It's been a couple months since I've been on, mostly because my car has been in the shop for a month and a half, and I still am not sure what's wrong with it, so here's the run-down:

Had valves adjusted, and then had the injectors rebuilt, and it was running great...for about 3 miles. Suddenly, everything went to heck in a handbasket. It sounded like I'd blown the engine, and I had smoke billowing out the tailpipe. Luckily, I was able to limp it back home, but it seriously limped, ie no power, and didn't want to go but just a smidge above idle.
However, the engine never ran hot, and the entire time, I was reading normal/high on my oil pressure. So, I loaded it up, and took it to my mechanic. He says it's a bit of a mystery. Somehow, the injection pump came out of time, but after re-timing it, he has had problems getting it adjusted correctly - when it runs good, it idles terribly, and when it idles good, it runs bad again. His current diagnosis is something has gone wrong with the pump itself. I don't doubt this, but was wondering if anyone would know of another possible reason this could happen, or another tack to try to fix it.

 

I am not real familiar with diesel models before 1978, but my basic diesel knowledge says there is a centrifugal advance mechanism on the front of the injection pump where the timing chain drives the pump. It acts much like timing advance on an ignition distributor for gas powered engines. As engine rpm increases, the advance mechanism advances the timing (necessary for proper completion of combustion by the time the piston is on its way downward) and then retards it again when rpm returns to idle. It sounds very much to me like this device has become inoperative, and needs fixin' or replacin'. I don't know if it can be replaced separately from the injection pump, so you should consult a service manual to see what is involved. Good luck.

 

Thank you....though I understand the basic principle of diesel engines, the injection pump is still pretty much a mystery. A diesel mechanic friend, who is more or less uninvolved in this, had mentioned that if it had really come out of time on it's own, a failure on the timing end of the pump was the most likely cause. However, your explanation of what that could be is far clearer. Well, looks like a new pump it is. Thanks again.