Valve Overlap does -8=0 ??
#1
05-12-2008, 09:45 PM
#2
05-12-2008, 10:44 PM
Road Captain
RE: Valve Overlap does -8=0 ??
Try this link to comp cams, explains in detail camshaft operation;
http://www.compcams.com/technical/TimingTutorial/
http://www.compcams.com/technical/TimingTutorial/
#3
05-13-2008, 07:00 AM
RE: Valve Overlap does -8=0 ??
Overlap is intake open + exhaust close. If the intake opens 10 degrees before top dead center and the exhaust closes 8 degrees after top dead center, that's 18 degrees of overlap...both valves are open for 18 degrees.10+8= 18
In the case of the 07-08 stock cams, the intake opens -12 degreesbefore top dead center, or actually 12 degrees AFTER top dead center. The exhaust closes 4 degrees after top dead center, so there is nothing openduring this8 degrees...negative 8 degrees of overlap. -12+4= -8
In the case of the 07-08 stock cams, the intake opens -12 degreesbefore top dead center, or actually 12 degrees AFTER top dead center. The exhaust closes 4 degrees after top dead center, so there is nothing openduring this8 degrees...negative 8 degrees of overlap. -12+4= -8
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05-13-2008, 01:50 PM
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RE: Valve Overlap does -8=0 ??
ORIGINAL: murphdog
Overlap is intake open + exhaust close. If the intake opens 10 degrees before top dead center and the exhaust closes 8 degrees after top dead center, that's 18 degrees of overlap...both valves are open for 18 degrees.10+8= 18
In the case of the 07-08 stock cams, the intake opens -12 degreesbefore top dead center, or actually 12 degrees AFTER top dead center. The exhaust closes 4 degrees after top dead center, so there is nothing openduring this8 degrees...negative 8 degrees of overlap. -12+4= -8
Overlap is intake open + exhaust close. If the intake opens 10 degrees before top dead center and the exhaust closes 8 degrees after top dead center, that's 18 degrees of overlap...both valves are open for 18 degrees.10+8= 18
In the case of the 07-08 stock cams, the intake opens -12 degreesbefore top dead center, or actually 12 degrees AFTER top dead center. The exhaust closes 4 degrees after top dead center, so there is nothing openduring this8 degrees...negative 8 degrees of overlap. -12+4= -8
#6
05-13-2008, 04:00 PM
RE: Valve Overlap does -8=0 ??
ORIGINAL: DCRANER
Very good information murphdog. This is a big reason why the 07 / 08's run hot. Good for EPA rules but heat is held in combustion chamber. Heat cure is cam change with decent overlap and a basic tuner.
ORIGINAL: murphdog
Overlap is intake open + exhaust close. If the intake opens 10 degrees before top dead center and the exhaust closes 8 degrees after top dead center, that's 18 degrees of overlap...both valves are open for 18 degrees.10+8= 18
In the case of the 07-08 stock cams, the intake opens -12 degreesbefore top dead center, or actually 12 degrees AFTER top dead center. The exhaust closes 4 degrees after top dead center, so there is nothing openduring this8 degrees...negative 8 degrees of overlap. -12+4= -8
Overlap is intake open + exhaust close. If the intake opens 10 degrees before top dead center and the exhaust closes 8 degrees after top dead center, that's 18 degrees of overlap...both valves are open for 18 degrees.10+8= 18
In the case of the 07-08 stock cams, the intake opens -12 degreesbefore top dead center, or actually 12 degrees AFTER top dead center. The exhaust closes 4 degrees after top dead center, so there is nothing openduring this8 degrees...negative 8 degrees of overlap. -12+4= -8
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#7
05-13-2008, 04:03 PM
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#8
05-13-2008, 08:12 PM
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RE: Valve Overlap does -8=0 ??
For what it's worth, a buddy of mine did SE 204's in his 08 FatBoy, result; Sounds like a Harley, power increase, heat reduced by about 25 degrees. He also has a basic Stage1 kit and FuelPak, but the cams turned it into a real Harley. 204's on the way for my Road King.
#9
05-14-2008, 01:46 AM
#10
05-14-2008, 08:34 AM
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