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.

Tony wrote:

> 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.

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

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.

On or around 15 Feb 2006 08:26:42 -0800, "Tony" <[email protected]>
enlightened us thusly:

>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.

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.
--
Austin Shackles. www.ddol-las.net my opinions are just that
If all be true that I do think, There are five reasons we should drink;
Good wine, a friend, or being dry, Or lest we should be by and by;
Or any other reason why. - Henry Aldrich (1647 - 1710)

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

>
> Any Comments?
>
Have it installed professionally.

Tony wrote:

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

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

> Solenoid in the lpg line

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

> Solenoid in the Petrol line
> Relay to switch over and switch the fuel pump off.

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

> When the carbs start to run dry of petrol, drop the revs and the
> petrol/lpg switch will engage the vaporiser solenoid.

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.

> Any Comments?

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

On or around 15 Feb 2006 10:38:51 -0800, "Tony" <[email protected]>
enlightened us thusly:

>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.

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.

--
Austin Shackles. www.ddol-las.net my opinions are just that
"I am tired and sick of war. Its glory is all moonshine... War is hell"
Gen. Sherman (1820-1891) Attr. words in Address at Michigan Military
Academy, 19 June 1879.

Austin Shackles wrote:

> 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.

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.

> 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.

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

On or around 16 Feb 2006 04:03:23 -0800, "[email protected]"
<[email protected]> enlightened us thusly:

>Austin Shackles wrote:
>
>> 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.
>
>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.

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.

>> 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.
>
>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.

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.
--
Austin Shackles. www.ddol-las.net my opinions are just that
"You praise the firm restraint with which they write -_
I'm with you there, of course: They use the snaffle and the bit
alright, but where's the bloody horse? - Roy Campbell (1902-1957)

On Thu, 16 Feb 2006 18:52:10 +0000, Austin Shackles
<[email protected]> wrote:

>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.

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.

On or around Thu, 16 Feb 2006 20:30:11 +0000, Tom Woods
<[email protected]> enlightened us thusly:

>On Thu, 16 Feb 2006 18:52:10 +0000, Austin Shackles
><[email protected]> wrote:
>
>>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.
>
>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.

I had a 2-litre O series engine that refused to run at all if the dashpot
was dry.
--
Austin Shackles. www.ddol-las.net my opinions are just that
"You praise the firm restraint with which they write -_
I'm with you there, of course: They use the snaffle and the bit
alright, but where's the bloody horse? - Roy Campbell (1902-1957)

On Thu, 16 Feb 2006 20:34:14 +0000, Austin Shackles
<[email protected]> wrote:

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

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)

On or around Thu, 16 Feb 2006 20:53:51 +0000, Tom Woods
<[email protected]> enlightened us thusly:

>On Thu, 16 Feb 2006 20:34:14 +0000, Austin Shackles
><[email protected]> wrote:
>
>>I had a 2-litre O series engine that refused to run at all if the dashpot
>>was dry.
>
>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)

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.
--
Austin Shackles. www.ddol-las.net my opinions are just that
"Nessun maggior dolore che ricordarsi del tempo felice nella miseria"
- Dante Alighieri (1265 - 1321) from Divina Commedia 'Inferno'

Austin Shackles wrote:

> 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.

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.

> 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.

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

On or around 18 Feb 2006 12:08:45 -0800, "[email protected]"
<[email protected]> enlightened us thusly:

>Austin Shackles wrote:
>
>> 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.
>
>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.

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

--
Austin Shackles. www.ddol-las.net my opinions are just that
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Austin Shackles wrote:

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

The ones I've seen do, and <quick look at 90/110 workshop manual> yes,
it would appear that there are return lines in all petrol fuel 110s.

Regards

William MacLeod

On or around 18 Feb 2006 14:12:58 -0800, "[email protected]"
<[email protected]> enlightened us thusly:

>Austin Shackles wrote:
>
>> it does depend on the pump. Then again, if it's an internal continuous
>> pump, does it have a return line to the tank?
>
>The ones I've seen do, and <quick look at 90/110 workshop manual> yes,
>it would appear that there are return lines in all petrol fuel 110s.


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.
--
Austin Shackles. www.ddol-las.net my opinions are just that
"It is a characteristic of the human mind to hate the man one has injured"
Tacitus (c.55 - c.117) Agricola, 45

Austin Shackles wrote:

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

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

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

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

Regards

William MacLeod

>From all the comments I understand what to do.
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!!.