New cooling idea

I had posted about my temp problems on another thread that some may have not read so thought I would start a new one here.
I have had trouble getting a stable temperature since my radiator change. Thought must be the thermostat which was a Robert Shaw one so tested in on the stove with a thermometer and it opened and closed perfectly and the same as the brand new one I had in the pan with it. So fitted the new one anyway but no difference. Once the thermostat opened at the right temp, it just had trouble closing it again I think due to the high flow of the new radiator combined with my high flow Hesco water pump. So tried just a standard one which improved it some but still had a similar problem. Did some thinking about it and thought I had too much flow. So I thought of fitting a restrictor in the upper radiator hose at the radiator end. Normally restrictors are used instead of a thermostat but couldn't see why both couldn't work together.

Well I happened to have a brass washer the right size to try first with a 5/8" hole and 1.33" or 34 mm outside and it made no difference. Too close in size to the standard thermostat opening.

So I tried a Rancho urethane upper front shock pin bush. It had a 3/8" hole which I thought might be too small even though the company I spoke to had gone as small as this to improve cooling by raising the block pressure. So I just put a drill bit in the vice and then screwed the bush over it to open it up to 1/2".
Well once the thermostat opened at the right temp, it just sat there idling with no fans at all ( I have twin electrics ) running with 24*C/75*F outside temperature. I had to bring the revs up to nearly 3000 before the temperature rose and the fans came on and cooled it straight back down. The needle fell until the fans switched off and then just sat there again. So it has been a success so far with a nice stable temperature at 190*-195*F with the fan coming on much later in time than before. This is showing the extra pressure inside the block and slower flow through the radiator is giving better heat transfer.
So this is something worth trying to get improved cooling and only takes a few minutes to drop a restrictor in. The reason it works is that greater pressure inside the block stops the coolant boiling off the cylinder walls andinside the head and the slower flow through the radiator gives more time for better heat transfer. You just need to try what hole size works best for your water pump, radiator and thermostat combination.
Since posting this else where yesterday a couple of people have contacted me and said that some old Mustang's and Audi's had a restrictor in the heater hose to boost the heater. When some replaced the hose and didn't know they had to swap the restrictor over as well, complained that their heaters were not working as well any more. This shows the better heat transfer with the slower flow.
The company I got some if my ideas confirmed with builds Nissan Patrols ( www.ontrack4x4.net.au ) used in the Outback and Winch Challenge events etc. Some are even turboed petrol's and they found getting to block pressure up to 16 psi ( like you radiator cap but that is only up there when around 125*C ) transferred the most heat. They needed to use high flow water pumps to get it that high but that is not to say restricting a stock setup with a Jeep pump you cannot improve the pressure enough at least to help.

I have had horible luck with robertshaw thermostats. They open and close no where near the stated temperaturs. I like you explanation as to why restrictors work. I never bought the notion that it keeps the water next to hot metal longer adding transfer time. OT you can also drill a couple 4mm holes in the thermostate flange to add flow.

Wanna come over and fix my cooling system in the red Jeep Marcus? We can go hit a few trails afterward.

I'm lazy. :laugh3:

and then you both can come to me .... solving my temp probs .... and we will go wheeling too ... on some of the places we still have ... (but there are always less and lesser places :shiver: )

greetings from Austria
Rainer

Woodstock said:

and then you both can come to me .... solving my temp probs .... and we will go wheeling too ... on some of the places we still have ... (but there are always less and lesser places :shiver: )

greetings from Austria
Rainer

Click to expand...

I liked your country when I was there last. Be great to wheel there but I know what you mean about having less places. It is happening here too with some states worse than others. Though the the Northern Territory here has actually opened up more tracks for tourism. The last route, they are working on the maps now, is 2500 kms round trip.
I have done sections of it already but nice they are thinking this way.

But I still think that there are more miles available in Australia than in Austria.

When you were here? What do you have done?

I linked your site at my webbrowser because of all the usefull infos there. And so I used a lot of things from there (so last i was lucky to find the info about the third connection of the combination valve. before i prepared for a 3 connector adapter - but then i would had to bend the brake lines. so it was an easy swap. and i like my rear discs :clap:

greetings from Austria
Rainer:wave:

Well our country is far bigger than yours ( same size as the lower 48 states of the USA ) so yes we have way more off roading. Just have to go further out of the cities now a days to reach it. The Outback still is pretty free which only some areas needing a permit to cross Aboriginal land.
I crossed through your country 4 years ago now.

I thought that you had posted this here but must have been on another forum. As I replied there my grandfather did this same thing to an old Kaiser he had and it worked great. I had forgotten all about it until I read Gojeeps article on the restrictor. Excellent work Marcus.
-Mike

I can understand how a higher pressure would help in the engine block as it would raise the boiling point of the coolant mixture but how does a longer transfer time make a difference on a closed circulating system?

It would seem to me if you cut the flow in half sure a incremental amount of water will be spending more time in the over one cycle but it will also be spending more time in the engine block. It also seems over a time period..say 10 min whether your coolant circulates through the system once, twice, or three times it will spend the same percentage of that 10 min inside the radiator.

What am I missing?

static heat transfer in the block, dynamic heat transfer in the radiator. the water is losing much more heat in the radiator, than it is gaining in the block, because the block does not transfer heat as efficiently as the radiator, that's the layman's explanation

That explanation is a little too simplistic to satisfy my curiosity...is it possible to get the non laymans version?

This is a good idea, but be sure you pick the right media for your restrictor! I followed Gojeep's lead. I bought a hole saw, grabbed the board we had in the kitchen and set out to make a restrictor like Gojeep's:



It seemed to stabilize the temp nicely here in the 110 degree Phoenix desert. Then I thought I'd put it to the test to see if had fixed my freeway speed hi temp problem. Not wanting to drive 10 miles to a freeway, I got on a long, lightly used stretch of road, dropped it down to 1-2 and got the RPMs to 3k and drove with the A/C off. It did ok, 2/3 of the way between 210 and the red zone. Then I did it again with the A/C on and it was heading to the top! Dang it!

So I was resigned to the fact that I needed a new radiator and followed so may others and bought the 3-core CSF from radiator barn. As I was lifting the old single-core out I reard a rattling sound and when I started looking I found this:



My nylon restrictor melted and was pushed into the return tank! So, the moral of the story is to choose your restrictor media carefully!

Bringing back another old thread. First let me say that with a new stock fan clutch and a few radiator flushes, and the pre-existing 180 degree thermostat, my 96 rarely sees anything above 210. However I'm always looking for a better way of doing something. Has anybody here in the states tried this? What did you use for the restrictor? How has it worked for you? I'm not looking for a reinvention of the wheel, just seeing if this is any more efficient????