Evening all!

Whats the best V8 in your opinions? 3.5, 3.9, 4.0, 4.2, 4.6???

The Reason I ask is that Ive been offered a 3.5 V8 fuel injected Disco on a manual box and LPG (Single point system) Any thing in particular I should be looking out for?? Or should I be looking at the later 3.9's?

SFB

You'll no doubt get plenty of replies from owners who are passionate about their particular engines &/or LPG useage, so I'll stick to a couple of facts to start you off. The original 3.5 has least power (on paper) but the strongest block. I refer to 'power on paper' because having owned both 3.5efi & 3.9 autos I can't say I found any noticeable difference in normal driving, these cars are designed for cruising not performance! All the subsequent blocks (3.9/4.2/4.0/4.6) were bored out to 94mm & can suffer from liner problems that effectively scrap the block. There is some evidence that prolonged use of LPG can accelerate this process.

norseman said:

You'll no doubt get plenty of replies from owners who are passionate about their particular engines &/or LPG useage, so I'll stick to a couple of facts to start you off. The original 3.5 has least power (on paper) but the strongest block. I refer to 'power on paper' because having owned both 3.5efi & 3.9 autos I can't say I found any noticeable difference in normal driving, these cars are designed for cruising not performance! All the subsequent blocks (3.9/4.2/4.0/4.6) were bored out to 94mm & can suffer from liner problems that effectively scrap the block. There is some evidence that prolonged use of LPG can accelerate this process.

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That pretty much sums it up however I am not aware of LPG accelerating liner slip.

Thanks Chaps, I think it could be a worth a closer loom this arvo then. Im quite liking the idea of the V8 noise more and more now. And Lets face it, if you want a V8 that goes fast you buy a TVR not a landy! Lol!

Medusa said:

That pretty much sums it up however I am not aware of LPG accelerating liner slip.

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Apparently it's the increased combustion chamber temperature that 'finds' any latent weakness in the block. As a demonstration of this - my last (& only) 3.9 developed a 'tapping' when warm that would disappear if I switched to petrol whilst driving, this later turned out to be the start of the dreaded slipped liner & resulted in a replacement block:doh: The same thing happened to a friend's RRC & although I suspect that the 'meatier' 3.5 block (of which I've now had three) would probably not suffer, I still would'nt touch the stuff with the proverbial barge-pole.

the buick was known for liner problems years ago, lpg increases heat-and 3.5 v8 liners slip as well but rarely.
4.6 the worst then 3950cc 4.0/3.9 and rarely the 3.5
Takes your chance

fanatic said:

the buick was known for liner problems years ago, lpg increases heat-and 3.5 v8 liners slip as well but rarely.
4.6 the worst then 3950cc 4.0/3.9 and rarely the 3.5
Takes your chance

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Thats the general opinion that I got from most people over the last few days, so I thought as its the 3.5 I was looking at buying I'd go for it and take that risk, plenty of old motors kicking around if I need to replace it?

Interesting from a point of view the classic 3950 not seen as many slipped liners.
The 4.0 which is 3950 uprated and 94mm block(same as 4.6) p38 and 4.2 classic seem to be greater affected.
Everything from fuelling to machining has been suggested.

The debate rumbles on

Short fat bloke said:

Thanks Chaps, I think it could be a worth a closer loom this arvo then. Im quite liking the idea of the V8 noise more and more now. And Lets face it, if you want a V8 that goes fast you buy a TVR not a landy! Lol!

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typical every v8 i have had runs nearly as quick as a tvr and i can still go off road!!!!!!
engine problems
heres the facts
4.2 started all the porus block issues as it was also the first of the closed loop fuel injection engines land rover produced
3.9 yes suffers porus block again only when in closed loop emissions set up
3.5 never seen a issue with but is under powered and mostly are well worn and ready for a overhaul!
4.0 and 4.6 suffer problems again because of the closed loop emissions!
now add gas into the equation single point first strangle the engine with a system designed to work on carbs not fuel injection loss of power on petrol and gas thrashed to make up for the power loss over heats tada porus block!
multi point gas set up properly is the only way to go but again gas burns very hot and will still cause porus block!
now another theory is poos quality antifreeze to weak causeing hi build up of staitc electricity which burn though the linners i always use a very hi strength antifreeze as it has static electricity aditives to help disperse static electricity build up also fit extra earth cables too