In January of 2009 a Hi Performance industry magazine published a story about the ADVANTAGES of using a larger than previously used camshaft journal and LOBE DIAMETERS.

The TRUTH is these larger diameters have little to do with the DEFLECTION and TWIST of a camshaft in a running engine.

Here are the ACTUAL TRUE FACTS!

Very few camshaft PROFILE design people take the time to CALCULATE the PRESSURE ANGLE (roller profiles only) and RADIUS OF CURVATURE of their design data.

Of course most racing and Hi Performance camshaft profiles are COPIES(MECHANICAL TRACING) of another camshaft designer's ORIGINAL PROFILES!  Therefore, these "copy type" profiles probably are not the "SAME LOBE DIAMETER" as the original.

Many years ago I was hired by a VERY LARGE engine manufacturer to solve a MAJOR PROBLEM with camshaft lobe WEAR with their roller type camshafts. I measured the sample camshafts and the "ORIGINAL DESIGN DATA" and the solution was easy for me.

INCREASE THE CAMSHAFT JOURNAL DIAMETER

They said that was not possible! I then suggested the DESIGN DATA be changed to REDUCE THE RADIUS OF CURVATURE AND PRESSURE ANGLES.  They said that this was not a good solution to them.

Many years later this same firm released a new "BIG CAM ENGINE" and their camshaft wear and warranty problems were then SOLVED!

For many years now the single most important goals for the camshaft profile design person is to:

"IMPROVE FUEL ECONOMY" and REDUCE EMISSIONS"

I my opinion this is easily accomplished by:

REDUCING THE "INTENSITY"

When designing for a roller follower A problem will be incurred with how to REDUCE this INTENSITY without causing an INVERTED FLANK PROBLEM One SIMPLE SOLUTION is to INCREASE the LOBE SIZE! Of course this requires a LARGER CAMSHAFT JOURNAL DIAMETER.

"ENOUGH SAID"