Valvetrain lightening, For higher revs.... Options

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Here's a picture of a rocker that we did for a 356.

And BTW. Our 356's rev 8000.

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QUOTE (Racer Chris @ Mar 12 2006, 10:58 AM)

Type IV rockers are forged and the outer surface is quite hard but the core is more ductile. A carbide drill is required to drill holes. I made fixturing to support the rockers with the web flat for drilling in a drill press. Thinning out the web is done with carbide burrs. EDM might save some time. The last step that should be done is to shot peen them after all material removal to increase their strength.

You're right about surface hardened. All rockers are. Not exclusive to type IV.

We go back and case harden ours, at my recomendation.
Then we shot peen it to get all the carbon crap off of it.

Heat treating it for core hardness is a good way to go.

And I use high speed steel anyway. Carbide does not like the shock of going into a convex curve. And I sharpen my own drill bits for that purpose. Skill saves on tooling costs.

The advantage of EDMing would be the ability to put an odd shaped hole into it. Like a square or a triangle. More mass out by being able to get into the corners.