Overheating Flathead

Millcroft - Just an observation: The suggestion was made that there might be / probably was some core sand, rust scale and other debris in the block's water jacket. You replied that the block had been boiled out. I know from past experience that removing the remnants of casting sand, heavy scale, pattern wire etc. required physically scraping and digging to get it out. Hot tanking alone will not do the job. The last engine I had built was hot tanked. After that, I spent several hours picking and scraping inside the water passages and got about a 3# coffee can of debris out of the block. After I finished that, the engine builder put it through his baking and airless blast cleaner. A lot of work but it runs cool. Hope this helps.
 
Thx everyone for all the suggestions. It'll take me some time to implement some of them. Hope it helps. dp1743
 
My 85 HP flattie in my 1934 always ran cool. It was overbored .045 with Henry aluminum heads. Never got above 180 degrees whether in town or in the mountains back in SD. Just purred along.

My '53 Merc also runs cool, about 170 to 185 or so. No thermostats in either engine. The Merc is bored .030, 4 inch stroke, Jahn's pistons, Isky 3/4 cam, Offy heads and intake, new MSD Electronic distributor and MSD coil and most importantly.... TRUCK Water pumps. These pumps have, (IF I recall correctly) 14 fins in each. I just recall they had a bunch more fins than the old car water pumps that had been on it. Then it ran warmer so I put the truck pumps on that had the most fins. There are also truck fins that have fewer fins so make sure if you change, that you get the set that has a ton of fins.
I have the Merc out now and up for sale. Time to maybe change to something else.
 
I would be very interested in hearing from 'millcroft', the originator of this post, as to how he is doing with getting his engine temperature problem resolved.
 
wow, i have a 51 merc with the stock radiator in it, i dont run a thermostat and run evans waterless coolant in it,never gets above 170.
 
If the motor has less than 1k miles on it, it'll probably run cooler with more miles. My 49 ran hotter than I liked (almost on the peg) for the first 600 miles & then starter to level off. Now it runs at around 170 until the outside temp gets above 90 then it goes up to about 190. And that's with 160 stats & an A/C condenser in front of the radiator.

It also helped when I got some new gauges that actually told me how hot it was.

I have 42k on it now & it runs better every day:)
 
I think my overheating problem will be solved shortly. I realized there were no deflector shrouds on the bottom or top of the radiator. I've ordered each. I also put in a mechanical temp guage which gives a somewhat cooler reading. I believe the guage on the dash (original type) is not calibrated correctly. When I get it together again, I'll calibrate that. Thirdly, my radiator sprung a small leak so while that is out I've ordered a new on with a 14" fan. With all of this effort it'll have to see some improvement. I'll let you know how it turns out.
 
Just for the heck of it use cardboard to make the air deflectors I mentioned in an earlier post. Just tape them in place and see if they help. They certainly can't make it worse.
 
dp, If you put an 8BA in your '40, which fan did you use?

I ask because I have become a big believer in Ford's six bladed fans, I suppose they were an option. I have found a couple on the 'bay that I have bought and used.

I have an 8ba in my '36 Ford pickup and I installed a six blade using the '46 type fan hub. I run 180* thermostats and my temp stays around that all day long. Pumps are Speedway.

I found a 6 blade to mount on the 59A off the alternator in the '36 roadster I am building. I made a fan shroud for that one. I just got that engine running so I do not have a lot of empirical data for it. However, the other day as it sat static in the garage I ran it mostly at idle and it would not come up above 155*. It was so cool that I am going to have to verify that I installed 180* thermostats with one 1/8" burp hole drilled in each. I have dual mechanical gauges, Offy heads and Speedway pumps on that one.

So, on the '36's, Ford designed the fans to be in the upper 1/2 of the radiator area and with the 6 bladed fans, this appears to be very effective.

Your '40 was designed to have the fan driven off the crank and I think that '40's have always had the reputation of running a little warm especially if the front side shrouds are missing. So, I guess I am suggesting to you, that a 6 bladed fan running near where Ford originally designed it to be might do the trick for you. For added effectiveness you might add a non-stock fan shroud.
 
tbird,
Thanks for the advice, but, I have a six blade fan on mine. I believe my problem should be rectified when I put the air deflectors in.
 
