Its always a good idea to double check the lift of the lobes and the base circle on a camshaft before fitting, however this is not as easy as it may seem.

The obvious method is to measure the height of the lobe and subtract the distance across the lobes (known as A & B dimensions - pics 1 & 2). However, the measurement across the lobes may well include a part of the opening ramps therefore making the camshaft apear to have less lift.

There several ways to check the true lift either by fitting the camshaft between centers in a lathe or fitting into the head and measuring with a dial guage. However, for a quick check with a vernier caliper the following method will give you the true lift.

First measure the diameter of the cam bearing nearest to the lobe (pic 3) and write this value down.

Next measure and note the height of the lobe (pic 1).

Now take a straight edge (in this case I'm using the side of an engineers square) and zero the calipers across its thickness (pic 4).

Now you can measure the distance between the cam bearing and the base circle of the lobe.

To get the true lift of the cam simply apply the following formula to your measurements:

Base circle = cam bearing diameter + (distance between cam bearing and base circle x 2)

Lobe lift = Lobe height - Base circle diameter.

This method obviously assumes that both cam base diameters are identical, so this is the very first check that needs to be done.

On mechanical cam profiles with lots of duration and a long lash ramp, the lift error can easily go up to 0.3-0.5mm. So even if the measurement trick is not too accurate, it will still be better then ignoring long ramps!