My 861 diesel suddenly stopped running while I was mowing. Pulled it into the shop and after searching I found that it had a broken camshaft. sheared off right behind the timing gear. As I got deeper into it, here is what I found: Hydraulic pump gear is not damaged. The crankshaft gear has one broken tooth. The skirt on number 4 piston broke off at the lower oil control ring groove. the pieces were in the oil pan. There is no engine balancer and appears that it never had one (no gear on crank). Rod bearing on #4 is standard size. Don't know what others are since I haven't taken them apart yet. My questions for the experts are can I replace the cam and piston/rings in #4 without doing a complete ring - bearing job. I am going to plastigage the crank to see if it is still in tolerance. It had excellent oil pressure at 40 - 45 psi and started easily even cold.