Strange, but thru all of the causes for flathead "overheating", I have never seen any mention of the bottom radiator hoses collapsing at higher engine RPM.
Ford bottom hoses used to be made with a thick walled material AND also included an internal spring that prevented the hoses from being sucked closed by the water pumps. Hoses supplied today are much thinner and do not include the spring.
It's very easy to check if hose collapse is occurring: just raise your hood and rev. up the engine to around 2000 rpm while watching the hose. If they collapse, there's is your overheating cause.
 
Good News! I got the old radiator finally fixed and installed. Put in two "high-flow" stats from Bob Shewman, (thank you Bob), replaced the sending unit to the temp guage, installed a mechanical guage on the right side, and temporarily installed upper and lower deflectors made out of cardboard. It was 90 plus ambient and the mechanical guage never went above 170 degrees. However, even with a new sending unit, the electric guage went to "Hot". Obviously the guage must be out of sink. I read someplace the guage could be adjusted. Is this so? If it can be done, I would like to try to syncronize it with the mechanical guage reading.
 
Hello Everyone! I bet each change helped a little and that is what it will take, a lot of small improvements, but those deflectors are my choice for the key element. If the air gets a chance to run around the radiator then the system just has no chance of working right. I've seen them, even the home made ones, on other cars.

I'd also second or third the recommendation to keep as much fluid in the system as you can. Our system is happy with about 3/4 of an inch of air below the filler neck. It stays at that level forever. It's a 50/50 mix. Original cap, not refurbed recently, I doubt it's making more than a few pounds of pressure.

I agree with the above encouraging comments, thank you 'barners for keeping it kind. There is no doubt these systems can be made to work correctly and withstand vigorous exercise as evidenced by the recent long distance touring experiences where a big bunch of cars climbed mountains, salt flats, and deserts.

Learning every day, -VT/JeffH
 
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For those of you without T-Stats how does it cool on the highway? What is the engine temp in cooler weather? My concern in 50 degree weather the motor would not reach a good operating temperature. I have Skips pumps and the T-Stats he recommended and I still run at 220 on a warm day. Trying to decided if removing stats might fix it.
 
With six quarter inch holes in the thermostats there won't be any stat left so you may as well throw them away , you are kidding yourself if you think they are doing anything. A small 1/8 hole or two will allow air to bleed easier when refilling.
dp1743 said:
Millcroft. Please let us know how you make out. I to have a overheating problem in my flathead. There were no thermostats in it when I got it, but, I heard that doesn't allow the radiator cool the fluid. Some say the coolest runs through the radiator too fast to cool. Anyway, I installed two 160 degree thermostats. I also drilled 6 quarter inch holes in the flanges of the thermostats. On normal days it works fine. However, yesterday and today it' s been in the 90s and the car tends to get very hot. Maybe the weather is just too much? - Dick
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38 Ford Guy said:
For those of you without T-Stats how does it cool on the highway? What is the engine temp in cooler weather? My concern in 50 degree weather the motor would not reach a good operating temperature. I have Skips pumps and the T-Stats he recommended and I still run at 220 on a warm day. Trying to decided if removing stats might fix it.
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38 what year car and what is the temperature at highway speeds. These old Fords have a poor fan and don't like heavy stop and go traffic or idling
on hot days. You also need to be able to fill the radiator and maintain a full system. If your radiator has the over flow of the top tank you need Skips 3 lb pressure valve. G.M.
 
50 Ford Engine but a Walker Radiator 16 lb system. Runs 220 on the highway turning 2200 rpm. Bring the rpms up to 3K it cools down.
 
I have a 8ba 255 .060 over in a 39 ford with 2 97s had problem with temp all over the lot at 2k,put Bubbas dist and temp is steady now ,but still run hot with elect fan at slow spees.
I have tried everything but a different car body. Mecury had big radiotors
I run no temstats the housing is small enough so you don,t need them, only when to cold.
 
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