3 litre diesel Vs V8 on LPG - discuss

CondorX5 · Post by **CondorX5** » Fri Oct 07, 2011 9:24 pm

There were a series of articles in the Range Rover Register and LRO from a few years back - the cars affected were the P38 4.6 V8 in particular. The 4.0 litre wasn't affected AFAIK. Specialist Landy forums also had a lot of info and discussions about the engine failures in LPG converted RRs at the time - the issue was the higher running temp of LPG which was outside of the tolerances of the 4.6 V8 RR engine. My P38 seemed to be one of the few on the forum not to have the endless problems of the LPG converted motors, although of course, the name Range Rover and the description "endless trouble" seem to go hand in hand quite often......and there were many non-LPGed RRs of the time with issues. They just didn't seem to have the high running temp issues of the LPG motors. I don't think anyone ever took the issue to a science or engineering laboratory as major motor manufacturers like Land Rover (or BMW) don't recommend LPG converting their cars anyway, so testing LPG conversions in laboratory conditions probably wasn't high on their agendas

AW8 · Post by **AW8** » Fri Oct 07, 2011 9:39 pm

I belive that CondorX5 was referring to the fairly well historically discussed alleged issue of failures on some LPG converted P38 Ranger Rovers with the Rover 4.6 engine. Allegedly there were reports of failures associated with that engines inability to cope with the higher engine temperatures resultant from some LPG instalations. I am unaware as to whether the issues related to certain brands ot types of LPG conersion.

My perception was that the unrelibility issue was more unique to that car being so eqipped as opposed to an issue with all LPG conversions.

I dont know how many instances of alleged failure there were &/or indeed how many failures,( if any) were found to be directly attributed to LPG conversions &/or that specific engine, however, I can confirm that there were alleged instances of failure(s).

I doubt it would take extensive research online to yield more information. I also suspect that chatting to those who were in the motor trade at the time & involved in buying selling same so equipped should be able to confirm there were allegedly some associated failures.

AW8 · Post by **AW8** » Fri Oct 07, 2011 9:48 pm

I hit the submit button & then saw Condorx5 had replied. I considered editing or removing, however, I left my post as it was typed........if nothing else it shows we both seem to have a simlar interpretation of alleged issues.

This was bigger inernet talk news a few years ago. The P38 has been out of production for 10 years now &, (despite the relatively large numbers made), these cars are a far rarer site on the roads in everyday use.

Whilst I dont have an LPG conversion I am not directly opposed to the concept of having same.

LPG negatives for me are the tyre foam, a (probably unfounded), fear of explosion risk, concerns re reliability, channel tunnel restrictions, plus the cost to secure the best kit & a decent instalation. Inefficency of having to use petrol when starting in cold is an isssue as I only currently commute 15-20 mins. I also have regular shared use of a more economical car. Some alleged reports of yellow dash lights triggered by LPG don't encourage. Not knowing if I would sell before break even point is another factor.

LPG positives are the obvious fuel cost saving & to some extent the greener credentials.

If seeking cheaper cost per mile & if money was no object I would perhaps buy a new F25 X3 3.0d. Then again, & ironically, if money was genuinely no object then savings per mile via the pump might be an even lower priority.

Of course economics will always be different relative to every individual set of circumstances. For some a saving Â£100 per month in fuel can have a significant & required positive impact on household finances. Any savings need to be considered relative to LPG instalation, & annual servicing costs plus the all relevant break even point.

Non LPG maintenace costs cant be ignored either a big non LPG related repair bill on a Range Rover or X5 could wipe out many miles of LPG fuel savings.

Fuel type aside Range Rovers & /or X5's are still generally likely to cost more to run than more cost effective choices.

tombs · Post by **tombs** » Fri Oct 07, 2011 11:41 pm

I'm going to have a chat with Chris Crane of Rpi on Monday (a client of mine anyway) to explore this further as my concern is that the comments by condor are unfounded and just a personal view about objecting to LPG because its "different" and that also the problem was with "porous" engine blocks on some P38's. Again, a professionally installed system thats certified each year should be safe, theres more evidence here: http://www.go-lpg.co.uk/danger.html

AW8 · Post by **AW8** » Sat Oct 08, 2011 12:48 am

For some reason unknown to me LPG discussions between some X5 drivers have often been quiet emotive.

