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Discussion Topic:
overheating
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autoluke |
07-21-2017 @ 8:12 AM
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Member
Posts: 86
Joined: Jul 2017
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Starting again to summarize my attempt to find the source of overheating...1941 Super Deluxe Conv. 1.Correct fan diameter for this flathead ? 2.Would a fan shroud be helpful ? 3.Other messages suggest that a hi-flow water pump may be helpful. Input ? Realize that this is an old topic, but I want to start at the beginning, as I am new to the Ford flathead.
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len47merc |
07-21-2017 @ 9:05 AM
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autoluke - thanks for starting a new thread. I'll weigh in here with the fundamentals - assuming these are in place your stock flathead should run ~185-195 degrees max even in 95-100 degree temps, idling and at speed. I will have to leave it to others to confirm your fan diameter question on a '41. Also, if the few items below are effectively addressed there should be no need for a fan shroud. I'd consider that a band-aid used to address a more fundamental system issue. So first of all, ensure: 1) Radiator is known to be clear. If unsure - take it out, have it rodded, cleaned, pressure checked and repaired if necessary. IMHO this the #1 cause of overheating. Just looking at it through the filler neck is insufficient to know your radiator is running clear 2) Block has been cleared of all residual mold sand. I couldn't believe how much was still in my 59AB after 65 years and 37,000+ miles 3) Stats are opening and closing at rating. Check them on the stove top in one of Momma's pots using her candy thermometer to show her how much you love her 4) Stats are being held firmly in place flush with the top of the head water jacket flange by the top hoses 5) You are running a 4# radiator cap Now a few comments: 1) Nothing cools any more effectively than your stock water pumps. Period. 2) Thermostat temp ratings only control the speed at which your car heats up - not the temp your car will operate at most effectively. You can run 155 degree stats if you want - your car will still run at whatever temp it is 'comfortable' at based on the ambient temps. My '47 runs at 185-195 (max) in 90+ degree temps regardless of stat rating. I am still running the original Buck Rogers-looking 177 degree stats but have taken data readings throughout the ambient temperature range with both original-style 155s and 177s and a calibrated thermocouple and know with complete confidence this statement correct. You can run it without stats completely - it will just take even longer to heat up but will still ultimately reach your system's 'happy spot' temp 3) Stats getting blown-up from the water pressure/not being held down effectively and canting in the bottom bend of the top hoses can restrict water flow and cause issues 4) There is a school of thought that high-flow water pumps circulate the water too quickly, thus preventing adequate time in the radiator to cool the water effectively. Have never seen any data that supports or refutes this claim. I can only validate that under identical operating conditions, using a calibrated thermocouple, I could not detect any measurable performance difference between the high-flow (helical impeller, marketing-driven) water pumps versus the stock originals, either at speed or idle. The lone benefit in my opinion of the newer water pumps is the modern sealing systems that are employed today - that's it Bottom line - the primary and most fundamental cause of overheating is a cooling system that is not operating as designed and the radiator is always, IMHO, the first thing to look at. If you have a clean stock radiator, a clean stock block/engine, original water pumps in proper operating order/impellers not broken or for some reason worn, and properly operating stats that are held in position and seated properly, then you should be able to cross most US deserts, climb Pikes Peak, drive to Meets for 12 hours non-stop in 95+ degree temps including idling at stoplights - all and not overheat. There are others on this Forum that can and may weigh in and attest to this. If you go through the entire system and know it is in peak operating condition, and you still have an overheating problem, then some of the more seasoned gurus on our Forum will need to step in. I've yet to see a flathead cooling system operating at peak efficiency have a problem in high ambient temps and routine city and highway driving. Fwiw All comments welcomed! Steve
This message was edited by len47merc on 7-21-17 @ 10:05 AM
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autoluke |
07-21-2017 @ 2:39 PM
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Member
Posts: 86
Joined: Jul 2017
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Steve Many thanks for your comprehensive summary. I will now go to work addressing all of the suggested trouble spots. Phil
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len47merc |
07-21-2017 @ 3:13 PM
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Posts: 1165
Joined: Oct 2013
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Phil - suggest you get some more replies from others before you take off. These are just my opinions - you might get some great ideas from others or some reinforcements here that'll give you more confidence to go in this direction. Either way there's a lot of great guys on here that can give you some more insight - give it a little bit more time and see what else comes up. Good luck!
Steve
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cliftford |
07-21-2017 @ 3:30 PM
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Posts: 845
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Steve's comments are pretty complete. I might add one thought: Are you relying on the original guage? Sometimes they are notoriously inaccurate. If so, get a laser thermometer and check operating temp. and the entire cooling system. Also check your cap and make sure it is holding pressure. On my '48 the temp guage is 3/4 of the way toward hot at 180 degrees
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len47merc |
07-21-2017 @ 3:59 PM
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My '47's gauge reads the same as cliftford's. Just the very, very thinnest of smidgens above 3/4 is 180 degrees. Dead on 3/4 is 177. Halfway between 3/4 and H is 195 degrees. Btw - dead on 1/2 is 145-150 degrees. Cliftford has a very good point here.
Steve
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sarahcecelia |
07-21-2017 @ 4:21 PM
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Posts: 1193
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One comment Steve, if I may- The 4 pound radiator cap has nothing to do with the temperature of the motor; it just raises the boiling point of the liquid in the radiator. I think it raises it about 3 degrees for every pound of pressure.I have the exact figure in my ring binder, but that's pretty close. So the 4 pound cap raises the boiling point to about 224 degrees.The best coolant in the universe is? WATER. I run distilled water in all 4 of my old cars, with 1 gallon of Prestone, to lube and prevent corrosion. I'm in florida and it gets to 95-100 degrees sometimes in the summer. I never have an overheating problem with any of them. The facts that you related to the guy, that wrote the thread, are right on!
Regards, Steve Lee
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sarahcecelia |
07-21-2017 @ 4:48 PM
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Those "guns" to read temperature are Easy to use, just aim and trigger, not too expensive, fairly accurate, and are the "tool to have"for any time you "think ?" your having a motor overheating problem.You'll probably find your temp senser(s) in cylinder head(s) are bad, or your temp gauge in the dash is off.
Regards, Steve Lee
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len47merc |
07-21-2017 @ 6:38 PM
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Posts: 1165
Joined: Oct 2013
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Anyone have an answer for autoluke on his fan diameter question? What fan is correct versus perhaps 'best' for a '41? According to the '41-'48 Ford Book, "...the V8 engine fan in 1941 was a 16 3/4" diameter, six-blade fan that bolted to the crankshaft pulley near the bottom of the engine". Due to a new fan hub and mounting bracket , the standard 1942 fan had 4 blades and was 16" in diameter. Lastly, the 51-A fan design of 17" diameter applied for '46-'48.
Steve
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len47merc |
07-21-2017 @ 6:39 PM
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Posts: 1165
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And lastly btw - note autoluke has not yet specified how he defines 'overheating', whether the gauge simply gives him the impression he is running hot versus he is actually boiling over versus simply spitting when it gets warm. It would be helpful to know your thoughts here as well autoluke.
Steve
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