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V8 running 100% LPG


Lewis

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I know very little about V8s or LPG systems and I've had a good hour searching the forum and been unable to find the answers so my apologies if this is old ground.

I building up a 110 as work vehicle and tow car, my general preference is towards a tdi but a V8 owning friend has been encouraging me to go with petrol. As even a 3.5EFI has more power than a Tdi this seems like a good solution for towing but the prohibitive fuel costs are a problem. A few friends have LPG systems but none seem to have been without issue, most common seems to be backfiring damaging the EFI AFM, so with this in mind I was hoping to delete the petrol side entirely and just run LPG

So what i want to know is :

What are the problems with running lpg on a V8? I've heard a little about bore wash but that this can be overcome with lubricants.

Which engine and kit should I choose?

Can an LPG kit be a diy prospect or should this be left to a certified installer? If so what costs are involved?

Is it possible to run on 100% LPG?

Thanks in advance

Lewis :)

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for outright grunt you can't beat a v8, but for torque (which you really need for towing) you need a diesel, as it's generated much lower down the rev range.

my old 3.5 was hopeless for towing, especially on lpg, as the power was in the wrong place. my 300 tdi disco will pull a twin axle ifor williams loaded up with 100+ bales at 60 mph happily all day long - and it will return a decent mpg (usually around 26 when loaded up)

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I know very little about V8s or LPG systems and I've had a good hour searching the forum and been unable to find the answers so my apologies if this is old ground.

I building up a 110 as work vehicle and tow car, my general preference is towards a tdi but a V8 owning friend has been encouraging me to go with petrol. As even a 3.5EFI has more power than a Tdi this seems like a good solution for towing but the prohibitive fuel costs are a problem. A few friends have LPG systems but none seem to have been without issue, most common seems to be backfiring damaging the EFI AFM, so with this in mind I was hoping to delete the petrol side entirely and just run LPG

So what i want to know is :

What are the problems with running lpg on a V8? I've heard a little about bore wash but that this can be overcome with lubricants.

Which engine and kit should I choose?

Can an LPG kit be a diy prospect or should this be left to a certified installer? If so what costs are involved?

Is it possible to run on 100% LPG?

Thanks in advance

Lewis :)

Lewis,

Firstly I'll steer away from the petrol/diesel debate as it will never be settled.

I am a V8 merchant through and through. I have driven Tdi engined LRs, and they tow very well, but give me my V8 any day :)

As Al has said, the torque curves are quite different for petrol and diesel, but a healthy 3.5 should tow very well, and of course 3.9, 4.2 etc are better still.

Yes it is totally feasible to run 100% LPG. I know one chap who runs his business using V8 Landies, and for tax-efficient reasons he has completely removed the petrol systems. He uses 4.6 units, one in a 110" and two in 150" 6x4 Defenders. He tows some seriously heavy stuff and covers huge mileages.

I think the crucial things that makes LPG and V8s a success or not is the engines overall health, and the ignition system's health. Oh, and the quality of the conversions, that helps too. Nearly every bad LPG experience can be put down to a shortfall of one or more of these three factors.

DIY installation is certainly an option, as long as you are competant in things mechanical, and vehicle electrics. I have worked on five installations now for myself and friends. I am a real fuss pot in getting things right, but it has paid off with reliability and overall owner satifaction.

For good advice on DIY LPG, talk to Tinley Tech. They are willing to talk though your intentions and are very helpful. They only supply good quality equipment too.

LPG forum is a good source of info too.

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One thing with running 100% LPG is that you can't refill (well I guess you could with a big enough Calor bottle and adaptors) at the side of the road if you run out...

Hence i still run around with 10litres of the expensive stuff onboard- usually in a Jerrycan so it doesnt go off :D

My 3.5 on gas easily tows a fully loaded Sankey- no problem! :D

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I'm not interested in a petrol vs diesel debate, I have experience driving both v8 and tdi in defender and either would suit my purpose regarding power and torque.

