cam grind verification

[Harpo]

How does someone verify the grind on a cam. Hopefully this can be done with a set of calipers.

Thanks

David

[Harpo]

In another post it was said that you can measure the lift. measure the top of the cam and subtract the side of the cam. Any truth to this?

[Mark Henry]

Most modified or reground cams are stamped on the end. Wayne's book has the part numbers of the stock cams.

What you describe is correct for lift, measure the total and subtract the base circle, but is only the easy half of the job as you also have to measure the duration of the lift. For duration it's best to chuck it in a lathe using a dial indicator and a degree wheel. Split duration cams, like I have, you have to measure both the intake and exhaust lobes.

[stownsen914]

If the cams are in the engine still, it's not hard to measure the lift and duration yourself with a dial indicator and a degree wheel. If they're out, as mentioned, look for the stamping from the grinder on the end of the cams and then look up the specs. Cams can be measured on the bench with a suitable rig (cam doctors) that measures both lift and duration.

Note that measuring lift alone may not be very useful. Duration and lobe centers are as important in determining a cam's performance as lift.

[Mark Henry]

I got Harpo the contact info of the cam grinder in question and suggested he talk to them.