Honest John - modern diesels

Faster pressure rise on injection so it bangs more.

Cos they rattle more.

The chap who got common rail diesels working in the first place said a few years ago that diesels would die out in favour of common rail petrol turbo engines as it's very easy to get the torque and economy of a turbodiesel in a much nicer petrol using common rail. Personally I hope he's right as diesels are horrible things.

Because they try to make diesels as nice and smooth as petrols, which is impossible. DMF's are just part of the "Diesels are good" illusion.

A neighbour bought a new diesel mondeo last year , it has now done 7k and has used up all its oil and wrecked the bottom end, what a wonderful advert.

Not good, I must say. However, mine's a 2002 Mondeo with 95K and it runs as sweet as a nut.

Rob

Hmm. As petrol wrecks common rail diesels due to the petrol destroying the extremly high pressure pumps required, how easy is it to make a high pressure pump that can cope with petrol?

They're not you know. I've just bought one. It's not noticably a diesel if you're moving or the engine's warm, in terms of sound or vibration. However, the power delivery is still bizarre.

Perhaps he should have checked the oil more often.

Yet mine has 105k on it and doesn't use a drop despite doing the odd

MichaelS gurgled happily, sounding much like they were saying:

Or perhaps the key is in the word "used". Turbo seals fail, oil is sucked through into the intake, burnt as fuel, until there is no more. Can't turn it off, because it's not injected fuel that's being burnt...

She should, but like many people assumed that a new vehicle will not use significant amounts of oil. why there isn't a low oil level light I don't really understand, it would only cost a pound or so extra and would have saved several thousand pounds in this case alone.

Eh? Pretty well all EFI petrol engines are common rail - long before it was used for diesels.

Agreed. On a new car you shouldn't have to check the oil. My 206 had a little gauge thing, seemed pretty accurate when checked against the dipstick. Not that it ever used a significant amount between getting it, giving it it's one service and getting rid of it anyway.

I mean the high pressure, properly metered, sequential injection setups like the GDi Mitsubishi lump as opposed to the "open all injectors at once" setup plenty of petrol injection engines are lumbered with.

These, combined with a turbo or two works beautifully - much better on a petrol than on any diesel engine - but tends to be used for more power than economy. The insane V12 and V8 Mercedes jobs are excellent examples. Over 600 bhp and telephone numbers of torque, but they'll still do 20 mpg driven remotely sensibly.

I think the TSi Golf motor could be the beginning of the way forward, but I don't think they really need the supercharger.

It would make sense to fit a "low level" light to more stuff. My old Alfa 164s had an oil level light that used to save the engine a couple of times a month.

My P38 probably has one, but doesn't seem to burn or waste any oil. Not bad for a 50 year old engine design with 182k miles on.

They feel like they are fueled by sandpaper though. Smooth they are not...

As I say, the /beginning/ of the way forward.

And since when were diesels smooth?

Why not? That's the problem, new cars normally use more oil than ones that have been run in.

"Dave Plowman (News)" gurgled happily, sounding much like they were saying:

They have a fuel rail sat at injection pressure, yes. But they're not direct injection very-high-pressure injection like common rail diesels.

Aye. The ZX has one. It's fecking brilliant. You can't convince a girl to check the oil regularly. However, it does work if you say "If that light comes on, you need to put some oil into your engine". And I like it for myself because I'm lazy. The 406 has a proper little digital gauge when you start it up. I don't know why they don't fit them to everything as standard - it'd save a lot of trouble for some people.