302 Thermal Control

[jbow03]

I was able to sort out all my radiator hoses and connections and things are tight and not leaking! Today, I brought the motor up to temp for the first time and things looked great. The fan came on at 190 degrees as it should, but the temp never got low enough for the fan to cut out. Nothing overheated, but I was hoping the system would be sound enough for the temp to rise... fan on, temp fall... fan off while at idle on a fairly mild day.

Here's my setup:
-302 Motor
-Mild Cam
-GT40P Heads
-Stock Reverse Rotation Water Pump
-180 Degree Thermostat
-FFR Supplied 20LB Radiator Cap
-FFR Supplied Overflow
-FFR Supplied Radiator
-FFR Supplied Fan
-Holley Sniper 2 EFI + HyperSpark Ignition
-Holley set to turn the fan on at 190 degrees and off below 180

I've seen where people use an alternate fan that's quieter and moves more CFM, but I'm surprised that on a fairly mild Texas day like today (85 degrees and inside the garage with the door open) it couldn't keep the heat down. Worried about 100 degrees that will be coming in June/July/August!

Ideas or thoughts? Thanks!

[SteveWorth]

I think that your water pump maybe rotating the wrong way.
My engine is a Blueprint 302 and their recommended water pump was a standard rotation described as clockwise.
https://blueprintengines.com/collections/water-pumps/products/aluminum-mechanical-water-pump-ford-sb-289-302-351w-passenger-side-satin-bpp16230

The accessory drive is a V-belt.
I have the same setup as you with the Sniper 2 controlling the fan - set to come on at 195 and off at 185. Running the car in the garage the temperature tracks correctly.

Hope this helps!
Steve

[gbranham]

If you've got your Sniper set to shut off the fan at 180 degrees while the car is idling in your garage, you're asking too much, in my opinion. Maybe set your Sniper to shut off at, say, 185 and see how it goes. FWIW, I've learned that EFI setups like a 195 degree thermostat. That's what I have on my 427 with Edelbrock EFI, and I have my fan temp shutoff set at 195. When the car is simply idling in the driveway, the fan will cycle frequently to try to achieve 195 degrees. While driving, it gets cooler. I also opted for a lower pressure fill cap, at 10 lbs. 20 lbs seems like a lot to me.

Greg

[BUDFIVE]

It took a while but eventually I got the cooling system working right on my 347 (302 based) last summer (in Texas). A few comments:
1) I think Steve and Greg are on track. Since the Sniper fan off setting is 180 that’s too close to the 180 deg thermostat. A good next try would be 195 on, 185 off. This still has 10 degrees of hysteresis but the range starts 5 above the thermostat.

2)To have proper cooling, It’s important to have all the air out of the system, replaced by coolant. Is the FFR supplied radiator cap vented? With this system (Overflow reservoir) we want a vented cap. I didn’t know there were so many different radiator caps. I ended up with a 16 psi vented cap (16 psi outflow open, vented for vacuum inflow).

How does it work? This detail may help someone on the forum reading the thread:
-Once the system is mostly full, and with the FFR style overflow tank nearly full, start and run the engine until fully warmed up.
-When the hot engine is turned off, as the system cools and contracts it pulls a vacuum, sucking fluid back from the overflow tank through the vented cap into the system, displacing air. Let the system fully cool.
-Do not open the radiator cap to fill, rather open overflow tank, note how much fluid left then refill it.
-Repeat above until after a cool-off the overflow tank remains at same level. Then the system is full of water. After this, the water shouldnt leave the system unless it overheats. When the ambient temperature rises and the water in the system expands, the system will be under slight pressure, but not 20 psi (or 16) to open the radiator for outflow. But when you open the radiator cap, you will lose fluid.
In the cap bottom pic the red arrow points to the vent. If the cap is vented you can grab this smaller plunger and easily pull it open with your finger nails.
213618

[austinsnake]

Good summary, Buddy. Thanks!

[jbow03]

Here’s (https://lmr.com/item/LRS-38501B/mustang-ford-motorcraft-water-pump-pw291-79-93?sc_src=email_2051103&sc_lid=290659857&sc_uid=Rf6578VnJX&sc_llid=1192609&utm_source=emarsys&utm_medium=email&utm_campaign=Triggered_Order+%7C+Order+Received+Fi nal-2019-12-18+17%3A53%3A00&utm_content=&sc_eh=f3fbbc33d9612dbe1) the water pump I purchased, it say reverse rotation and so I’ve got it setup that way with a CVF serpentine belt system.

