Curious but not serious!

[gunnarsilins]

I cannot resist the temptation, is there anybody with an answer!?

What would happen if I feed my diesel engine with petrol instead of diesel?

Would 75 hp become 750 for a few secs and my boat having a short moment of fame beeing the worlds fastest Moody?

<hr width=100% size=1>

 

[tony_brighton]

Not sure it would fire at all - diesel vapour is actually quite explosive hence the heat of compression is enough to make it explode whereas petrol requires a spark.

<hr width=100% size=1>

 

[tr7v8]

Up to about 20% petrol nothing, the calorific values are probably different but someone else will be more qualified on that. Once you go beyond this figure then aside from the fire risk, the main risk is of damage to the injection pump as it runs very tight clearances and depends on the lubricating properties of the diesel fuel to keep running.

Jim
-----------

 

[Eudorajab]

Give it a go and report back !!!!!

<hr width=100% size=1>

 

[longjohnsilver]

Have a mate who filled his diesel Merc with petrol, ran v rough until he realised his mistake. It did however knacker his fuel pump!

Expensive mistake.

<hr width=100% size=1>

 

[gunnarsilins]

Tempting!

Once I had a dutch 'DAF', a small ugly car with belt (!) drive.
Before I sent it to the scrapyard, because of the body rusting away, I emptied the engine of all lubricating oil and started it with a stick pressing the accelerator all way down to the floor. The engine ran for over three minutes, screaming on max RPM before it stopped abrutely with a loud, expensive sounding 'clonk-boom-chrasch'.

<hr width=100% size=1>

 

[gunnarsilins]

I thought compression...

....would generate enough heat to ignite petrol!

<hr width=100% size=1>

 

[Russell]

I filled up my diesel car one evening, and the next day it started misfiring and running rough. I tried putting my foot down hard 2 clear it, and it did seem a bit more powerful as the revs got up, but it still ran like a dog low down. I thought it might have air in it so I started 2 bleed it, and straight away I could smell petrol. Luckily I still had the receipt and it said 55 litres of diesel. Turns out the tanker driver filled the diesel tank at the garage with unleaded. Esso paid 4 my tank 2 b flushed, and they wrote me a letter saying they would be liable for any long term damage, but it doesnt seem 2 have suffered. I'm not sure what a modern turbocharged engine would have made of it though !

<hr width=100% size=1>

 

[Eudorajab]

Re: Tempting!

Remind me never to invite you to have a look at my motor !!!!

All joking aside .. sounds like an interesting experiment and something to do after a few jars of the amber nectar.

If only I could convince a good mate to give it a go !!!!!!



<hr width=100% size=1>

 

[tr7v8]

Re: Tempting!

Did it with a Morris Minor years ago 3 of us drained it of Oil and ran it round a field, to all of our suprise it ran for about 45 minutes and only died cos it popped a hose andoverheated. I think if the cooling system could have held it would have run for ages.

Jim
-----

<hr width=100% size=1>

 

[gunnarsilins]

Hmm, a sign...

...of British quality vs Dutch....?
But then it hits me, Volvo aquired DAF sometimes in the 70-ties!
So it must be the constant over-revving which killed the engine.

But 45 mins without oil, and still not seizing!
From now on I´ll never touch the dipstick on my car anymore!

<hr width=100% size=1>

 

[richardandtracy]

Petrol will ignite earlier in the compression stroke than diesel, and the detonation will be quicker as the flame front is faster. This means that the initial explosion will tend to slow the engine down before it reaches TDC more than a diesel. At low revs you'll be relying on the flywheel much more to keep the engine turning (hence rough running at low speed reported elsewhere).

Diesel engines are more strongly built than petrol, so are more likely to survive the quicker detonation of petrol than frequent serious pinking of a petrol engine. So, it'll probably be OK so long as you don't make a habit of it.

I can't answer for the injector pump, but petrol isn't a terribly effective lubricant - otherwise why would you need oil in a 2 stroke?

Regards

Richard


<hr width=100% size=1>

 

[Aeolus_IV]

Have heard elsewhere that the injection pump takes the hit (lack of lubrication), and is irrepairable once damaged. Very expensive to replace. However it is not intrinsically a bad idea, after all some cars are now "GDI" - Gasoline Direct Injection - a diesel engine running on petrol.

Jeff.

<hr width=100% size=1>

 

[tr7v8]

Re: Hmm, a sign...

DAF never made the engines either, the 33 was a modded Citroen 2CV and the others were Renaults. Yes Volvo did take over in the 70's to get the Truck division and killed off the true DAFs quite quickly. The Volvo 340, 360 (spit, choke) was built in the same factory and the 440/460 followed on from that.
The DAF Gearbox patents are held by Volvo now Ford and have led to the CVT transmissions in Fiat, Ford and others.

Jim
-------

<hr width=100% size=1>

 

[butler]

Re: Hmm, a sign...

you should get out more,

<hr width=100% size=1>

 

[tr7v8]

Re: Hmm, a sign...

Ummm, I did think it sounded a bit anorakish as I was posting it, thanks for confirming it /forums/images/icons/smile.gif

Jim
-----

<hr width=100% size=1>

 

[BrendanS]

Re: Real Anorak questions

What language do we get the word anorak from?

Answer: Greenland Eskimo

2. Which Cabinet Minister in England got married in a green anorak?

Answer: Robin Cook

3. Which sporting organization goes under the name ANORAK?

Answer: The Association of North Atlantic Kayakers

4. Within £5 how much does LL Bean's Mountain Classic Anorak cost?

Answer: About £61

5. How many points would you get for the word anorak on a double word score in Scrabble?

Answer: 20

6. What important place does Whitcombe L Judson have in the history of the anorak?

Answer: He invented the zip fastener in 1892.


<hr width=100% size=1>

 

[30boat]

Re: Tempting!

I once took a BSA 250 for a 1 hour spin around a field and when I returned the bike was told by the owner that there was no oil in the tank.I think the engine didn't mind very much as it always ran perfectly afterwards.And happened this with a notoriously unreliable engine.

<hr width=100% size=1>

 

[Sybarite]

The main problem is the diesel injection pump. It is manufactured to extremely fine tolerances ( 1/10 of a micron; components are manufactured as a set and are not interchangeable between identical pumps) and it is lubricated by the oil passing through it. If you run dry or use petrol you will probably need to replace the pump.

John

<hr width=100% size=1>

 

[chriscallender]

Re: Tempting!

I once picked up a nearly new rental car (couple of hundred miles on the clock) in California, drove it another couple of hundred miles down highway 1 then the oil pressure warning light came on. Pulled in at the first "gas station", the guy pulled out the dipstick which had no oil on it so he started putting oil in and it took a whole 5 litre can before it registred.

Turned out someone at the rental place forgot to put the oil back in after its first oil change! Wonder how long it lasted.

Chris

<hr width=100% size=1>