to clean up the "is condition", I recommend the following changes to the rule as currently written. given the weight, stroke, and polar moment of inertia are the same, there is no performance/horsepower to be found in a crankshaft. weight and stroke both continue to be explicitly controlled to the long standing numbers. the combination of "one piece", "ferrous", and "external profile dimensions" someplace between the two currently approved crankshafts implicitly controls polar moment of inertia. the final sentence provides retroactive compliance to competitors that purchased a SCCA crankshaft AND modified their block to enable installing it.
IS:
k. Crankshaft
An alternate cast steel crankshaft meeting original Ford Kent and SCCA
dimensions and weight is permitted.
Weight: 24 lbs. 8 oz. Minimum
Max Stroke (at piston): 3.056” +/- .004”
Crankshaft pulley: unrestricted
The crankshaft from the Cortina engine may be used.
The crankshaft from the Fiesta engine may be used.
The crankshaft may be shot peened
RECOMMENDED:
k. Crankshaft
An alternate single piece ferrous crankshaft that is equal to or larger than the dimensions of the original Ford Kent 711M crankshaft AND equal to or smaller than the dimensions of the 09-01-2015 version of the SCCA crankshaft AND compliant with the minimum weight and stroke is permitted.
Weight: 24 lbs. 8 oz. Minimum
Max Stroke (at piston): 3.056” +/- .004”
Crankshaft pulley: unrestricted
The crankshaft from the Cortina engine may be used.
The crankshaft from the Fiesta engine may be used.
The crankshaft may be shot peened
The block may be modified (ground/clearanced) to enable using crankshafts compliant with the dimensions of the 09-01-2015 or earlier unmodified SCCA crankshafts.
given Enterprises is selling (currently "
sole source") something better (improved strength and balance) than original Ford OEM crankshafts for reliability, I'm of the opinion that all the mumbo jumbo about "cast steel" (whatever that is in someone's mind) be deleted in favor of ferrous, a well defined term. when my supply of Ford 711M crankshaft cores is depleted, I'd much rather buy a domestically produced crankshaft that assures the valves will float before the crankshaft comes apart!! camshafts, lifters, push rods, rockers, valves, valve retainers, and valve springs are the same for everyone so there's only potential improved bottom-end reliability (ie: where most of the Kent cost is) !
Art
artesmith@earthlink.net