cooling question

[sixty9cobra]

Hi guys I have a 69 Mustang FB with a 630 flywheel HP 428 .040 over, Edelbrock heads, .700 solid, roller, Scat forged crank, aluminum flywheel, Hooker 1 3/4 coated headers, 3" Magnaflow exhaust, Edelbrock aluminum water pump, Edwlbrock Victor, Champion 4 row radiator, Focus electric fans. I have a 160 stat, The car stays at 180 idleing all day if the temp is above 80 degrees outside. As soon as the motor goes above 2000 rpm the temp rises as high as 210 going 70 mph in overdrive. Let it idle and it eventually cools off. I realize Champion is not the best radiator but it gets rid of the heat when the engine is turning slow. The Focus fans aren't the the best either but at 70 mph in overdrive turning 2200 should be enough air without fans. I put in an 180 stat figuring the water doesn't have enough time to cool off but didn't help. No thermostat the same thing. The only thing I can figure is with the big cam and lots of overlap doesn't make horsepower till 2000 rpm. I even bought one of those aluminum pieces that covers the top of the grill to force air thru the radiator. I would buy a 1100 dollar Griffen if I knew it would solve the problem. Suggestions please.

[Stangman]

Hey Harry hope all is good besides the car. So what is different besides the motor rebuild. Water pump, pulleys radiator, fans. Is the radiator an OEM design or is it an aftermarket cross flow. I’m assuming that you checked the usual stuff like timing. Is it possible that the carb is lean at cruising speed. Something like that and the timing being off could do it. Water pump cavitation?

[sixty9cobra]

It has run hot before the rebuild but never overheats. I guess I'm being more careful because this rebuild cost a small fortune between the forged crank roller valvetrain and the Victor purchase and porting bla bla. Timing is locked at 35 deg. Radiator is not a cross flow but probably a Chinese aluminum rad its pretty thick might be junk I'm not sure. Cavitation I have no clue how to check that, I think I slowly out grew something on the cooling system. If it didn't cool off when idling I would say its the radiator. Somehow I think its an airflow or possible developing more heat above 2 grand due to making horsepower ? I have no idea. I do know I'm running 50 degrees over the thermostat cruising on flat ground.

[Stangman]

So if it’s an OEM design I guess your running an engine fan. Does it have a clutch fan and are you running a shroud. Are you running stock pulleys.

[sixty9cobra]

Fans from a Ford Focus two electric fans in a plastic shroud fits right in place of the stock fan shroud. One of the members here suggested them he runs them on his Mustang and he lives in Cali. I thinks its fairly warm there.

[Joey120373]

I have seen this condition when the thermostat fails and is always open, it does not control the coolant flow and the coolant actually flows through the radiator to fast. It’s not common but I have seen it. Usually the T star has broken in two.

[sixty9cobra]

I have tried 2 or 3 different thermostats even a high flow Moroso.

[jayb]

What I had to do to make my Mach1 cool was notch the frame rails in front and put in a 31" long X 19" high, two core crossflow aluminum radiator.  Never a problem after that.  Believe it or not, the two cheap Summit Racing aluminum radiators have both worked very well for me:

https://www.summitracing.com/parts/sum-380431

https://www.summitracing.com/parts/sum-380431-3

- Edited to correct the part numbers

[sixty9cobra]

I assume your battery is in the trunk? I also was considering this radiator.

https://www.ebay.com/itm/KILLER-Aluminum-Radiator-Mustang-1967-1968-1969-1970-25-BIG-BLOCK-COOLING-POWER/263994887825?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649

[Cyclone03]

Been there done that.
I did Hot Rod Power Tour 2016, known as the hottest ever.
Set up was a Summit branded cross flow 28x19 with Ford Contour fans.

My experience was exactly what the OP has, idle under control  190 all day,going down the road temp would Climb,200/205.

I cut/fabricated little flaps in the shroud,that helped a lot but took a while to settle back to 190 going down the road.

I did 2016 Hot Rod Power Tour with that set up it was at best OK.

2 years ago I switched to a C&G performance dual fan set up with only the 11” fans themself creating a shroud , AC on 97* 200 at idle but the temp just falls at road speed and sits right on 185 AC on, 180 ac off.

This is in a 68 Mustang,I run both the radiator support and rear hood seal.

The fan openings are not large enough to let air OUT or through the whole radiator.

[WerbyFord]

I wonder if the electric fans & shroud are blocking the air flow at speed?
Can you ditch that setup & just try a clutch fan?
It might heat up at idle but if it runs cool at speed, then you've found the problem.

Also - do you have any vac advance? 35 total is a little low for cruise - they usually like 40-50 total timing (including vacuum) at CRUISE, of course that's too much if you have your foot in it  Over 50 or less than 40 at cruise can start to make them run hotter.

My guess is the high speed airflow though.

[jayb]

I assume your battery is in the trunk?

Of course.  Isn't that where they belong? 

[Stangman]

I agree with Jay about the cross flow radiator. I notched one side frame rail and got a 2 row 1.25 inch tube Griffin radiator with dual 11 inch fans from Jegs.. The radiator Jay is showing you you could put dual 12 inch fans and if I was to do it again I would get the fans from Spal. I also got a smaller pulley from CVF. Now all of this is great if it’s your problem. It does seem like you just need more cooling.

[sixty9cobra]

Good ideas guys most seem to like the 28" cross flow radiator, which means fabricating hoses which is no big deal. Better fans, battery in the trunk. No vacuum advance on this motor timing is locked, no Centrificall or vacuum advance. the good Spal fans are like 180 each. Something to think about.

[Stangman]

They come as a pair together in a shroud Harry. Get the relay kit, as a matter of fact get 2 and run each one on its own relay.