I’ll try the fill cycle tomorrow, are caps fairly easy to find and common type? Going to try the auto store tomorrow. Thanks for the help!

[Blitzboy54]

Here’s (https://lmr.com/item/LRS-38501B/mustang-ford-motorcraft-water-pump-pw291-79-93?sc_src=email_2051103&sc_lid=290659857&sc_uid=Rf6578VnJX&sc_llid=1192609&utm_source=emarsys&utm_medium=email&utm_campaign=Triggered_Order+%7C+Order+Received+Fi nal-2019-12-18+17%3A53%3A00&utm_content=&sc_eh=f3fbbc33d9612dbe1) the water pump I purchased, it say reverse rotation and so I’ve got it setup that way with a CVF serpentine belt system.

I’ll try the fill cycle tomorrow, are caps fairly easy to find and common type? Going to try the auto store tomorrow. Thanks for the help!

You have the correct water pump. Serpentine requires a reverse. To your original point I live in the NE and had the opposite problem. I had a hard time generating enough heat to keep the engine and my heater core warm in the fall. I moved to a 195 thermostat.

You will be fine with your current setup. The radiator is huge. I went with an external fan speed controller on my current build that oscillates the fan speed to maintain a fixed temp. Most of the time you can’t hear it. It would only go full tilt if it needed to.

[MB750]

Since the fan came on and the temp didn't keep going up, IMO you don't have a problem. Especially if this is a brand new engine with a full rebuild. Those tend to run a little warm until break-in is complete.

I'm assuming you have the head gaskets in the correct orientation? (coolant pass-thru ports at the rear of the engine)

Also, when you filled with coolant did you open the upper radiator drain? That allows air to seep out as the fluid level rises. I managed to add another quart doing that.

Put the early miles on around your home, and have someone on retainer to come drag you back if the coolant gets up past 240F and doesn't show signs of dropping.

[rich grsc]

The fan is NOT going to cool below thermostat temp, setting and idling, nothing wrong with you system

[BUDFIVE]

Jbow03, Peeling one more layer of the onion: Ford had a dozen different timing covers that were used on the SBF. Some were changes when they went to a serpentine belt and reversed the water pump rotation (from CW to CCW as viewed from the front). Some were changes because they needed new or different mounting bosses for other rotating accessories. Some timing covers supported std rotation (CW) water pumps and some supported reverse rotation (CCW) water pumps. So, Steve’s Blueprint motor with a standard rotation WP may (probably) not accept a reverse rotation WP. I think I remember you started with an 2000-2001 Explorer 5.0? If so, that motor had a reverse rotation WP so you should be fine using another reverse WP.

[jbow03]

Thanks again guys for all the feedback.

So the head gasket, my answer is “I think so”. I knew it could be an issue so I spent lots of time reading and prepping for that install. I think I got it right with a good (and correct) Fel Pro, but time will tell. This is probably another reason I’m overly sensitive to any potential heat issues! Trying to catch them now while the body is off if something like a new head gasket install is in my future!

[CraigS]

One hint for helping to get the thing full in the first place. There is usually a threaded hole in the intake a couple of inches behind the T-stat. It may be plugged or it may have a heater hose attached. When filling the engine via the T-filler, if you unplug this hole, it will allow air to come out as coolant goes in. I fill until coolant leaks out the hole, cap it or reinstall the heater hose, and then try to get a few more ounces into the T-filler. Then install the pressure cap. As BUDFIVE says, once you install the pressure cap you don't remove it. Do all topping up at the overflow tank. Eventually you will get it so when cold the tank is 1/4 to 1/3 full and when hot it is 2/3 to 3/4 full.

[Nigel Allen]

Is the fan running in the right direction? Could be wired incorrectly.

[jbow03]

Changed the fan parameters and filled per instructions. On at 195 off at 185.

Cycles like a dream. Thanks everyone!

[skidd]

I was just about to suggest bumping up the on/off temperatures. You had them too low IMO. These 302s in OEM cars run 200f-210f all day. Don't sweat the fan coming in above the 185f thermostat.

I just have a simple 210f thermo fan switch in mine. Fan comes in quick at 210, and shuts off about 190ish. It's not very precise. But, keeps the fan off for normal driving with plenty of airflow, and kicks on during traffic and lights.