I have been told by a prospective seller of a RR Classic 3.9, that LPG conversions ruin these engines in a short space of time. Can any of you members that run 3.9's on LPG enlighten me?

The only thing I can think of is Top end lubrication problems because Gas burns dryer than petrol, You can get lucrication kits which drip oil into your intake ( A bit like a Scott oiler on a motorbike), apparently it makes the gas burn more efficently and gives you a better consumption as well as upper engine lubrication. I know people that have run LPG on 3.9 RR's and Disco's with out this and not had any problems?

my 3.9 has had lpg on it for a few years before i got it, it does have one of the little oilers fitted to it though.

Well his idea of a 'short space of time' must be very different from mine!
I have two RR 3.9's both on gas, and been running on it for what I would say was a HECK of a long time. First one has had her LPG for probably 15 years or more of her 18 year life... we dont know for sure, but think she must have had it done wilst still under three years old in the old 'grant' scheme.
Other one's kit is a little newer, been on just shy of ten years.
Neither motor seems to have been rebuilt or replaced, and judging by the oil colour if either goes pop the likely culprit will be the usual level of neglect, rather than anything to do with the fuel!
I take it the car you are looking at isn't LPG converted and he's trying to suggest that hat is a 'feature' worth having?!?!
Put it this way; at 15mpg you'll almost certainly burn more quids worth of fuel a year than you will be paying for the car.
Lpg is about 40% cheraper than unleaded.... even if the stuff DID wreck engines, well.... you'd save enough in a year to buy another ruddy car, when it wore out.....
But they dont, the blokes talking out of his tail pipe.....
Go find one already converted...... sold by some-one that doesn't tell blatent and rediculouse LIES!
How many other things about it has he BS'd about, eh?! Walk away... no matter how good the car may be, I wont give my money to any-one that lies to my face and expects me to eat it!

I'm with Teflon, I have a 3.9 V8 disco that has been on gas for about 10 years, (I've owned it for a few months) it’s done 140,000miles & purrs like it was made yesterday.
I know the previous owner, so know he hasn’t rebuilt it. It also doesn’t have an oiler kit fitted to it as far as I can see.

my p38(same engine practically) is on gas, it has suffered slipped liners, new(er) engine in recently and judging by the condition of the engine it improves the engine, clean as a whistle, also the oily residue already in the air intake from the breather tubes looks sufficient to oil the top end!!!

My oil is much cleaner after I have been running on LPG.
I run it on petrol in the winter because I have outboard tanks. (don't like the cold)
People often tell porkies when they are selling something.
Just take everything with a pinch of salt.
(unless it's Ratty talking)

Thanks to all you guy's.... your advise is much appreciated. Yes, the Rangie is the best i've seen, and no, it hasn't been converted yet. I was planning to get that done if I buy it. I have looked at several already done, but sadly they were not good in the tin-worm department.

keep looking is my advice... my L reg 3.9 V8 disco was £1100 a couple of months back (the LPG conversion was already fitted) It has very very little rust, its almost perfect inside, It just has a couple of very small dents in the body & the window rubbers have perished (but dont leak).

to convert to lpg is about £2000. It will increase the total value of the car by about £200

They are out there... took me about 3 months to find mine & it was about 5 miles away from my house (I'd looked at the all over the south west & south east before I found the right one, every other one was rotten as hell)

I went for the disco 1 as the parts are silly cheap & I can do all the work (less electronic issues), others will say disco 2 is better as they need less parts because they break less. dont know about the rangie as I always wanted a disco