Higher running temps after 2.79 to 3.80 swap

I don't have my info with me right now but I went out and navigated their site and I beleive this is the part number I got.

7-570BU-FXX​

This is based off a 339 type radiator and they will tell you it is only for 70-73 but it will bolt into a 74 and I believe it will go into 75-77 also. I found out you can also get it cheaper going directly thru Griffin and not summit, jegs etc. they build it per order and you can add things like electric fan etc -- beware an electric fan will not fit with the factory style water pump -- I learned this the hard way and sent the fan back because I was not going with an electric wp.

Edit
I should correct myself here the electric fan would not fit when they added their custom mounts -- I did not want to run straps thru the coils on the new rad, if you mounted the fan directly against the coils and strapped it thru it probably would have fit

 

The purpose of pressurizing the cooling system is to increase the boiling point of the coolant. Each pound of pressure increases the boiling point by about 3 degrees. A 13 pound cap will elevate the boiling point of the coolant to around 251 degrees. This is why you never remove a radiator cap while the system is hot. Removing the pressure can cause the coolant to instantly boil resulting in a situation similar to Old Faithful but not as pretty and extremely dangerous. The 13 pound cap is plenty.

I would skip the flow cooler disk and go with a complete water pump of modern design. I would also never go below a 160 thermostat of a high flow design.

Maybe I missed it mentioned here but are you running a stock fan and shroud?

 

A 160 deg. thermostat is a good choice but make sure its high flow or performance type as mentioned before, it does make a difference. The other thing that hurts the efficiency of the radiator is mounting the trans cooler in line of the radiator front or back ,its best if you mount to side or under radiator, some creativity is needed here because there is not much room on these cars or as mentioned use a remote unit with its own cooling fan.

 

I had a shroud, but it was pretty much rotted when I got it. The radiator is the 3-core version, since the car originally ran an A/C, but all A/C components are removed including the condenser.

I will order the 160 high flow, and get away from the stock thermo.

Fan is stock 5 blade. It flexes with speed so the airflow changes with RPM. I think it actually flattens out, so I would think that higher rpms would give less air flow. Do they make a stiffer fan that doesn't flex flat?

I was thinking of overkill, and putting in an oversize radiator that would extend maybe 3" left and right of the current one. Those areas have little or no air flow, but I figure the extra surface area could not hurt. Jegs has a generic "Universal" for a good price, all aluminum, but I have not measured for fit.

Currently, the trans cooler is centered in front of the radiator. I have recieved several suggestions to move it to the side, so I will.

Has anyone used an oil cooler/remote filter setup? I would like to move my oil filter, maybe where the battery and voltage regulator are located, and use a PH1 filter. I could run a line to the oil cooler on the front right of the radiator, then line to the filter unit and back. Might be easier to stay on the same side as the current filter, and mount near the washer reservoir. Would this help with engine cooling?

I think I will build a cooling system that will work up to 500HP, just in case I ever get there. IF I don't at least then engine will be able to handle the TX heat even with later mods.

 

I think we are thinking too much here...
Dave's post early in the thread made the most sense of all...

Maybe the car has always run a little lean in your current rpm range, but you never noticed before because your old gears never cruised in that range.

Your description of the problem seems to be of the car heating while in motion. This should not happen, air flow while moving should be plenty to cool your car if everything is working. Your lower radiator hose may be weak and sucking narrow or closed at your constant cruising rpm. Again, if you didn't cruise that high before, you would not have had an issue with a weak hose.

Make sure your lower hose always has a spring in it.
Check your carb jetting.
Always use a fan shroud.

Dave

Edit: Find your true problem first, before throwing all kinds of tricks at it. You might get it cooler again, but you are just sweeping a real problem under the rug. Your oil cooler idea is why I bring this up. An oil cooler can be great if you really need it, but to use your oil to cool the engine is wrong thinking. Your oil must not get too hot of course, but it also must maintain a minimum temp to function properly. Have you ever looked inside an engine that looked like it had a layer of brownies baking inside it? That comes from the oil being run too cool... a lifetime of short trips, never allowing the detergent properties to function.

 

OK, I did some research on cooling systems, and a couple things came up the I have been messing with.

I think you may be right on the lean mixture. Not too long ago, I started a thread where my car wouldn't start without starting fluid, and was told to rich it up a little. So I did. Now it starts right up, but I wonder if I just riched it enough to start it, but am still running lean?

What, if any, is a good way to test my mixture? I have thought of buying a bosch sensor or buying a mixture tester.

Also, I have gotten the consensus that 16 lb cap will not necessarily increase pressures under the cap, but will increase the temp to boil. So the 16 lb cap is back on.

Also, I have been running 50/50 coolant, but in Texas, especially in my garage, it WILL NEVER FREEZE, so I read that 20% is plenty to keep the water from boiling and to provide protection to the metals inside the engine. So I drained half the coolant, and added a gallon of distilled water, giving me approximately 25% coolant.

