Which one flows better, factory 6 blade water pump or 8 blade

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Mine overheats when idling. Measured my pulleys, 7 1/4 crank, 5 3/4 water pump, so I have about 1.26 ratio which is about what YR has shown in the manual for ac. I bought the stock water pump about 2 years ago & lost the box. Just put it on. Think it was a six blade. Wish I took a picture.

My old water pump was a 8 blade. Did I reduce my flow going to the 6?

Has a Hayden thermal clutch, Mopar 7 blade fan, new cold case radiator, good fitting improvised shroud. It over heats when idling with ac on or off.

Think my next move might be high flow thermostat. Does anyone have a favorite? Milodon? Stewart?

View attachment 1715569375

View attachment 1715569376

View attachment 1715569377


Stewart Components for the thermostat.
 
what shroud is that?

It is two top halves of a Ford Explorer shroud. The bottom of the Explorer shroud wasn’t close, so I used two top halves. I really like the two piece feature for access. I am too cheap to pay for a repop, this was $5 at pick & pull. I can post some details if you are interested
 
the thermostat regulates to a minimum coolant temp, unless it sticks.
The maximum is governed by the ability of the designed system to get rid of heat. Stopped, at idle, with the hood closed, is usually the hardest case.
Your fan is trying to create a low-pressure in the shroud. Higher pressure atmosphere is trying to oblige, but with the hood closed; the engine is loosing heat right thru it's mass, and the headers are cooking everything in sight,together those two are opposing atmosphere right at the shroud. And if the engine is simultaneously sucking that almost super-heated air, it is just feeding the fire. No fresh air is entering the underhood, because you have sealed the cowl and sealed the core-support. so the underhood air is like a runaway nuclear reactor.
So some of that hot under-hood air finds it's way into the shroud and voila , no low pressure. No low pressure PLUS the air there is now 300 to 400 degrees.
The rad depends on the atmosphere pushing it's way thru it. Atmospheric pressure is very low, compared to what a 7-blade hi-pitch direct drive fan can create in a tight-fitting shroud. But when the underhood pressure is greater than the pressure in front of the rad, it just can't do it...... at idle.
The proof is in the pudding; just open the hood and let the hot air out. Then increase the engine speed to restore the low pressure area in the shroud.
The tight-fitting shroud and hi-efficiency factory style fan are your number one warriors in the battle for cool air.
You have to stop thinking that the fan somehow sucks; it does not suck.
The fan just moves air. It flings air radially towards the tips. When the air leaves the tips, it is supposed to hit the shroud and redirect towards the rear. But if the shroud is too far away, or the pressure on the engine side is higher, then the air will be much more willing and eager to return to the just-created low-pressure area in front of the fan. The hi-pitch factory fans have the tips bent to the rear, in an effort to reduce the air from going back around the front. The tight-fitting shroud acts like a duct, slamming the door to wrong-way air.
After that, only the rad stands in the way of higher pressure atmosphere from dive-bombing the engine. But you gotta help it.Your fins have to be clean, bare, and straight..
By personal experience;
I have found the Chrysler hi-efficiency, all-steel, hi blade-angle, curved-tip, large diameter,direct-drive fan, to be the best candidate for the job; in a tight-fitting shroud,half-way into it. If the rest of your combo is set up right, it will be impossible to overheat your engine. Once you have proved your system works, then you can start taking short-cuts.
The first short-cut I took, was to get the same fan in a clutched version, and installed a thermostatic clutch on it. An early 2000s Ford Pick-up showed up in the shop one day, and I heard that clutch cycling, and I just had to have one of those. On lunch-break, I went straight over to the dealer and got me one.
With those two settled, and the hi-flo Milodon, the Hi-flo stat,the blocked bypass, 14* of idle-timing, and fresh cold air to the carb, My overheating days were over.
The second short-cut I took, was to underdrive my pulleys in a preemptive strike against the belt derailing at 7200 rpm. I have a 4 speed, so as soon as the car is moving, it is rarely under ~2000 rpm.
In my system the 195 stat sets the minimum temp closer to 205*, And the T-clutch sets the max to ~207*
This; with a factory 1973 26" 2-row, A/C ,Dart rad, in a 22" factory core-support window. And no header-wrap. Hood seals still in place. Hood all the way down, all around, no tricks.
My rad runs 30* cooler at the bottom than at the top; so 207/177 or thereabouts, at idle, with the hood open mind you, so I can shoot it with the IR gun.
At the time I set this up the 367engine was running a 292/292/108 DC cam, with OOTB Eddies at 11.3Scr and the same 14* of idle timing. Since then, that engine saw a 270/276/110 at 10.7Scr , and currently runs a 276/286/110 at 10.95Scr. The cooling system has been rock-steady since year 2001, with no other cooling system changes..
Happy HotRodding.
 
