Z16s d21 datsun help please!

[Chezzle]

I have a z16s 1985 d21 Datsun. I’m after a little info if possible and a few torque specs.
i have recently put a Weber carb onto it and tuned it, got it running very well compared to the factory carb. during this time I replaced my inlet manifold gasket as it was leaking. 
not too long after it had water getting into the cylinder number one. Confirmed by removing the spark plugs and using a cooling system pressure test. Feeling like it was a the crappy thin gasket supplied in my kit, I pulled the manifold and used .8mm paper gasket roll to make an intake gasket, and used glass, sand paper and a flat surface to ensure the intake was flat. 

I re assembled it without covering it in sealants, knowing that that paper seals great given just pressure and flat sufaces. 

I hooked up all the cooling system without the carb or plugs in. I the. Rechecked the pressure of the cooling system. 
I could hear hissing coming from in the spark plug holes and strangely enough it was coming from all 4 cylinder depending on where in its strokes I rotated it too

, but no hissing from the intake carb port when I would block the plug hole with my finger

Which if it was in the manifold area I would’ve expect there to be hissing there? Any other ideas? Could it be the could coming from a crack in the exhaust port in my head? Sound then Back feeding into the cylinder when I’ve opened the exhaust valve? 
what’s your take on the situation?
I have the head off at the moment. And will taking it to get looked over and flattened. 
likely hood of block issues? I would love to avoid pulling the timing parts all off if I can. But if it’s a block issue obviously that can’t be avoided… 

 

also any info on the torque specs related to the z16s engine would be greatly appreciated 

[datzenmike]

What air pressure were you using? to pressurize the cooling system? How or where was the air applied?

 

Z16? Heard of them and the Z18ET. We only got the Z20S and E and the Z24.

[Chezzle]

It’s a z16s, and it was and hand pressure pump kit. A leak down ready kit for the cooling system.

I have recently confirmed it has cracked in the cylinder number one exhaust port. Well not cracked so much. But it most definitely has worn through to the cooling jacket. 
there’s a few probe looking tube things hanging into the exhaust port, the one In cylinder number one has actually mannaged to rub right through and expose the coolant gallery in the head. Why on earth are they even on the exhaust manifold for? 
annoyed but it’s no the end of the world, from what I read I can use any z16-18-20 head on my block as they’re the same. 
mum hoping once all this is sorted I can look at getting my hands on a cam for it. I may even attempt to just weld the port back up and use it. 

[datzenmike]

Many of our L series engines had an air pump. It's belt driven and injects oxygen rich air directly at the exhaust valve. Any unburned hydrocarbons light up and burn away reducing the emissions. It's natural to assume that your Z series engines did the same.

 

TIG welding should work. If you don't have emissions testing I would remove the pump, the pipes and plumbing and seal the holes in the exhaust manifold with these..

 

 

 

As to your Z16 we skipped right to the  Z22 and Z24 but yes these heads interchange. There was an optional Z20 but it is different and has a smaller combustion chamber because of the smaller dis[placement. Can you look on the side of your Z16 head near where the distributor is for the head ID??? Does it say W04???