I did not drive a whole lot today, but what driving I did do stopped at 190. I haven't riched the mixture up, and will try that tomorrow.

I also messed with the timing, since mine doesn't ping at "distributor turned until it stops advanced", I had it almost there, probably 20 degrees at idle. I backed it off to 10 degrees at idle with the vacuum line off. I figured I might lose some power, but I may not lose a head gasket.

I will update tomorrow after riching the mixture and running it a bit. May go to the track and practice my launches, then write back.

 

I still say it has little if anything to do with the gears. You should be able to cruise at 3000 RPM all day long without over-heating. And gears are not going to cause a "lean" condition.

A fan shroud makes a huge difference at slower speeds and at idle. A good 3-row radiator that is not corroded is essential. A good-working water pump and thermostat is also manditory. Your heater core could be corroded as well, and if it's a non-A/C car, it is in the cooling circuit at all times...

 

Brand new heater core. Non-corroded 3-core stock radiator. I don't feel that the gears are causing the lean condition, it is lean due to me leaning it. Last year, it was not burning all the fuel, and smelled like gas in the garage (with the door open!) when I ran it. Smelled bad enough that my clothes, the car, the entire house, would smell like someone dumped gas on it.

So I leaned out the mixture on the Edelbrock 1406 (two screws in the front of the carb), believing it was running too rich. Afterwards, it would not start without starting fluid. It ran well after being started, and still smelled bad. Forum contributors suggested other issues, and after rebuilding the electrical system, new spark plugs, distributor cap, rotor, coil, and most important, 8 mm plug wires, the smell went away. I believe I was grounding a couple of wires at the shock towers or exhaust manifold. Anyway, the smell went away, better burn of fuel. Since then, I have not riched the mixture up, so I may still be running too lean, but just rich enough to start the engine without the starting fluid.

Today, nice warm day, fresh coolant and water, good water flow, and 140 degree theromstat, I will run it about 2 turns richer on each screw, probably overrich, but just to see if it makes a difference. Then adjust mixture to a more appropriate level, let it cool down, run it again, etc. until it seems right.

I have nothing else to do today, so I will run a couple mini-experiments and see if I don't figure this heating thing out.

 

Those screw are just the idle mixture, to change the mix at higher rpm you have to change the metering rods.

 

Yup... what he said ...

 

I did not know that. Damn! I have been trying to NOT have to buy those metering rods.

I guess I will have to now.

 

Check your sparkplugs after driving it on the highway. They will indicate if the engine is running too lean, too rich, or just right...

 

They are new Split-Fires (gapped to .040, not .032 like the book says), and when pulled, they look brand new. White ceramic, but with no ash or other residue, and dry. You can't tell if they have ever been used.

I have run them since the cam/coil/plugs/wire replacement, maybe 200-250 miles, including a trip to the track for 4 runs and lots of hotrodding around town. They still look "fresh out of the box" so I am probably running a little lean.

Today, I backed the screws out 360 degrees, but after responses from the forum today, I would guess that I am still running lean, but idling richer.

I think I will live with it but build the cooling system to handle it. Eventually, I will get to 350 HP and will need the stronger cooling system anyway.

By the way, Can i drill holes in the thermostat, or something like that, to make them more "high performance"?

I still think I need the flow-kooler water pump and get rid of the stock-replacement. How is the Edelbrock water pump performance? It is shinier, and figured if it was as good as the flow-kooler, I would get it just to make the engine look better.

 

It really sounds like you're grasping at straws. Getting your engine to run at an acceptable temperature should not be that complicated. 200 is acceptable on a hot summer say in Texas. Even 205 isn't too bad. I wouldn't like it any hotter than that. Unless your engine has been excessively over-bored during a rebuild, your stock cooling system should easily keep it cool, providing that all components are in proper working order.

20 degrees initial timing is too much. 10-12 should be plenty. If you drive your car in the winter, your heater will not work with a 160-degree thermostat. A 180 should be fine. The stock thermostat is 195*, so 180 should be just fine. I've also had new thermostats go bad just a few weeks after being installed. A Fan shroud really helps. It's good for as much as a 10-degree reduction in temp. Of course it doesn't matter much at highway speeds. Has the system been completely flushed? Or have you just been adding new coolant to old? Sorry if any of these issues have already been answered--I haven't read the entire thread (it's long)...

 

I wouldn't drill holes in the thermostat. That defeats the purpose of having it there in the first place. As long as it's a high-po thermostat, once it's open it will flow all you need. Having a accurate thermo is the important part.
Yeah, many of the aftermarket pumps (Moroso, Edelbrock, Weind, etc) have caught up to the Flow Cooler and have similar designs, including the anti-cav backing plate....so I think you are fine there.
I'd continue tuning the pot though. Personally, I perfer to have a cleaner idle and a richer power circuit. Jet Performance dialed in my Holley 1850 pretty well using their stage 2 mods.