defiant00

This may be a total noob question, if it is I apologize...
I was looking at SSM's cams the other day and I started thinking, their cams are regrinds, correct?
How does a reground cam help? Wouldn't the point of replacing the cams be to get MORE lift and/or duration for the valves? If a stock cam is being ground, i.e. having material removed, that would do nothing but REDUCE the lift and duration, wouldn't it? If you are starting from a stock cam, there would be no way to ADD lift or duration, right?

P Zero

They probably add material to em and then grind away the new material.
-P.

fazm

No, the more you grind off, the higher/longer the valve will come up. (less material to hold the valve down).

someone correct me if im wrong.

powerProdigy

I AGREE WITH P ZERO ON THE ADDITION OF METAL WITH SPRAY WELDING...WHEN THE VALVE IS UP ITS CLOSED, THE TIME THE VALVE IS OPEN IS CALLED DURATION, SPECIFIED WITH NUMBER OF DEGREES THE CRANK SHAFT ROTATES WHILE THE VALVE IS OPEN.

cejaay13

They don’t add material. Only remove it. A reground camshaft usually starts with a used, stock-profile camshaft. The "base circle" of each lobe--the part opposite the high spot--is reduced to give an overall greater lift. The main criticism is that the reduced base circle can cause problems with stock valve lash adjusters, and that the ramp profiles (how quickly the lobe changes from base level to peak) are not optimal. They are cheaper because they can be made from old cams, rather than new blanks which are spendy.
Another consideration might be the hardness of the materials. I'm not sure about the cams you are looking at, but many cams are surface hardened; when they are reground they must be rehardened because the base circle metal has been cut beneath the hardened layer. If the cam has not been properly rehardened it will wear quickly, particularly because the lobe ramp is high. This shouldn't be a problem if you are going through a reputable place.

I'll get some just as soon as the warranty runs out. Good luck to you.

blackfoot

i dont think thats right fazm. if you take away lobe material, your valve will open less, losing lift.. also to me it sounds sketchy but if you lose lobe material, you can get valve slap if the lobe doesnt continuously ride the lifter anymore, because your bearing dont lower themselves in the head to compensate for the lack of meterial

boss 244

In all fairness, there can be disadvantages to regrinds. For one, regrinds are typically created by reducing the base circle of the camshaft. The heal area is usually reduced to create more lift. Thus, total lift is limited to the amount of material that can be sacrificed on the heal. If too much material is removed off of the cam heal, the lifters may forced to over extend in order to reach the cam. This can lead to premature wear of the lifter. For cams that use shimmed valve clearances, this is usually not a problem. Thus, regrind cams need to be correctly designed. There is no mistake about this.

[IMG]local://upfiles/41550/9366B03BBE9C4EDCB5305FBBFBAA95F9.jpg[/IMG]

blackfoot

i guess im not getting the picture, how would you get more lift with less meterial?!