The reason I am looking at V8s is due solely to cost; I need an engine and gearbox for my previously V8 110, I would need to spend at least £700 to fit tdi engine and box, rad intercooler etc, whereas I have access to several V8s and gearbox's for very little or nowt. Plus also have access to a couple of lpg systems and various parts.

Do I need a specific type of lpg system to run 100% lpg? Or is it possible to adapt one of the (presumably single point) kits I have access to?

Thanks for the links, will have a look now :)

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Not wanting the diesel debate, i'll stick to my 4.6 v8 on lpg over any diesel from landrover :)

Mine won't run 100% on lpg...so she starts on petrol runs for a couple minutes then automatically swaps onto lpg.

I always have petrol in the tank as i have a habbit of running out when there aren't any lpg stations about :lol:

G

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I guess the only difference would be that you might want some way of warming the vapouriser in very cold weather- perhaps something like a kenlowe hot start thing?

I start from cold everyday on LPG and have only had the vap freeze on me twice in the best part of what must be three years of LPG powered motoring. And that was only when we had the immense (for UK ) snow this year.

Other than that I reckon the setup would be the same... Just remove petrol equipment, keeping any relevant throttle butterflies/y.

Also, on the inlet backfire front- I have only had one. I believe you get them if you are running too lean, valves not closing properly (grind in) or have poor ignition.

As usual, an adult will be along shortly correct me if I am wrong... :ph34r:

*edit- Depending on the availability of LPG near you, you might want to keep the petrol setup. I have two near me and they have a habit of running out/ pumps breaking at the same time :angry:

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Do I need a specific type of lpg system to run 100% lpg? Or is it possible to adapt one of the (presumably single point) kits I have access to?

Depends on the engine I guess! If it's carb, that isn't difficult. Just remove the entire petrol side and the carb will act as the fuel/air valve, nothing more. :ph34r:

I think that the biggest drawback with LPG is getting fuel. You'll have to plan your fuel stops before departing rather than just fill up at whatever fuel station appears first should you run low. The other day when I drove from the top end of Derbyshire down to Leicestershire, I can't say I noticed many fuel stations offering LPG.

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I'm happy enough to keep the petrol setup, but my main reason for wanting rid was to simplify the engine somewhat and delete a lot of expensive parts with a tendency to go wrong. My main dislike of V8s comes from the unreliable (in my experience) EFI system. Would a carb fed setup with LPG be the ultimate answer?

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If you run on carbs, there is always going to be a problem of the ventury strangling the engine. there is a ventury in the carb (albeit variable) and when adding a lpg system upstream of this, you need to have an even smaller venturi to make it work. thats why an EFI engine will work better in this application. The above isn't quite true if you run an LPG injection system though. The question about running 100% LPG: yes you can, but as mentioned dont run out. I have tried running my LPG landy to Wales once and managed completely on the way down because it was a weekday, but the return on sunday had to happen almost completely on petrol because the gas stations were all closed on weekends.

This was a long time ago, but a problem like that will happen one day and then it is tears before bedtime... :rolleyes:

Daan

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I have found the only freeze up I have had is if I nail it up the road from a cold start (yes I know that's not nice to the engine )on a cold day. The rush of LPG through the vap is just too much for it, normal driving it's fine. Position of the vap in the engine bay can make a difference to freeze up potential.

You have access to various LPG parts. Do you know their history/condition? I'd be rather hesitant in using 2nd hand parts of unknown past.

My favourite vaporiser is the OMVL R90. My Ninety uses one of these with an OMVL Millenium closed loop system. I have single point circular mixer on the throttle inlet.

A new good quality system with one tank will cost you IRO £700.

There is a device available that is supposed to protect the 3.5EFI's flapper thingy in the event of a backfire, but I know little about them.

As mentioned by a few, LPG availability can be an issue, which is why I still have petrol running capability. Distance between fillups can be a bit of a bore. You should be able to get bigger/more tank(s) on a 110. I can carry 100 litres in four tanks on my RRC. The Ninety only takes 64 litres which doesn't go very far :o I tend to plan all major trips around fuelling points.