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It is two top halves of a Ford Explorer shroud. The bottom of the Explorer shroud wasn’t close, so I used two top halves. I really like the two piece feature for access. I am too cheap to pay for a repop, this was $5 at pick & pull. I can post some details if you are interested
awesome. if you have something showing how you mounted everything up :thumbsup:
 
awesome. if you have something showing how you mounted everything up :thumbsup:

I’ll take some more pics this week. It took a lot of fiddling, but nothing hard. I trimmed the Ford mounting tabs off and used Allen head cap screws To fasten it to the oem radiator mounting holes and some self tapping screws to hold the two halves together.

The one potential deal killer on this is that it doesn’t have the Mopar offset on the shroud. You have to scoot the radiator as far as you can to the passenger side to get clearance. I remounted my radiator about a half inch farther right to get a little more clearance. Also would depend on what fan diameter you had.

If you have moral objections to paying $200 for a fan shroud and you like to tinker, this is a probably a good project. I bought a couple sets of shrouds so I could have some practice. I got 4 tops and they charged me for two shrouds. $10. You would likely have to pull the radiator to do it. Looks nice when it is done.
 
the thermostat regulates to a minimum coolant temp, unless it sticks.
The maximum is governed by the ability of the designed system to get rid of heat. Stopped, at idle, with the hood closed, is usually the hardest case.
Your fan is trying to create a low-pressure in the shroud. Higher pressure atmosphere is trying to oblige, but with the hood closed; the engine is loosing heat right thru it's mass, and the headers are cooking everything in sight,together those two are opposing atmosphere right at the shroud. And if the engine is simultaneously sucking that almost super-heated air, it is just feeding the fire. No fresh air is entering the underhood, because you have sealed the cowl and sealed the core-support. so the underhood air is like a runaway nuclear reactor.
So some of that hot under-hood air finds it's way into the shroud and voila , no low pressure. No low pressure PLUS the air there is now 300 to 400 degrees.
The rad depends on the atmosphere pushing it's way thru it. Atmospheric pressure is very low, compared to what a 7-blade hi-pitch direct drive fan can create in a tight-fitting shroud. But when the underhood pressure is greater than the pressure in front of the rad, it just can't do it...... at idle.
The proof is in the pudding; just open the hood and let the hot air out. Then increase the engine speed to restore the low pressure area in the shroud.
The tight-fitting shroud and hi-efficiency factory style fan are your number one warriors in the battle for cool air.
You have to stop thinking that the fan somehow sucks; it does not suck.
The fan just moves air. It flings air radially towards the tips. When the air leaves the tips, it is supposed to hit the shroud and redirect towards the rear. But if the shroud is too far away, or the pressure on the engine side is higher, then the air will be much more willing and eager to return to the just-created low-pressure area in front of the fan. The hi-pitch factory fans have the tips bent to the rear, in an effort to reduce the air from going back around the front. The tight-fitting shroud acts like a duct, slamming the door to wrong-way air.
After that, only the rad stands in the way of higher pressure atmosphere from dive-bombing the engine. But you gotta help it.Your fins have to be clean, bare, and straight..
By personal experience;
I have found the Chrysler hi-efficiency, all-steel, hi blade-angle, curved-tip, large diameter,direct-drive fan, to be the best candidate for the job; in a tight-fitting shroud,half-way into it. If the rest of your combo is set up right, it will be impossible to overheat your engine. Once you have proved your system works, then you can start taking short-cuts.
The first short-cut I took, was to get the same fan in a clutched version, and installed a thermostatic clutch on it. An early 2000s Ford Pick-up showed up in the shop one day, and I heard that clutch cycling, and I just had to have one of those. On lunch-break, I went straight over to the dealer and got me one.
With those two settled, and the hi-flo Milodon, the Hi-flo stat,the blocked bypass, 14* of idle-timing, and fresh cold air to the carb, My overheating days were over.
The second short-cut I took, was to underdrive my pulleys in a preemptive strike against the belt derailing at 7200 rpm. I have a 4 speed, so as soon as the car is moving, it is rarely under ~2000 rpm.
In my system the 195 stat sets the minimum temp closer to 205*, And the T-clutch sets the max to ~207*
This; with a factory 1973 26" 2-row, A/C ,Dart rad, in a 22" factory core-support window. And no header-wrap. Hood seals still in place. Hood all the way down, all around, no tricks.
My rad runs 30* cooler at the bottom than at the top; so 207/177 or thereabouts, at idle, with the hood open mind you, so I can shoot it with the IR gun.
At the time I set this up the 367engine was running a 292/292/108 DC cam, with OOTB Eddies at 11.3Scr and the same 14* of idle timing. Since then, that engine saw a 270/276/110 at 10.7Scr , and currently runs a 276/286/110 at 10.95Scr. The cooling system has been rock-steady since year 2001, with no other cooling system changes..
Happy HotRodding.

