Cooling questions/suggestions

[famous bob]

Me too.....we ALL would I imagine. LOL I forget who it was on here but somebody had one where the brackets were almost a solid INCH forward of the tanks. Just stupid stuff like that. I'm like you not understanding, because until Vixen, I've always used factory radiators, either reconditioned or recored. I had a 65 Valiant radiator recored to a 4 core years ago and STILL had room for the Mopar viscous fan package. I've seen people argue me down that a clutch fan won't cool as good as some....but I don't think they've ever used one. lol

I have , a mech. fan is about 7ish degrees better than a clutch set up on mine -------both the same size...

 

[Dale Davies]

Hey all I am just looking to pick some brains here.
I have a 74 Duster with a mild built 318. The motor has been fully worked over from ground up with about 300 miles on it total. I am bored .30 over, block decked, 302 heads, comp cam Xtreme Energy 224/230, Summit long tube headers, Edlebrock performer RPM intake, and an Edlebrock 1405 4bbl carb.

Cooling system has been upgraded to 3 row aluminum radiator by Champion cooling with an aluminum shroud and dual 10in fans (currently on with ignition), the cap is a 16lbs cap. High flow water pump installed yesterday as well as a 160 high flow thermostat. I am testing distilled water with 10-15% coolant. But ultimately I am still getting/ having cooling issues.

Today I let it warm up to 160 and can see some coolant flow in the radiator. At an idle it got to about 170ish which I expected since it is 85 out and the pavement is hot.
As soon as I start creating more heat (throttle) the temp goes up, so I took it for a test drive. I went about 5 miles averaging about 45-50 mph. Temp climbed to about 180 and held for about a mile then anytime I gave it a little more gas the temp just keeps climbing. I eventually made it about 4 miles before I pulled over because the temp started hitting 205 and I was getting some vapor lock. (I have a full EFI conversion for the winter project) So i parked in the shade for about 10 minutes and popped the hood to let some heat expel then fired it up and finished the drive. The temp when starting it was about 199 and on the rest of the drive it dropped to about 197 until I hit my driveway 203.

I haven't checked it at cruising speeds yet just because it is supposed to be 100 out today so I don't feel the need to push it.

But is the accumulation of the heat under the hood (Headers) causing a lot of this issue or is it temp climbing solely from the internals getting that hot?

What size wiring do you have going to the fans. Wires to and from should be 8ga and run through a relay. Do not forget the ground has to be capable ot the same current capacity as the supply. The relays should be 30A or 40A. A temperature switch of 195° to 205° can be put in the intake manifold to ground the relay control circuit to turn them on and off. If the cool side of the radiator has a thread welded in, you can use a 185°switch. Make sure the radiator is grounded. A ground connection should have an electrician's anticorrosion spray paint applied due to dissimilar metal corrilosion.

 

[Hueydriver]

WOW, there is a lot of information to digest here. From my stand point I have a 360 from a 1978 Lil Red Truck installed in a 1971 Duster. There is no fan shroud but it does have an oversized aluminum radiator. Bottom line is it runs between 180-210 year round both at idle (after warming up) and at cruise (sometimes at cruise it will actually drop some). My ignition timing is correct and the engine runs smooth and strong all the time. I am far from being a master MOPAR mechanic, but my basic shade tree mechanic skills would make me ask if it be as simple as replacing the thermostat?

 

[Dale Davies]

WOW, there is a lot of information to digest here. From my stand point I have a 360 from a 1978 Lil Red Truck installed in a 1971 Duster. There is no fan shroud but it does have an oversized aluminum radiator. Bottom line is it runs between 180-210 year round both at idle (after warming up) and at cruise (sometimes at cruise it will actually drop some). My ignition timing is correct and the engine runs smooth and strong all the time. I am far from being a master MOPAR mechanic, but my basic shade tree mechanic skills would make me ask if it be as simple as replacing the thermostat?

I would test the thermostat in a pot of water and a thermometer good for 250°F. Hang it on a wire so it does not get direct heat from the pot bottom. Watch for when it just starts to open and then when full open. No need replacing a properly functioning thermostat. The other dituation is that the new engine may still.be tight, causing extra heat.

 

[Mikethegreat]

Some Dodge trucks in the 80s and 90s with the 360 sealed the front of the radiator with a flap so air could not go over the top.

 

[Pumpkinduster]

Sorry all for the delays I have been slammed with work and ran into an electrical gremlin on the car that will need to be fixed. But on the good news before I had the electrical issue my older friend that races older 40's-50's cars with chrysler engines looked over it with me and we found a couple issues with the timing and some crossing firing with 5-7 due to my plug wires pretty much touching all over. We corrected these and so far the temp has been keeping low. Left it idling for about 30 minutes and it never went pasted 175, where before 30 minutes of idling would have been 205ish.
Thank you all for the input and feedback i will double check it more once I have the other bugs fixed.