Burlington Crankshaft

Plum PurdyNow, after 80 years +, there is an integrally forged counter-slung crankshaft available for Model A engines built between 1928 and 1931 by the Ford Motor company. 

Forged overseas in a ISO 9002 (1998) and QS 9000 (2004) facility from 4340 non-twist steel, these aftermarket crankshafts are designed from original specifications for the Model A engine with the addition of the sling profiles from the late model B engine (also commonly called the model C engine, although there was never such a designation from the manufacturer.)

 

We call it the type AB-2 quarter-damped crankshaft, since what it really does is to dampen the pulses created by the in-line four cylinder engine. The original 63 pounds of flywheel was intended to do the same, and it succeeded very well in over-damping cylinders 3 and 4, and underdamping cylinders 1 and 2.

The original crankshaft was in fact balanced, although it had no counterslings. The problem with it was that it was completely un-damped.

Old style vs. new

The new type AB-2 crankshaft is on the bottom, and looks more conventional than the original crank on top.

Price is $1,250.00 Plus S&H.

Type AB-2 crankshaft is installed in engine block

With the new crankshaft installed, one can expect 25% to 33% less engine vibration. Additionally, wear on the main bearing journals will be greatly reduced. Automotive people know that it is impossible to completely dynamically balance a 4-cylinder, in-line engine without the addition of  2 rotating counter-shafts.

The type AB-2 crankshaft has been manufactured to original specifications, and will be in suitable condition to “drop in” to a properly prepared 1928-1931 engine block without further modifications. However, we recommend lathe-turning 20 lbs from the O.D. of the original flywheel, which would require it to be equipped with the V-8 pressure plate and re-balanced. But this modification is not mandatory.

 

 Ideal “stock” appearing Model A engine: 5.1:1 iron head, Model B touring cam, type AB-2 crankshaft, and 53 lb flywheel. Smooth running, slow idling, and characteristic exhaust sound at idle.Ideal "stock" appearing Model A engine: 5.5:1 iron head, Model B touring cam, type AB-2 crankshaft and 40 lb flywheel. Smooth running, slow idling, and characteristic exhaust sound at idle.

The AB-2 crankshaft is ideal for use in connection with Cragar, Riley, or Ardun overhead valve set-ups as well!

Disclaimer: Burlington Crankshaft has no relationship with the original manufacturer of this engine. Specifications have been utilized from published material and examination of original equipment. It is an aftermarket part and accessory.

The crankshaft was designed and tested in the U.S.A., it is manufactured in China.

 Plum Purdy