Restrictor washer instead of t-stat

[Tom's36coupe]

Have been running washer's with 1 inch diameter hole in them instead of thermostats. I know most people like to run thermostats but only drive my car in the summer so don't really care about warming up. Just like the idea that water is circulating all of the time. Anybody else doing the same, how about hole size too. My motor runs at 180 going down the road in 75-80 degree weather, only gets hotter when sitting in traffic then the fan turns on.

[Old Henry]

I can't think of any reason to restict flow in the coolant system unless you're trying to warm it up faster. Why do you do it? Just curious. Why wouldn't water be "circulating all of the time" without the washer restricting the flow? Why not just leave it and the thermostat out? That's what I do in the summer.

[tub1]

i run a ristrictor with a 5/8 hole slow the water down so the fan can do its job cool the water no restriction means water flow to fast

[flatjack9]

Originally Posted by tub1

i run a ristrictor with a 5/8 hole slow the water down so the fan can do its job cool the water no restriction means water flow to fast

Wrong!

[PeterC]

GM - Re "The fans on all of the old Fords don't provide enough air on hot days at very low speed or idle for prolonged operations". Does this comment hold true for the 6 blade truck fan as well?

[19Fordy]

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Originally Posted by Tom's36coupe

Have been running washer's with 1 inch diameter hole in them instead of thermostats. I know most people like to run thermostats but only drive my car in the summer so don't really care about warming up. Just like the idea that water is circulating all of the time. Anybody else doing the same, how about hole size too. My motor runs at 180 going down the road in 75-80 degree weather, only gets hotter when sitting in traffic then the fan turns on.

This question about using washers to slow down flathead water flow is as old as the V-8 itself. I think early stock car racers used the washer along with the "break off every other impeller blade" trick. But the trouble with the washer is that restricts a "smooth" water flow and creates cavitiation (bubbles) in the coolant thereby reducing the amount of water actually touching the inside cylinder walls - reducing heat conduction.

[G.M.]

The washer theory has been around for over 60 years but is not a cure for over heating. The early radiators had an open over flow off the top of the tank. Later the over flow came out of the neck of the radiator between the top seal of the cap and the seat about 1" down in the neck. A pressure cap was used and the spring loaded bottom end of the pressure cap sat and sealed down on that bottom seat. The spring pressure in the cap varies and determines the amount of pressure the cap will hold. A 4 lb cap is all that is required on the old Fords. A compression leak in the engine will increase the pressure in the system and allow the pressure cap to open and release water. Water temperature much over 200 degrees will also raise the pressure in the system and open the cap. On the early open over flow the water backed out the over flow due to the restriction of the radiator tubes. Well over a gallon of water will back out causeing the engine to over heat on hot days. The restrictors slow the water going into the top tank giving it a little more time to FREE flow through the tubes. With the restrictors not quite a gallon escaped and with slightly more water didn't boil over as much except on days over 80 or 85 degrees then it runs up near or over 200 degrees. With a pressure cap on radiators with a seat down in the neck and the over flow comming out the filler neck or on the early radiators a 3 pound pressure relief valve can be installed in the over flow tube. This with a tight sealing cap will act like a pressure cap. The 144 radiator tube openings in the radiator add up to 3 1/2 square inches, the hoses dumping water in the top tank add up to 4 1/2 square inches so you are trying to put 4 1/2 pounds into a 3 1/2 pound bag. This causes the water to back out the over flow. The washers slowed the water and not as much was lost and the engine ran a little cooler until it got hot outside and they boiled over or run up at 200 degrees or more. With the cap or valve water is forced through the radiator tubes and much more heat is transfered by the tubes and fins. With a pressure cap or 3 lb valve the water can be filled up into the neck and stay there for months as long as the water temperature don't get much over 200 degrees and there is no compression leak putting compression pressure in the system and opening the valve or cap allowing water to excape. The water will stay filled for months with a sealed system with the above conditions. This allows the engine to run much cooler. High volume water pumps moving more water will provide even better cooling. The fans on all of the old Fords don't provide enough air on hot days at very low speed or idle for prolonged operations. There is no problem on 95 or 100 degree days as long as the car is going down the road with a sealed system full of water. Speeds of 75 MPH do not cause high temperature with a good system as described above. G.M.

