I have a question about valve stem seals. I have two sets and both sets have the same type seals for the intake valves but the exhaust seals are different. One is a "deep" umbrella resembling more of a thin-wall vacuum cap with a hole in it, and the other a thicker shallow "cup" shape. Which is better for oil control? If the deep one is, is it supposed to fit all the way down on the valve guide or ride up and down with the valve stem? Same question for the intake seal, all the way down or riding the valve?
Thanks!
Push them all the way down, the movement of the valve will find their happy spot... The deeper cup keeps more oil out of the guide... But then you gotta consider lubricating the guides... Exhaust doesn't suck oil in like an intake will, so do you really need the better seal?
FWIW I use the deeper design seal..