improved Kent crankshaft rule proposal

[Art Smith]

k. Crankshaft (current GCR language)
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.

k. Crankcase (proposed)
Any steel crankshaft meeting original Ford Kent dimensions ±1/32" 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.

revised wording explicitly allows open source procurement of crankshafts and provides a compliant path for competitors looking to purchase significantly improved reliability. meeting Ford Kent dimensions and weight is sufficient. laser scanning Ford Kent crankshafts enables compliant fabrication of steel crankshafts AND objective verification of compliance with the rules as written; clearly something we don't have today. Ford Kent crankshaft dimensions DO NOT require modification of Ford Kent cylinder blocks for installation!! conceptually it's hard to imagine concurrently meeting two sets of requirements unless the two sets of requirements are identical. that's also clearly NOT the case as it's my understanding that at least some of the non-Ford crankshafts being sold and installed as compliant require modification of the cylinder block to be installed ! NO performance improvement (stroke, weight, & moment of inertia controlled), NO required cost increase (ie:revised wording is permissive), objectively verifiable compliance criteria, and likely cost reduction as a result of open source wording.

Art
artesmith@earthlink.net

[T Brzezicki]

Any steel crankshaft meeting original Ford Kent dimensions ±1/32" and weight is permitted.

Engine measurements are in decimals, not fractions. These aren't bird houses we are building for Aunt Milly.

[DanW]

Engine measurements are in decimals, not fractions. These aren't bird houses we are building for Aunt Milly.

True, but some SCAT cranks don't fit in the Kent blocks without interfering with the block skirt at the corners. Casting pattern dimensions are sometimes in fractions for non critical areas.

I would agree with the proposed change. I had to pay to have my block skirt ground to clear the SCAT crank, then get it cleaned again...

[chrisw52]

True, but some SCAT cranks don't fit in the Kent blocks without interfering with the block skirt at the corners. Casting pattern dimensions are sometimes in fractions for non critical areas.

I would agree with the proposed change. I had to pay to have my block skirt ground to clear the SCAT crank, then get it cleaned again...

that's interesting to know, now that I am close to an engine rebuild

[DanW]

that's interesting to know, now that I am close to an engine rebuild

Chris, when you are ready to pull the trigger for a new crank, call Jay Ivey and ask him about the skirt clearance. It may have been older inventory.

There is also an alternative with the throws ground for clearance.
https://www.pegasusautoracing.com/pr...sp?RecID=12691

[Stan Clayton]

Hmm, I wonder if my steel BDD crank will pass muster. I'm confident it's stock stroke, but I need to check its weight.

EDIT: 29.8 pounds...LOL.

[steve zemke]

Engine measurements are in decimals, not fractions. These aren't bird houses we are building for Aunt Milly.

Many casting prints are in fractions. Plus or minus a 32nd of an inch is pretty good casting practice for large iron and steel castings. Engine machining prints are in decimals.

[T Brzezicki]

Many casting prints are in fractions.

Engine machining prints are in decimals.

Enough said