I have a problem with a P7-R and was wondering if anyone can help.

When I first bought the engine brand new I went through the typical break in cycles. Around the fifth or sixth tank I noticed that the crankshaft was hard to turn when the piston was all the way down. So I took the back plate off and noticed it was rubbing quit a bit, so I sent it in for warranty repair. I know it may rub a little, but this was excessive rubbing, so much it become almost impossible to move the crankshaft at all.

They went ahead and replaced the crankshaft and sent it back to me.

Now I got it back, and all looked good, was spinning with no rubbing when the piston was at the bottom. But now it is rubbing again after about 6 tanks.....

I have checked the clutch bell nut, I have tried to make sure the crankshaft is pushed forward as much as possible, but those do not seem to be the problem.

Anyone have any idea what could be causing the crankshaft to shift rearward far enough to make the con rod pin rub the rear plate?