NYT article - GM cylinder dropping

[Marteney, Steven J.]

Which would imply it should be just as easy to turn the engine with or
without the spark plugs.  As the gas is compressed, the leak down negates
the compression.  No dice.  It doesn't happen that way, at least not when I
build my engine and was turning it on the stand.

This will be my last post on this, but in closing.  It takes energy to
compress a gas.  Conservation of energy says all that energy will be
returned, but it doesn't say in what form.  So to say the MOST efficient way
is to leave both the valves closed doesn't seem right.  There is more
pressure at the top of the piston in that case, which means more force on
the oil between the bearing and the rod, which means more "friction."  Now I
will admit all this may equate to a neglible difference between the two
ways.  Some day I hope to understand it all.

Back to GMECM topics!
Steve

BTW - Thanks for the info.  I really don't want to come off as a total jerk.

-----Original Message-----
From: Ron Schroeder [mailto:rjs at bnl.gov]
Sent: Wednesday, May 30, 2001 3:23 PM
To: gmecm at diy-efi.org
Subject: RE: NYT article - GM cylinder dropping


At 01:15 PM 5/30/01 -0400, you wrote:
>How come it's easier to crank an engine with all the spark plugs out (same
>as valves open) than it is with all the plugs in?

At low rpm, the leakdown negates a lot of the energy that could be returned
from the compressed gases in the cylinder.



Ron Schroeder
WD8CDH
E. E. S.
wd8cdh at bnl.gov
rjs at bnl.gov
ron at 112motors.com
631 344-4561 Day
631 286-5677 Nite
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