429/460 Overheating Issue

[BOBOCobra]

I fought this for an entire summer. Similar issues. Here is how I fixed it.
Overdrive WP pulley. I had to make one as you cannot get an aftermarket pulley smaller than the crank. I did a 20% overdrive. 180 high flow t-stat. Brought idle temp down 10-15 degrees just by moving more water. Next, mounted 2 deraile high flow puller fans (need relays as amp draw is high), one comes on at 190, other at 205. Fully shrouded and covers 80% of core. shrouded fish mouth so ALL air goes through the rad. dropped temp another 10 degrees. I run 100 degrees over ambient on highway and max 210 in traffic on 105 degree days. Once second fan kicks on in traffic it cools down to 200. So, at WOT the pulley is spinning at 6500 rpm, tends to cavitate just a bit but air burps. I run WOT now and then, I run traffic every day, pick your poison. Move more air and more water and make sure rad is clean

[BOBOCobra]

Ran out of space but do the simple things before you start running lines from the back of the heads, etc... Again, you need air and water flow, and the reason you are getting hot is you are lacking on both. Key point you made is that it cools at 2500 rpm idle, you are simply moving more water so you need to do that at idle by spinning the pump faster and having a high flow pump without idle speed of 2500. I idle at 950, pump is almost 1200. The only way to dissipate the heat is move air through the rad fins. There is no such thing as too much. Pull through more air with shrouds and high CFM fans. My fans are as close to the rad as I can get and tilt slightly down to push the hot air down the tunnel. I use a 12# cap and spit about a pint into the overflow on a hot day. 521CID, 580 HP....I generate a LOT of heat

[cycleguy55]

Originally Posted by BOBOCobra

I fought this for an entire summer. Similar issues. Here is how I fixed it.
Overdrive WP pulley. I had to make one as you cannot get an aftermarket pulley smaller than the crank. I did a 20% overdrive. 180 high flow t-stat. Brought idle temp down 10-15 degrees just by moving more water. Next, mounted 2 deraile high flow puller fans (need relays as amp draw is high), one comes on at 190, other at 205. Fully shrouded and covers 80% of core. shrouded fish mouth so ALL air goes through the rad. dropped temp another 10 degrees. I run 100 degrees over ambient on highway and max 210 in traffic on 105 degree days. Once second fan kicks on in traffic it cools down to 200. So, at WOT the pulley is spinning at 6500 rpm, tends to cavitate just a bit but air burps. I run WOT now and then, I run traffic every day, pick your poison. Move more air and more water and make sure rad is clean

CVF Racing makes pulleys as follows:

• Crank Pulleys (1V, 2V, or 3V): 5.7" diameter
• WP High Flow pulley (1V): 5.4" diameter (5.5% overdrive)
• WP High Flow pulley (2V): 5.2" diameter (10% overdrive)

10% overdrive is what I have on mine - works like a charm.

Ford BBF V-Belt Pulleys: Ford 429 & 460 Big Block Engines

Custom may be the only way to go if you want more than 10% overdrive.

[BOBOCobra]

I went back and looked and I was actually wrong as I tried it a couple times, I ended up at 25% overdrive. 10% was minimal waste of time, 20% was close, 25% was right on. Crank pulley is stock 5.25" and WP is 4". I had to machine a small relief on the back side of pulley to clear the pump drive neck. Not a big deal. 2V drive. At idle I'm spinning pump at 1266 rpm but I run a C6, if manual you can idle at 1100 and spin the pump 1450 and it will move enough water to keep it cool unless there is a restriction or a huge air pocket. I do have a catch can and and overflow from the catch can an a 12# cap. I have a small 6AN air bleed line from high pressure side to catch can so any air comes out on hot side. Bottom of catch can drains to low pressure side rad outlet with 10AN. That allows some hot water to suction hose but it is small volume. It insures I never suck air at high flow condition as it pulls slightly from catch can, vacuum pulls air from hot tank and/or from overflow and keeps everything in a nice closed loop and bleeds the air out of the rad before it is pushed to low pressure side or creates a pocket in the high pressure tank. It may sound complicated but it is really very simple. A lot easier than drilling intakes and cross-overs.

