Thanks Jack, very well explained. Fortunately I don't have an overheating problem but I never understood the cooling system this way until I saw your video. Well done and thanks.
Not a mechanic or engineer, but I'm just stopping by to confirm, one major factor is indeed the many years worth of rust inside. I operate injection molding machines, and I found some of our molds don't cool as well as they ought to. Turns out, they're fairly clogged up with rust. Just blowing them out with compressed air (blew out a cloud of rusty mud!) made them cool nicely, and keep the boss cool too LOL.
Great info Jack! As far as having a push pump I have seen model T pumps adapted to performance A engines which are pushing the coolant into the block vs. sucking it through if I’m not mistaken. I never saw the advantage of that set up until now. People also put aftermarket pulleys on that are smaller in diameter so the pump turns slower. This might reduce some of that negative pressure that causes the overheating issues as well. Please keep the videos coming, I really enjoy them.
I'm machanical engineer too, your video is perfect in the regard of the Model A cooling system, the most important aspect is when the coolant becomes so hot that it brings the pump in the cavitation zone, then, the flow decreases making the problem worse, it is the infernal spiral.
I have eliminated the most common issues with the cooling system on a A but running down the road 55-65 on a 90 degree day the water temp will hit 220 and usually stays there. My trips are usually 30 to 40 miles at a time. The car has a brand new 3 core radiator and at first I had a problem with the coolant being forced out of the radiator while cruising and I use waterless coolant so no chance of boiling or steam. I added a electric water pump between the lower radiator and the engine and stopped that problem. My engine is totally rebuilt with higher compression head down draft carb and electronic dist. I also use a 6 blade radiator fan. The water pump is a leakless with the reduced impellor. The electric pump I added does 50 GPM. I think it should run cooler down the road and I believe air flow through the radiator is not as good as it should be at higher highway speeds due to the head lights up setting the air flow into the radiator. The lower pans in the engine bay will not help air flow through the radiator.
Jack Bahm seu video me ajudou a entender o sitema de arrefecimento do meu Ford A 1928. Estou com esse problema de aquecimento, já conferi o ponto do motor, retifiquei o motor, troquei a bomba de água mas o problema ainda persiste. Vou verificar o radiador na tentativa de encontrar alguma solução para o aquecimento. Obrigado do Brasil!!
If you are bubbling out at low speed, then it may be combustion gases getting into your water jacket, tighten the heard bolts to 55 ft.#. If it is still there, you may need a new head gasket. If the problem is at higher speeds, as most are, your radiator is plugged. Most are. Have it re-cored or buy a new one. If you have the ability to check the flow rate of your radiator, it should flow around 36 GPM. Good luck.
It's probably the result of cavitation in the pump and other points in the system where there is much flow and some void (vacuum) turbulence pockets that makes the cooling fluid water boil below it's designed boiling point. Water vapor has a lot more energy and destroys pump vanes and increases corrosion. Try Evans waterless coolant.
What are the signs of overheating? I can drive mine at 45mph for more than 10 minutes like you say, but coolant is spitting out of the cap and coming out of the overflow.
Jack, Nice information and talk about a serious problem that has many limited to short drives. My question is why so many radiators are plugged and what preventative measures can be taken? Sometimes it is difficult to see your poster. :)
+Henry Carr You can't do anything to an old radiator. They are plugged with no flow, so you can't put in anything to attack it. When you put in a new one, or a rodded out one, you should put an old sock over the rad inlet to catch any chunks you stirred up. Run it a bit, then take the sock off. Keep antifreeze in it and drive the car. You have to drive it.
The only reason I know of that I've had boil overs with my Model A has been from loss of water. And I've found that loss of water can easily occur from those old large slot dome headed screws which hold the clamps. A thick screwdriver with a good flat end is needed to tighten them because once that slot becomes worn after using a thinner screwdriver, the screw can't be tightened enough and water leaks out. I've also had the rear wall of my fan pully break off and then the fanbelt won't turn the fan. Since my fan has been reinforced and powdercoated, I really want to save it. Can that rear wall of the pully be Mig or Tig welded back on?