Until reading your post I didn't know who Chris Crane was. I have never owned a Rover engined vehicle however, a quick search of the net would indicate that the gent you refer to is a rover engine guru. From a technical perspective it will be interesting to hear what his views are.

Thanks for posting the link re the tank & fire risks............this has caused me to re-evaluate my prior unfounded concerns somewhat.

I must add that in all the years I have been active on this & other BMW boards I have never seen evidence of a confirmed case of engine failure attributed to a decent LPG instalation.Though not my current choice I admit to having given some consideration to having an LPG instalation in the past.

IanP · Post by **IanP** » Sat Oct 08, 2011 6:04 am

A couple of comments on LPG engines;
I had my V8 apart after a blowup and was able to check out valves, rings etc and they were all in very good condition after running on LPG for a couple of years. If it hadnt been for the cam chain, I can see no reason why the engine would have kept going.
While I was working on this I had the opportunity to have a look at a small engined car that had been run on LPG from new, and used as a driver training car. This had suffered valve seat reccesion to the point where it would not run but did not suffer from any overheating problems.
Possibly engines that are worked hard will suffer from damage if they are on LPG (small engines or big ones that tow???)
Somewhere I have seen a comment that BMW temperature gauges stay at halfway as long as the coolant temp is between 80 and 110C (could be wrong with the figures) so you might not know if the engine was running hotter than normal
There is no noticeable difference when the system goes from gas to petrol or vice versa. If you can tell then the system is set up wrong.
As to the tank location, how often do you need to get to your battery?, if a space saver tyre is really needed the get a cross axle tank (which will lose you boot space)
i personally went looking for an LPG 4.6, as I work on diesels for a living and dislike them. 340bhp and 30mpg equivalent. Whats not to like?
Or if you want to go the whole hog, the diesels can be converted to run on LPG

Neil48is · Post by **Neil48is** » Sat Oct 08, 2011 7:23 am

And lets be honest the P38 had its own special set of problems before you even mention lpg. The 4.6 engine is decades old and started life as a 3.5 litre,sqeezing another litre out of a car is asking for trouble enough. The bores on a 4.6 are so thin it is no wonder there has been so many problems. My 4.8 is the second LPG car i've had,the first being an ML55. For me personally the argument is a no brainer. The spare wheel isn't an issue as can still be used depending how imaginative your installer is,in my experience they will pretty much do what you ask them. As for economy the LPG makes far better sense,someone in this thread made a point that he'd seen over 30 mpg running on petrol in a 4.8,thats pretty amazing in itself but if the same vehicle was on LPG it would have been more like 50 mpg !! I recently towed our 2 tonne caravan down to the south coast and saw an equivalent of 24 mpg at 60-65 mph. The diesel just could't live with that due to engine size and having to work much harder. As it is, i can drive a 360BHP car at 30 mpg all day long without giving the goverment quite as much money,especially considering they don't know what to do with it !! Its simply not a case of not being able to afford to run such a car but a case of having your cake and eating it and bloody well enjoying it.

My Tuppence worth.

JimmySpeed · Post by **JimmySpeed** » Sat Oct 08, 2011 8:26 am

[quote=""CondorX5""]. They run best on petrol - fact. [/quote]

Sorry, what? It's all well and good having an opinion but to start passing things off as fact when you can't actually say it for a fact is a different story. You would need to have driven them all to know for a fact.

How does it run differently on either fuel?

As said, any LPG switchover that you can feel is a bad install, my system and the 2 others I test drove when looking for mine drive no differently whatsoever. The fact that I can switch it over at anytime just to check confirms it. I've tried it at various points in the rev range, passengers never notice.

[quote=""CondorX5""]

And the fact that you convert to LPG certainly doesn't remove the need for servicing and maintenance of the car - you have that in addition to your LPG service, if you are looking after the X to manufacturer standards.

