Hello all,
Well, I'm gona do it. The cam in my "79" CD has several nasty flat spots, so I'm changing it. It really looks sad. Now my engine is NA and has the old malable iron cam, code 00, so I will upgrade to the chilled cast iron cam. (part #617 051 08 01) This also requires the carbide rockers, new chrome nuts, and valve springs. So I' ll do the valve seals, check valve & fuel pump timing also. Now my question is why new valve springs? Maybe the new cam has a different profile and stronger springs are required. Anybody know for sure?

In general terms, the only reason you'd need different springs is if the new cam has more lift (which would bottom the springs) or will allow higher rpms. I can't imagine that the cam profile is so radically different that your current springs can't close the valve fast enough. But there might be considerations unique to your engine.

Sixto
91 300SE
81 300SD

Thanks. I hear what your saying. When you look up the cam at the dealer or even PartsShop here online, they say the springs are required. They only cost a few bucks apiece so no big deal. Not like the rocker arms anyway! Just my curuosity at work here.

The issue with springs is not the cost to purchase but the cost/effort to install. Consider at least new valve seals if/when you replace the springs.

Sixto
91 300SE
81 300SD