Will a cylinder head manufacture give you port length and minimum cross sectional
area? I'm looking for a procedure for measuring the port length. I've only found one
idea so far.
https://hotrodenginetech.com/porting-pointers/
Measure the length of the port from the intake mating surface to the valve seat. Do the same for the intake manifold, measuring from the port entry in the plenum to the runner exit. As a rule you want the centerline or average dimension of these two lengths. This is somewhat difficult to achieve, but you can get very close by using a length of string to measure the length of the port floor and the port roof and then average the two lengths. Add these together to establish the existing fixed port length. You can't change this, but you can tweak the cross section and work on the most restrictive areas to increase and improve the quality of flow. The overriding caveat is to do no harm. As soon as you start grinding you begin increasing the cross section which tends to slow the airspeed and raise the effective engine speed requirement where maximum torque and horsepower are produced. Note: Measure the exhaust ports the same way.
area? I'm looking for a procedure for measuring the port length. I've only found one
idea so far.
https://hotrodenginetech.com/porting-pointers/
Measure the length of the port from the intake mating surface to the valve seat. Do the same for the intake manifold, measuring from the port entry in the plenum to the runner exit. As a rule you want the centerline or average dimension of these two lengths. This is somewhat difficult to achieve, but you can get very close by using a length of string to measure the length of the port floor and the port roof and then average the two lengths. Add these together to establish the existing fixed port length. You can't change this, but you can tweak the cross section and work on the most restrictive areas to increase and improve the quality of flow. The overriding caveat is to do no harm. As soon as you start grinding you begin increasing the cross section which tends to slow the airspeed and raise the effective engine speed requirement where maximum torque and horsepower are produced. Note: Measure the exhaust ports the same way.
Last edited by a moderator:
