Hi Micheal,
If your D4 is a 6u or 7u they have a D315 engine, the D318 is only two more cylinders
So the same would apply to the d4.
You can also make shore that the engine turns over buy hand buy operating the decompression lever and give it a few turns over and feel for any abnormal signs.
Regards
use a borescope to check the manifolds for obstructions or damage. especially if the exhuasts havent been covered.
see if it turns freely
Thanks for the responses. As soon as we get a warmer day, ill get the picked up and will post some pictures.
After all of the above. Then, If you can get the pony running, Turn the diesel over without compression and see if you get oil pressure.