Yes it has a plug, but according to the archives, the plug can trap air in the water pump.  I’m going to take a trip out to the airport, and see if that isn’t it.

 

Well, no luck with the plug.  I got one little bubble out of it.  I definitely did still have some air in the system.  I heated it up, and when I parked it on its’ nose, I could hear the air perking up to the header tank.  I ran it through a couple of heat cycle, and now no more air.  Still only heats the top ¼ of the core at 1000-2000 RPM’s .  I ran it a 4000 for about 60 seconds, watching the temperature rise quickly, and hurried back to check the cores after shutdown.  The top half was pretty hot, but the lower half was only warm.  Better at 4000, but still not great.

 

Maybe it would be a good idea to recommend a small hole (3/32" or so) be drilled through the plug, though I'm still a little skeptical of the theory.  Did you attempt to slow the water pump rotation with different pulleys?  Maybe that would account for the lesser flow.

 

I do have an under drive pulley on the crankshaft to slow down the water pump and alternator.  I think also though that the AN16 line provides quite a bit a restriction as compared with 1-1/2 or 1-3/4 radiator hose.  I think that there is less resistance in the core, than there is in the AN16 hoses, which is why it is not forcing it to the bottom.

 

 

As a side note, has anyone else noticed that it's getting hard to remember the details of all the projects going on?  This is probably good news, that there's more projects, but it could just be advancing age :-)

I’m sure that it’s more projects, and not whatever it was we were talking about.

 

Unless someone has a better idea, I think that I’m going ahead with the tubes in the core.

 

Regards,

Steve (trying to love evaporator cores)