Cam experts:What effect does grinding a cam
03-20-2005, 08:08 PM
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Cam experts:What effect does grinding a cam with so many degrees of advance.I was looking at a custom ground cam with 114 lsa and three degrees of advance. Would that improve or degrade idle quality, change peak power rpm.etc,etc Someone who knows what they are talking about, please explain it to me.
03-21-2005, 09:06 PM
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I understand lobe separation angles, its either the installation procedure of installing the cam with a certain amount of advance or retard[ cloyes sprocket] or having it ground with a certain amount of advance or retard .The cam card will show the specs usually followed by a plus or minus number, for example +3. What does grinding or installing a cam with x number degrees of advance do to the characteristics of the cam.
03-21-2005, 11:21 PM
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When a cam is advanced, the valve events happen that many degrees sooner in relation to the piston movement.
The exhaust will close sooner and usually closer to TDC,
and the intake will open sooner.
This normally picks up lower RPM power, and in some cases is a better match to the engine combination depending on where in the rotation that you are getting your maximum piston speed.
If the maximum intake valve opening correlates to the max piston speed, then you can get better cylinder filling overall... not just at a lower RPM.
With a very long intake duration period, it sometimes becomes very advantageous to advance the camshaft to bring these events closer inline to match the desired power band of the engine.
If an engine is set up with long rods for extended dwell, then that allows you to run a less advanced camshaft in order to make more upper RPM power.
It's all about matching the valve events to the position & speed of the piston.
The exhaust will close sooner and usually closer to TDC,
and the intake will open sooner.
This normally picks up lower RPM power, and in some cases is a better match to the engine combination depending on where in the rotation that you are getting your maximum piston speed.
If the maximum intake valve opening correlates to the max piston speed, then you can get better cylinder filling overall... not just at a lower RPM.
With a very long intake duration period, it sometimes becomes very advantageous to advance the camshaft to bring these events closer inline to match the desired power band of the engine.
If an engine is set up with long rods for extended dwell, then that allows you to run a less advanced camshaft in order to make more upper RPM power.
It's all about matching the valve events to the position & speed of the piston.
