I recently overhauled a 3 cylinder perkins in a Massey Ferguson badged Landini for a neighbor. It had about 7500hrs and the oil pump gears came apart and split the pump and it spun the #3 rod bearing. I tore it down and had a reputable machine shop do the head, check/repair the rods, replace the liners, repair the crank. I reassembled (parts supplied by the machine shop) and my neighbor put it back in the tractor. I went over and assisted with the first start and retorqued the head after it had warmed up.
After he'd run it for about 10 hours I had a call that it was low on power and smoking. It broke the rocker arm on the #1 intake valve. I found the machine shop had installed the new guides 0.100" too high in the head and the valve caps were contacting them (also 2 were in upside down). I removed the head and they did it again. I reinstalled the head and we started it up, did a retorque but we had a fuel leak and some other issues so we didn't run it long. A few days later he fixed the other issues and it is apparently now leaking coolant from one of the studs that holds the #1 injector. Has anyone run into one of these heads cracking into the injector stud hole before or have a reason why? Thanks, Sam