Fitted a brand new alternator to the SD yesterday, it seems to have fixed all the oil leaks I had off the old one, and charges soo much better. It's made for a TD42, and much cheaper than the SD33 options. For anyone curious you can modify the factory alternator bracket to accept a TD42 alternator (my build thread, post #18), then you just need to grind a pressed sleeve flat on the alternator that pokes out.
My old TD alternator was dying, it was only a second hand unit, but the final straw was after I put chalk on the belt to quieten it while the car was running, and dusted the alternator with chalk by accident. I don't know if it got into the regulator or what, but the trigger for it to start charging wouldn't happen until above 2200 rpm, which I don't even reach until after the engine and oil are warmed up. Once it started charging it would charge even at idle, but it wouldn't start until it initially got over that 2200. On top of that as soon as it had any draw the voltage would drop significantly, with the car idling and the headlights on it was down near 11v, and any other accessories would decrease it further.
This new one triggers charging once it initially reaches about 850rpm, much much better, and can charge well even at idle with the headlights on, and doesn't leak oil from the vac pump. Very happy camper.
I also FINALLY plumbed up the PCV valve into the intake, so hopefully since there's less pressure in the block and it's sucking out the combustion gasses that make it past the rings it'll both leak less oil (rear main is pretty bad, rocker cover gasket may need attention, sump gasket may be bad, head gasket that won't be affected by the PCV vaccum needs changing), and also keep the oil less black for longer. I know diesel oil, especially in old diesels, goes black very quickly due to the extra carbon that diesel produces when it burns, but this'll at least help. Also I can comfortably wash the engine bay now without fearing water going straight into the PCV.
Pretty simple method of hooking it up, got a 1/2" hose joiner barb and some 1/2" hose, drilled a hole in the silicon bend coming out of my airbox thats smaller than the barb, and pressed it in. Shouldn't leak given it's pretty tight and under vaccum, and is an easy solution until I get my pre-turbo piping made out of stainless and get a barb welded in. If I get scared that it's leaking I'll just sikaflex it in there, but for now it seems pretty good.