Here's what I have. 1950 Ford sedan with the original 8ba flathead with a C4 auto behind it. New water pumps from speedway, flushed and descaled block, recored radiator 12 lbs cap and 180 thermostats with little holes to help rid air pockets. Auto cooler is built into the bottom of the radiator. Have played with timing and a/f mixture at highway and city speed with very little change. I have run two different versions of cooling methods, the first was without a/c, a mechanical fan with a shroud and with a/c with a condenser in front of the radiator with a spal 16" fan and shroud and adjustable fan thermo switch. Cleared air pockets using different methods that even include vacuum filling. With both versions, the car cools fine while driving in the city but once on the freeway, the temps climb up to 200-210. Pull off the highway and drive on surface streets and it drops it back to 180-185. I have all the gaps sealed up around the radiator and I have the lower skid plate and the upper hood plate in place. When I check the heads, radiator, thermostat housing and hoses with a ir thermometer I always get a reading that is 20-30 degree difference compared to the two temp gauges in the car ie, temp gauge says 200 and the ir says 175-180 on heads or thermostats housing. Heads are same temp +- 5-8 degrees. Is that normal or should it be roughly the same temp as the gauge? I am going to triple check the temp with a stick in thermometer with cap off and the probe at the water neck and see what the difference is there if any. I also just got my wind speed meter back from a warranty repair and can then see what is the air speed with the electric fan. Let the fun begin. Posted using the Full Custom H.A.M.B. App!
It could be that your gauge is just off. If you shot it with a gun and the temp is lower that kinda says something. I have never had a gauge yet that was spot on. Some will say this isn't accurate, but I put one of those Mr Gasket radiator caps on my 27 with the gauge in the top of it. My gauge was reading 210 and the radiator cap said 180, which was also what my gun said. Also check your belt tension. My Sons rod started running warmer than normal and when we pulled the belt we saw where it had been slipping at speed. Put a new belt on and tightened it up, no more problem. Don
2 things come to mind, 1 the water is passing thru the radiator too fast to transfer heat at highway speeds but slows down enough to transfer @ lower speeds.This will sometimes happen to people who remove thermostat all together. Choice 2 would be (you state I sealed up gaps around radiator) is that @highway speeds the air is actually being packed in front w/o being able to pass thru fast enough to allow proper air flow thru radiator. Fans and an a/c condenser in front can restrict air flow enough that as the coolant flow increases at highway speeds there is not enough air passing thru to cool it properly. Remember with a shroud the fan blade should center in the outer edge of the shroud. if it is too far in it WILL restrict air flow @ higher speeds unless the shroud has flaps that can release air pressure or is open @ bottom to perform same task.
Why are you running a 12 pound radiator cap ? 4 pound would be what I'd expect to find on a flattie . Don has a good point about possibly a belt slipping , BUT , don't overtighten the belts , the bearings in Flattie waterpumps won't cope with belt/s too tight . You should be able to grab the belt at it's longest span between pulleys and move it 1/2"-1" . If your temp is rising at highway speeds my gut feeling is it's an air flow problem. edit: Just re-read the original post , you're running a C4 auto behind the Flattie , you make no mention of what rear end is in the car ? If it's still the stock rear it may be that with the C4 at freeway speeds that little old flattie is pulling some really big numbers! If it's screaming it's lungs out the coolant will be circulating really fast , that and the AC condensor impeding air-flow won't be helping . Food for thought? . .
I used to remember something about a flatheads number 1 issue with overheating was timing... Also, electric fan could be impeding airflow at speed. If it were me, I would plug in a cheap mechanical temp gauge in each head, then I would put a switch on the electric fan, shut it off at freeway speeds and see if there is an affect. from : http://www.vanpeltsales.com/FH_web/flathead_overheat_troubleshoot.htm "11. Be sure that the ignition timing is correct. Timing that is too far advanced will cause the engine to overheat. Adjust the timing to within factory specifications. Pre 1949 distributors should be removed and adjusted on a distributor machine.<?XML:NAMESPACE PREFIX = O /><O> "</O>
the radiator trans cooler is not helping,install a after market unit along the frame where air can reach it,
has the engine been bored alot? I had this same problem with my rod a 47 chevy pick-up my engine was bored .060 over thin cylinders. I tried everything water wetter, another product called kool it. ended up going to a griffin aluminum radiator now the faster I go the cooler it runs. in the fall up here in nh. I have to turn off one of my fans just to get the thermostat to open. I running a 160 degree with vent holes.hope this tid bit might help purp47
Thank you all for your replies, right now I am thinking it is an air flow problem. I am going to upscale the wiring and the relay to 8 guage wiring and a 70 amp relay. Not sure that this will help or not. 31 5w, I am currently running the electric fan with the a/c and the electric fan is mounted on the shroud that covers the complete back of the radiator. When I was running the engine driven fan, the fan blades had the correct amount of depth into the shroud. I would like to put some holes in the shroud that are covered with a flap but there is very little room. I am planning to go with the CCI fan and shroud combo and I like the fact that it has several large blades that allow air to go around them when they are turned off. 4t6ford, I have an 8" rear end with 2.90 gears and driving down the road @ 60mph the engine is around 2000rpm, so it's not screaming. My ot cars are close to the same rpm's going 65 mph. Diavolo, I do have mechanical temp gauges. One for each side then I have the electric gauge to a third sensor and all three are roughly the same. All three sensors are mounted in such a way that all three are in the coolant and not in an air pocket that would give me a false reading. As for the timing, I have verified tdc and set the timing correctly and I am only adjusting 3-4 degrees in either way to see if it help. I have also adjusted timing using the vacuum gauge method and so I am pretty sure that the timing is where the motor likes it and during the adjustment, the temps never showed any crazy swings. Right now it is at 4-5 degrees and the motor runs the smoothest at that amount. I had a friend spin and check the distributor to make sure the vacuum diaphram and the internals was working correctly. I have a pertronix inside it with nos cap and rotor. 1941 coupe, I am not sure why I should run a seperate cooler for the trans. Will the trans fluid make the coolant in the radiator hotter during highway speeds?
