Overheating at idle

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Would a 7 blade fan be worth a try?
Yes, it is what the "book" calls for.


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OP, this was answered correctly in post 9.

You need to over drive the water pump. And the fan. Low speed cooling issues are usually a water/air issue.

If CVF has a 20% over driven pulley set please post up the part number.

I’m at 6% over right now but I would gladly go 20 over.
CVF serpentine kits as mentioned have 6.4" Crank & 5.3" Water pump pulleys. Their V belt pulleys are 1:1.
Part #'s as follows:
360-SERPENTINE-ALT (Alternator only)
360-SERPENTINE-PS (Power Steering)
360-SERPENTINE-AC (AC & PS)
These are polished. Prefix with B- for what they call their stealth black finish.
 
I ran the car this evening and found a ton of HOT air is just spewing from under the car. I suspect that a lot of this hot air is cycling back through the rad. I was going through some parts and noticed I haven't installed the splash guards yet. Not sure if thats going to be a game changer with airflow? I took some pics and in the green highlighted areas, would adding some panels to cover those areas be beneficial? I'm thinking maybe than hot air won't be short cycling back through the rad and seems like a lot of the newer vehicles have plastic that is covering this area.

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I've preached that a lot on here before and it falls on deaf ears. You look at every new car made and the under side of the engine bay is closed off so that air has to be forced through the grille and radiator.
 
Also, 3 row radiators have less cooling area than 2 rows. More is not always better. Most of the time when you see someone on here with cooling problems, they just put a new 3 row radiator in….
Well......not all of them are less efficient. Most of the el cheapo chinkesium radiators are, but a true 3 row high efficiency radiator will stomp the guts out of most any two row for cooling.
 
There is a LOT that contributes to rad efficiency. Copper tube rads are limited to tubes about 1/2" long because of copper's poor strength. Alum tubes are often 1 or 1.25" long. The extra length allows for much more fin area. Even though alum is not as good as radiating heat as copper, the great increase in fin area & fin design result in a more efficient radiator. The fins are what dissipate the heat...
 
I have verified my 180 high flow stat is fully opening with the pot of water on the stove method prior to installing. I did some research on overdriven pulleys and found the only way to get anything overdriven was to change the entire pulley set up to serpentine like the CVF 1:20 set up as the stock overdriven pulleys are super hard to find. I figured I would try the stock non AC Pulley I had as that wasn't really in the budget at the time.
I would look for an A/C WP pulley.
 
Going to try a new radiator cap today as that's the cheapest easiest thing to do. If that doesn't work I do plan on trying to find a 7 blade fan. I'm not sure about the pulley swap just yet as they are super hard to find and the 1:1 ratio available from cvf is too small of a difference to justify. Also going to try directing more air through the front of the Rad by playing around with some panels under the car to prevent hot air short cycling back into the Rad.
 
