Packard Forum Index » Pre-War (1899-1942)

I was speaking only of the math of grinding it but there are other considerations too that outweigh the math. For typical cam wear it's a minimal amount the must be removed so grinding alone is fine but for severe lobe flattening, building it back up prior to grinding is the best method and the process makes the lobe hard again. I'm not sure if the cam is hardened all the way through but I suspect it's primarily surface-hardened where extreme wear would go into the slightly softer material underneath so simply regringing it would not be the best of ideas. I have a cam (and entire engine) that came from a 1951 Packard 300 racing car and it has a lobe or two that would benefit from lobe rebuilding rather than simple grinding.

Here's a diagram I found showing the lift with respect to the heel. If only the lobe is ground, the lift is obviously shorter but if the heel is ground too, the lift remains the same.

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