Water Ports

Revision as of 05:58, 8 June 2012; view current revision
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Coolant passages are below the intake ports in some A-series Cylinder Heads. They can be large holes or small holes.

Overview

• A12GX has Four Large coolant holes, one beneath each inlet

  

• Other heads have either no coolant holes, small ones, or a mix:

  

• Standard Datsun 1200 heads have no coolant holes on the intake side.

Interchange

A-series heads will interchange with either dry or wet Intake Manifold with the following caveats:

• If the intake doesn't have coolant passages, tap the head's coolant ports and install plugs

  

• If the intake does, but the head doesn't, cold-weather starting and cold-idle may suffer due to insufficient heat. However, warm-engine operation should be OK.

  

Port Plugging

Discussion: H89 water gallery pluging?

Directions for plugging the cylinder head with blind plugs:

Nissan plug parts
99996-H1149 STUD & PLUG KIT 

You can buy grub screws in many places, most auto shops for example. Measure the hole, tap the mext mm up and screw in a plug. A bit of form-a-gasket, copper seal or anti-seize on the threads will help prevent corrosion.

If your dry inlet manifold comes down far enough to cover the holes, you can use silicone sealer like this:

This is an easy way to seal it, but coolant may leak when you change the manifold. Just re-seal it each time. By contrast, blind plugs are a one-time semi-permanent solution.

Used RTV silicone sealer. After fitting the intake/exhaust gasket, before fitting the intake manifold, press some RTV into the water ports, the put a button of goo over it. Let it tack up slightly before fitting the intake.