if it were me...
put a stock water pump and thermostat in your cooling system. A stock mopar water pump flows 20% more than a GM or Ford. The stock thermostat will keep your coolant in the rad longer.
Get rid of the clutch fan...they operate at about 80% speed at idle due to fluid slip.
Try a little more initial timing. Retarded will put the fire in the heads rather than the cylinders where the coolant will absorb the heat. A good test is to check and see if your headers glow in the dark.
If that all fails..just open the vault and get a griffin muscle car rad with 1 1/4" tubes. Then go find a red light and sit there without worry at an ambient temperature of 90 plus.
I was told in the early 1970's that a 340 A/C WP impeller had one less "blade" on it.
I believe Caterpillar rads had alternate tube rows at a slight angle so that the air exiting from between two tubes in the first row, was directed at the sides of tubes in the next row.
2 row, 3 row, and 4 row radiators are somewhat counter productive. All the coolant is passing through all the tubes at the same time. The front row gets the coolest air. Each consecutively gets warmer air, reducing its effectiveness.
A cross counterflow radiator is more effective. You can not buy them, you have to build it. Your coolant will flow horizontally like most new vehicles. You look for an aluminium radiator with a width that will fit your core support. Take a measuring tape to a wrecking yard to find a couple of vehicles with adequately large cores. Then check for new radiators that are less expensive from the same manufacturer, you will need two.
With the plastic tanks removed, you need to build or have a welding shop weld hot and cold tanks with hose connections. These will both be on the left or right side, so the tanks will be tapered so the one hose will pass the other tank. For the other ends, you need a small radius 180° aluminium bend to weld between the two tanks where the coolant will make the 180° turn out of the rear core and into the front core. Then you need another piece for the outside and two end caps to seal it up. On the hose connection end 3- 1" tabs can be welded between the welds between the tanks and cores. Small "channels" can be bent and welded to the left and right ends to seal the air between the two cores. A bit of foam pushed between the tabs to seal the hose connection end tanks.
Hot coolant goes into the top hose connection on the rear core and the coolant returns to the WP from the lower hose connection on the front core. The hottest coolant is cooled by the warmer air. Then the coolant returns to the other end through the front core to be cooled by ambient air. This should keep coolant flow velocity in the tubes high enough to be turbulent, increasing efficiency.
Paul Lamar described this in his royaryeng.net blog or chat. Yes I know, rotary engines and aircraft. Paul has diagrams for this in the discussion. Consider this, rotary engines are notoriously difficult to cool, aircraft run at 75% power for hours, and weight is a concern. Paul passed about 4 years ago. Sad loss as he was very intelligent and inventive. Should still be able to find the site.
I just tried to find the original site, but since Paul passed, it has been changed. I sent an email to see if the original site can be accessed or if I can get a pdf of the cross counterflow radiator process. Paul Sr used two Dodge diesel radiator cores to build a radiator for a time to climb aircraft. This light kit plane had a 650HP two rotor engine that ran on methanol. It is now at the Smithsonian.
They had problems with the injectors getting plugged with corrosion in the aluminium fuel lines after sitting for a week or two. I wrote Paul and explained that Indycar teams drained the methanol every night and put a gallon or two of gasoline in the tank and started it until it ran crappy, indicating the fuel system was purged of methanol. The next time they needed to run the engine they drained the gasoline and put methanol in.
They started doing that with the time to climb engine, and had no more problems.
Hopefully I get a positive response from Paul Jr or another admin.
 
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Going to try a new radiator cap today as that's the cheapest easiest thing to do. If that doesn't work I do plan on trying to find a 7 blade fan. I'm not sure about the pulley swap just yet as they are super hard to find and the 1:1 ratio available from cvf is too small of a difference to justify. Also going to try directing more air through the front of the Rad by playing around with some panels under the car to prevent hot air short cycling back into the Rad.

I can pull out the receipt and give you the part numbers for V pulleys that will get you to 6% over. If you are less than 1:1 now and you can get to 6% over that’s a huge increase.

But, I will say you will have to do some shim work to get the pulled lined up. IIRC I’m using. BBM WP pulley and a small block crank pulley. Or the other way round. But it’s not hard to get them lined up.
 
I can pull out the receipt and give you the part numbers for V pulleys that will get you to 6% over. If you are less than 1:1 now and you can get to 6% over that’s a huge increase.

But, I will say you will have to do some shim work to get the pulled lined up. IIRC I’m using. BBM WP pulley and a small block crank pulley. Or the other way round. But it’s not hard to get them lined up.
Thanks! I would greatly appreciate those part numbers when you get a chance.
 
So tried the new radiator cap (MOTORAD 16 Psi), took it for a nice cruise with very normal operating temps 180-200 depending how fast I was going, brought it home sat in the driveway idling in park for approximately 15 mins and slowly temp increased up to 235 so I shut it off. I could hear coolant going into the recovery bottle. Don't have the IR gun yet but see pics for some temp readings I took of the incoming air going into the rad. Air coming in the bottom through the open space under the bumper is SIGNIFICANTLY higher by 33 degrees. So I'm going to try to cover that spot up with something and recheck.

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