I agree with Bruce Lancaster. After fixing a lots of flatheads with cracks around the exhaust valve seats, a little research into the cause enlightened me to the fact that you get cavitation and boiling around those areas which prevents the water from cooling there. My solution was Evans Coolent which will not boil. A little more expensive but it sure does the trick....your temp gauge may read a little high for your taste, if so put some black tape over it and go on down the road. It sure prevents those nasty exhaust valve seat cracks. Of course if your problem is leaky head gaskets then......fix it. I take 'em to 55lbs. Phil
Thanks Phill so Evans coolent runs hotter but doesn't boil is that correct? I don't have any leaks around the head and after testing there seems to be no emissions in the radiator so I don't think I need to retention. Will check out Evans Cheers
Evans Coolent does not run hotter but won't boil till about 300+. I just said hotter because some folks use it because they have a marginal cooling low pressure system and it prevents boilover especially when you come on off the road. The main reason I recommend it is because it protects the exhaust seats on older engines. -Phil
A few comments regarding flatheads. They were known as "Hot Water Eights" and for good reason. The design choice of running the exhaust through the water jacket was a poor one and contributed to the heating problem. The slowing the water flow down was discovered by the circle track racers early on. They either knocked every other fin of the water pumps or drilled a hole in the impeller fins. Another trick was large washers in the water outlets. It is and was hard to believe that slowing the flow down and increasing the time for heat transfer to occur in the radiator is false . I was there when flatheads were new and in every of day use. I remember carrying water bags and pulling off to the shoulder to let it cool down and then adding water and going down the road. A common test for causes of overheating was to take the fan belt off and check for bubbles in the coolant. I suppose that What I am trying to say that Flatheads normally will run hot. Let the Flames Begin!!
I also am running a little warm, I run a 6 blade fan, 25% antifreeze and water wetter. It has helped greatly, but if I get above 3000 rpm, the temperature goes up to 190 degrees. I'm running 160 t-stats. I'm also thinking about a fan shroud. My engine was rebuilt about 8 years ago and has been sitting without water in it. I flushed it several times, but I'm sure there is rust inside. It runs so good, I hate to tear it apart.
One thing that has not been mentioned and I learned as a snot nosed learning mechanic (late 50,s and early 60,s) and still learning today is engines need to be timed correctly, too slow no power and it will run hot and too fast ad it will misss and can cause major engine damage if not corrected.
is 190 too hot? I see you run a 160 t-stat but that is just the lower limit. many new cars run that hot or hotter, will 190hurt a flat head? I run a Y block in my 30 sedan and cool it with a standard Model A radiator, I soldered on a pressure type neck and closed off the stock overflow tube. On the hottest of days it will run close to 200 but will not blow water out. 4 lb cap.
They'll run fine up to 200...the thing that is damaging is the cavitation/steam pockets that form around the exhaust seats. Not to sound redundant but, that's my case for Evans Coolant....
Hi guy once again thanks for all the input You guys are a wealth of knowledge. Last night I retested the radiator for exhaust gasses and there is no sign of any in the cooling system(thank god for that) I had a couple of 160f thermostats which I tested in a pot in the mrs kitchen. I think she thought I was boiling eggs or something. Drained the system and fitted them one on top of either head outlet. Then took her for a 20min run,engine temp on the mechanical SW Gauge is sitting on about 180 when cruising and approx 190 when stationary. Coolant seems to have found its own level. Removed radiator cap when we got back, no foaming in the top tank this time,but there are still a few small bubbles when the revs are raised Hopefully this will sort her out for the time being as I'm trying to make it to the reliability run in a weeks time. After that I will remove the radiator and have it converted to a pressure system with an over flow. Will then run Evan cooling system additive. Would have liked to run that now but I'm having a hell of a time getting the lower hose to seal bloody repo hoses with that showy red line are hard as old Nicks dick!! and the additive isn't cheap!! So standard coolant will have to do for now. Fnjunk
Will be interested to know how you come out. I bought a 49 ford pickup once with a 289 ford motor and the stock 4.27 rear axle. My temp gauge would go straight up and peg when running on the hiway over 3000 RPMs but ran cool below that RPM. I pulled the t'stat housing to find no t'stat at all. I installed a 180 degree thermostat and the problem went away. Some guys say cavitation is the culprit...some say the coolant doesn't have time to lose it's heat in the radiator. I really don't know but I know installing the thermostat worked for me. Good luck.
if you do go to a pressurized system, you might want to torque your heads to 55lb. the general rule is cast heads 65lbs. Alloy heads 55lb. Also don't forget the pressurized system will put more strain on your head torque
just some interesting facts I found out here when looking into the evens coolant. http://www.engineeringtoolbox.com/ethylene-glycol-d_146.html
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