cam shaft profiles ..
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DJpowerHaus
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My FP3 cams are pretty wild according to the valve spring recomendations, but they idle like a kitty cat with a 10lb flywheel. I dont think they have too much overlap like an N/A cam would have though.
Getting the engine bolted in is about 10% of the way there.
The next 80% can go quickly with help and skill.
That last 10% takes about as long as the 90% that came before it.
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Gentleman Rogue
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screemin eagle
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77amc
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if this helps, Just think of a circle. That's 360 degrees, with NO lift.
Now you talk about '272s', that means the lobe or a portion of the circle is raised away from O (or no lift) from the start of it going away from O to when it comes back to O takes 272 degrees of rotation for that portion away from O.
Now if the lift is .480 or say .500 (half inch) Think of it like an egg and the 'point' is the farthest away from O lift. Now there MUST be a ramp to the point where it's the farthest away or there would be too much resistance against the lobe causing a bind. That's why roller rockers help because they stay in contact with thier lobe but make it easier to go higher (lift) for a given rotation and have a stronger spring to keep it against the lobe to stop valve float.
This is where the cam designers figure out where the piston is in relation to the farthest lift of that particular lobe so there won't be contact between the valve and piston head. They can shape it with a gradual ramp up or steep and gradual after it's highest point away from O.
The lightened flywheel just makes it easier to turn over the engine ie. faster response to rev up.
They don't work fantastic if you have lots of accessories, especially if they take a lot of torque to turn. (high amp alt pumping up several hundred watts and with the air on full blast).
A heavier one carries itself around easier since it's harder to stop from spinning compared to a lighter one (the accessories resistance will stop it faster).
Does this help? E
Now you talk about '272s', that means the lobe or a portion of the circle is raised away from O (or no lift) from the start of it going away from O to when it comes back to O takes 272 degrees of rotation for that portion away from O.
Now if the lift is .480 or say .500 (half inch) Think of it like an egg and the 'point' is the farthest away from O lift. Now there MUST be a ramp to the point where it's the farthest away or there would be too much resistance against the lobe causing a bind. That's why roller rockers help because they stay in contact with thier lobe but make it easier to go higher (lift) for a given rotation and have a stronger spring to keep it against the lobe to stop valve float.
This is where the cam designers figure out where the piston is in relation to the farthest lift of that particular lobe so there won't be contact between the valve and piston head. They can shape it with a gradual ramp up or steep and gradual after it's highest point away from O.
The lightened flywheel just makes it easier to turn over the engine ie. faster response to rev up.
They don't work fantastic if you have lots of accessories, especially if they take a lot of torque to turn. (high amp alt pumping up several hundred watts and with the air on full blast).
A heavier one carries itself around easier since it's harder to stop from spinning compared to a lighter one (the accessories resistance will stop it faster).
Does this help? E