[520SC]

Been following this thread for a while now. I'm working on a cooling problem as well. With just the original 4-row Griffin radiator and a 16" high wattage fan, the car can peak out between 235F and 240F when stuck in rush hour traffic (air temperature 87F). I added an HVAC aux heat exchanger and a 265 watt fan in front of the Griffin, tapping off the thermostat bypass line and returning to the inlet of the water pump. Hose diameter in this section of the system is 5/8" ID. Peak temperature in traffic is now 225F. An improvement, but I'm looking for 210F max. I'm soon to install a fan cooled oil to air heat exchanger. If I get a 5F drop, I'll be happy.

Now, to my "educated guess" with regard to big block engine cooling. You cannot follow the same rules you'd follow for a small block or a standard sized FE engine. 460 cid or larger engines will always require much more BTU removal capacity.

That being said, if I am unable to reach my goal of 210F (max), my plan will then shift to installing another "regular" sized radiator, to replace the HVAC aux radiator. I"m thinking it'll be a 3-row. It will tee off my main radiator hoses using a 2" tee and a 2 1/2" tee. I'll install a 16" high wattage pusher fan at the front of the car. So, the car will end up with two "full" radiators, one 4-row, and one 3-row.

No more messing around.

[520SC]

There are actually two completely different situations in which the car will run at a steady 225F: 1) Idling in rush hour traffic, and 2) On the highway traveling at 60 mph. My C6 transmission coupled with 3.73 rear end gears causes the engine to run at pretty high rpm, so it generates a lot of heat.

The "sweet spot" for my car (where it locks in at 210F) is 25 mph to 40 mph.

I agree that a puller fan is more efficient than a pusher fan, however, if I'm going to "stack" radiators (one in front of the other), I won't be able to fit a puller fan between them. So, I'll be running one puller fan and one pusher fan.

[BOBOCobra]

215 is kinda high for the "sweet spot", you have no cushion. Mine ran at 215 or so at ram on 80 degree days so I drove in traffic and shot the rad with a gun and there was a 30+ degree difference from inlet to outlet. That was way to much difference. I pulled the rad and it was full of gunk, either a bars leak or alumaseal type crap. I had to heat soak it and flush it 15 times and got half a small coffee can of crap out of it. that at least got my ram temp down to 190 and then I could do the rest. difference was then only about 10-15 degrees. inlet was 190, outlet was 175, ran about 195. It just seems odd you would need to stack rads on a street driven car, the back rad will be pulling hot air from the front rad... Have you made certain your rad is clean and you have no air pockets in the high pressure tank side? Water jackets are clean? Have you shot with a thermal for cylinder hot spots?

[520SC]

210F, not 215F.

What water source did you use to backflush the radiator. Seems like the water pressure and volume available in my garden hose wouldn't move much out of there.

[520SC]

"the back rad will be pulling hot air from the front rad."

A similar situation exists when someone swaps out a 2-row radiator for 4-row radiator. The front two rows deliver hot air to the back two rows, yet most will agree that the 4-row radiator will provide more cooling.

[BOBOCobra]

Sweet spot should be no more than 195.
Take it to a rad shop and have them boil it. The heat will loosen up any gunk in there and they can flush it out with pressure washer with hot water. Backflush the block to get the jackets as clean as possible in case there is crap in there and all your doing is pushing crap around.
If you want to try at home disconnect the upper and lower hoses. Take your hose and a 100 psi air hose with a long nozzle and trigger and stuff into the lower outlet and wrap with a rag to get it as water tight as possible, let the water fill up the rad so it is coming out the top inlet and then hold the rag, hose and air nozzle tight and blast with air. it will force a lot of water back through the core and out the top inlet. you then need to let it fill up again with water and repeat. Do it 4 or 5 times. If the water is dirty do it till its clean. It will make a mess but it gets a lot of volume through the core quickly until the air takes over and you have to refill. You can leave the upper hose on the rad and try to direct the flow away from the block. 2 person job, The problem is the water is cold and it wont loosen any hard gunky crap stuck in the tubes but it will flush the tanks and any loose stuff. Or, you can buy a new rad and do your best to backflush the block before you put it in. Ron Davis in Arizona will make one based on your CID and space. He is a good source to talk to.

