Dan, thanks for the insightful reply. It would seem that we are on the same page regarding coolant flow. I have to believe that the flow from the thermostat opening would far exceed the lesser flow from the inlet from the aux. radiator. That combined with the slowing effect of the flow through by the larger heat exchanger (radiator) does insure ample mixing of the two.

Although my findings are not scientific, the results are what I wanted. Please keep us informed of the results from your changes.

Terry, five beers into a case McSilver. 

If you're not on the edge............ you're taking up to much space.

I'll take a whack at the first one, if you look at the thermostat housing the #4 water flow is entering at the top and is creating a counter current flow condition. I mean that it is battling the coolant flow direction from the thermostat and causing some restriction of flow and turbulance. How much you can't tell unless you do some major measurements and calculations so I won't even guess. This cooled flow, since it is against the normal flow direction will create the mixing effect you're looking for. The rest of the mixing will be accomplished as it travels out the hose, into the inlet tank, through the core tubes, into the outlet tank, hose and water pump.  Ample mixing and since the overall inlet temperature to the radiator is lower you have increased the overall capacity of your cooling system. (I deal with air coolers and heat exchangers on a daily basis) So in the end, it's a good thing.

2nd - Who knows the air temperature, but if you wrap your headers with insulating tape it will lower the air temperature entering the radiator from that direrction. One factor to consider in this case is that since the aux cooler is at the cold air intake location (front grill) that the inlet air temperature to the radiator is incrementally warmer due to that heat exchange. Once again the affect is minimal and the overall cooling capacity has been increased.

3rd - I dunno, I don't have one nor have I ever used one as an add-on. I have used a pusher fan but not for radiator cooling, it was to keep the AC condensor working in stop and go 100+ deg driving conditions.  There is a loss in air flow across any air cooler (measured by inlet and outlet pressure) and a puller may work to minimize this loss thereby increasing the total air flow across the tubes/fins resulting in increased cooling. It works in theory but unless tested as Terry has with his modifications, not easily verified.

All in all a great topic as I was looking at much more expensive ways to send #4 water to the radiator and have decided to try Terry's idea first. Cheaper, faster, easier and I don't have to wait for a nozzle to be added to the radiator once I fit the MKII shrouds on it.     dan

"I don't know much, but what I do know I know little of "

Benny, I agree that having the two heater cores in parallel is not as effective, but they are really only being used one at a time. The interior water valve is shut off and flow is diverted to the front core ( this makes it possible to run without the heater, and still have flow from #4). Now when I want heat I just close the flow to the front core with the valve. But not surprisingly when I open the water valve for the heater core in the cabin and have both cores working there is a drop in engine temp, I would say about 5 degrees. Its kinda like having extra cooling capacity on reserve.

 Mur, I'll get right on that scientific analysis of every possible cooling theory that can be applied to the A series engine......... I'll just have to finish this case of Kokanee first, so my finding are not bias. Here, here to the power of free thinking.

Terry 

If you're not on the edge............ you're taking up to much space.

It'd be fun to organise some precise test gear and do some Marcellesque scientific testing.

For example, Partsguy is returning cooled coolant to the top of the rad.  Does this mix in with the super hot coolant coming out of the thermostat, or does it not mix.  Is this a good thing, or a bad thing?

What is the temperature of the air that the fan is pulling in and pushing through the rad?  Would better heat guards on the header pipes help?

All these folks who swear by having an electric puller fan-is it that the puller fan removes that hot air before it is pulled through the rad?

And yeah, it isn't very messy Terry.  In fact it is kinda neat.

Simple, clever, very cool.......no pun intended.

The only issue I can see is that now your heater and aux cooler are in parrallel, so they are sharing the flow, which means neither will be as effective as they could be if they were in series.  But overall, it's a clean little installation.

Here ya go Benny. I made a sandwich plate out some 3/4" steel plate and tapped it to 1/4" NPT, I also had to use longer studs which can be found at most Automotive Parts outlets.

Terry 

If you're not on the edge............ you're taking up to much space.

