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FlowKooler or Milodon water pumps

Well lets see...got the Flowkooler installed, ran some of the Sumitt coolant and Got out this morning with 70° temps. It went well ok? Got up to temp pretty fast 180-190 took it out on the freeway for about 5 miles at 65 then pulled off and ran down city streets light to light for about 6 miles. Now i use both factory guage and a mech one. The factory gauge showed just short of the right middle mark. Hard to desctibe but the guage has a cold / off mark than a section were i would assume it is its operating range. About a 1/4 way left to right starts it then at the 3/4 mark it ends the range. So the temps stayed just short of the 3/4 mark which would be within operating range? Now the mech guage showed about 185-210 most of the time it was at the 190 mark. Seemed hot for the temps outside. Is it me or should my temps be 180 when its 70° outside? Repeated the same event when it was 85 out and basically the same thing. Took out some of the Sumitt coolant and put in some zerex G-05 and ran it in the garage for 15 min. Temps sat at the 3/4 mark or 190° the whole time. Interesting note while at a light i could see the gauge drop a little. Then would go back up cruising. There was a time when i would run at 180 on cool days.

Not sure if i should be concerned? Could be a tune issue too. Just seem to remember running 180 all the time unless it was over 90° outside then that was a different story.

Thinking i may have found a balance finaly not sure.

What is the science here?

My set up is this
160° Mildon high flow stat ( interesting note Mildon high flow stats have a small notch or hole built into them for air relief i guess)
The Flowkooler pump
440source passenger side outlet aluminum housing same port size as stock
26" aluminum ECP radiator 2 row 1" tubes
16 lb cap
Twin 12" electric fans with shroud pulling 3500 cfm
Timing at 10° inital 35 total
9.6:1 compression ratio.

One thing to note is the fans cool things down pretry fast. However i noticed they are pulling in super hot air into the engine bay so much so im not conviced my mech gauge is reading accurately. I noticed the temp gun reading at the stat housing would read one temp with the fans running but blocking the hot air with something gave a bit of a cooler reading. Note to self lazor heat gun reads hot air too.

The only thing i have changed since i felt it used to run at 180 all the time on cool days was the heads and carb.


Edited:
On another side note reading temps with the temp gun outside of the radiator with the gauges in the car reading the temps noted above, checking fins from top to bottom. When reading the top fins read anywhwre from 165-172 middle was about 140-154 bottom was 99- 118. Standing pretty close to the front of the car about 2 feet from the radiator at the most.

Bigmanjbmopar..
Not to belabor the point or be facious, the science is Thermodynamics. In addition to your stated conditions, can you be more specific re the following items: size of the radiator, its construction (copper or aluminum), number of fins per inch (air side), water pump sheave drive ratio (pump RPM vs crankshaft RPM), ideal average water pump RPM to deliver best volume. Necessary to try and determine flowing velocity in the engine and radiator.
Your "mechanical" gauge is a vapor pressure type (likely) with bulb inserted in the coolant stream. When the bulb is heated by the coolant, the internal vapor expands driving the guage pointer higher. In essence it is a pressure gauge calibrated to read temperature. I would believe its readings compared to the dash temp gauge, which is a volt meter driven by a thermister immersed in the coolant, whose resistance changes with respect to temperature changes. If it original, its accuracy is marginal at best.
As far as the thermostat goes...once its opening point is achieved, there is nothing more it can do....the radiator must be capable of handling the heat load presented. IF the coolant temps continue to incresse, several factors must be considered: its size, the circulating velocity and GPM, the ambient air temperature .... trying to cool hot coolant (200°F) with 100°F air is difficult. Its called the approach temperature and is a function of radiator surface area, coolant specific heat characteristics and air side volume and temperature. The greater the temperature difference the more heat is exchanged. Is your temperature readings (185° - 210°F) acceptable? My RS23V0A GTX exhibits similar readings under similar conditions and I'm OK with those readings. These may or may not be acceptable to you....only you can make the choice of what is acceptable to you. Just my opinion of course.
Bob Renton
 
We have had some extremely hot 90 degree days with high humidity and mine never gets above 185 never ! Most of the time she's running around 175 then if I get into traffic she will creep up to 180/185 but as soon as I start moving she drops right back down I have the 22 inch direct fit Cold Case radiator 2 row 1 1/4 tubes with a modified 180 stat. Factory shroud with a 7 blade clutch fan. 10.5 to 1 compression. I'm running 70% distilled water 30 percent antifreeze, factory water pump and NO Electric fans don't need them. Timing is around 10 degrees initial and 35 total. When it's cooler out side low to mid 70's she won't even make it to 170 degrees.
 
Is your engine stock or modified?


We have had some extremely hot 90 degree days with high humidity and mine never gets above 185 never ! Most of the time she's running around 175 then if I get into traffic she will creep up to 180/185 but as soon as I start moving she drops right back down I have the 22 inch direct fit Cold Case radiator 2 row 1 1/4 tubes with a modified 180 stat. Factory shroud with a 7 blade clutch fan. 10.5 to 1 compression. I'm running 70% distilled water 30 percent antifreeze, factory water pump and NO Electric fans don't need them. Timing is around 10 degrees initial and 35 total. When it's cooler out side low to mid 70's she won't even make it to 170 degrees.
 
Stock block, ported X heads, ported Edelbrock Performer RPM intake with a Edelbrock 650 AVS-2 carb, Hughes Engine cam kit 518 lift 224 duration
 
Well since this is all in experimentmode i think i will change the stat to a 180° i bought both 160 & 180 Mildon stats just for this reason. Could be the 160 is just too soon and the radiator is on the edge of not being able to handle it all.it will be 99 this weekend so more testing will be done first then swap stats.

