zip you mean you put a thermometer on the outside top part of the radiator??????? and not touching the actual liquid coolant??? and you expect to get an accurate temp reading?lol?  that is probably 10degrees off zip.

when i was having the same issue before, this is what i did,  i bought a used engine Coil, installed it.  i start the engine in my backyard(don't rev it)  let it idle until it gets really hot to the point that the coil fry and the engine stops. Now i grab a permanent marker and put a mark on the temp gauge exactly when the engine stopped.  that mark is my "red" zone. 

then i put a new engine coil and the car runs again.

PS: you need to have a new good running temp sending unit before you do this procedure to begin with.

You are over-thinking it a little. The small hose (probably 1/2" = area 0.196 sq. inches) and the even smaller opening where it connects to the engine is much smaller than the main top hose (approx 1. 25" = 1.227 sq. inches) connected at the thermostat. The cross-sectional area of the rad hose is about 6 times the heater hose. Therfore the proportion of coolant flow through the heater hose is 1/6 that of the rad hose. In a typical car with a heater, the longer 1/2" hoses and the heater core also add resistance to flow, so the effective flow rate is maybe 1/12.  Add into that the fact that the engine designers would have taken into accound this alternate coolant circuit when figuring out the thermostat selection for opimum operating temperature. They also wanted flow across the the head through its coolant passages to ensure that the head heated up evenly, so placed the heater take-off at the far end of the head. To sum up, the thermostat controls about 11/12 of the engine cooling system, and the heater circuit helps keep the heat even across the engine. In the case of Zippy's Moke, I am sure all is well. Besides, if he found the engine temperature to be off a little, he could replace the thermostat with one of a slightly higher or lower rating to suit.

To back-track to the problem of not having any thermostat, there are two (at least) basic concepts:

1. Without one, an engine does not maintain it optimum operating temerature - the thermostat modulates the temperature by opening and closing to suit. 
2. Without one, the flow characteristics of the cooling system are thrown off and you risk uneven head temperatures (hot/cool spots) and the risk of premature gaskeet failure and uneven cylinder temperatures leading to uneven combustion (one or more cylinders not being as efficient as the others).

Wrong again !!!!!

BTW FWIW i don't believe that picture/set up is Zip's Moke.

To clarify a couple of points;
The previous picture of the bypass from heater take off to upper radiator hose is from my old '59 Mini with a 1380. I was trying to overcome an overheating* problem. (more on this later) The Moke needs none of that as I could fire it up and let it idle in 95 degree heat and it would run out of fuel before it overheated. (Picture to the right)

As for the 1380 "overheating" my temp needle was always hovering around the "H" mark and I assumed that was a problem. So, I tried in the following order:
New fancy two core radiator.-no difference
Mixture of water, water wetter, and antifreeze-no difference
Added the heater take off to upper hose.-that, at least dropped it off a bit
Added an auxilary fan-That dropped it off the "H" mark
Added a heater core as an auxilary radiator-no difference

Finally, (are you listening Boison?) I took the advice of several on this forum and actually measured the temperature in the upper radiator. As long lost ADO16 (Todd) used to say, "Always confirm the customer complaint...."
Turns out that, when the gauge was reading "H" the water temperature was only 180 degrees. There was a mis-match between guage, sender, and voltage regulator.
So, by not using others advice, I spent a lot of time, money 'n effort chasing a problem I didn't have.

Adding a heater take off to upper hose bypass will only add a bit of time to warm up. The original poster was looking for a way to get heat out of the cabin. This is only one option.

after a little analysis, let me ask sir zippy, does your engine attain the Optimum temperature it needs to run perfectly?hmmmm maybe not, why?? because in all actuality that whole set up of yours where in you have a hose coming from the valve going to the T-rubber tubing attached to the radiator is bypassing the thermostat. in essence, the water flow continuously.  The thermostat is the ONLY one preventing the water from circulating, but with that little valve hose directly linking the engine block to the radiator ,water flows with no interruption.   again in all actuality, it's like you dont have a thermostat at all.

i remember last year, cupcake jumped hard on me when i took the thermostat off on my mini so damn Special.  i don't want cupcake to get mad at you zip.

ahhh, maybe moke is different, i see.

So, here is how it does work:

The water pump takes cool coolant from the bottom off the rad and pushes it into the engine. It ccirculates, getting hot. It only has two ways out to get back to the rad - through the heater valve and system and through the themostat. The thermostat stays closed until the engine reaches its optimum running temperature (somewhere around 190 degrees F.). Meanwhile the coolant is permitted to flow through the heater unless the heater valve is closed by a sweaty driver. As Alex stated, it is preferable to keep the heater valve open so that the back end of the head gets adequate circulation.

