Understanding camshaft regrinding

[Iciclehead]

Hello all, I am just getting ready to get the cams for my project. I contacted one of the very fine camshaft regrinders on this board and he gave me some information that I don't understand....and rather than bothering him, I thought I would ask the collective brain trust on this board.

So, here is the gist. He recommended a particular grind on new billets for what was a price tag a little higher than I thought I would need to spend. I asked whether or not he could use my existing Euro SC camshafts as a base rather than going to new billets.

He got back to me and said the chance of using my old camshaft cores was slim as it would be on a 113 lobe center, albeit for a lower price.

I don't understand what he means and/or the implications. I presumed that the process was to build up the core with weld material and then regrind it into any profile you wanted.....is the process more complicated than that?

Thanks

Dennis

[Speedy Squirrel]

A picture is worth a thousand words. What he is referring to is called the Centerline, or lobe centerline. Apparently, to locate it where he wants would move it so far that not enough material would remain to grind it onto your current cams. Check out this article for instance (and think of hands on a clock that reads in degrees instead of hours):

P66618 Image Large Photo 7

[KTL]

That's right. You can't regrind a different profile on your existing cams if that profile has a different lobe spacing.

For instance the well known S cams have a lobe spacing/lobe separation angle/overlap of 98 degrees. A typical SC/Carrera cam has 113 degree lobe spacing. The difference in lobe spacing is too great simply to re-profile the cam by grinding. What is typically done to re-use a set of stock cams is to hardweld them. Then you can put whatever profile you want on the old cams.

I recently had a set of tired Carrera cams hardwelded by Webcamshafts. Not cheap but cheaper than buying new ones. Here's an example of a set of S cams (Web's version) created by hardwelding onto a set of stock cams.

S Cams for Carbs- Webcam 149S Hardweld

When you look at the side of the lobe in the pictures, you can see where they built up the profile by welding.

[Speedy Squirrel]

Iciclehead, may I ask who offered the billet cams? I am interested in finding someone who can a) gun drill the steel cam, and b) grind a profile to my spec.