inspect the engine no. itself on the engine, if it says A18A* then its a 1.8 block - inspect the cylinder head for the casting no. if its PH1 you have a 1.6 head.
The timing belt marks on this engine are a bit obtuse, the crank timing mark can only be seen through the timing adjustment hole besides the engine no. stamp on the bell housing of the cylinder block. It should have a pointer and a T mark which denotes TDC. The cam marks are set by the cam pulley - it has two lines on either side which should align with head head machined surface for the cover. Install belt and let the tensioner apply tension, rotate the engine counting 3 teeth on the cam pulley and tighten tensioner, rotate engine twice and then, loosen and tighten again then recheck timing.
You will find it very hard to purchase the 1.8 timing belt, The 1.8 A18 Accord/Preludes are very rare in Pakistan.
For knock, firstly check the belt timing then check the distributor advance mehcanisms for sluggish response, it will probably be siezed or slow after all these years, Overhaul it and install a new seal, Use silicone grease only on the ignitor mounting base on the distributor (shiny silver plate on the side of it) - otherwise you might cook it.
For the water jacket Im believing you are talking about water pump, its very easily available, get the OE Honda pump or a GMB pump (get one with a whole cast impeller, do not buy the plastic fan or steel fan one it doesnt move at the required rate). Make sure the engine has its 82C thermostat valve in place and make sure to use the bleeder screw to purge any air when filling coolant/water, otherwise your engine will heat up like mad.
If you are talking about the round plugs on the block, then its best to replace all of them - they are 8 in total, 3 under the intake manifold, 3 under the exhaust, 1 behind the timing belt and 1 in the clutch bell housing. If one has rusted I can gaurantee all are rusted.