Big Block cooling

wyocobra · #1 (**permalink**) 03-23-2003, 09:14 AM

Can anyone out there help me on this one? Have about 150 miles on Lone Star Classics Competition 427 kit. (great kit,drives like a dream) Problem so far seems to be heat. Am running 1970 casting 454, bored 20 over to clean up some scratches, Edelbrock highperf water pump, 160 thermostat, Permacool 16inch, 2950cfm fan, 180degree snap switch, as well as manual override switch capability, 600hp Griffin 2row radiator. Winter project has been to complete full front shrouds inside radiator front opening. Should now have 95% of frontal air going thru radiator. Only real question of big Bowtie officionatos---- do I really need the 3/4 inch bypass hose from the waterpump to the front of the intake manifold. I have a highrise filler and no heater or heater hoses. To bypass, or not to bypass, that is the question...

ac andy · #2 (**permalink**) 03-24-2003, 03:23 AM

Maybe you would fix it by putting a Ford motor in it! Ha Ha.

Jeff Frigo · #3 (**permalink**) 03-24-2003, 03:54 AM

Andy:

Too bad you don't have the "correct" Ford.

ac andy · #4 (**permalink**) 03-24-2003, 04:20 AM

And what would the "correct" Ford be Jeff? (No malice intended).

Jeff Frigo · #5 (**permalink**) 03-24-2003, 05:05 AM

If you have to ask, well forget it.

Ron61 · #6 (**permalink**) 03-24-2003, 05:32 AM

Wyocobra,

I am not much on Chevy engines but I think you should leave the bypass hose in. That allows some water circulation before the thermostat opens. I don't run a heater on my stroker either but I did leave the bypass hose in. Another way if you just don't like the hose showing is to drill a couple of small holes in the thermostat flange. There are previous threads about this and even a couple of pictures of how people drilled the holes. On a hot day you want water to circulate from the moment you start your engine.

Ron

frankym · #7 (**permalink**) 03-24-2003, 07:13 AM

Ron61 said it, start by exhausting the usual tricks before you go nuts. 3 small holes (1/8 diam) in the thermostat flange is what I have seen. You have the high speed fan, I presume it's in between the motor and the radiator, so make sure it's pulling air and not pushing it, kinda dumb, but the polarity of the wiring could be backward. Other things to help would include building a shroud or adapting one for your car, channeled air will create a LOT more air flow than just a big fan in the middle. Also, baffling the radiator might help, many of the problems I had with my previous big block was that the water was flowing too fast through the motor and it never got a chance to cool off inside the radiator fins. Never been involved with baffling, but that radiator of yours shouldn't need it. check the fan, make sure it's really 3000cfms by mfg, I had the black magic fan and that thing was a beast, and it was around 3000 cfms, some of these fans are only 1200, so make sure you check with the Mfg. Also, make sure it's switching on in advance of getting too hot and that it's staying on, you should be able to sit in your garage idling. make sure you've bled all the air out of the cooling system too. Your temperature sensor may also lie a little, are you physically overheating, are you boiling over or does the temp gauge just scare the begeesus out of you, sometimes the temperature sensor will lie a little because of its location.

wyocobra · #8 (**permalink**) 03-24-2003, 10:19 AM

Thanks to everybody for your input.. The frost is almost gone here in Wyoming. Time to look at the Cobra from a different perspective.. from the inside looking forward. I have added full shrouding inside the radiator opening this winter as well as adding dual fans. All this should help. Actual engine breakin should help too. When I parked for the winter (Nov.1, temp 30 degrees), the engine temp seemed to be getting cooler and more consistant. Hoepfully, summer cruising will bring better engine temps.

Karl Bebout · #9 (**permalink**) 03-25-2003, 07:58 AM

Mister Wyoming, I've had two rat motors in my old NAF hot rod and have not had over heating problems, even during our "balmy" Southern Arizona summers. The 402 had cast iron heads and now my 496 has Edelbrock aluminum heads. I've gotten stuck at traffic lights when the air temperature is 105-110 and not gotten an engine temperature over 190. I use a 160 degree thermostat, a mechanical (belt driven) fan that pulls, an electric pusher that blows through the tranny cooler before the radiator, and I have stainless steel cowlings above and below from the radiator back to the area of the water pump. I don't switch the electric fan but rather have it run whenever the ignition is hot and I don't run over 37 degrees total timing. Hope you get your overheating ills cured. Sounds like you're doing everything right. If people see a Cobra overheat they are liable to think it has a Ford engine. Ouch.

wyocobra · #10 (**permalink**) 03-25-2003, 10:21 AM

Karlos, thanks for the support. Wyoming weather getting nicer. About time to roadtest the winter additions to the cobra. More breakin time on the engine should help too. Still have to fine tune carburation and timing. I still use old-school muscle car tactics. Tune by ear and general performance. Check with basic timing light after locking down old Mallory dual point. Seems to run pretty well at 14degrees btc at idle. Old school-- basic 6 degrees plus one degree per thousand feet of elevation. Works well!