[BOBOCobra]

Ron Davis will make one WITH the fans and shrouds properly done if you don't want to fab it up yourself. He might have a 3 month backlog this time of year (racing season)

[520SC]

Originally Posted by BOBOCobra

Sweet spot should be no more than 195.
Take it to a rad shop and have them boil it. The heat will loosen up any gunk in there and they can flush it out with pressure washer with hot water. Backflush the block to get the jackets as clean as possible in case there is crap in there and all your doing is pushing crap around.
If you want to try at home disconnect the upper and lower hoses. Take your hose and a 100 psi air hose with a long nozzle and trigger and stuff into the lower outlet and wrap with a rag to get it as water tight as possible, let the water fill up the rad so it is coming out the top inlet and then hold the rag, hose and air nozzle tight and blast with air. it will force a lot of water back through the core and out the top inlet. you then need to let it fill up again with water and repeat. Do it 4 or 5 times. If the water is dirty do it till its clean. It will make a mess but it gets a lot of volume through the core quickly until the air takes over and you have to refill. You can leave the upper hose on the rad and try to direct the flow away from the block. 2 person job, The problem is the water is cold and it wont loosen any hard gunky crap stuck in the tubes but it will flush the tanks and any loose stuff. Or, you can buy a new rad and do your best to backflush the block before you put it in. Ron Davis in Arizona will make one based on your CID and space. He is a good source to talk to.

I'm scheduled for an appointment at a radiator shop for Tuesday morning. There's nothing currently adding to radiator inlet can clogging (if, indeed, that is the problem). The engine is brand new. The Griffin radiator was the only major component I reused. The engine that came out of the car had a rotten water pump and backing plate, and I could see evidence of rust at every water hole in both head gaskets.

[FWB]

get rid of the flex fan, they move less air than a factory fan

[ByronRACE]

Backwards head gaskets directs all the water flow into the front 1/4 of the block; the rear overheats. Water has to flow across the bottom, then up, and back across the top. I've seen it done wrong a number of times. Under heavy load, it'll boil the water in the rear and overheat everything badly if it's under load. One of the instances was in a jet boat. Because of the plentiful cold water and using the lake for the cooling system, it didn't show the problem except the gauge...and that went from normal to "pegged hot" faster than the owner noticed. Total loss. It was at WOT for a good 10 minutes like that before it melted stuff and started banging.

Additionally, if you want the 460 to burp well in a Cobra, make a hole in your intake manifold on both sides in the rear, drill and tap for small pipe to hose fittings, and run hose forward to your filler neck, which should be higher than your heads. You want the fittings to flow a tiny amount of water; make the flow path no bigger than 1/8" per side. It's just for air bypass. Do that and you'll never have trapped air in the rear even if the nose is pointed downhill when you fill the system. Without it...you may. It's hard to find a filler neck that works well in a Cobra. I forgot where I got the basis of mine; I modified it quite a bit. I don't like the big burp tank in the front; with a neck like this...there's no need for it.

http://www.racesystems.com/cobra/images/Running1.jpg

[Speedwaypj]

Lots of good info all - thx for the response....

The radiator is new; and I have taken it off and back flushed.....seems to flow fine. I keeps acting like it has air....

- I believe I need to get a surge can on it to give the water someplace to go.
- I ordered a "Cooling System Vacuum Purge And Refill Kit" to try to eliminate any air pockets...
- I plan to drill/tap rear of Edelbrock Intake where the rear water passage hit the intake and install petcock to relieve any air that may be trapped there.
- Sounds like an undersize water pump pulley might help.
- need to check total timing.
- I plan to add two front fans (ERA type); currently have flex-fan with shroud.

There is a lot of knowledge on this forum...thank you all.
PJ

[ByronRACE]

What about the backwards head gasket issue? I know it's a pain in the butt, but you have to get that right.

