BBC compression mapping

[JLerum]

Rob,

Glad you enjoy the book. For anyone who really gets into the dynamics of engine building it encompasses a LOT of what I think makes an engine so much better than most. You have heard it before that "it is all in the details".

As stated Rob has now compression mapped the L-72 with its GM cam. You may be wondering so what does this mean? It simply means that dynamic compression is extremely important in physical process of making an engine the best airpump possible. In a nut shell,... make all the peices work together as best as you can to get the last ounce of performance possible.

Rob.........Don't forget the IVC is not just measured anywhere. It should be measured at the .028 lash setting with the degree wheel on the crank <font color="red"> </font color> the cylinder head and valve train in place. As the intake valve rocker just releasing contact with the valve stem you are then at IVC.

The cam doctor did not work well with the lobe measuring at less than .020! It ran some really huge numbers that obviously would be a mistake in calculations. In my mind the short block needs to be built to the specs and then the decking of the head and gasket thickness with a advancing or retarding of the cam to get the end result.

Jim