Change of Plan !!! LPG ???? Any Ideas

I had a change of plan after looking about at the dealers and e-bay / Aauto trader, the idea was to buy a 2.5 DSE, hoverever, it seems I could get a 4.0 petrol fitted with an LPG kit for less than I was possibly looking at for the DSE at the cheeper end of the market place, - anyone have any experience of running LPG, would a get a sound saving with the fitted kit & petrol set up as opposed to diesel, (well Im no mechanic and prob only run about 3-4k per year on private milage if that.

Many thanks all, any assistance most welcomed.
Cheerz
Harley.
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If you get a V8 with LPG budget £3 to £5K for a new engine when the liners slip. The diesel is more economical and more reliable.

Datatek said:

If you get a V8 with LPG budget £3 to £5K for a new engine when the liners slip. The diesel is more economical and more reliable.

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I have had both and much prefer diesel. More reliable and much much more convenient as far as buying fuel is concerned.

I know you are talking a P38 on Gas.....and my experience is with a 1993 3.9 Classic on Gas but I was returning around the 12-14mpg mark.

It was a weekend and one day in the week play thing - Weekends, doing 25-30 miles on A roads into town and back or into the country for a few Clay shoots etc...and one evening a week on a motorway for a 50 mile round trip to a shooting club I belong too.

The book says around 17-18mpg on petrol, but as LPG is around 20% less energetic during its burn you could say that it is less efficent than petrol, but it is almost half the price in cost....

So expect a dip in MPG of around 15-20%, but save 45% in cost at the pump, so averaging out I reckon I saved 32-38% in fuel cost running on gas.

Gas burns cleaner, but the petrol injectors can get clogged up following continued use on gas, so give it a good run every couple hundred miles on petrol to keep them clean and lubricated (as the petrol acts as a lubricant on the needle valves etc).

I am certainly not going to distrust Datatek on his note on slipped liners, but I thought that could happen on a straight Petrol V8 anyway....is this a more common occurance when running on LPG, Datatek???

Saint.V8 said:

I am certainly not going to distrust Datatek on his note on slipped liners, but I thought that could happen on a straight Petrol V8 anyway....is this a more common occurance when running on LPG, Datatek???

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Most one here that have suffered liner/block problems seem to have been running on gas. Gas has other drawbacks, you can't use the channel tunnel and many road tunnels in Europe.

Noted...many thanks Datatek.

Didn't know about the Channel Tunnel thing...good job I didn't attempt to cross the stream to France...although it did go on the Isle of Wight Ferry once or twice....!!!

How much does petrol cost in the UK? Using our prices of around EUR 1.55 a litre, a 35% saving (according to Saint here) on 4000 miles @ 16mpg is about EUR 617 or GBP 534 per year. Set that against your cost of conversion and your maintenance budget and then just decide if it works for you.

I have owned both V8's on gas and I must admit that I find them to be good..... well as good as a P38 can be!!

I normally fill my lpg tank once a week at a cost of 69.7p litre (asda), so that in total is approx £40/45, then I have to put £15/£20 petrol in approx every 2 weeks (you need this to start the car and run it until it is warmed up) I also run it on petrol alone (1 day a week) just to keep everything sweet and lubricated, as petrol does.
I use the car mainly around town and on short trips, so it's not at it's best economy wise, but still I average 220/240 miles on gas.

Don't buy a v8 then convert it yourself as then you are hit with a fitting bill of approx £1500/1700, I know I looked into it (Thats from an LPG fitter in my area, have heard of much higher prices else where). Just buy one that has been done and has a full certificate of compliance, also, If you buy a car with 90/100k miles on clock then convert it, it's a good chance the engine won't like it and will go wrong.
My 4.6 (51 plate) had it's system fitted when car was only 6 months old and has now covered over 100k on original engine without any major faults (overheating etc) so therefore I would recommend the LPG conversion over a diesel.

Obviously someone else will disagree because they have nothing but trouble with their system, but if it's not the right type of kit and not fitted properly onto a high mile unserviced vehicle....... you will have problems

All in All......I would go for LPG on a V8 just because I love the sound of it and there is no compromise on power.
Hope this helps you

I bought mine with the sole intention of converting it straight away and keeping it. So far had it 4 years, although like most p38's there isn't much of the original car left, it's more a collection of new parts bolted together over the last 4 years! If i'm right, i believe the engines run hotter on gas, which is what leads some people to make a link between gas and failed blocks or gaskets. My gaskets went a couple of years ago, but was suprised by how straight forward it was to replace. Since then had no issues, well, no engine issues anyway.

I'll say go v8 and gas any day! But don't remind me of that when it breaks. Notice i didn't say if it breaks... Good luck!

P38_love/hatething said:

If i'm right, i believe the engines run hotter on gas, which is what leads some people to make a link between gas and failed blocks or gaskets.

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To be honest I haven't noticed any difference in temp gauge, it's always in the middle.

Must admit my 4.0 did overheat but a new thermostat sorted that one out

If you wanted economy, go diesel.
If you want a smoother quieter more refined driving experience, go petrol with an LPG conversion.
Its true, diesels are more forgiving if past servicing has been a bit sketchy, and take less looking after.....which is why farmers n soldiers like them!

v8p38 said:

Last edited by v8p38; Today at 02:23. Reason: spelling mistakes!!!!!!!

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Charming that anyone still does that and rare enough to be worth complimenting!

Any particular reason you are considering the 4.0? The 4.6 is actually (slightly) more economical and more powerful. I did read somewhere that the better blocks were allocated to the 4.6s too.

My view is that you're just as likely to suffer slipped liners on a non lpg engine. If you're unlucky enough to have a bad block then it doesn't matter how you're fuelling it.

Mine's done almost 140k now, at least 80k of which has been on lpg. No engine problems.

As for the channel tunnel issue, I thought that was due to be relaxed? Not that I care about it.

With the low milage you say you will be doing the cost of fuel is not such a big issue. My 4.6 has now done 133k and most of that has been on gas.
You can get all the above problems with any P38 but at the end of the day would you rather have a 4.0/4.6 v8 or a 2.5 diesel? i know what i would choose.
Ps look at the number of threads about chipping diesel cos they are SOOOO slow.

discomalc said:

Ps look at the number of threads about chipping diesel cos they are SOOOO slow.

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And then the gearboxes break.

I too had the same dilemma was looking for a decent diesel until I discovered how slow they were. Fine for some, just not for me.

In the end I've got a 2001 P38 4.6 Vogue with 127k on it - of which approx 50k has been on gas. My only current issues seem to be exhaust related. One of the major by products of burning LPG is water (more than petrol)... so a SS exhaust would be sensible if you predominantly run on Gas.

As someone has already mentioned, get one that someone has spent the £££'s on. You'll have to own it too long to recoup the cost of conversion yourself.

As far as liner issues go, they're most likely to slip when temperatures get out of range, so keep you cooling system up to scratch and you should be fine.

A 4.6 doing 12mpg over 12000 miles a year gives the following figures according to Capital Autogas Calculator with petrol at 137p and LPG at 74p a litre

Annual cost of petrol £6228
Annual cost of LPG £3737

Annual saving £2490

So the install of £2000 would pay for itself inside of a year.

ericbeauchamp said:

A 4.6 doing 12mpg over 12000 miles a year gives the following figures according to Capital Autogas Calculator with petrol at 137p and LPG at 74p a litre

Annual cost of petrol £6228
Annual cost of LPG £3737

Annual saving £2490

So the install of £2000 would pay for itself inside of a year.

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Wish I could find lpg that cheap.

kooky_guy said:

Any particular reason you are considering the 4.0? The 4.6 is actually (slightly) more economical and more powerful. I did read somewhere that the better blocks were allocated to the 4.6s too.

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I think that last bit is a myth - when I was looking at P38's everyone told me the 4.0 were more reliable due to the thicker walls, but I have no experience personally!

kooky_guy said:

Wish I could find lpg that cheap.

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How much do you pay? It's between 72.9p-74.9p up here in Bucks, which is usually expensive for everything! The BP on Farnham Road near Sleaford (near Alton) is 70p /litre according to the app on my iPhone - maybe worth a try?

MikeV8SE said:

I think that last bit is a myth - when I was looking at P38's everyone told me the 4.0 were more reliable due to the thicker walls, but I have no experience personally!

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Pretty sure the capacity is changed by stroke not cylinder size so that would be wrong. The walls are the same thickness on em.

MikeV8SE said:

How much do you pay? It's between 72.9p-74.9p up here in Bucks, which is usually expensive for everything! The BP on Farnham Road near Sleaford (near Alton) is 70p /litre according to the app on my iPhone - maybe worth a try?

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Sleaford? Have to look out for that. My two local ones are 77.9. Just come back from a weekend in Devon and that was all about the same except for one place which was 86.9 - thieving gits.