lpg conversion

I am attempting to add lpg to my LR 110 V8 carb engine. The switch I have is a lo gas. Can any one tell me how the petrol is stopped when changing to lpg.

Reply to
Tony
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You should really have documentation before doing this.... it sounds like you don't have the necessary parts or any kind of instructions, what all parts do you have?

Petrol is stopped in two ways, one you have a cut off relay in the line to your electric fuel pump and two, you have a electrically operated valve in the petrol fuel line.

Regards

William MacLeod

Reply to
willie

I have a switch. The wiring diagram shows it to the lpg tank , coil and evaperator. Pipes etc. Nowere on the diagram does it show if I need to switch the pertol pump off. The change over from petrol to gas sequence shows that once the switch is in the gas position the engine revs drop and the gas sol valves open.

Reply to
Tony

On or around 15 Feb 2006 08:26:42 -0800, "Tony" enlightened us thusly:

that's an incomplete set of instructions, I'd think, or incomplete description by you. If you want accurate advice, more info is needed

What engine? carb or injection? makes a difference.

On a carb engine, you have to shut the petrol off and let the carbs run dry, then switch the gas on. On an injection engine, at least for the LR V8 ones, you have a cunning pair of black boxes which interrupt the electrical supply to the injectors, when the gas system goes live. Normally, the latter sort has an auto-changeover which works as you describe on falling revs.

That kind of switch is not going to work well on a carb system though.

Reply to
Austin Shackles

Ok I think I have most of the answers. Land rover V8 on carbs

Solenoid in the lpg line Solenoid in the Petrol line Relay to switch over and switch the fuel pump off. When the carbs start to run dry of petrol, drop the revs and the petrol/lpg switch will engage the vaporiser solenoid.

Any Comments?

Tony

Reply to
Tony

Have it installed professionally.

Reply to
SimonJ

OK, as Austin says you may find that LPG with carbs can have issues.

There may be up to 3, possibly one on lpg tank, one in engine bay and one on vapouriser!

Yes,remember to add the relay to cut the petrol fuel pump feed! Otherwise you'll wreck the fuel pump.

Well, the revs will drop themselves when it runs dry ;-)

On a properly kitted out 110 you should hear a lot of clangs/clunks on switching from petrol to lpg! How many positions does your changeover switch have? You should have three for a carb vehicle. If you have two then you will have problems - you go along on petrol and decide to switch over to lpg, so flick the switch - now you still have petrol in the carbs bowls and the gas is flowing freely, you engine will run that rich it will probably stall. The third, middle position allows you to drain the carbs. This is one reason why I don't really like letting other people use carb lpg vehicles, it isn't a simple flick the switch operation like it is for efi. You will probably find yourself with problems with your carbs if you use lpg for extended periods as well, they may gum up due to lack of fuel flowing through to cool them down.

If you're in Ontario, Canada, then your fuel prices still don't warrant a lpg conversion ;-)

To do a LPG conversion well there's quite a lot that you need to take into account, the mounting of the tank in an approved, secure manner, the running of the pipework and so on. Your LPG electrics should also include an auto shut off system to make sure that if the engines not running it doesn't keep the system flowing indefinately. I'd have thought you could find a local supplier who can help you with locally sourced parts, otherwise I'm sure you can find someone here to export the bits you need, nothings all that heavy apart from the tanks and vapouriser.

Regards

WIlliam MacLeod

Reply to
willie

On or around 15 Feb 2006 10:38:51 -0800, "Tony" enlightened us thusly:

You don't actually have to turn the petrol pump off. You need a solenoid valve in the petrol line to shut the petrol off, though.

You also want a 3-way switch, with on-off-on. The petrol-to-gas change involves switching to "off" which kills the petrol supply, then wait 'til the engine starts to die, then go to "gas". Otherwise you end up running on both fuels at once.

going the other way, you tend to find a pause while the float chambers refill - this is a good argument in favour of leaving the pump live, as it supplies petrol more quickly.