This engine does not like more than 200 for some reason it will struggle to restart


Bigmanjbmopar..
Not to belabor the point or be facious, the science is Thermodynamics. In addition to your stated conditions, can you be more specific re the following items: size of the radiator, its construction (copper or aluminum), number of fins per inch (air side), water pump sheave drive ratio (pump RPM vs crankshaft RPM), ideal average water pump RPM to deliver best volume. Necessary to try and determine flowing velocity in the engine and radiator.
Your "mechanical" gauge is a vapor pressure type (likely) with bulb inserted in the coolant stream. When the bulb is heated by the coolant, the internal vapor expands driving the guage pointer higher. In essence it is a pressure gauge calibrated to read temperature. I would believe its readings compared to the dash temp gauge, which is a volt meter driven by a thermister immersed in the coolant, whose resistance changes with respect to temperature changes. If it original, its accuracy is marginal at best.
As far as the thermostat goes...once its opening point is achieved, there is nothing more it can do....the radiator must be capable of handling the heat load presented. IF the coolant temps continue to incresse, several factors must be considered: its size, the circulating velocity and GPM, the ambient air temperature .... trying to cool hot coolant (200°F) with 100°F air is difficult. Its called the approach temperature and is a function of radiator surface area, coolant specific heat characteristics and air side volume and temperature. The greater the temperature difference the more heat is exchanged. Is your temperature readings (185° - 210°F) acceptable? My RS23V0A GTX exhibits similar readings under similar conditions and I'm OK with those readings. These may or may not be acceptable to you....only you can make the choice of what is acceptable to you. Just my opinion of course.
Bob Renton
Stock block, ported X heads, ported Edelbrock Performer RPM intake with a Edelbrock 650 AVS-2 carb, Hughes Engine cam kit 518 lift 224 duration


So pretty much stock running what you have in a stock block Is fine.

When you stroke out and bore is when the mods require a different approach i had a clutch fan and the stock 2 row with 3/4" tubes when i first did the engine swap and it wouldnt stay below 220. And the clutch fan put so much of a load it was ridiculous. From there we started with an aluminum rad then clutch fan and shroud no good then flex fan still no good on hot 90+ days so better pump and housing and we started to see 180 more then went with the twin electric fans and seemed ok but still would get to 230 on 100 days then switched to Evans coolant and was great until 100 days then the 230 temps again. Then distilled water and purple ice which is pretty good but then at idle we got to 225 and this is where we are at needed the flowkooler to keep the at idle temps down which it does well. Now to find that perfect balance i will switch back to a 180 stat but a high flow instead of a stock stant.
 
I purchased from Summit a FlowKooler Robertshaw High performance Stat. Summit # BRA-330-180 then I modified it by drilling 3- 3/16 holes equally spaced and this stat works perfect. I had a 160 degree stat and Chris from Cold Case said that wouldn't work and I had to go to at least a 180. Glad I did, as I stated as hot as it's been even sitting in traffic she just makes it up to 185 then drops right back down to 175 once I start moving.
 
Well since this is all in experimentmode i think i will change the stat to a 180° i bought both 160 & 180 Mildon stats just for this reason. Could be the 160 is just too soon and the radiator is on the edge of not being able to handle it all.it will be 99 this weekend so more testing will be done first then swap stats.

This engine does not like more than 200 for some reason it will struggle to restart

Bigmanjbmopar,
The 180° F thermostat will start to open at approximately 177°F and be fully open by 190°F. The balanced flow opening design is best but not the cheapest. The radiator will just receive ~185°F water which you are still trying to cool with 99-100°F air, which is a function of surface area and CFM air side. As i mentioned b4, this surface area is determined by the fins per inch of the w folded material between the tubes.
Most of the claims presented by the radiator manufacturers representatives (especially at big swap meets) is: "this radiator will cool engines of 500+ HP" without any regard to operating conditions. When asked about the Btu capabilities at what volume (GPM) of coolant and maximum air side inlet temperature, they usually tap dance and refer to "this model will handle 750 hp" so it will handle your _______(fill in the blank) HP engine. IF you look at the typical installation using electric fans, note that the fans do not cover the entire surface area of the rad, therefore do not utilize the total surface area of the rad...a real waist of effort and $$$$ in my opinion
Perhaps your hot start issue is related to the starter motor and solenoid assembly and/or fuel percolation? Have you ttied insulated the starter from exhaust heat (headers)?
For my $$$$ I want the most information available...if the vendor cannot supply it to your satisfaction, pass. You need to know what your buying.... do your own due diligence. An additional consideration: save your $$ on these snake oil additives...use plain water and a corrosion inhibitors or a 50% glycol water mix. Just my opinion of course.
Bob Renton






So pretty much stock running what you have in a stock block Is fine.

When you stroke out and bore is when the mods require a different approach i had a clutch fan and the stock 2 row with 3/4" tubes when i first did the engine swap and it wouldnt stay below 220. And the clutch fan put so much of a load it was ridiculous. From there we started with an aluminum rad then clutch fan and shroud no good then flex fan still no good on hot 90+ days so better pump and housing and we started to see 180 more then went with the twin electric fans and seemed ok but still would get to 230 on 100 days then switched to Evans coolant and was great until 100 days then the 230 temps again. Then distilled water and purple ice which is pretty good but then at idle we got to 225 and this is where we are at needed the flowkooler to keep the at idle temps down which it does well. Now to find that perfect balance i will switch back to a 180 stat but a high flow instead of a stock stant.
 
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