I think that I have a bent valve in one of my cylinders becuase the compression is lower! What should I do? Take is to a machine shop? Buy a new head? How much is that stuff? Thanks

 

First of all, how much lower is it compared to the others? What makes you suspect it is a bent valve? It could be other factors as well. Do a leak down test to confirm your assumption. Doing a thorough diagnose will save you time and money. The helms manual states that a B18C should have a nominal of 270 psi, a minimum of 135 psi and the variation between cylinders should not be more than 28 psi. Does you numbers fall within the specs?