this may or may not be advanced for you guys, but it is for me.

when a cam is being used that has around .550" lift, it is deemed normal by everyone and not too hard on the valetrain, mainly springs. but when you approach .600" lift everyone says that its a valvetrain killer.

so my question is, why does only a mere .050" lift make it a whole different story on the valvetrain?

you would never think that less than a 1/16" would make such a difference...

 

These are just "rules of thumb". And the concept is a little outmoded as technology changes. Newer "premium" valve springs will survive much longer than previously with high lifts. But they aren't cheap, I just spent over $300 on a set. Cam life can be an issue with high spring pressures as well. A billet cam core will help in that regard.

So, if you use a billet cam and premium valve springs I'd say you are ok, privdied the rest of the valvetrain is also up to snuff (pushrods, rockers, and rocker studs).

Rich Krause

 

Small diameter springs with a high lift cam will die a lot quicker than wide diameter springs. Converting from a stock style single spring with damper to a larger double spring is a big improvment. Spring pockets usually need to be enlarged.

It's not just the lift but how steep the ramps are. A relatively mild ramp will gently allow the valve to open and close. Rolller cams have a very steep ramp that can slam the valve open very fast. Even with the same lift, a steep ramp cam will wear out valve springs quickly. That's why roller cams need bigger and stronger springs.

Stock Eliminator cars are only allowed .430 lift or OEM whichever is greater. A stocker cam will just hammer the valve open, keep it open for a long duration then slam it closed. Although the lift isn't that great the force of opening the valve so quickly is very hard on the springs. It's not unusual for a Stocker to replace valve springs a few times a year.

 

thanks...