What I heard was that the Boys in Belgium were going to allow the Brits
only a mule to ride into London.
Less airborne emissions and full employment for the crossing sweepers! Ray
At 09:33 PM 12/6/97 +0000, Paul Hunt wrote:
>... Leaving thousands of asthmatics dying in their wake.
>
>And what's this we UK-ers hear about Minivans and Cherokee-type vehicles
being
>classed in the USA as small trucks and allowed to pump out 50% more
emissions than
>cars?
>
>PaulH.
>
>Ray McCrary wrote:
>>
>> Actually, the new high speed diesels that are now in the cars and light
>> trucks not only run at comparable speeds, but last a very long time indeed.
>> Most of these engines are quite small.
>> Ray
>>
>> At 09:54 PM 11/29/97 -0500, Mere wrote:
>> >Hello Peter and List:
>> >
>> >I must take exception to this "diesel engine thinking" regarding wear on
>> >engines. Yes, starting places offers wear opportunities on engines but an
>> >engine with good oil and decent oil pressure will not wear unduly at
>> >startup. However, the idea that engine life will be enhanced by
leaving it
>> >running is questionable.
>> >
>> >I believe, as others have stated, that there are only so many revolutions
>> >in the life of an engine. Leaving it idling for lengthy periods does not
>> >allow efficient running as idle mixtures are the least efficient in
>> >carbureted engines which will add greater products of combustion to the
>> >oil, and contribute to poor temperature differential within the engine.
In
>> >cold weather, an idling engine will actually cool off if the car heater is
>> >left on. As manufacturers have recognized, one of the most important ways
>> >of avoiding wear is to drive the car as soon as possible after cold starts
>> >so that the warmup is not prolonged. The sooner it is warmed the less
wear
>> >can occur.
>> >
>> >A cold engine has larger clearances than a warm engine and cold oil has
>> >higher viscosity than warm oil. Thus the cold oil in the cold engine will
>> >stick better to vertical surfaces and will fill larger engine clearances
>> >better than hot oil. As the oil and engine warm the clearances
decrease as
>> >viscosity declines. The real culprit in startup is cylinder wear but
>> >proper oil and pressure reduces this problem almost instantaneously.
>> >
>> >What determines cylinder wear is the simply the number of times the piston
>> >travels up and down in the bore. Every one of those cycles causes wear.
>> >Why does a large displacement V8 engine seriously outlive a small
>> >displacement four cylinder engine? It does less work at much fewer RPM.
>> >
>> >It is not at all unusual for a small-block Chev or Ford taxicab to
>> >accumulate over a million kilometers in service. This is possible because
>> >of two things. It is started less often and it does less work because of
>> >its large displacement and lower revs.
>> >
>> >Diesel engines however thrive on steady running and don't like to be shut
>> >off because of problems inherent with compression ignition and proper
>> >mixture control. Diesel trucks go for millions of miles, not so much
>> >because they are diesels but because they run at very low RPM and have
very
>> >large displacements. If diesels ran at the speeds of our LBCs they
>> >wouldn't last much longer relative to the work they do.
>> >
>> >John McEwen
>
>
>
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