340 overheating problem

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Had a flex fan on last year only for a couple runs. Got hot but not as hot as it does now. Keep in mind it was cooler then.
At the start of this season I ran the electric set up u see now and it ran cooler. Ever since we pulled the engine and put it back in for the second time it's running hotter.
But it's hotter outside now.
Only changes when engine was pulled was a different cam
 
So guys just an update.
Put a new mechanical auto meter gauge on it. Still getting overheating issues.
I feel like its an air pocket. ( I could be completely wrong!!) but after every cruise once the engine has cooled down, the fluid drops about 2-3inches.
So I add more water every time.

It seems to be staying cooler for longer now. But once she gets above 195-200, the temp just keeps rising.

Engine is running richer then i want right now. Timing is @ 34 total.

I'm running out of ideas. This problem happens going down the road @ 50mph. Not just idling in traffic.
The only thing left to do I change thermostat or add another fan. And not 100% sold either of those is gonna fix anything. I know the thermostat is opening. (About 185).
 
Do you know what your cam is degreed in at? I installed my cam "straight up" dot to dot and discovered it was cut 5 degrees retarded. I tried everything to fix my overheating including shroud, be cool rad, push fan with my mechanical fan, water wetter etc. Nothing solved the problem til I fixed the cam timing.
 
Thanks guys. I'm not sure what its degreed in at. My engine shop is very good at what they do, and that part I haven't asked. I'm sure they did it as per lunati's instructions. But that is one area I have no expertise in.
 
I see by your avatar photo that you have a fiberglass hood.

Do you have a factory style rubber core support / hood seal installed ?

If not, I would suggest that you install one.

The seal keeps engine heat from being drawn over the top of the radiator core support and back through the radiator.

If you search for a couple of my old post on "My cooling improvement project" , I tried about everything you can think of and in the end the core support / hood seal is what was the most and biggest help of anything.

Herb
 
340Duster247 said:
Had a flex fan on last year only for a couple runs. Got hot but not as hot as it does now. Keep in mind it was cooler then.
At the start of this season I ran the electric set up u see now and it ran cooler. Ever since we pulled the engine and put it back in for the second time it's running hotter.
But it's hotter outside now.
Only changes when engine was pulled was a different cam
Click to expand...

it still sounds like you were chasing the running hot problem last year also.

my suggestion:

get a stock 26" A/C type radiator just to test. grab from a salvage yard or whatever.
heck even new they are like 60 bucks.

i had a 340 dart ran the piss out of it 120+mph or whatever it was fine. all i had was factory clutch fan/shroud and a 26" radiator from a car with A/C i got at a junk yard lol.
 
Have you installed an overflow bottle on the radiator since your picture? That should allow the rad to be totally full of fluid at all times, and the coolant will go back and forth as required.

Just a thought.
 
Drop kick that electric fan, and put on a stock style 6-7 blade with a fan shroud and the previously mentioned hood seal. Most of the over heating problems I read about have an electric fan.
 
X2 on a stock fan
an electric fan must push at least 3000 cfs to be effective,and one that seems to be
preferred is the 2 speed 90's Taurus.
..i had a continuous overheating problem but it was my gauge.
 
I was running a flex fan w no shroud on my 69 340 and it always ran 195-210* after messing and messing around I went to stock 7 blade fixed fan with a shroud and now it runs 175-180* all day. I found it surprising it made that big of a difference, but that worked for me.
 
So I installed a 160 thermostat and now runs cooler longer , but once it gets hot, it keeps climbing.
As far as the water pump. Just a factory one. Never counted the blades.
I do have an overflow on now.
I double checked the Cfm on my fan and its 2200. I'm thinking I need another fan. Like a dual set up or some type of shroud. It's just that I'm limited for room.
 
What are you running for engine coolant? I started using EVANS waterless coolant because it will not boil. Once water turns to steam the temp shoots up. The EVANS is not advertised as something to make an engine run cooler but theoretically it should be less likely to climb as high.
 
The EVANS ran me $42.50 @ gallon and you DO NOT mix it with water. An added benefit it has is that it does not break down and need to be changed every few years. - Nor does it cause corrosion like conventional antifreeze/water mixtures. It's supposed to last the life of the vehicle without the need to ever change it. Because it resists boiling it is possible to remove the radiator cap no matter what the temperature reads without it acting like a geyser.

One thing that you may need to look into is having your block and radiator flushed. Conventional coolants tend to be corrosive and build sediment inside the cooling passages over time. Once that gets bad enough the water passages can no longer remove heat as efficiently.
 
340Duster247 said:
So I installed a 160 thermostat and now runs cooler longer , but once it gets hot, it keeps climbing.
As far as the water pump. Just a factory one. Never counted the blades.
I do have an overflow on now.
I double checked the Cfm on my fan and its 2200. I'm thinking I need another fan. Like a dual set up or some type of shroud. It's just that I'm limited for room.
Click to expand...

Ac water pump has 6 blades.
Non Ac pump has 8 blades.

An Ac water pump uses a smaller pulley, which makes it spin more revolutions.
Standard 8 blade pump uses a larger pulley.

I run 8 blade water pumps only.

I would make sure I had an 8 blade pump, along with a stock fixed fan.
 
To OP
JMO if temp sits between 210-220 and you want it at 190'ish .......maybe adjust the fan controller to turn the fan on 20-30 degrees less than its current setting.
 
I second that radiator to hood dam rubber strip. It made a big difference for me.You really need to have that.
 
When I troubleshoot overheats, I always start with a gutted t-stat, straight water, and a mechanical fan. With a gutted stat its also possible to check water circulation by observing it through the filler neck when the water is cold. I have moved my cam timing around from 3*retard to 4* advance with no appreciable change in running temps. Granted my current engine is only about 430hp..... I run a 26in factoryA/C rad, a Milodon hi-flo pump, a hi-flo stat, expansion tank and a 7-blade clutch fan.And the hood/cowl seals are in. And fresh air. Works for me.
 
So I thought I'd let everyone know I got it all figured out. I added another fan, the same as I have as a puller, in the front as a pusher. I got a smaller trans cooler for the now tighter fitment and she stays cool no mater what.
Never gets over 185. Even hammering on it.
Thanks guys for all the help. Hopefully this thread will help more in the future.
 
Thanks for posting the solution. So many times the thread just stops. Happy hunting!
 
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