Where does the take-off come from on the #4 end of the engine?  It's hard to see where it actually connects in.

Did you tap into the body of your heater valve somehow?  Do you have a detailed view of that end of the set-up?

Mur, what messy? I like to drive my mini without the heater running when it is 30 degrees outside. How about you?

Terry 

If you're not on the edge............ you're taking up to much space.

now dump that messy aux rad.  ick.

You mean COLDER Dave!

If you're not on the edge............ you're taking up to much space.

Tropical and Calgary two words that should not be used in the same sentence! Calgary is only cool because your there Dave.

You should have just stayed in Calgary...it's cooler here....

Dan, I'll keep the metal fan on the garage wall and use it for whacking things once and a while  Chuck, it is possible that it was on backwards, but I don't think so. All I do know is there is allot more air force through the wheel well at idle, which would indicate more blow through the rad. To look at the difference between the two blades, the steel blade has far less pitch.

All I know for sure is that the changes made, have given me peace of mind.

Thanks for the replies gentlemen!

Terry 

If you're not on the edge............ you're taking up to much space.

Something else going on. The original, many-bladed ones were not that bad. Not as good as a new plastic one, but shouldn't have made a huge difference. Mounted backwards?

Hang on to your original metal blade fan. It's handy if you want to slice and dice vegetables and saves you money over the Vegematic gizmo. 

"I don't know much, but what I do know I know little of "

Okay, after completely revamping my cooling system here are the results. Changed the plumbing from the aux. radiator back to top of main radiator..... some improvement. Changed the rad cap(no change). Added an expansion tank(some more improvement). Installed plastic fan blade............HUGE improvement. I can now run with the heater off and the temp never rises above 195 (thermostat rating). I can actually see the drop in temp when the thermostat opens.

Final conclusion, original metal fan blade was just not up to the task. Tropical blade was not needed.

Happy Camper, Terry 

If you're not on the edge............ you're taking up to much space.

I have as rare  variable fan for a mini , full blade looks like a tropical when at rpm its more like a normal mini fan   four bladed  yours for 10.00   plus shipping, have to make sure its the right way blade first.

Chuck & Dan, great input! Chuck, the matrix is in direct air flow behind the grill, so it should be helping. This was kinda bugging me so I was up early this morning and did some re-working on the extra matrix plumbing. I now have the return going into the thermostat housing(drilled and tapped) ......... as it should be (right mur?). There is some improvement, but still have some overflow discharge. I suspect that the newer rad cap I have on at the moment is not holding pressure, I will replace the cap, and let you know the results. 

Thanks, Terry 

 

If you're not on the edge............ you're taking up to much space.

With an aux radiator, I find running from the head through the aux. to the lower hose works fine if the aux is in air flow or uses a remote fan. Without the aux. I've just modified an upper hose (split and inserted a sleeve with a 1/2" nipple) to take the flow back. Not as clean as some of the other suggestions, but much better than dumping back into the lower hose.

Terry, have you considered taking the #4 water return back to the radiator inlet? You can do this one of two ways, 1- buy a spacer that goes under the water outlet neck and return #4 there (thermostat goes under the spacer so the flow rate isn't regulated by it) or 2- have a 1/2" nozzle added to the radiator on the flat below the radiator cap. This way all the water returning to your engine gets cooled through the radiator and the additional cooling you're getting from your aux cooler just adds capacity.

I'm fitting a super 2 core next week and contemplating option 2 above as I have the same problem at high revs anywhere above 85 deg F. I've seen the copper bypass tubing the works cars used to direct the water from #4 back to the radiator (or somewhere else) and was going to bend some tubing, install a small valve on it to control the flow rate and see if it helps.  Conisdering it was 100 deg F here yesterday it limits the times I can drive the Mini, but then again, do I REALLY want to drive a Mini in that kind of heat anyways?

Or you can try one of these options and a borrow'd plastic fan (those old small blade metal ones could slice tomatoes but don't move much air) to see if it meets your needs instead of paying $60+ usd for a tropical fan if not needed. (I'm cheap).     dan

"I don't know much, but what I do know I know little of "