What Les says about the petrol circulating all the time is correct. If the injectors are not cooled in this way the seals are likely to go hard and leak as as result, and then not work when you most need them.

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There are a couple of filling stations locally which have lpg, and the tank previously fitted in the 110 was 120 litre, but that notwithstanding I can see the wisdom of having petrol ability just in case.

Could you convert to run a large single carb with lpg injectors to help elimate any issue there?

Or is the best option a Hotwire efi engine with simgle point injection in the inlet tract?

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Or is the best option a Hotwire efi engine with simgle point injection in the inlet tract?

Above is what I have with the addition of Megajolt, and IMHO it's great.

I leave the EFI to get on with the petrol fuelling (only used at startup and for emergencies), the MJ gives me bespoke LPG and petrol maps, and the basic venturi setup works fine on LPG.

Mine starts fine on LPG, but I always start it on petrol to exercise the injectors and circulate the fuel in the pipes a bit.

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If you run on carbs, there is always going to be a problem of the ventury strangling the engine. there is a ventury in the carb (albeit variable) and when adding a lpg system upstream of this, you need to have an even smaller venturi to make it work. thats why an EFI engine will work better in this application. The above isn't quite true if you run an LPG injection system though.

Ive been running about 95% of the time on LPG with a BLOS propane carb which is a neat solution in the style of a flat slide carb which avoids having to choke down the inlet tract with a mixer venturi. If you want to keep costs down and simplify your install on a carb engine or EFi plenum the BLOS is worth a look at.

http://cgi.ebay.co.uk/LPG-Carburetor-V8-Land-Rover-Range-Discovery-LOOK-/160433831792

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I use LPG 99% of the time but I do have a small petrol tank (30Ltr) just for whenever. I also have MegaSquirt with duel maps so I have none of the spark issues that you get with a dizzy. Woodytz and I am looking at direct injection LPG using MegaSquirt. I've never had the vaporiser ice up in normal use only when the water level was low due to a leak. The motor starts on LPG all the time even in the ferkin coldest winter we've had so far. So in answer to your first question..... yes you can. :lol:

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I had a mate at uni who ran his 3.5 on a pair of forklift mixer carbs. I didn't pay enough attention at the time I'm afraid to say, but he had no provision for petrol at all, and seemed fairly happy with it. There's probably a host of reasons why this is a bad idea, but I don't see that it's bad in general principle.

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I like the idea of Zoltan's setup, I was talking to a mate yeasterday who is big into V8's and he advised carbs for my (EFI hating) application, so the BLOS carb could well be the solution :)

I have access to a selection of 3.5's and have a carb inlet manifold and strombergs available so i can get started straight away, but what Rover V8 would be best?

My thoughts were a 3.9 on SU's with the intention of megasparking eventually, is this a good plan? Should I avoid the serpentine engines?

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FWIW I reckon MS'n'EDIS on a whatever-you-have EFI setup would pay for itself very quickly, plus make the car so much more usable in the meantime. LPG needs different timing & big sparks for full effect, and I beleive I'm right in saying that even if you ignore petrol completely the standard dizzy & amp would not be ideal for the job.

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I ran the standard dizzy with LPG for about 6 -8months on the v8 and it was fine, or so i thought...

However, with Megajolt (so giving me the big fat sparks Fridge mentions) it was a different animal!

The best mod I ever did to my car... or my dads...

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I ran the standard dizzy with LPG for about 6 -8months on the v8 and it was fine, or so i thought...

However, with Megajolt (so giving me the big fat sparks Fridge mentions) it was a different animal!

The best mod I ever did to my car... or my dads...

Must get my bum in gear and finish off my MJ. I can relate exactly to the first bit as Quagmire relates, only mine's been LPG without MJ since 2001.

Looking forward to some big sparks making me fly :ph34r:

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