[/quote]

Of course, my point was that it's an ADDITIONAL Â£60 for the LPG service - in comparison to the other service items on this car it's nothing. And in fact that next to the road tax savings and the fact that my oil will stay cleaner than yours hence less DIY changes, it's almost negated.

The bottom line is, the only negative facts that anyone can safely give about LPG in general is that you lose your spare wheel well and battery access may be impeded unless you relocate it. Performance, reliability and maintenance costs are no different if you have a good modern system, but that cannot be said for every installation.

CondorX5 · Post by **CondorX5** » Sat Oct 08, 2011 10:24 am

Hahaha - looks like you need a chill pill

FWIW, I've driven an LPG coverted RR and an X5, and both were in my opinion, not as good as they were on petrol. That's a fact in my life. Obviously not yours. Seems you aren't going to be happy until everyone caves in and agrees with you about how fantastic LPG is - well, its not going to happen, fella, as I said before, everyone is ENTITLED, to their OWN opinions. For me, LPG is just plain wrong. For you, well, clearly you're in love with it! Its a personal preference (we're all entitled to those, too). You're very happy with yours, so go enjoy it. Just don't try to force it on everyone - there's a thin line between expressing opinions and having a discussion about them (we certainly don't always have to agree!) and attacking others with different opinions. I don't agree with you - you don't agree with me, so let's leave it there, shall we?

JimmySpeed · Post by **JimmySpeed** » Sat Oct 08, 2011 11:34 am

Ooooh, looks like someones got their knickers in a twist, just because I said you was wrong?

I'll get you one of those special chill pills when I get mine :rolleyes:

lezmtaylor · Post by **lezmtaylor** » Sat Oct 08, 2011 12:11 pm

When the last forum was alive I can remember a member getting in a right twist with me and my lpg 'd 4.4.
I had considerable experience(had my own transport company) having run Ford Transits(2.0 litre ohc) converted and supplied by Ford Mo Co. The warrantee was the same as petrol vehicles, and the engine oil and filter service intervals could be doubled due to running on a gas as opposed to petrol vapour.Spark plug life was also doubled.Engine life was frequently twice the that of petrol powered.
Later I changed direction and had more experience with lpg fork lift trucks, the same was found.
So as soon as I purchased my 4.4 at 4 years old in 2006 I had the lpg conversion fitted, my local BMW (who supplied car) dealer had no problems with the installation and did not negate warrantee work for lpg reasons.
I like the fact that I am dual fuelled, can run it at a cheaper rate, get equiv of 35 mpg and help a little with emissions, engine life, oil wise, is much better.
Don't lets get into a big tizzy about this, some like lpg, some don't, each to his own

CondorX5 · Post by **CondorX5** » Sat Oct 08, 2011 1:29 pm

I agree with you Lez, just because we all don't like the same thing, shouldn't mean unnecessary personal attacks, should it ? - its all about respect, really. I'm happy to respect other people's views, even if I disagree entirely,and I expect the same. My own experience with LPG in the past was entirely the opposite of yours, so I'm happy to stay away from it, pay the premium for petrol, etc, and as you say, each to their own

JimmySpeed · Post by **JimmySpeed** » Sat Oct 08, 2011 4:27 pm

[quote=""CondorX5""]I agree with you Lez, just because we all don't like the same thing, shouldn't mean unnecessary personal attacks, should it ?[/quote]

No personal attacks intended fella, and certainly no offence intended - and I'm sure its the same on your part. Sometimes things get lost in translation on the internet I think.

I'm happy to disagree, have a good and heated debate and banter (e.g. knickers in a twist

) but none of that was meant to be taken personally - thats just not cool on the 'net so:

shadrack · Post by **shadrack** » Sat Oct 08, 2011 6:47 pm

think u need the chill pill condor x5!! lol
what i meant was lpg cars have engine failure-fact, petrol cars have engine failure-fact, and so do diesels what i meant was you are no more likely to have engine failure due to lpg its just random luck in my opinion, each to their own although having my old lpg x5 2 years problem free. why give the government all that extra fuel duty running on petrol!!

dirtymonkey29 · Post by **dirtymonkey29** » Sat Oct 08, 2011 7:35 pm

Is LPG/petrol/diesel the new religion?

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