The original spec sheet of Nissan CD17 speaks of very high mileage/lit - I had a VW 1.6 diesel that returned 22-24 in the city, your engine should return about 20. If you drove this car brand new then you must have experienced the 20 km/lit
I have not met or known of any mechanic in Pakistan who has the dial guage to setup VE pumps. its very simple to make and you are an engineering student so its really easy for me to explain too.
You need to measure the stroke of the plunger in the pump head to measure it you need to make an adapter out of any metal, with 8x1.00mm threads (fine threads) then other end of the adapter (about 3 inches) you mill it to accept a standard dial gauge. use a neat fitting metal rod in the adapter so the rod contacts the pump plunger and also preloads the dial gauge about 2mm.
for measurements, you can use the same dial gauge without the pump adapter to measure valve guide wear too. The bores are measured with the a telescoping bore gauge and the pistons with large micrometer, The crank journal is also measured with a regular micrometer and if you need it polished to a new size, make sure that the oiling holes are dished and the journals are shiny smooth. When setting the crank in place, measure the clearance with some plastigauge strips.
The finer bits are that you would need a new set of headbolts, connecting rod bolts and the crank main pulley bolt - they are all TTY type.
When having the valve seats faced, you should make sure the valve height is perfectly set as mentioned in the service manual, it is measured from the top of the head to the valve tail when installed and make sure the seat margin is generously wide, Setting the timing belts is very finicky as there are no timing marks on the head - only on the pulleys, go back on this thread to find the timing belt alignment marks - you basically mark the belt and then line up the crank to TDC mark on oil pump then install belt to cam pulley with your mark on the belt, the pump belt is similarly aligned, 80% of pump timing belts on nissan CD17 that were really loud and poor running that I saw in Karachi were misaligned - and the pump ustaad then fudged up the pump setting and nozzle pressures to make the engine somehow work - no matter if it ran like crap.