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Petrol Engines LPG on a carb V8 ?

3

30EK42

Offroader
What is the best LPG system fitted to the old carburettor Range Rovers and Discos etc ?
Not that I have such a vehicle, I have a series 2A 88 which is getting a V8 transplant.
I'm not really wild about LPG, but this vehicle is going to be my daily driver, so I have to be realistic.
There's stacks of old Rangie LPG gear about, and it sells for very little when it comes up.
I'm just wondering what I should look for - single mixer ring, dual mixer rings, BLOS LPG "carb" etc.
I've read a lot about early systems strangling the performance of the engines they were fitted to, I'd like to avoid that as much as possible.
And before the finger wagging starts, I'm well aware that messing about with used (or even new) LPG systems is not something to be undertaken lightly.
Hoses and pipes need to be 100% good nothing less, unless you like being blown up.
 
My V8 had a single mixer plate and certainly didn't lack power, though there was a noticeable power and response difference between gas and petrol.
As a result of having to push the pedal harder to get any ooomph from the gas you use more of it and that then makes the savings less attractive. From memory I was getting @14mpg's from the petrol and about 18mpg's max from the gas but the refueling station here is (was) in entirely the wrong direction for anything useful to me. And so I'd have to use extra fuel (usually petrol) to drive out of my way to get the gas :rolleyes: If you have LPG filling stations nearby then it might work out cheaper, but not by much....

My set up was in an 88, the gas tank took up most of the rear load bay. Regardless of being leak checked a couple of times it would always stink of gas. Another issue I found running on gas was that because it runs hotter/leaner on the gas it'll eat plugs a lot quicker, a set of 8 plugs a couple of times a year will eat into your fuel cost savings. The 8cyl likes a healthy fat spark and when your plugs start to degrade you get lumpy running, poor starting and shocking mpg's. Don't get me wrong, I'm a big fan of the Rover V8, it's a lovely little engine but If what you want is a reliable economical daily driver a V8 may not be the best choice of engine swap ! ....which was exactly why I put a 300tdi into my 109, yeah less power at the top end but more than enough for hauling loads and 26<28mpg's, sometimes more !!! ;)
 
freqmikey said:
My V8 had a single mixer plate and certainly didn't lack power, though there was a noticeable power and response difference between gas and petrol.
As a result of having to push the pedal harder to get any ooomph from the gas you use more of it and that then makes the savings less attractive. From memory I was getting @14mpg's from the petrol and about 18mpg's max from the gas but the refueling station here is (was) in entirely the wrong direction for anything useful to me. And so I'd have to use extra fuel (usually petrol) to drive out of my way to get the gas :rolleyes: If you have LPG filling stations nearby then it might work out cheaper, but not by much....

My set up was in an 88, the gas tank took up most of the rear load bay. Regardless of being leak checked a couple of times it would always stink of gas. Another issue I found running on gas was that because it runs hotter/leaner on the gas it'll eat plugs a lot quicker, a set of 8 plugs a couple of times a year will eat into your fuel cost savings. The 8cyl likes a healthy fat spark and when your plugs start to degrade you get lumpy running, poor starting and shocking mpg's. Don't get me wrong, I'm a big fan of the Rover V8, it's a lovely little engine but If what you want is a reliable economical daily driver a V8 may not be the best choice of engine swap ! ....which was exactly why I put a 300tdi into my 109, yeah less power at the top end but more than enough for hauling loads and 26<28mpg's, sometimes more !!! ;)
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If you're telling me that the fuel economy on LPG was equivilent to 18mpg petrol then that's only a 28% saving and definately not worth it IMHO.
I have an unused 90L tank which is too heavy for my liking and too high up when fitted.
As you say, it takes up half the load area.
Add to that spark plug/ignition issues and (I believe) LPG requires a slightly different ignition timing.
OK so maybe not a brilliant idea after all.
Well not for a SWB 2A with a V8 fitted.
My philosophy with my V8 build is to keep things as simple and basic as possible, and a LPG kit certainly adds a lot of unwanted complexity that I could well do without
 
The changeover switch alters the ign timing for ya (with a lot of set ups) so you dont have worry about that so much but yeah not as dramatic a saving as you may imagine in a V8, obviously a lot of variables tho. And consideration of things like where you have to fuel it all come into the equation. Stick with just the V8 and remember weight is your enemy, especially if part of that weight is a heavy right foot ! ;)
 
Too much weight and too low gearing eats up fuel.
Getting the gearing/powertrain right would seem to be the most difficult compromise with a V8 conversion.
I think my best strategy is to build it (petrol only) first and think about maybe adding LPG later after I've fettled the other issues
 
