I ran a JP with the two-piece crank sprocket/oil pump drive for well over two years with no outward issues while running double gaskets...Not a whole lot of mileage, but there was a good deal of heavy throttle during its time in my engine.
That being said, when I removed the set last week, the crankshaft itself showed evidence of the chain itself having been in contact with the chamfered area. The front cover showed no wear at all, and the chain was still working fine (though stretched significantly). The chain did not appear to be on the verge of failure or anything, but the gouges on the crankshaft were certainly not reassuring in the least.
