don’t be nervous- it’s fine!” and he was right. We filled up with a small amount of LPG. This was a mistake as with really low amounts the mixture can lack pressure, so not much good for setting up. So bite the bullet and decide to at least half-fill the tank to check it out.

Check right away that the engine still runs smoothly on petrol. The tick over might have increased if you have clamped the breather pipe to the bottom of the carburettor off. Other than that the car should still be happy in petrol mode.

Check when stationary that switching the changeover switch to its centre position should shut the petrol solenoid and close off petrol flow, at the same time opening the LPG solenoids with a noticeable clonk. Gas should flow for a few seconds, then the solenoids should close again as the safety lock-out operates.

The same should happen with the switch right across to LPG mode; without the engine running only enough gas to prime the system should be released.

Get the engine warm, then with it running change the switch over to mid-position, then to gas. Chances are the engine will struggle like a suffocating man before finally expiring. Nervously you survey all the work of the last four days, wondering why on earth you bothered. Never fear! It will work.

Get an assistant to do the changing over for you, whilst you fiddle with the two controls on the vaporiser. The larger knurled screw adjusts sensitivity (whatever that means) and the smaller one idle but helpfully the vapouriser comes in a roughly set-up condition so don’t go too far from its received setting. They are both horribly interdependent. Mucking with one affects the other and the combinations are infinite. But by a process of trial and error, the sensitivity screw can be set to get the engine to run across the rev range without faltering. Then using small changes adjust to idle screw to achieve a smooth tickover. Don’t waste too much time with this unless you have a CO analyser- you’ll never get it right without one. Once you have got the thing to run satisfactorily, book into your local friendly garage. (Preferably tell them beforehand). Explain what you want done and give them a tour of the installation. Chances are they’ll be fascinated. Then leave it with them. That’s exactly what we did, I’m sure Marlen Motors of Dursley won’t mind a mention; they had it in, adjusted it to the handbook specifications and thereafter it ran sweetly and cleanly. The end result is better than I could have expected: Ok it is Summer and cars start easier, but we don’t use petrol even to start from cold. Just gas and full choke for a short while.

At some point you will want to check that multivalve overfilling cut-off. If you opted for a seventy litre tank, 56 litres is your lot. For us it was exactly that. Whatever the capacity, keep your eye on the amount going in. Allow for a margin of error, but if it shows no sign of stopping flow (it should stop cleanly) then use that tank up and check your work. Don’t be tempted to drive an overfull tank. The 20% for expansion rule is a sensible one, considering how hot the interior of a car can get.
As an aside, it is usually slower to fill gas anyway. Filling on a hot day might be unusually slow. Suppliers recommend going either morning or evening.
Filling itself is a bit scary at first;- the wheesh! of vented gas as you disconnect the filler is disconcerting.

Cash benefits
With the benefit of a few years’ experience, what savings do you get on this system? To fill a 340 with petrol at time of writing costs about £50 and you can expect 250 miles from that outlay.

To fill with gas costs £40 (at £0.72 per litre) and with careful use you can expect about 330-350 miles. (see notes).

After some time using the previous converted 340, I extended the service intervals as the oil was coming out pretty much the same colour it went in. Same for the plugs. I would recommend from experience, though, fitting the valve lubrication system supplied by Tinley Tech. It takes less than an hour to install and not a great deal of money to run but does reduce valve recession which is brought about by the ‘dryness’ of the gas running. Once the vapouriser is set to give the optimum mixture, it can be pretty well left alone. After 10 years you are supposed to renew or check the tank, but I’ve yet to get that far.

Insurance

This was the unexpected slap in the face. Well, it had to come from somewhere! Having agreed with our insurers before anything had been done that we were going to alter the car, (they said, ‘no problem, just let us know when it’s done and we’ll make a note’) the insurers then did an about turn and denied all knowledge of our intentions and cancelled the policy. We had to shop around to find cover, but when we did, it was with the stated agreement that we get the work certified by a LPGA approved garage. Not easy, as they naturally only want to certify work they have done. Finally, however, I found an installer in Monmouth who inspected my work, made two or three recommendations and said he would send the certificate when I sent him photographs of the alterations. I used him for the second install as well. Our insurance was happy with his certificate. By the way, keep the tank certificate as well as it might be needed.

DVLA might want to know about the conversion, but it depends on various factors, age of car amongst them. After checking their website, we decided that they did not want to know what we had done, but it might not be the same for other vehicles.

Conclusions

The install second time round was better in every respect. Quicker to install, quicker to set up, we knew what to expect and in fact exceeded our expectations in most ways except economy (see below). The car was newer (22 years old) and a beauty with it. (After all, installing a system in a car that will fail MOT because of chassis rust is a waste of time.)

Do install the valve lube. It doesn’t cost much relative to the install, but it does save wear and tear on the valve seats. All the same you will need to carry out the 6000 mile tappet adjustment on schedule. If the valves (and it is mainly the exhaust valves) go out of adjustment, the car becomes prone to stalling on deceleration and the idle becomes lumpy.