In Zippy's Moke, he doesn't have or need a heater. To provide the circulation Alex writes about, Zippy provided a by-pass hose, making use of the heater hose port and a spare lower hose as shown. Thus the hot coolant from the back of the engine is permitted to flow back to the rad dirctly. where the heat will be removed.

I was wondering if anyone was going to mention Lizard Skin. I'm also a fan and plan on doing this to my car. Look forward to a review.  

Not a clue how things work in the real world eh? I'm actually starting to get entertained by some of your theories.
 

sir zippy, you mean, as the thermostat opens half of the hot water goes to the radiator and half goes back to the engine block??? that decreases the cooling potential by 50%.  WHO designed that re-routed radiator hose system??i want to have a one on one debate with him.

The cheap, hillbilly way to try it out:

The upper radiator hose is just a cut down lower hose with the heater take-off.

Sounds like the heater tap being open is the biggest problem here. I would suggest (and I know there has been much debate over this) running the tap open, and directly into the base of the thermostat via a thermostat plate with a tap. This will run the hot water from the back of the head to the top of the radiator to be cooled and relieve the hot spot on that side of the head as well as cooling the water before re-circulating it.

After that, there is a LOT of heat transfer from the engine, header, and exhaust through the firewall and the exhaust tunnel. Consider some sort of thermal insulation in the tunnel under the car and also inside the car along the floor and the firewall. I've personally decided that I'm ok with adding some additional weight to my car to get a substantial reduction in heat and noise. So I've elected to spray Lizzard Skin on the underside of my car, firewall, and bulkhead. I have both types of lizzard skin on there as well. The ceramic heat treatment as well as the noise barrier. Ill let you guys now how it works when the build is done and I take it for a spin. But I'm pretty positive it will be substantial.

Application:

Both layers applied and dry:

Primer over Lizard Skin:

Paint Matched to rest of the car:

Not in everyone's budget or level of detail, but I wanted it for my build.

   would you like me to install A/C in it for you.???

here's another great idea, i know some of you are secretly taking down notes...toldya, im here to help in every little way i can.

//youtu.be/QHQ0v3da2g4

A nice 10" fan blowing on the driver sure helps.

 Correct. I would use a zip tie on the valve, see if that shuts it off.  Although, I would never advise anyone to stop the flow from the head at that point, re-routing the flow to the upper radiator tank, thermostat housing, or upper radiator hose would be the better way to eliminate the heater core from the system. Adding another small heater core in line would help maintain the coolant mass as the coolant capacity of any mini is small. This is only going to help with cooling while driving at speed, not idling.

Ok so the heater knob was pulled out and when I tried to push it back in it was rather tough.  I went to do it manually at the block and it seems like it won't close all the way.  It's about 85-90 from what I can see.  I did touch the hose coming into the car to the heater and it is still hot.   With the heater valve shut I shouldn't be getting any heat from that hose correct?

You are an idiot!!! NO ARGUEMENT!
 

uhm wait, 212degrees at 70mph???   isn't it that the faster the car runs the faster the fan rotates and the more air passes through the radiator thus the temp should go down???  my theory is that  heat is inversely proportional to speed.

that's why you'll notice that the temp goes up when you are at the traffic light.

i know someone might say that the faster the car, the more gas is being burnt and the more heat is produced. BUT the volume of air that passes through the grill when at high speed is enough to bring the temp down. (arguement settled), next topic please.

PS: did you see Dirtbags reply to me below? if a person replies with such words as "idiot" "gfys" etc, it means that his intelligence quotient is very very low...can't blame them...lol

Mine runs about 212 Degrees running about 70mph and about 180 Degrees anything below 50mph.  Keep in mind also that im in Nevada where its in the low 90's and at 5000ft altitude. 

this is just a simple version of what im building, but instead of the air directly heating the ice, i will use an old refrigerator condenser and a 12v water pump and 12v fan. 

this video is ok but i find it so elementary, im building a better version but you might  get an idea from this at some point.

//youtu.be/ITtlxjvLQis

 and this is what im working on right now, of course i am not going to use a water ice chest(looks unprofessional), instead i will use aluminum with high grade styrofoam lining. now i am hunting for a non running refrigerator laying around the curb, ahhh can't wait for the spring cleaning in my area../ i will take the condenser out and use it for this build./ one good size block of ice can last 4hours./ and longer if the insulation is excellent.  and of course ain't gonna spend $600 and buy this, i gotta do my own.!!!!!im a fabricator remember?

//youtu.be/wPEpTABfFEE