The vacuum pump can be useful for power brakes, and if you have A/C, to run the various mode doors. If you don't run a brake booster, the pump comes off the alternator with three screws (typically No. 2 Philips head). However, the rotor's shaft will be hanging out in the breeze. Keep your hands away!
(click on any image for larger)
This last pic is of the 720 PU version of the alternator, which has a smaller vacuum pump and thus a shorter rotor, but it gives you some scale.
Oh, and member zoomsplatt cut down his LR160 rotor, to fit the longer rotor to the shorter 720 vacuum pump, so you could cut yours flush. His pics are in
this post. Don't throw away the pump; while they don't seem to wear out, a couple folks have broken theirs, or otherwise needed one recently.
On the engine oil cooler: all the Nissan diesels I've seen have one, even the little SD22s and CD17s. Also, the gasser turbo engines have them. Yeah, they're plumbed so it's a mess, but I have to assume that Nissan thought a lot of them, since they used them on any application that even
might get the oil hot.
It'll run without the oil cooler. I don't think it's a good idea, though. You could remotely locate a cooler, but that won't make the plumbing any better.
Interesting IP layout, esp. in the area where the CSD would be. Has a lever for a manual fast idle + base timing advance. You probably won't need to hook it up, my '82 Wagon has had a frozen CSD for at least 12 years, and I only miss the fast idle in the dead of winter.
Judging from the accessory belts, it's been steam cleaned within an inch of its life
Not knowing the miles on it, you'll want to budget replacement of the cam belt soonest. It if breaks or strips a cog, on diesels it's "Goodbye, engine". All OHC diesels are interference engines.