So far, we are delighted with the results of the second install. It has yielded a car that runs sweetly, requires fewer oil, oil filter and spark plug changes, costs a great deal less per mile to run and has the bonus that a reserve of petrol can be kept in case of emergency. Running on gas eliminates the usual bugbears of petrol running; dirt or water in carb, plug fouling and so on. And as this system starts on gas no matter what the weather, it really is ideal. If the car becomes involved in a road incident, mention it is LPG and watch the emergency services adjust their priorities!
[*] The power valves do contribute very largely to the economical running of the car. Once the gas mixture is set to its optimum (by a gas analyser) the power valves need to be set to give a proportional flow of gas. The instructions refer to setting the engine revs to 3000rpm then screwing the valves in until the engine starts to limit. Then it should be backed off by ½ a turn. In practice, we found that whereas the first car achieved 350 miles on a thankful (56 litres) our second conversion was a hundred miles less until we started screwing in the valves. At the point of writing the fuel consumption is definitely around 320 miles per thankful, but there might be possibility of even more improvement yet. The limiting factor will be when the car struggles to climb steep gradients; that will be the point at which it might need screwing out again.

[classicswede]

Thanks for putting this up Joe I'm sure many will find it interesting reading. I have skimmed through and have a few points that need tto be mentioned

When bolting the tank frame down if you go through the chassis make sure that you fit a steel tube through teh chassis so that it does not crush. Without the tube teh bolts will gradualy come loose as the chaissis squashes

Your despription of the filler pipe fitting is not clear (I'm sure teh photos will show it better). As per the front to back pipe make sure the floor vent is installed and secured down, you need to drill a 30mm hole for this one. If you wing mount the filler the pipe needs to come down the side of the wing (vented) outside then back in through the floor vent and through the tubing to the valve box. Worm drive clips are teh best thing to use to make sure they are sealed.

NEVER use PTFE tape on the olive compression fittings as it can cause leak problems and potentialy block the small bore pipes.

The copper pipe line should be clipped about every 300mm 12" with a maximum spacing of 600mm

If you use soapy water to leak test make sure you wash it off after as the soap is corrosive

Other than those few small points a good guide for 300 series installation. I initaly used a 80ltr tank but then changed to a 90ltr tank by adjusting the plastic side trims.

[Chris_C]

A quick point from me (the article sounds great, I have no experience of LPG and that all made sense!)

But, I wouldn't use kitchen or bathroom sealant on the penny washers holding the tank in. Both of these contain acetic acid (it's the vinegar smell when you use them) which will munch metals like you won't believe. Tiger seal or similar (from a factors or bodyshop) will cost a half snadgers more, but is the correct stuff for fitting panels etc.

Nice one Joe! If you have issues dropping pictures in (as the forum will stop you from editing after a time) hit the report post triangle and we'll work out a way it can be done.

[gordonr]

i have had first hand experience of driving a lpg berlingo van
as the last company i worked for had all their vans converted
when the grants were still available
word of warning though nearly all the vans suffered stalling problems
in cold frosty conditions usually cutting out completely as you were gearing down for a junction or roundabout, the ex bosses jaguar had the same problem
half his fleet were converted at different garages , it made no difference
ive even heard of other makes having the same problem

it got so bad i just ran the van on petrol when it was cold as one time it cut out
when i was turning right , hence no power steering etc ( scary )
another colleague refused to have his replacement converted and insisted on a diesel van instead and the boss reluctantly gave in

i wouldnt have lpg after what happened to me on numerous occasions cutting out without warning

[Joe Harding]

I had issues with the first conversion which I determined were down to valve settings needing to be so much more in spec. Hence the note about sticking to the 6000 mile service.

Thanks to others for the advice. I did trawl through endless regs before deciding on where to route pipes etc. Not bedtime reading.

[classicswede]

Originally Posted by gordonr

i have had first hand experience of driving a lpg berlingo van
as the last company i worked for had all their vans converted
when the grants were still available
word of warning though nearly all the vans suffered stalling problems
in cold frosty conditions usually cutting out completely as you were gearing down for a junction or roundabout, the ex bosses jaguar had the same problem
half his fleet were converted at different garages , it made no difference
ive even heard of other makes having the same problem

it got so bad i just ran the van on petrol when it was cold as one time it cut out
when i was turning right , hence no power steering etc ( scary )
another colleague refused to have his replacement converted and insisted on a diesel van instead and the boss reluctantly gave in

i wouldnt have lpg after what happened to me on numerous occasions cutting out without warning

The problem is not difficult to solve and is an issue only found on the early mixers systems. There is a little device that you can use that delays the change over untill the engine is warm eough. This is very usfull when the driver is not capable of driving teh car in the correct manor when cold.

[Joe Harding]

1) Shows cradle in place in boot. (The car colour may change during these pictures as I have used the first install pictures!)

2) Shows tank installed with pipeline to vapouriser in place

3) Shows conveniently-sized hole already in the boot just waiting to be used.

4) Second pipeline to filler with T-piece (from plumber's shop) that acts as a drain should gas escape.

5) Best route for pipeline to vapouriser inside chassis member. Silicon rubber to seal ends.

[Joe Harding]

6) Shows site of T-piece into primary heating circuit

7) Second T-piece heating circuit return

8) Location of vapouriser on passenger side wing. It needs to be close to level with the carburettor.

9) Air filter housing with low-pressure gas/air pipes installed

10) Gas manifold clamped over carb mouth (it is much better to make a clamp then leave it to the spring to hold it in place. Any slippage can foul the choke mechanism)

[Joe Harding]

11) Another view of the air filter with manifold installed

12) Bracket made to fit petrol solenoid (Note this is an upgraded version of the one supplied in the kit)

13 & 14) Just some eye-candy

I realised I didn't take a picture of the filler location. I'll do that when we get a sunny day.

[Joe Harding]

We get 30.4 mpg on lpg which equates to 375 miles on a 56 litre tankful, costing currently about £40. Slightly better than the V70 which costs about £90 to do 680 miles.