I have been following the links here for some time now. This is the first time I have posted anything. This is a terrific source and has been most helpful to me as I have recently replaced the engine on my 81 300 SD with a used.
The used engine was sold to me as being in excellent shape, it may have been at one time but... Well I believe now that it had sat for a very long time out in the dry California sun. When I got it in I replaced the oil and water pump. I also replaced the gasket behind the oil filter, as that would be a tough change later. I noticed at that time that the gaskets were mosty dried up.
After the install it started leaking oil out of the rear main. I then had to pull the engine again and replace the rear main seal, which was brittle and had thrown off some chunks. That was only a 30 hour job...
Next the number five intake valve has been trouble. Broke two rocker arms before I finally figured out the valve is either sticking or the spring is not strong enough to return it correctly. In doing this little project I did have the uncommon privledge of setting the valve lash at least a half dozen times. Next will be to replace the spring. Have it in hand and that is scheduled for the long weekend.
The point here is that setting the valves can be a pain, but you know what they say, practice, practice practice...