>>>>>>Recirculated exhaust gasses containing crankcase oil vapours, over time clogging up
>>>>>>the
>>>>>>EGR valve and building up on the flaps.
>>>>>
>>>>> No..in a diesel, oil in the exhaust will be entirely made up of
>>>>> unburnt diesel not engine oil. Any tiny amounts of engine oil will be
>>>>> completely and massively irrelevant compared to the unburnt diesel oil
>>>>> quantities.
>>>>
>>>>No, you are wrong...
>>>>
>>>>Engine oil enters the combustion process from worn rings, worn valve stem oil seals,
>>>>the
>>>>PCV system, thrashing the engine from cold, and from damaged / worn turbo seals
>>>>especially in engines run on the incorrect oil spec.
>>>>This oil burns differently to diesel oil and leaves carbon deposits behind.
>>>
>>> I disagree. If a modern diesel has *so* much engine oil in it's
>>> exhaust so as to utterly overwhelm the effect of unburnt/burnt diesel
>>> oil in the exhaust
>>
>>that is not what I said. I was reponding to the statement you made "in a diesel, oil in
>>the exhaust will be entirely made up of unburnt diesel not engine oil."
>
> It is in effect 'entirely' as the portion of engine oil artifacts is
> negligible in this case (swirl flap failure). I'm an engineer not a
> pedant.

It is not negligible in a worn engine as some of those were.
Those engines had covered tens of thousands of miles, they were not new engines. Over
time, the oil vapours had collected on the high turbulence areas whose parts were cooler
during the over run.
I am pedantic, I've already said so, but you did not believe me. I doubt you are an
engineer from an automotive background.


>>Do you think that when a car starts up and blue smoke comes from the tailpipe, that
>>that
>>blue smoke is unburnt fuel ???
>
> Unburnt (in varying degrees) diesel can produce all sorts of colours
> of smoke. I've seen white, blue, brown, black...and variations in
> between.

Blue smoke is engine oil burning, brown / grey / black smoke is unburnt fuel (petrol or
diesel). White is usually steam, sometimes auto transmission fluid, sometimes coolant
from a blown head gasket, or cracked cylinder head.


> I might be very slow on the uptake here but I'm starting to piece
> together comments which suggest, to me, that your expertise/experience
> is more in petrol engines than diesel ones? Some of your comments
> while very true of petrol engines are not quite so true of diesels,
> IMHO.

Worthless

>
>>>then the engine is a wreck and worthless IMO. Who
>>> cares at that point if it munches the swirl flaps. I've never owned a
>>> diesel that burned *any* measurable amounts of engine oil. Burning
>>> diesel oil produces carbon deposits..often called soot.
>>
>>No, the soot (or particulate matter) is unburnt fuel. Hopefully, none should get past
>>the
>>DPF.
>
> Yawn. 'Burning' diesel in a car produces soot because it doesn't all
> actually *burn* - yes, I do know that.

That is *not* what you wrote before.

>If I were to have to (as it would seem) explain precisely how a 4 stroke deals with
>it's fuel in
> every sentence

YOU do not need to explain to me. It is you whose knowledge is superficial.

> or use shorter more commonly used simplifying words
> like 'burned' then this conversation would be a lot more tedious than
> it already is.

You made it tedious. You think you know more than you do.

> Nevertheless, the soot in diesel exhaust *will* be available to build
> up on the swirl flaps to a vastly greater degree than any engine oil
> artifacts..no?

Yes and no. It depends on how the car is driven, and the trips involved. There is no set
answer as there is no set driving pattern.

>
>>> Mentioning the fuel wasted by A/C while owning a 335d *is* a tad
>>> bizarre.
>>
>>We get an average MPG of 39.4, which is better than our 330d, and nearly as good as our
>>320d s, and much, much better than the Ford Focus. That is not computer mpg, but
>>calculated from miles driven divided by gallons used.
>
> Why didn't you get much better mpg from the 320d - it's got much
> better figures than the 335d.

You see ? Again, no actual knowledge of facts.


>Was it faulty, poorly driven or badly
> maintained?

None of the above. The Govt. figures are not achievable as they are determined in a lab,
and this car is driven differently than those before. It only does longer trips. The
others did not.


>>The research I have done points to different makes of fuel performing differently. I
>>will
>>not *give* away info that I have been paid to ascertain.
>
> LOL..a 5th Gear episode (repeated in the last two weeks on Quest)
> showed that..there's no need to be precious.

I have not seen the show. What did they say ?


>>>>>I've not been convinced by the cheap/expensive fuel
>>>>> debate - particularly for diesel.
>>>>
>>>>You will if you continue to use supermarket fuel extensively.
>>>
>>> I don't believe so. It didn't happen in the past so, unless something
>>> like the Nikasil problem is lurking in my engine, I don't expect any
>>> problems now. It's certainly not something I worry about in a diesel.
>>
>>You should do.
>
> Forgive me if I don't.
>
> When/if the injectors fail (as they are likely to do in most
> installations given time) I'll just replace them. Big deal. Worrying
> about stuff like that carries too high a mental cost.

I doubt that you even care if one of the next owners of your car have to find the cost of
repairing something caused by your ignorance and superiority complex.


>>The direct injection Piezo injectors in your BMW engine are more susceptible to fouling
>>from poor quality fuel than the injectors of 10 years ago.
>
> That's not unexpected..the nozzles are getting smaller and delivering
> smaller amounts of fuel.

So fuel quality and additive technology is more important than before.

>
>>I have written before that
>>during manufacture, the Piezo injectors are flow tested by the manufacturer to enable
>>them to have a "correction factor" that needs to be programmed into the ECU of the
>>receiving car, for that particular cylinder, to accurately inject the precise
>>quantities
>>required per injection, up to 5 per cylinder per 4 stroke cycle.
>>Thus, the cleanliness of your diesel injectors is more critical than those in most
>>petrol
>>cars.
>
> I expect it'll become similar for petrol engines as they move more to
> smaller capacity, direct injection and boosted air.
>
>>No, the cost of living is higher, meaning people have less disposable income. There are
>>also more OAPs whom cannot afford newer cars.
>
> LOL.


Why ?? A town not far from where I live has an OAP population of 33%. What is funny
about that ?


>>>>The different models have different variations fitted to the cars. Our (August) 2009
>>>>335d
>>>>only has one of these functions. That is the "Brake Energy Regeneration", nothing
>>>>else.
>>>
>>> So how do BMW do it?
>>
>>Do what ?
>
> Doh. "Brake Energy Regeneration" - as suggested in the last statement
> you made prior to my question.

I have already explained. I wrote that before, too.
Obviously, reading comprehension is not your strong suit.


David Skelton



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