Be careful of the fan. It can end up in your skull or hood or radiator. I doubt that you will find anyone who would weld it for you. If you do it yourself, make sure it is perfect, and stay away from it when the engine is reving. The tapered attachment to the water pump shaft is a major problem. The belt load is cantilevered forward of the taper and it always beats itself up and fails over time. I wrote a paper on this joint. I'll look for it. If you can get those hoses tight and drive 45 mph for 10 min straight, your rad is OK. jack
Jim Ervin I don't think that clamps are your problem. Drive 45 MPH for 10 full, steady minutes, and if you overheat, and I think you will, your radiator is plugged.. Most of them are and people keep playing with bandaids and fooling themselves. jack
Hi Jack, I'm well aware of the old problems with Model A fan blades breaking off. But as I said, mine was totally reinforced maybe five years ago and I've never had a problem with it, well at least not yet. It's just the rear ring of the pully which broke off, thankfully in my own yard. This morning a friend of mine was able to Mig weld it back on. Now I just have to grind down the welds, give it some new paint and put everything back together and try it out. I haven't heard of that belt load problem but could that be the cause of the rear ring breaking off?
I found my old write-up and will paste it in here. I don't think a bad joint would cause that pully to come apart. Sound like you are all set. jack Model A tips on the water pump connection to the fan assembly. The joint between the fan assy. and the water pump shaft has given Model A’er fits over the years. It is a taper fit and it must fit tightly or there will be problems down the road. The design of this joint is not the best. The belt load is about 2 inches aft of the tapered joint. The belt load puts a cantilevered (offset) force on this joint. If there is any movement between the shaft and fan assy., this force will cause a pounding out of the two tapers. This force rotates 360 deg. every time the fan makes a rotation, and it turns faster than the crankshaft. Many people try to fix a loose joint by tightening the nut on the nose of the shaft. This does little to fix the problem and most of the time results in a stripped nut or shaft. Clamping the fan assy. tighter on the shaft can not overcome the forces tending to wobble the fan assy. on a loose fitting shaft. So what do we do about all this? Check the fit often, and don’t start on a long tour with a loose joint. In time, it will pound out and make noise, and may end up causing damage to the radiator or hood. If you find a loose joint, check the fit with the mounting nut off. If it is loose, replace the fan assy. with one that has the proper taper for the shaft you are dealing with. If it is not a snug fit, it will get worse and the problem will repeat. I have been successful twice fixing this problem on the road. Not sure why it fixed it, but it got us home. Take a small piece of shim stock and form it into a conical shape and place it in the joint leaving room for the key. You will have to do this a few times until you get it in the correct place to cause a tight fit. Be sure you have bandaids handy because that shim stock is very sharp. This problem may be a little worse with an altenator. I think we run higher belt tension when we put an altenator on due to the smaller pulley. Keep you belt tension as low as you can. Don’t put anymore load on that water pump joint than you have to. Jack Bahm 2007
would a 4 blade fan help with pulling in more air and help with the cooling?? I have a 31 A model that I've had to install an electric fan to force more air through.
Jack Bahm Hello Jack, the 4 blade fan worked well, but still was running alittle hotter than I liked. I bit the bullet and spent $1100., had a buddy of mine build me special radiator with bigger tubes....everything works like a champ now.
Is this for a properly functioning system as Ford designed? Like, IOW, could a model A not ride for 10 minutes at 45mph without overheating? It seems to me that any classic car that is going to see the road should have a newly cored radiator and the proper pump in good working condition. From my experience, it is parades that kill classic cars. It's the constant low speed often just stopped and idling that causes the overheating of old cars.
Clean tubes transfer approximately 15,000 btu per square foot of tube surface. And dirty tubes transfer approximately 10,000 btu per square foot of tube.
I would start with just a new radiator. Most cores are plugged, but the owners never want to admit it. The best you could do is put a three row AA radiator on, but you may be OK with the two row. Don't think a radiator shop can clear an old core. Most can't, no matter what they say. The only way to clear a core is by rodding it out mechanically, and that is hard to do because of the design of the A core. Good luck.
@@JackBahmlll Thank you so much for your advice ! I don't have a model A yet but have watched nearly all of your videos and I feel more confident that I can maintain the vehicle . You explain things very clear and easy . I absolutely enjoy the simplicity of the model A and how everything is mechanicle. Thank you again for taking the time to teach me .
Tell them that there are about 250,000 Model A's over here and there should be a good market for a new, old radiator. They are getting $400 for the ones we have. They fit and look OK, BUT USUALLY HAVE A MODERN CORE IN THEM.
