NYT article - GM cylinder dropping

[Marteney, Steven J.]

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?

Also, if you pull one spark plug, gas mileage decreases.  If that were the
case, the other 7 cylinders would just pick up the pace a bit and efficiency
wouldn't be lost.  Or, how about this?  Try turning an engine with a wrench
BY HAND with the plugs in and out.  Which is easier?  I'm trouble with this
explanation.

Steve

-----Original Message-----
From: Ron Schroeder [mailto:rjs at bnl.gov]
Sent: Wednesday, May 30, 2001 12:43 PM
To: gmecm at diy-efi.org
Subject: RE: NYT article - GM cylinder dropping


At 09:11 AM 5/30/01 -0400, you wrote:
>Hope it's a bit more sophisticated than that.  Shortening the lifters means
>both valves are closed (non-OHC engine) which equals massive pumping
losses.
>(Try pulling one plug wire and then go check your mileage.)  Seems like
they
>meant to say it "telescopes" the intake lifter but expands the exhaust
>lifter so the exhaust valve stays open all the time.  Don't think you'd
want
>to leave BOTH valves open all the time.  Although, may create an
interesting
>EGR effect.  :-)
>
>Steve


The lowest losses are with both valves closed.  The energy it takes to
compress the air in the upstroke is mostly released on the downstroke.

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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