Petrol and Kerosene

[Bob Eager]

+1

[The Natural Philosopher]

which wont be affected by a very small percentage of water or petrol

[Dave Liquorice]

Apart from the fact the engine in question is a petrol one. B-)

[Dave Liquorice]

I doubt the compression of a petrol engine (less than 10:1) is enough to make even kero go bang. Diesels are nearer 20:1.

This is true and for a modern computer controlled engine to run rough it does have to be *very* unhappy or have something well outside spec.

Friend visted a couple of years back and complained that his car was lacking power, motorway hills would slow him to heavy speeds. Ran smooth enough no lumpy idle or anything. Took the plugs out, each one had a little umbrella of deposit over the earth electrode and the gap was nearer 100 thou than 25. No way would an old, points/coil based engine have run let alone run and be smooth with plugs like that...

Tried local garage for a new set but no joy, cleaned and regapped as best I could but the earth was well erroded. Chap goes back home and complains that he had trouble holding it below 80, hills or not...

[Johny B Good]

I rather gathered that you were referring to a kerosene contamination of a petrol engine vehicle. In hindsight, it's a pity you didn't make this clear in the first place but it's their own fault for making the assumption of diesel contaminated by kerosene and going off half cocked.

BTW, why the mixed naming convention UK "petrol" and USA "Kerosene"? I'd have stuck with the more consistent petrol and parafin. A yank, of course, would have used gasolene and kerosene or perhaps more likely gas and kerosene.

If the engine has been rattling and 'Knocking', then it might need a new set of pistons if the old ones have suffered burning from detonation of the resulting low ocatane fuel mixture if the engine's management computer couldn't figure out how to "Get out of the rain" and retard the ignition or else create an alarm, perhaps reverting to a low power emergency limp to nearest garage mode.

There is _some_ justification for suggesting the possibility that an engine recondition might be in order but I'm sure a swift inspection with a borescope of the piston crowns through the spark plug holes will resolve whether or not such a repair is desirable.

[Bob Eager]

Of course. Luckily for me! I managed to defeat the Fuel Angel I'd fitted a year earlier after a previous mistake...

[Johny B Good]

As Fredxxx points out, it all depends on the amount of "run badly" involved. FSVO, you'r probably correct but for large values of "run badly", the piston crowns may be almost burnt through from the severe detonation effects of such a low octane fuel mix, depending on how clever the engine management computer is. The rough running may simply be the symptoms of the engine management trying to minimise such low octane induced damage - they may have felt worse than if it was left unchecked to burn the piston crowns out.

At the very least, a look at the piston crowns with a borescope should provide the answer, assuming a swift word with the car manufacturer's tech support fails to offer any reassurances as to the engine management knowing how to safely handle the problem of parafin in the petrol (or kerosene in the gasolene).

[Tim+]

True, BUT you have to work hard to squeeze diesel through a petrol filler tube due to the smaller orifice so petrol in a diesel car is by far the commonest misfuelling problem.

I'd be interested to hear how the OPs son managed it. ;-)

Tim

[Mike Barnes]

That was my experience.

But I don't know about long-term.

It was a hire car. :-)

[Dave Liquorice]

Only if the car has a restricted orfice, that only came in with unleaded and CATs.

From the OP's comment a garage may have had a delivery of ready mixed petrol/kero. They certainly use the same tankers for some fuels on a fairly regular basis as the otherwise fixed/static hazchem plate(s) have the last two numbers of the code changeable. I suspect this is only between kero and red, though it could include petrol. Mixing red and white diesel is probably not a good idea, if the detectable concentrations of the tracers are to be believed.

"Kerosene"?

Parafin seems to be a retail/small quantity term. Heating oil is refered to as kerosene on the bills.

[fred]

ed he has got petrol mixed with kerosene in his tank. Apart from how this h appened (apparently there is recent history linking it to a particular fill ing station), what detrimental effect will it have had on the engine. Garag e is talking in terms of a reconditioned engine

Apparently there are two grades of Kerosene. Light a.k.a. Paraffin, and hea vy a.k.a. heating oil.

In my original comment I mentioned he had petrol mixed with kerosene in his tank. I made no mention of diesel. People jump to conclusions.

[Martin Bonner]

Well, yes. There is that minor, technical, detail I suppose. ...

[Fredxxx]

Very understandable ones in my book, especially give the sparse nature of your posts. Diesel was mentioned just 20 minutes after your first post and you chose not to correct in yours nearly 2 hours later. Its quite rare for any petrol to be contaminated with kerosene as such, unless you're running a very old tractor.

For info:

There is an overlap of paraffin chain lengths in diesel fuel and kerosene.

Also, paraffin is a generic name for an alkane that includes natural gas to heavy waxes.

BTW Diesel was an inventor. A diesel engine uses diesel fuel, sometimes called DERV.

Even now you haven't answered some of the questions raised, yet sarcastically criticise others who help.

[Dave Liquorice]

"Light" and "heavy" are sort of duty terms. Kerosene, paraffin, JetA1, Heating Oil, are all very similar "light" 28 sec oils. Diesel, red, white, gas oil are all very similar 35 sec oils.

The 28/35 sec is a viscocity measurement. How long in seconds a standard quantity of the oil, at a standard temp/pressure, takes to run out of a standard container with a standard hole in it.

As for the various oils, they will vary in composition both chain lengths, impurities and/or addatives.

Quite agree it was perfectly clear what wrote.

People read what they expect to read not what is wrote. The reverse is also true but not in this case.

[fred]

WTF, I'm supposed to monitor this group in order to correct those who didn' t bother to read and digest my original post.

If I could have answered the questions raised I would have done so. As the problem lies with my son-in-law I obviously can't have up to the minute inf o and as he isn't tech savvy he is incapable of quizzing the garage concern ed as to why they think the engine is knackered. Any info I have is coming via my daughter.

He does say now that they did a compression test and found no compression i n two cylinders.

Lord knows how long he ran the engine while it was mis-firing.

If you've read sarcastic criticism into my posts then none was intended.

And yes I know Diesel as a mans name, and that he committed suicide by jump ing off a channel ferry, and no I didn't Google that.

[Tim Streater]

No but you are supposed to know how to snip.

[fred]

Gives me no problems.

[The Natural Philosopher]

I thought it was a standard ball bearing dropping down a standard tube actually.

[The Natural Philosopher]

None at ALL?

then he has stuck valves or a blown head gasket

Even a piston with no rings will give some compression.

[Vir Campestris]

Up-thread someone mentioned piston crown damage :(

Andy