Can regrinding is common in the racing world. And yes, it does involved having a smaller "base circle" profile. Most, if not all, engines have a maximum amount of clearance that limits the max lift available for a given engine. This is usually determined by the size of the cam bearing (typical for cam-in-block arrangements.) To get more lift and duration, the heel is ground closer to the centerline of the camshaft. This becomes the baseline for the closed valve and increases the difference between the closed and max lift points. The slack is take up by either longer pushrods, lifers, or the normal adjustment method for the followers. In high bucks racing, teams may use many experimental shafts that will be reground on the way to a final profile which can be supplied by the manufacturer as a new part once the final specs are determined. Some extreme camshafts are ground from billets with no reliefs between the lobes since the smaller base circle tends to weaken the shaft and allow flexing. I never heard of any cam being welded. I suppose it's possible, but being one of the most highly stessed parts in an engine, and relatively less expensive than most of the other hardware, I don't see why anyone would. Aside from the aformentioned billet steel shafts, most are cast iron, which is VERY difficult to weld properly not to mention pricey in itself.
Hope this was helpful.
Jay
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Jay
'68 912 V8
[This message has been edited by JordonJames (edited 05-25-2001).]
[This message has been edited by JordonJames (edited 05-25-2001).]
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