If you can buy the 3.54 axles that go with the engine donor vehicle you'll save a lot of faffing around and also have disc brakes which you'll need.. Then it's just a choice of gearbox....oh wait, the donor will probably have one of those too :rolleyes: you can see where I'm going with this :D
 
freqmikey said:
If you can buy the 3.54 axles that go with the engine donor vehicle you'll save a lot of faffing around and also have disc brakes which you'll need.. Then it's just a choice of gearbox....oh wait, the donor will probably have one of those too :rolleyes: you can see where I'm going with this :D
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Yes exactly.
When is a Series Land Rover no longer a Series Land Rover ?
That's why I'm keeping my V8 conversion as traditional as possible.
So no to fuel injection, fancy radiators, four barrel carbs, tube manifolds, disc brakes, power steering etc.
I might go as far as a Salisbury axle conversion for the rear, or, if my pockets are deep enough, a 4 pinion rear diff (rover axle) with Ashcroft half shafts.
Ashcrofts high ratio transfer box conversion is a hell of a lot cheaper than an overdrive, but lacks flexibility.
Dare I put 140 Bhp through a Fairey OD ?
So many descissions and compromises to make.
 
Some years back I looked at doing an LPG conversion on a V8 Merc I own. The savings did work out, it was around £1500 to convert and would take 10 years to pay back. The Merc V8 has a large inlet plenum and the advice was that it should not have a mixer ring as a spit back had been known to blow the manifold and bonnet off. The advice was drill the manifold for individual injectors and put in a piggy back ECU on the engine ECU and do proper port injection. That's why the estimates were high, but the performance and economy claims were much better than a simpler system. I don't know if this type of system was fitted to the Rover V8s, if it was its probably worth looking for.
If I were re-engining a Series now (mine has a Perkins) I think I would look at an Iveco, well made, cheap parts, good performance and economy and a decent number about from crashed white vans. You'll get low emissions, PAS pump and perhaps even an AC compressor.
 
robwlondon said:
Some years back I looked at doing an LPG conversion on a V8 Merc I own. The savings did work out, it was around £1500 to convert and would take 10 years to pay back. The Merc V8 has a large inlet plenum and the advice was that it should not have a mixer ring as a spit back had been known to blow the manifold and bonnet off. The advice was drill the manifold for individual injectors and put in a piggy back ECU on the engine ECU and do proper port injection. That's why the estimates were high, but the performance and economy claims were much better than a simpler system. I don't know if this type of system was fitted to the Rover V8s, if it was its probably worth looking for.
If I were re-engining a Series now (mine has a Perkins) I think I would look at an Iveco, well made, cheap parts, good performance and economy and a decent number about from crashed white vans. You'll get low emissions, PAS pump and perhaps even an AC compressor.
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Thanks for that !
My own conclusion (not having considered LPG for a very long while) was that multi port injection was indeed the only really practical way to do it.
That would mean choosing a V8 with a fairly advanced digital fuel system, transplanting it into a series vehicle and getting it working properly (some feat in itself), then adding digital multiport LPG on top of the petrol system.
Not entirely beyond my abilities, but IMHO, a massive overdose of technology in a series Land Rover.
I think that sort of kit would be much more at home in a RR or Disco.
I'm looking at a far more basic (analogue) level of technology with simple things like a pair of good old fashoned carbs and a dizzy.
At that level LPG doesn't work out too well, so I think why bother complicating a very simple vehicle for dubious improvements in fuel economy.
Likewise I don't doubt your recomendation for an Iveco van engine, but I feel that a Defender 90 might be a better home for one, and where the PAS pump and AC could be put to good use.
I've aquired the remains of a Perkins Prima (Montego TD) conversion which will power my economy daily driver Land Rover.
Yes, I know that they're noisy and basic, but that's a perfect match for the LR IMHO
 
My LWB is powered by a 55 year old Perkins and its a great engine. A bit noisy and very low revving but also very economical and simple. I think its a great match for the Series and the economy means we are happy to do 200 miles on a weekend to go camping. I mention the Iveco because I think it raises a question when re-engining older vehicles. TDIs are getting old now and don't make the sense they used to, they are noisy and will not meet any emissions, there's a case for leapfrogging a few generations of engine and getting an engine that could meet some of the current requirements. I actually think there is a stronger case for re-building the original engines and making a few careful upgrades, but that's another topic.
 
