[Fairmont79]

Welcome to the forum! These things do rattle a lot, most of the noise is the clutch rollers at rest, they have just enough room to vibrate creating noise. As to your motor, drain the oil, check for any metal. If you have good compression chances are the top end is good. Pull the rocker arm cover and see if it had good lubrication. The bottom end on these are splash fed, so low oil may have been your issue. I'd recommend a good wet clutch compatible synthetic 10/40, or 20/50 oil. There is a sump at the bottom of the motor held on with 4 torx bolts, any broken parts usually end it here, plus it is recommended you clean the screen every 6 months or so. Download a free service manual at K&T Lawn Equipment, or Country Cat.

 

[Fairmont79]

Oneway is a possibility! I forgot all about that! When mine let go, it was sudden! One big bang, then complete silence except for mama and her WTF? LOL
My piston broke at the pin on one side, bent the rod, and smacked the head! Piston was up out of the bore on one side! Stock parts going back in it except for the exhaust system!

 

[Fairmont79]

Sump screws are a pain! Put that on a todo list for later. Top end is usually the first thing to fail when you lose oil pressure. The bottom is pretty much bullet proof! One way bearing could be your problem as they have been known to fail. Don't need one anyway! I yanked mine out 3-4 years ago and never regretted it! You could cut your filter apart, but usually the screen in the sump traps most pieces. Pull the plug and rotate by hand, you may hear a metallic sound as you pass TDC, but that is the compression release and it is normal. See if you can feel anything that may cause concern. They use hi quality bearings on these, I've pulled many cases down to bare bones and have only found two bearings that were suspect!

 

[Fairmont79]

Worn lifters will cause you headaches!