Funny cam profile

[VHDREAMS]

thanks luke, that makes more sense, seeing as 0/360 is tdc, 180 is BDC, so basically its open during the end of the intake and start/half of compression stroke, how does centrifugal force stop it opening though?

Wouldnt centrifugal force only slow it closing?

Cory

[lukevl]

Its hard to explain plus there are a few different types. Basically there is a weight at the end of the cam which pivots down the centre of the shaft and a spring holds the weight in towards the cam centre line. When it starts to spin the weight swings out and a dowel pin or something similar slides back into the cam so it no longer protrudes out the base circle of the exhaust lobe. Put it this way, if the decomp was out under operating load, it would not take long for the dowel pin to take some nice meat out of the bucket.