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Re: Positive vs. negative piston deck height
[Re: patrick]
#173203
12/28/08 12:29 AM
12/28/08 12:29 AM
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Joined: Feb 2004
Posts: 4,501 Gainesville,FL
goldmember
master
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master
Joined: Feb 2004
Posts: 4,501
Gainesville,FL
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Alot of good points,most don't add up to 2 hp,but good points. Most post what they read or internet info.Keep it safe and don't try to get it too tight.
Last edited by goldmember; 12/28/08 12:30 AM.
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Re: Positive vs. negative piston deck height
[Re: 360view]
#173204
12/28/08 01:39 AM
12/28/08 01:39 AM
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Joined: Jan 2003
Posts: 6,591 Canton, Ohio
Sport440
master
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master
Joined: Jan 2003
Posts: 6,591
Canton, Ohio
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Quote:
it is worth pondering the "crevice volume" effect
crevice volume is generally thought to be a bad thing because it 'quenches' the flame and creates unburned hydrocarbons ... which reduces both power and fuel economy
there is crevice volume in the little gaps of the head gasket joint
there is crevice volume in the 'ring land' from the top of the first ring to the piston crown
could the undesired two crevice volumes be combined to eliminate a bit of both?
some engine builders try to do this by having the piston come above the deck enough to cover the head gasket joint during the peak of the combustion event
it is an approach that might gain a bit of power and fuel economy
in one of the last 'Engine Masters' competitions one of the top engines had a very large value for positive deck and this may have been one of his strategies
there is also a small effect in being able to use a tiny bit longer connecting rod
it is worth thinking about
another small detail
"The Devil is in the Details"
I like that idea as you described it.mike
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Re: Positive vs. negative piston deck height
[Re: Sport440]
#173205
12/30/08 12:23 PM
12/30/08 12:23 PM
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Joined: Jan 2006
Posts: 8,162 USA
360view
Moparts resident spammer
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Moparts resident spammer
Joined: Jan 2006
Posts: 8,162
USA
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