robwlondon said:
My LWB is powered by a 55 year old Perkins and its a great engine. A bit noisy and very low revving but also very economical and simple. I think its a great match for the Series and the economy means we are happy to do 200 miles on a weekend to go camping. I mention the Iveco because I think it raises a question when re-engining older vehicles. TDIs are getting old now and don't make the sense they used to, they are noisy and will not meet any emissions, there's a case for leapfrogging a few generations of engine and getting an engine that could meet some of the current requirements. I actually think there is a stronger case for re-building the original engines and making a few careful upgrades, but that's another topic.
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Point taken about the TDI engines.
The days of the cheap TDI are long gone.
TBH I wish I'd done one 20 years ago (sigh)
If I were stinking rich I'd just run a V8 as my DD and to hell with the fuel costs.
But last time I did that I was doing £60 a week on petrol probably more like £80-90 now.
Unfortunately my meagre income wont stretch to it
 
I had a similar experience, many years ago i drive a Jaguar XK140 when you could get them for reasonable money. It did 16 mpg no matter how it was driven. I went self employed and at the end of the first year found petrol was my largest expense. It came as a bit of a shock and the car had to go. Of course I should have stored it as it rocked in value but that didn't seem likely at the time. Now I'm happy with my 63hp Perkins and the 30+mpg, the reality of the XK was that while it could do 140 it was mostly doing 30 but still at 16 mpg.
 
RPI used to sell an electronic ignition for the V8 that had selectable ignition timing, one setting for petrol another for gas.
Another problem with running gas with SU carbs is wear to the jets and needles. Apparently the gas is a lot "drier" than petrol so it doesn't lubricate the carb internals in the same way.
Needles and jets are not cheap so that is another cost to bear in mind
For replacement engines the Cummins 2.8 is popular in some countries.
www.cummins.com

R2.8 Turbo Diesel | Cummins Inc.

Not all engines are crated equally. When critical components such as fuel pumps, filters, accessories, starters, and flywheels aren’t included in an engine package, you have to piece together these components from various manufacturers, hoping for the best. For the vehicle specific components...
www.cummins.com www.cummins.com
 
Neil said:
RPI used to sell an electronic ignition for the V8 that had selectable ignition timing, one setting for petrol another for gas.
Another problem with running gas with SU carbs is wear to the jets and needles. Apparently the gas is a lot "drier" than petrol so it doesn't lubricate the carb internals in the same way.
Needles and jets are not cheap so that is another cost to bear in mind
For replacement engines the Cummins 2.8 is popular in some countries.
www.cummins.com

R2.8 Turbo Diesel | Cummins Inc.

Not all engines are crated equally. When critical components such as fuel pumps, filters, accessories, starters, and flywheels aren’t included in an engine package, you have to piece together these components from various manufacturers, hoping for the best. For the vehicle specific components...
www.cummins.com www.cummins.com
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Thanks for that.
I've just been reading RPIs technical stuff for a second time.
They won't actually quote a price for the dual fuel ignition amplifier "POA"
However their system was developed about the turn of the millenium I think.
Things have moved on since then.
LPG burns slower than gasoline, so the spark was engineered to be 10° more advanced than the petrol setting.
But now modern petrol burns slower than the old leaded stuff, so the petrol advance curve needs to be moved.
RPI are obviosly clever folk, so no doubt they will have an answer - maybe an ajustable amp box would be a solution ?
Another can of worms opened no doubt.
 
My series 3 v8 runs on lpg. I havent really looked in to it yet but have been driving with it for 1500kms now so it works great.
There is mixer or what ever you called it below the air filter box? there are 2 hoses connected to it which go just in front of the carbs.

In the beginning i used to do the cold starts on gasoline. However now i also do the cold starts on lpg. Benefit is that you cant flood the engine on lpg like you can on gasoline. Also its immediatly vapour/gas like from the start compared to choking on gasoline.

With fuel consumption of 3kms per liter its nice to have an lpg system, after the restoration i also plan to daily drive it during the summer etc...😁
 
Laro109V8 said:
My series 3 v8 runs on lpg. I havent really looked in to it yet but have been driving with it for 1500kms now so it works great.
There is mixer or what ever you called it below the air filter box? there are 2 hoses connected to it which go just in front of the carbs.

In the beginning i used to do the cold starts on gasoline. However now i also do the cold starts on lpg. Benefit is that you cant flood the engine on lpg like you can on gasoline. Also its immediatly vapour/gas like from the start compared to choking on gasoline.

With fuel consumption of 3kms per liter its nice to have an lpg system, after the restoration i also plan to daily drive it during the summer etc...😁
Click to expand...
Thanks for that.
My collection of V8 engines and conversion stuff slowly keeps growing, so I've now got the possibilty of building two series 2A V8 powered 88".
Obviously, building two identical vehicles would be utterly pointless.
I'm thinking of a basic V8 petrol suitable for offroad work and green lanes.
Then later on a more sophisticated V8 with LPG.
The way fuel prices are going here in the UK, I'm going to need it.
 
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