New Build 440 overheating

[Chryco Psycho]

I agree the slits are designed to force coolant all the way to the back of the heads not just bypassing at the front , opening those will cause more damage

 

[aar2244]

Been through this with 540 hp 440 with vintage AC. 4 core radiator is not ideal, went with a Ron Davis unit two 1" rows, but the key is the electric fans, two 13" Spal fans with 3554 combined cfm. Runs at 180 degrees at idle with AC on in 95 degree Florida weather. Like most guys building a car we always look for the best prices $400 champion rad with poor cfm electric fans, then tried cold case $600 with better fans. Then spent $1500 on Ron Davis but guess what, you get what you pay for, works great. Moral is don't cheap out on cooling system. Also used high flow water pump and thermostat(160).

 

[aar2244]

Just another note, every application is different. You don't need to spend 1500 on rad, shroud and fans if not needed. I also have a 440 with an 871 blower on it. I run it with no hood, champion 3 row radiator, no shroud(no room) and two 12" puller fans 2500 cfm. This motor will run at 185 going down the road, 195 at idle.

I would suggest start car(cold) with radiator cap off, when thermostat opens check flow, should be like a river. If it is not then water pump and thermostat should be changed to high flow units. But I think your problem is air flow at idle. The electric fans don't have enough cfm at idle. Get some spal fans 3000 cfm or better with shroud.

 

[chargerdon]

My two cents. I agree with Physco that a good engine driven fan can create a much greater air flow that electric fans. HOWEVER, at Idle the engine driven fan simply isn't spinning fast enough to cool a High Performance engine with high performance camshaft. So, the most effective system is to use the engine driven fan to pull the air thru AND also add electric pusher fans so that at idle while stopped in traffic, you also get the benefit of the electric fans that spin the same speed at idle. With electric thermostat or a simple on off switch you can stop it while on the highway.

My only problem with that is that on my 74 challenger with air conditioning there isnt enough room between the condenser and the core suport frame for them to fit. I would have to go to the puller system on the engine side, and then of course i would lose the engine driven system.

Couple of suggestions ...in the summer time drain the 50/50 mixture of water/antifreeze and just use plain water PLUS a anti-corrosion additive. Plain water is about about 18% more efficient that 50/50 mix. If you live in cold climates put the 50/50 back in during the winter.

 

[Huskidrive]

How are you guys measuring your temps? Analog gauge, stock gauge or infared temp gun. I have a 1970 383 with a 22 inch 4 core copper/brass radiator...stock fan and shroud. My stock gauge sometimes climbs about 3/4 of the way to hot. I checked the thermostat housing with the infared gun and it read 184.7, I pointed it to the bottom outlet and it read 143.5. I'm pretty happy with those numbers. 90° ambient temp. Car driven for 30 minutes.

 

[DaveInDenver]

I have two Challengers that have undergone the same engine change-up, build design & overheating redults.

I recently changed out a 318 CID/904 Auto for a 440 CID/727 Auto. Installed a Holly Sniper fuel injection system.

The engine was built by a highly respected machine shop that focuses on race engines. We used standard heads, factory high performance exhaust manifolds, 15° advance, 4-core champion radiator with electric fans, new factory style water pump and 160° thermostat. Coolant is 50/50 water mix.

The Sniper's water temp reading runs about 195° to 202° in mixed driving. If I spend too much time at traffic lights, temps reach 225° or even higher.

I attempted to work any Trapped air out of the heads by raising the front of the car while the thermostat was open but no difference in results.

I thank everyone for your expertise & input....and the winning solution is using a 195° thermostat.

For years I have used 160° and never had a problem. I guess I was lucky! Never again...

 

[Steve340]

So are you saying you changed the thermostat and problem gone?

 

[DaveInDenver]

So are you saying you changed the thermostat and problem gone?

Yes
It is fixed
I drove it for 40 miles in 90° temperatures. The average temperature was 205• with a high of 208° when climbing hills. The 440 is still in break-in process.

 

[BSG]

The pics from Brice show the big triangle area on the spark plug side completely blocked off does the block have those as well? I would find it tough to believe that those 3/4 inch triangle cooling jackets are meant to just dead end there at the head gasket? Would it be too much to ask to add a pic of the block side?

