Atwell-
>
>At 11:12 AM 2/17/98 +0000, Romano Kroemer wrote:
>>Listers,
>>
>>after the recent threads about oil-filters with drain-back valves and
>> starting cars after long storage, I thought I would share my car-starting
>> method with this list:
>
><snip>
>
>My understanding of the wear incurred at start-up is thus:
>
>It is the strain of engine compression on the pistons, pressing on the
>cylinder walls and crankshaft, that are bad. Cycling the engine without
>starting it does nothing to reduce this wear.
>
.. but this compression is always there, also when the engine is running.
My understanding of wear at start-up is that there is no oil where it should
be for some seconds, while the engine is revving already at 1000+ rpm. Then
the oil-pump has done enough work to distribute the oil and the oil-pressure
has come up.
So, if I cycle/revv the engine at a lower rpm (with the starter motor only),
until I have distributed the oil/built up oil-pressure, I should induce
less wear.
Am I missing something here? Enlightment please!
- Romano
>This is the rationalization behind the practice of some folks who, before
>starting an engine that has been sitting a long time, REMOVE THE SPARK
>PLUGS and crank the starter long enough to generate oil pressure.
>
>"Pre-oilers" that use small electric pumps provide oil pressure independant
>of the engine. Some use a pressure system instead of a pump. Drawback:
>these pre-oilers can cost several hundred dollars.
>
>Speed shops such as Jegs or Summit (in the USA) can provide exact info.
>
>my .02 ...
>
>BTW, I have also heard that the oil film inside an engine will protect the
>cylinders for two weeks to a month. Can anyone verify this?
>
>
>
>Atwell Haines
>'79 Spitfire FM96062 UO
>
>"47.5% of all statistics are made up on the spot."
>
--
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Dr. Romano T. Kroemer
Phys. & Theoret. Chem. Lab.
University of Oxford
South Parks Rd. | Tel: ++44-1865-275475
Oxford OX1 3QZ | Fax: ++44-1865-275410
England, U.K. | Email: romano@bellatrix.pcl.ox.ac.uk
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