Surge can is completely unnecessary unless you have air in the system or don't have a high point for filling.

The rear air bleed is a great idea. I would not install a valve...you want that bleed path present all the time in the event of thermonucleatic boiling in the heads that cause air pockets to form over time. You know those tiny bubbles that seemingly form out of nowhere on the bottom of your sauce pan when making pasta? That happens in your heads too. Those tiny air bubbles will collect back there and before you know it, you have a big air pocket. Look at some factory high performance engine designs and you'll find these bleed paths are either there from the factory, or added afterwards by those that push their engines and have discovered the problem.

Timing is unlikely to do what you're describing. If it was that far off, your exhaust would be glowing red or it would be running so bad you wouldn't have had it running for that long before you shut it off.

A mechanical fan and shroud will provide more flow than your planned pushers. If you want powerful pushers, look at SPALs offerings. Push fans are not nearly as effective as pull fans. You will burn twice the amps making a push fan work. Do this only if you have to; pull fans are much better if you have the room for it. I didn't have room; believe me I tried; and am running a pair of powerful SPAL pusher fans. They draw over 80amps at first power on, and over 40 amps sustained on high. I run a 200A alternator mostly because of the fans.

http://www.racesystems.com/cobra/ima...nSpal1750s.jpg

My radiator is a huge, heavy, ridiculous brass monster made by some supplier for West Coast Cobra in Canada. If the car is moving at all, the fans are off. This includes road race duty in hot weather. They don't come on until I pit. I hate the weight and bulk and over-all appearance of the radiator, but boy does it work. http://www.racesystems.com/cobra/images/radiator2.jpg

If I did it all over again, I'd let Matt design the whole thing...radiator, fan, and Shroud assembly...with my Meziere water pump built into the radiator tank. That would probably take 30lbs off the nose of the car. https://the-fan-man.com He's also a good source for the SPAL fans if you're looking for them.

[Speedwaypj]

FWB said - you keep mentioning a flex fan, gives me an image of a cheapo aftermarket mechanical fan"
Actually, What I am using is similar to this: Flex-a-lite 1317: 17" Stainless Blades Blue Center | JEGS

[FWB]

Originally Posted by Speedwaypj

FWB said - you keep mentioning a flex fan, gives me an image of a cheapo aftermarket mechanical fan"
Actually, What I am using is similar to this: Flex-a-lite 1317: 17" Stainless Blades Blue Center | JEGS

that is exactly what i envisioned, you simply are not moving enough air through your rad. get rid of that fan. its for teenagers from the 80's to put on their camaro for bling.

buy one of these used and install it, you will thank me later.
93-96 lincoln mark VIII fan and shroud assembly make sure you get about 8 inches of harness with the plug.



you are comparing your close to stock motor to Byrons, which had twin turbo's and was a beast, i do love it. but you are doing modifications that will not fix the fact you have no
air going through your radiator to cool it

[Speedwaypj]

Thanks....If I go to a used electrical fan that mark VIII fan is tops from everything that I have read. As far as a new fan, it seems like a SPAL would be a good choice.

[Speedwaypj]

ByronRACE thx... I was only going to do the petcocks because I'm not sure if that is the issue...then I would plumb it in.... but from what you say, maybe I'll plumb it now.

- checking Temp Delta.. but what/ where? Radiator Input vs output? What's a good value ?? 10 ; 15; 20 degrees?
Air delta? I have an infrared Thermo gauge but suggestion for Air medium?

Sooo would any of these following points below hold water(not really a pun).......or can crack/void be so small it only leaks under running high cyl pressure?
- Wouldn't the compression test indicate bad head/block/gasket?
- Wouldn't the radiator test (26/28 hrs) indicate bad head/block/gasket?
- I've run it for about an hour several times...if bad head etc, wouldn't it burst the hoses? Max was 20 PSI..

I'm pulling the intake today to drill/tap for petcocks (maybe bleed lines)....but i'll wait until I get my "Cooling System Vacuum Purge And Refill Kit" from ebay($35 investment) to add coolant.....
Have any of you used the vacuum purge system? YouTube videos look logical...

thx again all!
PJ