Solid cam damage diagnosis help

[PRH]

I'm starting to think the recommended spring pressures are too high for the fast ramp.
But then again I think too much. lol

The problem is..... it’s a catch 22.

If you run a lot of spring load, the risk of failure is higher.

If you don’t run enough, the valvetrain gets unstable at a lower rpm, and then you start breaking other stuff because of that.

The MP bracket race springs were pretty high rate springs.
Larry Sheppard was a big proponent of running plenty of open load for good valvetrain control.
The MP recommended SB spring for the bigger SFT cams was P3412068.
The specs are [email protected]/[email protected], for a calculated rate of 462lbs/in.
That’s a pretty stiff spring for a .600 lift SFT cam......416lbs open load.

The nose radius on the really high lift fast rate lobes is pretty small....... so the point loading is very high.......which makes them more susceptible to wearing/failing.

A slower lobe with a little less lift and a broader nose radius might survive a certain amount of open load where the higher lift/small nose radius won’t.

 

[Wyrmrider]

I don't know how fast rate asymetricl affects the nose radius unless you carry the change to the deceleration ramp too long trying to get more lift (mosty for advertising)
You can do a dwell nose cam with a huge nose with a fast rate

 

[PRH]

You can do a dwell nose cam with a huge nose with a fast rate

And those don’t have that really high point loading because they have a very broad nose radius.

They are not “fast rate/high lift”.

 

[Wyrmrider]

well not exactly fast rate at the cam
just over a larger radius
but let's say fast rate, big nose lift or lift appropriate for the port