[Tom's36coupe]

I have been using a 7lbs cap on the radiator, too high perhaps...

[G.M.]

Tom I mentioned above how a pressure cap works to keep all of the water in the system. It is NOT used to raise the boiling point of water, that is not a factor with these engines in the stock configuration it is used to keep all of the water in the system. The other feature of the cap I failed to mention is that it also functions as a safty valve. The 7 lb cap isn't in a dangerious pressure range but I prefer a lower range of protection. The higher the pressure the more damage it can cause to people and components. If my pressure gets over 4 lbs I want it released into the air rather then blow a hose, split a radiator seam or blow hot steamy water on me or someone else. I would say the water temperature would have to get in the 210 or a little higher to open a 4 lb pressure cap. If the temperature gets this high there is a problem and the pressure should be released before damage occurs. If I'm driving and it's 95 to 100 or more and I get stuck in stand still traffic I get out of there or pull over and wait until it cools or get moving when It gets near 200 degrees. In less than a mile when I get moving the temperature will drop back in the 180 range. I was driving my 39 in June on I-95, the temperature was over 105 outside and I got stuck in a 8 or 10 mile traffic jam with very little movement. When it got over 200 I went up the shoulder lane looking for a place to get off. Moving even at a very slow speed the temperature dropped very slightly and I got up to where the traffic was moving and someone let me in and in a mile or so the temperature was back to 185. I don't promote going up the shoulder but I did it with caution and didn't have much of a choice and figured with the old car people don't get hostle and a cop may understand the problem. G.M.

[jimTN]

GM is right on this. Have the overflow pressure on both Fords and non Fords that have the early style exposed overflow tube, helps a bunch. Use pressure caps on my 37 up Fords. I have found that heating in an old Ford that has a SOUND motor is most often caused by a bad rad core. Age and salt caused the fins to seperate from the tubes and loose insulation and this is something you cannot see with the eye.

[Tony Martino]

My 2 cents. Been running a stock Merc flatty in my 31 for 7 years. I use a 4 pound cap, Speedway water pumps, 160 degree thermostats, and NO fan! drive all the time and the temp seldom goes over 180. In 100 degrees I have to keep moving but other than that never have a problem. Also, if you run restrictors, it is adding to the slight restriction from the thermostats, so not a good idea to use both.

[fourtydlx]

Try that in ca. on a freeway,Very hard to get off on 110 degree day,I know ,dont get on freeway,have to run fan out here.

[FL&WVMIKE]

By just speeding up your idle speed, will help you a lot. The old Ford water pumps just do not pump water at idle speed. They only stir it up. At a faster idle, you will pump more water and also change more air in the engine compartment.
MIKE

[blucar]

As mentioned in the earlier comments to this topic, restrictive washers and/or cutting every other blade off of the impeller was very common in the 1950's, the thinking being that the twin pumps pumped the coolant through the engine to fast... Wrong
I have found it to be very interesting, that old habits die hard. When anti-freeze was alcohol based it had a boiling point of 180 degrees, therefore it was only used in the winter with thermostats and/or grille covers to warm the engines up.
When the weather warmed up, motorists pulled the thermostats and dumped the anti-freeze.... With out the thermostats engines ran hot going up a hill and cold going down a hill.. ergo a lot of cracked blocks and/or heads.
As a result of the old habits passed on to younger generations, the spring ritual was to dump the anti-freeze and pull the stat. I knew a lot of people that did that up through the late 1960's.
My father was a little ahead of the curve... The " Prestone-Zerex" containers stated "Permanent" so he quit dumping his "coolant" every spring.
I found that 3-4 lbs of pressure cap, 160/180 thermostat and a 50/50 solution of coolant did not stop my engine from overheating in traffic or on hills, however, the coolant did not freely pass out of the radiator via the overflow, then the engine would cool down to the set point of the thermostat.
A pressure cap raises the boiling point 3 dgr for every pound of pressure, a 50/50 mixture of coolant also has a higher boiling point than water.
I have found that one of the best automotive inventions during the past forty + years has been the coolant recovery tank..