 

[Chryco Psycho]

Many opening were to remove the sand casting from the core not just for cooling flow

 

[SmudgeServices]

I have this same problem
440 bored .30 over. freshly rebuilt in 2015, I'm not sure which head gaskets are on it. clutch mechanical fan with a shroud.
I've been through a variety of thermostats. despite the thermostat, she always runs well while moving (temp decreased) but when stuck at red lights for some time the temp starts to climb. I'm in Texas heat. originally a 180 thermostat. 160 delayed the climbing but once she was over 195 it gets out of control climbing fast.
installed a high flow water pump but didn't help so I installed a 3000 cfm electrical pusher fan. it helped slow the climbing but didn't stop it.
based on this thread I have a 195 i thermostat in now, runs about 205-210 while driving, a slower climbing temp when stopped, but definitely keeps climbing. luckily I haven't been stopped long enough for it to hit 220, that mark scares me.

idles at 800rpm... I figure I'll raise the idle rpm to 1000 or 1100 to get more pull from the mechanical fan? maybe I should check my timing... ?

 

[Chryco Psycho]

Timing can make a big difference , more advance = cooler .
The fact that it runs cooler when moving proves that you have a fan or rad problem but if the clutch fan is older & not locking properly that could be the problem or the rad may not be flowing 100% .

 

[Xcudame]

I know everyone gets excited about 220°F or 230°F water temperature at idle, but as I've mentioned before, a 50/50 mix of antifreeze and water won't boil until 268°F. May be worrying about nothing.

 

[SmudgeServices]

I know everyone gets excited about 220°F or 230°F water temperature at idle, but as I've mentioned before, a 50/50 mix of antifreeze and water won't boil until 268°F. May be worrying about nothing.

I'm less concerned about boiling explicitly and more concerned about damaging various engine parts. isn't that still likely?
I can't imagine factory recommendation would say that high a temp is safe, right?

 

[Xcudame]

As long as it's not for long periods of time. Have you every looked at the temperature of a modern car? My 2019 Cherokee trailhawk runs 215°F under normal conditions.

 

[SmudgeServices]

yeah, I forgot to mention that I replaced the fan clutch with a new one. even tried a larger plastic one for a bit but switched back to the factory one (still using the new clutch fan) after it proved no change.

radiator is 26". pulled it out and had it tested about 3 years ago, they said it was flowing good.
my brain hurts from having tried everything. that's why I'm down to timing as the only option I can concieve.

800rpm idle is pretty standard right?
was just out in the garage and saw the timing gauge on the balancer is pretty hard to see due to the fan shroud. it'll be a ***** to hit with the light. fml

 

[SmudgeServices]

As long as it's not for long periods of time. Have you every looked at the temperature of a modern car? My 2019 Cherokee trailhawk runs 215°F under normal conditions.

good to know, thanks!

 

[Chryco Psycho]

I have not used a timing light in decades , at idle you can advance until rpm is not rising , you can do the same thing around 2500 rpm , usually the timing curve is too long & needs to be shortened , I do this by welding the slots in the advance plate , typically 16* at idle & around 36-38 @ 2500 works best .

 

[Xcudame]

We're building big blocks making 400, 500 and 600 hp. They're going to generate a lot of heat! That's going to raise the water temperature at idle, in gear, stuck in traffic. It costs some horse power, but I think a single clutch fan driven off the water pump and using a fan shroud is the best bet. And as long as you cool down below 200°F with cruising faster, everything is probably OK.

 

[BSG]

Check the accuracy of your gauge is a good start. My factory vs am gauge were 15 to 20 degree's diff. Check the clutch if the fan is not almost direct drive by the time your up to temp is another good fairly inexpensive place to start or if its not super stiff when hot. I once found an overheating problem with one of those infrared temp guns following along the top of the head almost instantly found the problem was between the 3 and 5 cyl. Thought i had a blown head gasket, cracked block something i tried everything, eng was fresh when i parked 20 years earlier ended up just needing one of those ultrasonic cleanings. Hell even went and bought a core 340 thinking the worst. Still have it