1980 300 SD engine stopping problem

[MBNY]

I am having a problem with my 1980 300 SD shutting down
randomly. On local running it runs fine. When I go long
distances or run for extended time the car will just shut
down. I cannot start it right up, but must wait about 15 to
20 minutes and then it will start. It is not running hot. I
changed the cam on the timing chain, which needed changing.
It runs better but it still will shut down if I run a long distance.

Any suggestions?


MBNY