I have a b16 head and I was wondering how to calculate lift as everyone measures it. I tried measuring the cam lobes but that doesn't match anybody elses measurements. How do I measure intake lift off of primary, secondary and vtec lobes?

 

You need to know whether the specs you are comparing to are cam lift specs or valve lift specs. The first thing you need to do is measure the cam lift. It is the only spec that is easy to measure off the cam (meaning duration is a pain in the butt). The following diagram shows how to measure "cam lift".



If the cam acts through a rocker arm to lift the valve there will usually be a ratio that is greater than 1. You will need to research what rocker ratio your engine has. Also, the rocker ratio may be different between the different lobes.

For example, if you measure the cam lift and find that it is .300" and you have a rocker with a 1.5:1 ratio then the "valve lift" will be 1.5 times .300" = .450".

 

Mount a dial indicator on the head, with the shaft resting on the valve spring retainer. set the valve lash on that lobe to 0. then spin and measure the amount the valve opens.

 

ok. thank you