I have a shelf full of serviceable cams with the only information being the casting # on the shafts.

For the most part, the casting number will give a good indication of the cam type, however, the early style Solex and L cams all have the same casting number making it difficult to tell them apart. In addition, when a cam has been reground, the casting number is meaningless and one must rely on the cam grinder's markings which are not always so reliable.

So I decided to map these cams by building my own cam doctor. I used a cam tower, cobbled degree wheel, a set of rockers and heads with valves. I used a single valve spring to lessen resistance. I measured the valve lift using my trusty dial indicator and mapped it to the degrees of camshaft rotation on the degree wheel.

I put together a simple spreadsheet to calculate the the cam parameters:

1. Lift
2. Duration at 0.05" lift
3. Lobe Center spacing

I started with a known E cam and a known L cam to see if I could reproduce known results. My data reproduced the known parameters for the E and L cams. See the attached spreadsheet. I then starting mapping the mystery cams (regrinds) and found two sets of S carb cams.

For my first two trials, I did an entire map to make sure things made sense. After that, I found it was only neceassry to establish the 0.05" lift cam positins on each side of the ramp for the intake and exhaust valves to calculate the cam parameters.

Enjoy the pics and data and if anyone wants a copy of the spreadsheet send me your email.

http://forums.pelicanparts.com/911-e...am-doctor.html