Flathead runs hot - won't cool

Don't know what your elevation is but assuming you're near sea level (under 1,000 feet elevation) with a 7 lb. radiator cap your water won't boil until 225 degrees so maybe you're ok. Modern engines with 15 lb. caps typically run at 220*. But, then, again, with their typical 15 lb caps they're good to 240*.

As others have said, it will certainly help to lose the coolant flow restrictors and have the fan turn on earlier.
 
What are you running for coolant? Tap water? Distilled? Antifreeze? Water Wetter/Purple Ice? Could make a difference.
 
I think I remember reading something about putting alum heads pre 48 on 8ba.I think the heads are blocking is there holes to be opened.
 
Ol'Ron mentions holes that need to be plugged in a late block to use the early style heads. There is a picture of these on page 5 of his book. There are also differences in the cooling passages in the center of the block and head between early and late designs. I think those details can be found on the Vanpelt site. I reread your threads on the HAMB and here again. They are making me think there is low flow through the heads. As ugly as this may sound, you might pull a head to check that the cooling hole configuration matches the block.
 
Restrictors don't cool your engine. The only way it LOOKS like they cooled your engine is if you didn't fill the radiator up tp the filler neck and when it runs you lose coolant because the perssure cap IS NOT WORKING due to the fact it don't seal down on the seat about an inch down in the filler neck. You didn't answer who's high flow pumps you are useing. These after market supposed hi volume pumps are high volume by their literature only. Stock 39 type pumps deliver 65 gallons in 5 minutes. These supposed high volume pumps 75 gallons and Skips pumps with the exclusive turbine impeller delivers 110 gallons.each in 5 minutes. The water needs to be forced through the radiator in these engines. In order to force the water and it stays there formonthsor coolant through through the tubes that restrict the flow the overflow tube must be blocked by the pressure cap or Skips 3 lb pressure valve installed in the over flow tube. With the valve the cap gasket must seal or water will leak out of the cap. The radiator needs to be filled up into the neck and it stays there for months. Pressure caps on these engines is not to increase the boiling point only to hold the water from going out the over flow. The pressure in the system with temperatures below 210 never gets to 3 lbs. A 4 lb cap is all that is required and this acts to hold the water from the over flow tube and is also a safety valve to release pressures above 3 or 4 lbs to keep from blowing hoses and damageing the radiator and you. We have correctd thousands of old Fords with the exact same problem as yours. they all all tried the same things as you have for the past 60 years with the same results. G.M.
 
do a block test to check for combustion gases in the radiator. use temp gun to check various places on the heads, esp. the water outputs. also shoot the radiator to see how it is cooling. good luck...jack

oops...just re-read the post . you already been there-done that. ignore the above, except for the good luck...jack
 
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something else to try..


[SIZE=-1]To Determine the cause of overheating in a car, check the radiator hoses while the engine is warm. If the upper radiator hose is warm and equal in temperature to the bottom hose, the problem is in the radiator. If the upper radiator hose is cool while the lower hose is hot, the problem is in the engine block.[/SIZE]
 
jdl,

I don't understand your theory. The hot water from the engine exits the engine at the top hoses, so the bottom hoses should always be cooler than the top hoses unless the radiator is not cooling the coolant.
 
jdl said:
something else to try..


[SIZE=-1]To Determine the cause of overheating in a car, check the radiator hoses while the engine is warm. If the upper radiator hose is warm and equal in temperature to the bottom hose, the problem is in the radiator. If the upper radiator hose is cool while the lower hose is hot, the problem is in the engine block.[/SIZE]
Click to expand...

TomO said:
jdl,

I don't understand your theory. The hot water from the engine exits the engine at the top hoses, so the bottom hoses should always be cooler than the top hoses unless the radiator is not cooling the coolant.
Click to expand...

I was going to say that same thing.
 
Need more radiator, 2" radiator isn't much. If the block is clean,if the fan is moving air,I would think radiator size.
 
My 36 had the same issues and I tried everything you have including Skips pumps, what fixed it was increasing the jet sizes a lot, Flatheads do not like light tan plugs a little black cured my car, it ran stronger and never overheats
 
This may not have anything to do with the problem.
Sailboat 26ft can only go 6 knots when using engine any trying to go faster then boat that little prop about 8" can slow that boat down.When car is moving at least 20mph you don,t need a fan.
Is the fan going backwards or even in right direction,may try switch fan off when moving.Also any thing is possible is there any packing matierial in raditor from shipping.
 
jdl said:
Hi guys, read it again.. they key is warm top & warm bottom versus cool top & hot bottom ( talking about cars here :) )
Click to expand...

Think again. Can't get cool top and hot bottom when hot water comes out of the top of the engine, goes down through the radiator that cools it, and goes in cooler at the bottom of the engine. Feel your hoses with your hands when engine is hot enough to open the thermostats and see.
 
JonC said:
My 36 had the same issues and I tried everything you have including Skips pumps, what fixed it was increasing the jet sizes a lot, Flatheads do not like light tan plugs a little black cured my car, it ran stronger and never overheats
Click to expand...

Now I've heard that more than once. Ken ct said to use 49 jets in my 94 carb instead of the stock 51's but now I'm running hotter than I used to. I'm going to try going back to the stock 51's and see if that makes a difference. Good to know.

Thanks.
 
original post reads like the rad is working proper ie cools water down about 25 deg. sounds like you should look at the timing and fuel system, but do only one theing at a time, start with timing Laurie
 
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