I bought some brass plugs from Home Depot and plugged the heater hose outlets (see the below pic). I previously had a peice of heater hose connecting the two but I posted here on zcar.com and was PMed that I should not loop the heater hose, also refer to the recent post TonyD about looping this section of heater hose.
Thanks for the replies. NPT is a US standard (inches), where I would think the Datsun motor is metric based. Its sounds like there is a thread pitch close enough and the brass is soft enough to seal. Thanks.
HealyZ---that 10mm line (or 8mm) is a bypass around the thermostat back to the pump inlet, this compliments another passage in the right front of the block that does the same thing. These are there to prevent cavitation of hte pump should some moron rev the heck out of the engine before the thermostat is cracked open. If your engine is not overheating, and you plan on running a heater, leave that small line in place as it helps the car warm up faster. It also, as stated, allows circulation within the block while the thermostat is closed. That is a good thing.
For ultimate performance and heat removal these lines and internal passages would be attended to in some manner...a manner in which I'm not inclined to discuss at this point.
Tony D, You're the man. It makes sense to have these small lines in place. I looked through the FSM and did not see a diagram on where these are routed. Anyone have a picture or could explain where these small lines go?
Healy Z, I'm REALLY swamped at work now and will likely be working late.
Go to Cardomain and look under username Sharkie73Z, there should be a red 260ZT project. There are 10 or 14 pages on that site, one of these pages shows where the little bypass hose goes---in short from the lower thermostat housing to the pump inlet where you have the yellow line. The webpage shows the line and etc.