Converting a petrol engine to run on diesel
- Thread starter Hawk Tuah
- Start date
I certainly wasn't considering it. It would be easier and cheaper just to buy a diesel engine.the block wouldnt really be able to take it, would be better off converting to LPG as its a lot cheaper then diesel anyway
I'm just interested in the actual mechanical differences between the two.
they can, but its expensive making sure its all strong enough.
standard duratec is like 10.5:1 and produces 150bhp, to get roughly 230 you need 13:1.
to get this you would need new pistons, conrods, crank and cams. Not to mention you would need Throttle bodies to let it breath.
Direct injection on gasolines is more like diesels now. Key differences why they are different is the burn rates and flash temperatures.
With dervs you control the burn by the rate of fuel injected (fuel is injected as the fuel burns). The fuel flashes at a much higher temperature so it can be compressed more - this calls for stronger engine internals though
Typical gasolines the spark ignites it, compress it too much and it will ignite itself. The fuel is already in the cylinder as it entered with the fuel.
Direct injection on a gasoline means that the fuel can be injected later, this allows for higher compression ratios and also optimisation of injection for emissions and power. Early days though.
go read about HCCI or CAI for the next steps of gasoline engine technology
With dervs you control the burn by the rate of fuel injected (fuel is injected as the fuel burns). The fuel flashes at a much higher temperature so it can be compressed more - this calls for stronger engine internals though
Typical gasolines the spark ignites it, compress it too much and it will ignite itself. The fuel is already in the cylinder as it entered with the fuel.
Direct injection on a gasoline means that the fuel can be injected later, this allows for higher compression ratios and also optimisation of injection for emissions and power. Early days though.
go read about HCCI or CAI for the next steps of gasoline engine technology
Associate
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Remembered reading this a while ago which might be of interest:
"Despite being cast in aluminium the AJ6 cylinder block is extremely stiff and rugged, having been designed with the possibility in mind that there might be a diesel version at some future date. This same unfulfilled requirement was the reason for the almost square bore/stroke ratio, which of course became considerably under-square for the long stroke 4 litre and must also have influenced the decision to spread the valves at a relatively wide angle of 47 degrees."
http://www.jagweb.com/aj6eng/aj6_performance.php
Not much more in the link about diesels but interesting nonetheless
"Despite being cast in aluminium the AJ6 cylinder block is extremely stiff and rugged, having been designed with the possibility in mind that there might be a diesel version at some future date. This same unfulfilled requirement was the reason for the almost square bore/stroke ratio, which of course became considerably under-square for the long stroke 4 litre and must also have influenced the decision to spread the valves at a relatively wide angle of 47 degrees."
http://www.jagweb.com/aj6eng/aj6_performance.php
Not much more in the link about diesels but interesting nonetheless
Right, glowplugs aren't an essential (look at the 2.5 banana transit engine), swap out the plugs for injectors, mount an injector pump in place of the alternator (or just use the unused mounts that most blocks have), In cold conditions use a flame plug in the inlet tract to give a bit of extra heat to the ignition.
SHould take a couple of hours tops
SHould take a couple of hours tops
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You firstSHould take a couple of hours tops
Driven by a nice V or poly-V belt. Might have to reset the timing occasionally, probably no more than every 5 engine revolutions though
Thats easy.
Clarkson style
got boost?
I certainly wasn't considering it. It would be easier and cheaper just to buy a diesel engine.
I'm just interested in the actual mechanical differences between the two.
na i know you wasnt and its a good "project" idea to make it work
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I wonder if you had an engine with everything on, glow plugs, spark plugs, you could make it so it runs on both petrol and diesel... Probably easier to go twin engine.
I wonder if you had an engine with everything on, glow plugs, spark plugs, you could make it so it runs on both petrol and diesel... Probably easier to go twin engine.
No, unless you can somehow magically control the compression ratios when you feel like it.
Check out the Saab variable compression engine
very intersting stuff!
I hope you weren't saying that with a straight face
Of course
Driven by a nice V or poly-V belt. Might have to reset the timing occasionally, probably no more than every 5 engine revolutions though
Well duh! You'd have to do it up TIGHT the first time .....
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BMC managed it. The b series came in a diesel version, I know, I've got one! I'm not sure how much the block differs but I don't think its much, perhaps just some mounting holes but I've never compared to my petrol b series that closely. The head is bound to differ but only in as much as there needs to be a hole for the injectors and the glow plugs. Forget ecus, why do people think engines need a million bits of electrics to make them go nowadays? Listers don't even need a battery! I think the bmc just uses the dizzy drive for the injector pump.
Fundamentally its all the same, just different stroke and valve timing and head, with a couple of different bolt on thingies. Admittedly to change the stroke you probably end up to changing the piston, crank and con rods. And you'd need a new head, and cam shaft. So appart from the block you'd not have much left from the orriginal engine.
Oh and you'd have a diesel b series. 35 raging horses!
Fundamentally its all the same, just different stroke and valve timing and head, with a couple of different bolt on thingies. Admittedly to change the stroke you probably end up to changing the piston, crank and con rods. And you'd need a new head, and cam shaft. So appart from the block you'd not have much left from the orriginal engine.
Oh and you'd have a diesel b series. 35 raging horses!