No, my boiling problem is now solved. And it was caused, like I said, from the lower clamp on the upper rad hose which, I believe, needed tightening as well as moving it up a little. After seven months, I think I can safely say that it wasn't a plugged radiator, just one of those little Model A problems of something coming loose.
I had a prospect radiator manufacture in Minneapolis for an electrodeposition paint tank. One of the many parameters for an E-coat tank is ... we need to throw 1.3 amps per surface area-square foot of 'work' in the tank. We calculated the square foot of all the crinkled-up cooling fins plus the tube's outer surfaces times the number of radiators an hour to be produced and concluded that Minneapolis did not have enough available electricity. We would cause a massive 'brown out' and everyone's refrigerator motor in town would fry. I sketched this back in 1977 as I talked to a prospect about an E-Coat tank. I sketched this so I didn't forget anything. ~~~~ www.finishingtalk.com/community/user-uploads/skip/Electrodeposition%20Painting.jpg
build a fan shroud or find a suitable size one from a junkyard car , it sounds like you need to increase the airflow going across the rad, food for thought
I drive a 1931 Townsedan, heavy car, at 50 mph plus in Houston when the temperature is 98 degrees. Never had an overheating issue and do not have a fan shroud. Ford only used a fan shroud for a few months on the early Model A's. It was abandoned as Ford felt it was not needed. Suggest before you feel you need a fan shroud you find the root cause of your cooling issues. Just saying.
I Invoke My First Amendment Rights There are a lot of good new ones out there that work good as long as there is not much junk going around. You would have to compete on price and market the fact that your core has big tubes for better flow of junk. jack
Brassworks makes a fantastic radiator. They make some that are like the original and some that are more of a modern style. When this video was made these radiators may have not been available. You would have to compete with them. They have a fantastic following and a fantastic reputation. www.thebrassworks.net/shop/index.php?cPath=11_18
Is there anyone out there using EVANS WATERLESS COOLANT? I saw this on Jay Leno' garage. Looks like a quality product used on many antique automobiles. Any suggestions? Thank you in advance!
If your core will flow at 36 GPM, there is no reason to spend the money for it. Just another band aid that people use. Fix or replace your core. Just my opinion.
@@JackBahmlll Thank you sir! You are considered by many to be a guru of everything Model A. I'm learning alot about maintaining the Model A. I haven't found "THE" vehicle for me but living in Phoenix, ya gotta keep 'em cool. Thanks again! Keep the videos comin'!
They sell filters, but once a filter catches the junk, you can remove the filter. I think an old sock would do the job. When you put on a new core, give it a short run with the sock in there, then remove it. Should work. Once the junk is stuck in the tubes, the filter won’t help.
If you can not cool it with 2-1/2 gallons you will not cool it with 3 gallons. The centrifugal pump slings water uphill through the neck and into the upper tank. It's virtually impossible to flow water through a tube faster than 32 feet per minute. Ford sized their Model 'A' radiators easily on the correct side.
thats very interesting , now ive got a question about a 70s chevrolet cooing stystem and how to descale the iron block and radiator.would it be safe to fill everything up with tap water and add a small percent of sulfuric acid let it run mix well.sit overnite then run again with a garden hose old school flush for awhile? ive descaled other things that way works very well..but would that really get the cooling channels in the block and heater system cleaned out to flow again like it was ment to?
thunderstorms06 Be careful with that acid. It may do things you don't want. People have screwed things up even with bleach. If there is no flow in the tube, the acid won't get there. jack
Thanks Jack, very well explained. Fortunately I don't have an overheating problem but I never understood the cooling system this way until I saw your video. Well done and thanks.
I have never believed in the impeller being too big theory. I am glad I watched this video.
Thanks Jack, I am new to Model A's and this helped a lot. I enjoy all your video's.
Great video...I've considered using a radiator for the AA truck- it's larger, as you probably know. Comments? Thanks for an interesting video.
Awesome video. Thanks Jack. I'm learning so much!
Not a mechanic or engineer, but I'm just stopping by to confirm, one major factor is indeed the many years worth of rust inside.
I operate injection molding machines, and I found some of our molds don't cool as well as they ought to. Turns out, they're fairly clogged up with rust. Just blowing them out with compressed air (blew out a cloud of rusty mud!) made them cool nicely, and keep the boss cool too LOL.
Incredibly nice video. Well done.