Reply to
Austin Shackles

I think you do need to turn the petrol pump off. Otherwise you have a pump that is designed to flow fuel freely not flowing anything for potentially hours at a time. If this were a EFi vehicle I would agree with you as the fuel pump would keep the injector rail cool and save the injectors gumming up, but I really think this is a bad idea on a carb vehicle.

And I've never found the vehicle taking more than two seconds at the very most to restart running on petrol after LPG. You expect it to take a little time so you choose when appropriate to swap over.

Regards

William MacLeod

Reply to
willie

On or around 16 Feb 2006 04:03:23 -0800, " snipped-for-privacy@macleod-group.com" enlightened us thusly:

The petrol pump is probably an SU type intermittent thingy one. once it pressurises the fuel, it does nothing. The sort that, when you turn the ignition on, goes

"diggadiggadiggadiggadiggadiggadiggadigga, digga, digga, digga, dig, dig, dig, dig. dig. dig. dig. dig."

If it's that sort, then all it will do is do the occsiosnal "dig". It's not a continuously-operating pump.

unless, of course, all the oil has fecked off from the carb dashpots. In which case restarting on petrol can involve filling up the dashpots first.

Reply to
Austin Shackles

Does having oil in the dashpots matter?

Mine have none in and it still runs alright on petrol (with a tendancy to not drop the revs very quickly!). I've only done about 10 miles on petrol over the last few months though.

Reply to
Tom Woods

On or around Thu, 16 Feb 2006 20:30:11 +0000, Tom Woods enlightened us thusly:

I had a 2-litre O series engine that refused to run at all if the dashpot was dry.

Reply to
Austin Shackles

My saab is bone dry and starts and runs fine on petrol. I know its empty as i had the carb innards in a box in the boot for ages and the oil leaked out everywhere! (had to put it back in when i ran out of lpg)

Reply to
Tom Woods

On or around Thu, 16 Feb 2006 20:53:51 +0000, Tom Woods enlightened us thusly:

this is the odd thing about the carbs with dashpots, no to motors behave the same. I've seen one that ran fine but wouldn't idle.

Reply to
Austin Shackles

I wouldn't be happy recommending that setup myself Austin, I don't know what pump is in the OP's vehicle, but LR did fit internal pumps as well as external pumps to their V8 110s and I bet that some of these at least are not going to last long if they have to work extra hard pushing fuel into a dead end when they are designed to free flow.

Doesn't seem to make much difference, though in our case the vehicle got vacum lifters added to the carbs. Still lost oil though. The petrol's pulled thorugh quickly enough, I've always been happy enough with the speed of restart on petrol.

Regards

William MacLeod

Reply to
willie

On or around 18 Feb 2006 12:08:45 -0800, " snipped-for-privacy@macleod-group.com" enlightened us thusly:

it does depend on the pump. Then again, if it's an internal continuous pump, does it have a return line to the tank?

Reply to
Austin Shackles

The ones I've seen do, and yes, it would appear that there are return lines in all petrol fuel 110s.

Regards

William MacLeod

Reply to
willie

On or around 18 Feb 2006 14:12:58 -0800, " snipped-for-privacy@macleod-group.com" enlightened us thusly:

I assume they have a " 3-way filter", then? 3 lines, one from tank, one to engine and one back to tank?

If so, you can put a stop solenoid into the line to the carb, and leave the pump running or not as you choose.

Reply to
Austin Shackles

Correct, the book shows "vapour seperator" in the diagrams.

Yes, indeed. I wonder how the OP is getting on with his conversion? Tony, what state are you at?

Regards

William MacLeod

Reply to
willie

I have most of the parts but pressure at work will only allow me to do the job in about 2 weeks. so far New springs, shocks, bushes. Winch, lamps, roof rack, paint, carpets, engine seals, swivel balls, dual charge battery, roof tent, awning, hinged spare wheel carier, carpets, change of seats,headlamps,wheels and tyres,snorkel, central locking, alarm, etc. Still to come LPG, dvd/tv,radio,cb and lots of wireing.

All this on a 110 county!!.

Reply to
Tony

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