deano87
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Registered: 21st Oct 06
Location: Bedfordshire Drives: Ford Fiesta
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Ok, bare with me on this one.
If someone is doing lots of miles (and demonstrated by salesman up and down the country) they buy a diesel car for many reasons. One reason is that they can cover a lot of miles.
However, is this because:
1) diesel engines are deliberately built 'better' with strong internals, better quality metals for this purpose
or
2) the technology required to use a diesel engine against a petrol means they are stronger
or
3) they aren't any stronger/more reliable than petrol equivalents?!
For example, treated exactly the same, would a 530d BMW outlive a 530i (petrol)?
Something I've always wondered 
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DaveyLC
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Registered: 8th Oct 08
Location: Berkshire
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They are built stronger because they run on the principal of pre-ignition which is something that kills petrol engines.
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richc
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Registered: 24th Mar 07
Location: Ilkeston
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quote:
Originally posted by DaveyLC
They are built stronger because they run on the principal of pre-ignition which is something that kills petrol engines.
Close thread 
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Ben G
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Registered: 12th Jan 07
Location: Essex
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don't rev as high as petrol engines 
good mpg too
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pow
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Registered: 11th Sep 06
Location: Hazlemere, Buckinghamshire
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I give this thread 3 replys
[Edited on 10-02-2009 by pow]
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DaveyLC
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Registered: 8th Oct 08
Location: Berkshire
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quote:
Originally posted by Ben G
don't rev as high as petrol engines
Because most would self detonate if they could
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pow
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Registered: 11th Sep 06
Location: Hazlemere, Buckinghamshire
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Ahhh Ben, you never fail to deliver  
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deano87
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Registered: 21st Oct 06
Location: Bedfordshire Drives: Ford Fiesta
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quote:
Originally posted by Ben G
don't rev as high as petrol engines
Isn't it all relative though?
Redline of a petrol engine is 7krpm, redline of a diesel is 5krpm, but a redline is a redline, so pushing the limits of the engine?
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Ben G
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Registered: 12th Jan 07
Location: Essex
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it was a joke deano, A JOKE MAN
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Ben G
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Registered: 12th Jan 07
Location: Essex
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quote:
Originally posted by pow
Ahhh Ben, you never fail to deliver
had to slip the old mpg joke in somewhere 
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Ollie_B
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Registered: 1st Jun 08
Location: North Wales/Wirral
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i would of thought the diesel engine would have to be built better, as it works on compression, meaning higher forces and more strain is put on the engine.
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pow
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Registered: 11th Sep 06
Location: Hazlemere, Buckinghamshire
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quote:
Originally posted by Ben G
quote:
Originally posted by pow
Ahhh Ben, you never fail to deliver
had to slip the old mpg joke in somewhere
Your da best 
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deano87
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Registered: 21st Oct 06
Location: Bedfordshire Drives: Ford Fiesta
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quote:
Originally posted by ollieb123
i would of thought the diesel engine would have to be built better, as it works on compression, meaning higher forces and more strain is put on the engine.
I'm not mechanically minded, but I just see it as all relative. So it's built stronger, because it needs to be, not because it is just so it lasts longer, if that makes sense. So if a diesel engine hadn't been built stronger because of compression, it wouldn't last as long as petrol  but then if a petrol was built at the same strength of diesel but without the compression, it would go forever.
meh, think I got the answers I needed
[Edited on 10-02-2009 by deano87]
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daymoon
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Registered: 1st Aug 08
Location: Selby, North Yorkshire
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diesels have much bigger compression rate (about 20:1) where are petrols are about 10:1...
because diesel isnt easily ignatable, u need more preassure, more preasaure means more stress.. but petrol engines are made from aluminium alloys( i think blcks are made from cast iron) and diesel block made from something stronger...
i think that because diesels deliver most of torque and bhp at low revs, they dont need to rev high, so last longer...
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Ollie_B
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Registered: 1st Jun 08
Location: North Wales/Wirral
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haha i see what your saying, and to be honest i don't know but i would think they are made better because they have to be, and its a coincidence that they last longer, due to the low revs and the other factors...
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DaveyLC
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Registered: 8th Oct 08
Location: Berkshire
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Diesel is technically easier to "ignite", it requires pressure and heat.. If you notice diesels dont have spark plugs because once the glow plugs have warmed the combustion chambers you just have to keep supplying the diesel before the compression stroke and boom it will explode when it gets compressed in the hot cylinder.
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jr
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Registered: 20th May 02
Location: Kent
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quote:
Originally posted by DaveyLC
Diesel is technically easier to "ignite", it requires pressure and heat.. If you notice diesels dont have spark plugs because once the glow plugs have warmed the combustion chambers you just have to keep supplying the diesel before the compression stroke and boom it will explode when it gets compressed in the hot cylinder.
So simple to understand, if anyones unsure read daveys post again 
[Edited on 10-02-2009 by jr]
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_Allan_
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Registered: 24th Mar 04
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quote:
Originally posted by Ben G
quote:
Originally posted by pow
Ahhh Ben, you never fail to deliver
had to slip the old mpg joke in somewhere
and to be fair you've got a lot of miles out of them
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sand-eel
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Registered: 15th Mar 07
Location: carluke/braidwood--IRNBRULAND
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Diesels are just more beefy, higher compression and stress and much more heat than petrol engines.
Petrols can be made all aluminium (mine is) diesels tend to have cast iron blocks and aluminium heads, there might be all aluminium diesels engines but would require super cooling.
They do rev less which does mean they last longer as the moving parts are not turning as fast as petrols, truck engines only rev to about 1500rpm and can do 1000000miles literly.
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deano87
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Registered: 21st Oct 06
Location: Bedfordshire Drives: Ford Fiesta
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Some answers I needed
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Nic Barnes
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Registered: 5th Apr 04
Location: nowhere near ginger people
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quote:
Originally posted by deano87
Some answers I needed
this in relation to why you cant compare a 90k 1llitre 12v to a diesel engine from last night by any chance?
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ianofbhills
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Registered: 10th Feb 01
Location: newcastle
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petrol is a solvent and breaks down the oil used to lubricate the engine bearings.
diesel is a heavy oil
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Daveskater
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Registered: 29th Apr 08
Location: Oxford, UK Drives: Jap wagon
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You don't need an AFM on diesels
Numberwang!
Originally posted by AlunJ
I like you Dave, you are a man of men
Originally Whatapp'd by Neo
Dave's maybe capable of a drive-by cuddle
Look at my pictures
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pow
Premium Member
Registered: 11th Sep 06
Location: Hazlemere, Buckinghamshire
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I have one.
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Daveskater
Premium Member
Registered: 29th Apr 08
Location: Oxford, UK Drives: Jap wagon
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My old manager said "they just need air, not an exact amount like petrols". Maybe it was just the Isuzu Marine engines that we had then 
Numberwang!
Originally posted by AlunJ
I like you Dave, you are a man of men
Originally Whatapp'd by Neo
Dave's maybe capable of a drive-by cuddle
Look at my pictures
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