The 1983 SD had about 226,000 miles before an oil return line ruptured that caused the oil to drain from the oil pan while the car was running that resulted in the car developing a major knocking sound as well as made the engine lose power. Anyway, I lapped the valves and replaced the head gasket but the knocking sound would not go away. The head has all valves, springs, and prechambers and the valve stem seals were replaced, but will probably need replacing again if the head is serviced at a machine shop. Thanks

Benzdiesel