----[Please read http://ercoupers.com/disclaimer.htm before following any advice in this forum.]--------[Please read http://ercoupers.com/disclaimer.htm before following any advice in this forum.]----
The definition of valve overlap is when both the intake valve and the exhaust valve are open simultaneously this occurs at the end of exhaust beginning of intake on the same cylinder. The more cylinders the more overlap happens. The effective length of both the intake stroke and the exhaust stroke is greater than 180 degrees, power and compression strokes is less than 180 degrees. (The Otto cycle is completed once every two revolutions, 720 degrees)
Robert Q. Steinman, Ph.D.
-----Original Message-----
From: Richard Wilkens
[mailto:[EMAIL PROTECTED]
Sent: Thursday, October
30, 2003 5:08 PM
To: [email protected]
Subject: Re: [COUPERS-TECH] Jugs
and valves
Pete,
Are sure this is not a trick question? Can I take a guess?
There are four places this would happen. For example one would be about
30-40 degrees ABDC (After Bottom Dead Center) depending on the cam. The
engine would be something like this:
One cylinder (piston going up) is on the compression stroke and both valves are
closed (exhaust has been closed and intake just closed).
Another cylinder also has the piston going up and is on the exhaust
stroke. Exhaust valve is open and intake has not yet opened. (30-40
degrees After Bottom Dead Center)
The third piston going down (30-40 degrees ATDC) and is on the power stroke
with both valves closed.
The last piston is going down on the intake stroke with the intake open and
exhaust just closed.
My guess is there are six valves closed at one time.
Since there are four cylinders there are least four places this will happen and
it will last until the piston gets high (low) enough for the valve overlaps to
come into play. It will not happen at TCD (Top Dead Center) because of
the value overlap
Did I get it right???
Richard
At 02:26 PM 10/29/2003 -0900, Pete Thomson wrote:
----[Please readhttp://ercoupers.com/disclaimer.htm before following any advice in thisforum.]---- Hi everyone, can any of you enlighten me as to which position, relative to Top Dead Center on any cylinder, is the position during which the most valves are closed on a C 85 ?
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