cant find the link now.
But theres a file someone made called mini cams.xls
It lists aload of cams with there specs, duration etc.
You will be able to look at the cams you have been told about and compare.
And found this info for you…
> Lift
Lift refers to maximum valve lift. This is how much the valve is “lifted” off its seat at the cam lobe’s highest point. The intake and exhaust valves need to be open to let air/fuel in and exhaust out of the cylinders. Generally, opening the valves quicker and further will increase engine output. Increasing valve lift, without increasing duration, can yield more power without much change to the nature of the power curve. However, an increase in valve lift almost always is accompanied by an increase in duration. This is because ramps are limited in their shape which is directly related to the type of lifters being used, such as flat or roller.
Duration
Duration is the angle in crankshaft degrees that the valve stays off its seat during the lifting cycle of the cam lobe. Increasing duration keeps the valve open longer, and can increase high-rpm power. Doing so increases the RPM range that the engine produces power. By increasing duration without a change in lobe separation angle will result in increased valve overlap.
Overlap
Overlap is the angle in crankshaft degrees that both the intake and exhaust valves are open. This occurs at the end of the exhaust stroke and the beginning of the intake stroke. Increasing lift duration and/or decreasing lobe separation increases overlap. At high engine speeds, overlap allows the rush of exhaust gasses out the exhaust valve to help pull the fresh air/fuel mixture into the cylinder through the intake valve. Increased engine speed enhances the effect. Therefore increasing overlap, increases top-end power and reduces low-speed power and idle quality.
Timing
For timing take this as an example 22-62, 62-22.
* The first 22 shows how many degrees the inlet valve opens before top dead center,
* The first 62 shows how many degrees the inlet valve closes after bottom dead center,
* The second 62 shows how many degrees the exhaust valve opens before bottom dead center,
* The second 22 shows how many degrees the exhaust valve closes after top dead center.
The duration and overlap is calculated by using these values.
To conclude, any given camshaft will be perfect only at one engine speed. At every other engine speed, the engine won’t perform to its full potential. A fixed camshaft is, therefore, always a compromise. In the next article we will look at the different camshaft arrangements and how these help the cams perform better.
