Hi there Peeps,
I have a turbo W2 headed 410 stroker that seems to have flattened the lobes on the cam.
The cam was run in and has shown that it broke in nicely, just has a flat spot over the nose.
This eng would be lucky to have a thousand kms (620 mls) roughly on it .
I believe that the issue is to much spring pressure.
Current springs in the heads are Comp Cam 953s.
Installed height 1.875 @ 160 lbs with 405 lbs over the nose. Spring rate is 473 lbs/in. Lift at valve is .505"
Cam that was in there was", Dur 238 @ .050" both in & ex. 114 lob sep and .3512"lobe lift. Rocker ratio 1.5
I push anywhere between 15 and 20 lbs boost into it and don't think I'll go above that.
Now the question is.
A: Do I have to much spring pressure for what I'm using?
B: What is, if any formula in working out spring pressure with boost?
I have done some searching and there seems to be a fair bit of info for rollers both hydraulic and solid but cant seem to find info for the good old solid flat tappet.
Any help would be appreciated.
Cheers.

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What type of oil are you using? Did your break in package contain a zinc additive? Moly lube on the cam when installed? Spring rates at max open look a little high for a flat tappet, but I wouldn't expect the wear to be that fast.

 

A spring with roughly 50 lbs more open pressure than na should be enough. What does cam manufacture recommend for open pressure na?

 

I use the ULX motor oil which has a high zinc content. Cam was broken on with just outer spring and moly on the lobes plus proper breaking oil with the zinc. Everything was done as it should have been.
Cheers