300e engine knock
 

I just replaced my engine with a used 88 model. After installation it ran great for 10 mins. and then started knocking. I thought it would be a rod or main bearing. I removed all the bearings and they seamed to be in good shape. Does anyone have any ideas of what else it could be?
By the way when I pulled the pan there was a little bit of metal shavings in the bottom.

thanks,
Jim