I agree it is probably an airflow problem but it may also be a radiator is not up to task of the trans cooling and condensor. A few things... Increasing the wire gauge should have no effect unless you are already running too small a wire for the electric circuit. If they aren't melting, no issue. I don't know the adjustments to your Spal fan but if I had a way to make it always on, run a direct, keyed power source to it thru a switch temporarily and see if fan off and fan on make any differences at speed. At least that would eliminate the possibility that the fan is somehow blocking flow. A cheap test with just some wire and a switch. You said the trans cooler is in the radiator... you had them do this when they re-cored your radiator? Two things I think of is they didn't put enough cores back in and your radiator is insufficient to cool the engine now. The other is that the trans cooler may be just adding enough to bring the original design, if that's what it was cored with, to a too hot to handle state. With that AND the a/c condensor, it may just be enough to cause a problem. Make a call to the guys that re-cored the radiator and ask about the work and if they would have recommended a larger capacity considering the a/c and trans cooling. The trans doesn't need a lot to keep it cool. A simple cooler from a favored dealer mounted by the frame with airflow would do a good job of keeping the trans cool without it adding more heat to the cooling system. The condensor is going to add at least 20F to the incoming air that then goes thru the radiator. Again, the original radiator design didn't account for this. Another reason the radiator may just not be up to task, even if it was re-cored.
"water running too fast through the cooling system"....is a common misconception. Energy in equals energy out, regardless of the velocity of the coolant. An increase in flow/velocity actually scavenges and dissipates the heat better and LOWERS the average temperature in the engine. I think your issue lies with either the radiator itself; is it capable of handling the heat of the motor and trans? Or, with the water pumps; belts tensioned properly?
Another area... Does your radiator have an overflow valve to prevent loss of water at high speeds?? Agreed..Pumps running too fast is a misconception. If you changed your fan to electric to prevent high speed overheating it wont improve it. An electric fan impedes flow and only improves the problem during idle and slow speeds. Most high speed overheating is due to either loss of coolant or improper timing advance. Be absolutely positive it is advancing correctly.
Diavolo, What a great reply, thank you! Here is what I was able to get from the shop that did the radiator. He popped the top and bottom tanks, cleaned, rodded and did any other vodoo they do to the core. He said he intergraded the trans cooler. It sounds like he has new lower tanks with trans cooler built in and put it on mine. The guy is old enough to be my grandad and has been doing this longer that I have been alive. What a great guy. I had the radiator done while the engine still had the manual fan and before the A/C. With the manual fan, it still was getting hot on the freeway so I made up a shroud, low speed was great, high speed still getting hot. That was January to mid May, that's when I added the a/c to get ready for the summer. Outside temps were high 40's during January up to low 70's in May. I am still think it is airflow, changing fans never made the problem better or worse. As for the water pumps, both are new, both belts have the correct amount of tension. If there was an issue with the pumps, I would think that there would be a problem on the slow speed side instead of higher speed. I am still going to upsize the relay to a 70amp and up the size of the wiring. Couldn't hurt. Plus if I decide to go to a Cooling Components electric fan, the wiring will be in place. I think I might also remove the front splash guard that closes in the front sheet metal to the front cross member. That might give the blocked air a place to go. PeteJoe, I have verified the distributor is working several times. Plus, I have been playing with the timing, 4* btdc to 6*btdc to 2*btdc to 8* and down to 0*. I noticed some variations but nothing to write home about. Thank you all for your help. Keep the ideas coming if you have any.
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