LPG Any thoughts, opinions or experience?

[aston]

In the past we owned a Jeep Grand Cherokee, converted to LPG never seemed to run right, Sometime later I had a VW aircooled converted to LPG, again it never seemed quite right, And rightly or wrongly I am looking at large engined LPG cars for sale, I am wondering if I was just unlucky or is it simply rubbish and hassle.
Any ideas, comments or experience?
Thanks as usual Aston

 

[old-git]

Owned an old (R reg) Range Rover for around 4 years with a very basic LPG system. It worked flawlessly, roughly halving my fuel bill when LPG was round half the price of petrol.

It had a pair of cylinders, one along along each sill, so no boot space or spare wheel issues.

 

[TCJBOLDIE]

Had dual fuel LPG system on a couple of work utes a long time ago when it cost way less than 1/2 petrol price and had a drip feed UCL to protect valve seats was ok no problems from memory.

 

[HDi fun]

I've often wondered about valve seat recession problems and why it's an issue given that diesel engines have 'dry' valves ie. fuel injected into either the combustion chamber diretly or the pre-chamber in IDI engines. This is what deterred me from converting my BMW 528i.

Personally I wouldn't rush at anything apart from a factory system.

 

[TCJBOLDIE]

My utes were before Injection so the seats were hopefully protected by the http://www.moreyoil.co.nz/moreys-power-booster-lubricating-system/ as in those days =pre ULP hardened seats were not ex factory

 

[gladrags]

went to see a Range Rover with LPG fitted once, the guy told me he had to keep the jubilee clips slack on the inlet manifold rubber hose connections because it blew back sometimes and sent the MAF to an early grave. Didn't buy it, in fact never owned an LPG system. I knew someone who worked in a factory where they used LPG fork lift trucks and he said they took the heads off about every five years to do the valves. he said the engine internals were spotless, no carbon build up like petrol or diesel engines.

 

[obi_waynne]

https://www.torquecars.com/news/lpg-conversions.php

 

[HDi fun]

Fiat is talking nonsense re warranty. In this example ( ^ ^ ) they'd have to prove that the LPG equipment had caused the mirror to fail. Not easy.

I also think that 5% is ambitious in terms of lost efficiency or efficacy. I'd go closer to 15% in terms of lost power.

 

[gladrags]

it's surprising what a post can prompt, I took a look at valve recession and discovered something; that valve rotation is caused by the action of the helical valve springs. thinking back to push rod engines i always thought it was the tappet (or rocker arm) moving in an arc against the valve stem that caused the valve to rotate because the valve had straight linear travel so i'll need to add that to my huge store of things I didn't know. it's a poor day when you don't learn something.

 

[Cubefish]

My humble Citroen C1 was converted to run on LPG about 4 years ago, and runs flawlessly. I have to travel about a mile from cold before the LPG system is activated, and the switchover from petrol to LPG is barely noticeable.

I use a lubricating agent with my BRC system - necessary, apparently, to stop recession. Flash Lube I think it's called. The reservoir stores about 500ml, and that lasts about 10,ooo miles.

When reading up about servicing LPG vehicles, it was mentioned that the spark plugs have a narrower gap than when running on petrol; if the spacing is not correct, then the vehicle will not run well. Fortunately, this isn't an issue I've experienced. The worst thing that has happened to me is a sensor failing resulting in the LPG fuel not working.

 

[HDi fun]

What is the rationale behind cold start with petrol?

 

[TCJBOLDIE]

HDI I seem to recall that the early LPG carby converter systems recommended petrol start and change over shortly after for easier starting.

With the MOREY lubricator installed my hard working utes never had valve seat recession problems before they were sold at 100,000miles or so.

The latest petrol direct injection motors will have "dry valves"

 

[Cubefish]

I also think that 5% is ambitious in terms of lost efficiency or efficacy. I'd go closer to 15% in terms of lost power.

In normal driving conditions I don't notice a great deal of difference. But one route I drive involves two very steep inclines, and they just at the distance from my home where the LPG system clicks in. The loss of power is painfully noticeable; once the changeover from petrol to LPG is complete, there's no problem negotiating the hills.