AJ, the picture is what my fan set up looks like. It is a seven blade fan off a 80s dodge truck. Is this a good fan?
I have a Hayden 2947 thermostatic fan clutch and a new cold case radiator, and a stock 180 t stat. My shroud fits very tight and contains the whole width of the fan.

It goes from 190 Cruising to 230 idling with the ac on after a few minutes. I don’t know if it would go higher, I stop it because I don’t want to over heat.

I bought a milodon t stat I have not installed yet. It is a pain to install with factory air. If this doesn’t work, I think high flow water pump is next?

9B573719-DB50-4FDC-A1C6-BBAF2467CAA6.jpeg


E7CA5860-0621-46F3-B59B-A1FB2636384F.jpeg
 
the fan looks a little deep in the shroud. usually you want about 1/2 of it outside
 
the fan looks a little deep in the shroud. usually you want about 1/2 of it outside

I have heard that more than once, but it it makes no sense. It would seem that configuration would only reduce efficiency. Electric fans are not designed that way, nor is any application that I can think of. Walking through pick & pull looking for fan shrouds, I didn’t see that once.

I am speaking with no real data to back me up, so mine is just an opinion.
 
I have heard that more than once, but it it makes no sense. It would seem that configuration would only reduce efficiency. Electric fans are not designed that way, nor is any application that I can think of. Walking through pick & pull looking for fan shrouds, I didn’t see that once.

I am speaking with no real data to back me up, so mine is just an opinion.
i've seen stuff both ways, the fan comapnies say 1/2 & 1/2, so who knows...
 
i've seen stuff both ways, the fan comapnies say 1/2 & 1/2, so who knows...

Yeah, I am certainly not an expert. That is the trouble with the internet, it is hard to tell facts from opinions. Back in the day, my dad used to refer to some things as “old wives tales”.....
 
Yeah, I am certainly not an expert. That is the trouble with the internet, it is hard to tell facts from opinions. Back in the day, my dad used to refer to some things as “old wives tales”.....
back in the day? some of us are old enough to still call them that :lol:
 
AJ, the picture is what my fan set up looks like. It is a seven blade fan off a 80s dodge truck. Is this a good fan?
I have a Hayden 2947 thermostatic fan clutch and a new cold case radiator, and a stock 180 t stat. My shroud fits very tight and contains the whole width of the fan.

It goes from 190 Cruising to 230 idling with the ac on after a few minutes. I don’t know if it would go higher, I stop it because I don’t want to over heat.

I bought a milodon t stat I have not installed yet. It is a pain to install with factory air. If this doesn’t work, I think high flow water pump is next?

View attachment 1715569864

View attachment 1715569865
would that shroud fit a 22" radiator ?? any idea what year Ford Explorer you got it from ??
 
I don’t remember the years on the explorers. I just used the top halves of the explorer shrouds for the top and bottom of my shroud. They were only $5 for a shroud ( 2 top halves made one shroud) so I bought several to practice with. They fit my cold case 22 radiator really well with some hillbilly mods. If you are interested I can post pics.
 
I don’t remember the years on the explorers. I just used the top halves of the explorer shrouds for the top and bottom of my shroud. They were only $5 for a shroud ( 2 top halves made one shroud) so I bought several to practice with. They fit my cold case 22 radiator really well with some hillbilly mods. If you are interested I can post pics.
If you have the time, sure would like to see that. Thanks
 
It is two top halves of a Ford Explorer shroud. The bottom of the Explorer shroud wasn’t close, so I used two top halves. I really like the two piece feature for access. I am too cheap to pay for a repop, this was $5 at pick & pull. I can post some details if you are interested

I modded my alum shroud to be split in the middle , a lot of g m m pick ups are that way .
 
There is an interesting physics principle at work with respect to number of impeller blades and volume.

It's the same principle that causes a 4 blade ceiling fan to move more air than a 5 blade fan.

Don't ask me to name the principle, though.
 
I always wondered and thot about people saying to use the factory 5 blade fan , I dont see how it could move as much air as more blades , best I remember , it was for fan noise only.
Maybe already replied. The 5 blade is more along the lines of thinking while disengaged...it will let more air pass through it and not block it. Jmo
 
Thanks for the pictures. Looks great. Going to need to find an Explorer. Do you remember if it was a V8 ford ?? What size/number fan are you using ?

I don’t remember. There were a lot of slight variations in the shrouds. I bought the shallowest one I could find. I have used a seven blade clutch fan and also a six blade direct drive.

I still have not solved my idle over temp issue. Some say that the fan is supposed to be 1/2 way out of the shroud, but I have not been able to determine if that is real.
 
Update on my Ford Explorer shroud. Looks like it is too deep for my setup. Causes it to run hotter at idle. Looks like I will scrap it. Nice try, but looks like I failed.
 
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