[Tom's36coupe]

Think I will dump the restrictors, also any suggestions on finding a 4lb radiator cap. Checked with CarQuest they only have 7lb....

[Old Henry]

Originally Posted by Tom's36coupe

. . . any suggestions on finding a 4lb radiator cap.

Here's a 4 pounder from Mac's for 8 bucks: http://macsautoparts.com/early-v8-ra...0R3CHL1075611/

[Al Corbin]

GM's explanation is the first I have seen that really makes sense. The claim that an engine overheats with too fast flow because the water is not in the radiator long enough is like saying you'll get less sunburned in a convertible if you go faster

[Flathead Fever]

　


In 1949 Ford redesigned the flatheads cooling system. Besides moving the water outlets from the center of the heads to the front they also decreased the size of the upper radiator hoses. Based on this modification by Ford Engineers there could be some merit for installing restrictors in the upper hoses on the earlier 24 stud engines. The problem I have with doing this is I don’t know if Ford restricted the upper hoses on the 8BA engines to slow down the coolant flow or if it had something to do with redirecting the coolant flow to the front of their newly designed heads. I would think that if restricting the upper hose size in the earlier heads would have improved the cooling system Ford would have made this change long before 1949. These engineers must have experimented with different flow rates and restricting the flow probably did not make enough difference on the earlier engines to warrant a change.

I measured the inside diameters of a couple of 8BA thermostat housings. A crusty original measured 15/16" and a new aftermarket housing measured 1". If you want to install a restrictor in an earlier engine
I definitely would not go smaller than one-inch.

Here is a photo of a 59A head next to and aftermarket 8BA thermostat housing there is definitely a big difference.

[G.M.]

Flathead the Prestone #330-160 for the 49 to 53s has a larger opening than 1" and offers no restriction of flow. PeterC a stock six bladed generator mounted fan provides more air but is far to noisey for me. I have a 39 pick up I call Mr.coool which has a modified 6 blade industrial fan which makes about the same noise as a stock 4 blade, a radiator shrowd, 4 lb pressure cap and Skips modified pumps with the turbine blades. These pump almost twice the water as stock pumps. Any of the above changes improve cooling but put them all together and you get optima cooling. I also use 2 gallons of long life perminent anti-freeze, 2 bottles of Purple Ice and a large bottle of Barrs aluminum grainular stop leak. At the National Ford V/8 Club Meet in Maryland about 5 years ago the temperature was right around 100 and we ran the 39 P/U at a fast idle for over 2 hours and it never got to 180. I raced it little a few times and the temperature dropped 4 or 5 degrees. This demonstrats what these improvements will do to improve cooling. More water flowing through the system and more air flow directed through the radiator with the shrowd and with the 4 lb pressure cap the coolant was filled up into the filler neck providing more water in the system. The turbine pumps while providing more water also reduce air in the system. Water or coolant with air mixed in don't cool as good as a solid water mass with hardly any air. G.M.

[Mart]

I believe thermostats are the preferred option, but second choice is to run a restrictor. The pumps push coolant in the bottom of the block. The thermostats or restrictors restrict the coolant flowing out of the top of the motor, but still allow plenty to cool the motor. The point is, that the restriction at the outlet raises the pressure locally within the motor. This slightly raised pressure helps prevent localised boiling and steam pockets.
I would say a 1" hole in the restrictor is too big.
I have offy heads on my French motor with 8ba style outlets. I have a piece of heater hose in each outlet to act as a restrictor. That has 5/8" bore, but is a loose fit so some also flows round the outside.
As with most the posts above, I'm just stating what works for me. your results may vary.
As a footnote I must add that I did have some overheating problems, but it was all down to a bad radiator. Changed the rad and all was well. You can chase you tail trying to fix the supposedly traditional "flattys always run hot" problem with all the hot tips and snake oil remedys but sometimes a basic component (like the rad) might be the whole problem.
I speak from bitter experience.
Mart.