47 Ford 239 59A Crank Groove?

[Ford1941]

While in the process of rebuilding my 47 59A engine, I noticed that on the end of my crankshaft, just behind the rear oil slinger and in front of the flywheel mounting area, there is a spiral groove that appears to have been machined-in (see picture). I have been told that this was done by the factory to help channel the oil back toward the engine as part of the centrifugal / labyrinth rear main seal system, and that there is no problem with the crank. Can anyone confirm that this is true, that this spiral groove is supposed to be here and that this is not a problem with my crank? Thanks, Scott

 

[CWPASADENA]

While in the process of rebuilding my 47 59A engine, I noticed that on the end of my crankshaft, just behind the rear oil slinger and in front of the flywheel mounting area, there is a spiral groove that appears to have been machined-in (see picture). I have been told that this was done by the factory to help channel the oil back toward the engine as part of the centrifugal / labyrinth rear main seal system, and that there is no problem with the crank. Can anyone confirm that this is true, that this spiral groove is supposed to be here and that this is not a problem with my crank? Thanks, Scott

You are correct.

A lot of engines with rear main rope seals used a shallow "reverse screw"
grove to help encourage the oil back into the engine.

Chris

 

[Ford1941]

Chris - Thanks for the quick response. That confirms what I have also heard. Scott