Eric's cam challenge

Bewy said

Agree that seat timing matters, but when the adv duration varies so much between different manufacturers, & even within the same manufacturer, how does that provide useful info for picking a cam? See the Pontiac & Chrys cam, below, top row. I believe it was Crane who introduced the 050 measuring point as he believed that the duration at that lift gave a useful indication of the power range for profile. The others followed....

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Once again, you MISSED the blatantly obvious.

Seat to seat timing is what the engine sees. Not the at .050 timing.

That’s why you can have a 280 “advertised” (because the manufacturers refuse to publish the checking height) that is 230 at .050 and another 280 “advertised” cam that is 255 at .050.

That cam with only 230 at .050 is slooooooow compared to the 255 at .050 cam.

Even at that you need to see the at .200 numbers to get a clue as to what you have.

I mean really, the “advertised” duration for mechanical cams SHOULD be at the lash point.

When you add lash it makes it more difficult to figure out what you have.