Great info Jack!
As far as having a push pump I have seen model T pumps adapted to performance A engines which are pushing the coolant into the block vs. sucking it through if I’m not mistaken. I never saw the advantage of that set up until now.
People also put aftermarket pulleys on that are smaller in diameter so the pump turns slower. This might reduce some of that negative pressure that causes the overheating issues as well.
Please keep the videos coming, I really enjoy them.
Jack, you appear to be an Engineer. Most valuable discussion. I am a Mechanical Engineer. NPSH and all of that, right? Nice discussion.
Michael Eisenbise Yes, BSME from LSU.
@@JackBahmlll go tigers.
I'm machanical engineer too, your video is perfect in the regard of the Model A cooling system, the most important aspect is when the coolant becomes so hot that it brings the pump in the cavitation zone, then, the flow decreases making the problem worse, it is the infernal spiral.
I have eliminated the most common issues with the cooling system on a A but running down the road 55-65 on a 90 degree day the water temp will hit 220 and usually stays there. My trips are usually 30 to 40 miles at a time. The car has a brand new 3 core radiator and at first I had a problem with the coolant being forced out of the radiator while cruising and I use waterless coolant so no chance of boiling or steam. I added a electric water pump between the lower radiator and the engine and stopped that problem. My engine is totally rebuilt with higher compression head down draft carb and electronic dist. I also use a 6 blade radiator fan. The water pump is a leakless with the reduced impellor. The electric pump I added does 50 GPM. I think it should run cooler down the road and I believe air flow through the radiator is not as good as it should be at higher highway speeds due to the head lights up setting the air flow into the radiator. The lower pans in the engine bay will not help air flow through the radiator.
Very good. Thank you.
Jack Bahm seu video me ajudou a entender o sitema de arrefecimento do meu Ford A 1928. Estou com esse problema de aquecimento, já conferi o ponto do motor, retifiquei o motor, troquei a bomba de água mas o problema ainda persiste.
Vou verificar o radiador na tentativa de encontrar alguma solução para o aquecimento. Obrigado do Brasil!!
If you are bubbling out at low speed, then it may be combustion gases getting into your water jacket, tighten the heard bolts to 55 ft.#. If it is still there, you may need a new head gasket.
If the problem is at higher speeds, as most are, your radiator is plugged. Most are. Have it re-cored or buy a new one. If you have the ability to check the flow rate of your radiator, it should flow around 36 GPM. Good luck.
thanks jack great vid,very very interesting.
It's probably the result of cavitation in the pump and other points in the system where there is much flow and some void (vacuum) turbulence pockets that makes the cooling fluid water boil below it's designed boiling point. Water vapor has a lot more energy and destroys pump vanes and increases corrosion. Try Evans waterless coolant.
Miguel Ángel Simón Fernández
Definitely Evens.
$40 well spent and you only have to buy it once👍🏻
What are the signs of overheating? I can drive mine at 45mph for more than 10 minutes like you say, but coolant is spitting out of the cap and coming out of the overflow.
Jack, Nice information and talk about a serious problem that has many limited to short drives. My question is why so many radiators are plugged and what preventative measures can be taken? Sometimes it is difficult to see your poster. :)
+Henry Carr You can't do anything to an old radiator. They are plugged with no flow, so you can't put in anything to attack it. When you put in a new one, or a rodded out one, you should put an old sock over the rad inlet to catch any chunks you stirred up. Run it a bit, then take the sock off. Keep antifreeze in it and drive the car. You have to drive it.
The only reason I know of that I've had boil overs with my Model A has been from loss of water. And I've found that loss of water can easily occur from those old large slot dome headed screws which hold the clamps. A thick screwdriver with a good flat end is needed to tighten them because once that slot becomes worn after using a thinner screwdriver, the screw can't be tightened enough and water leaks out.
I've also had the rear wall of my fan pully break off and then the fanbelt won't turn the fan. Since my fan has been reinforced and powdercoated, I really want to save it. Can that rear wall of the pully be Mig or Tig welded back on?
Be careful of the fan. It can end up in your skull or hood or radiator. I doubt that you will find anyone who would weld it for you. If you do it yourself, make sure it is perfect, and stay away from it when the engine is reving.
The tapered attachment to the water pump shaft is a major problem. The belt load is cantilevered forward of the taper and it always beats itself up and fails over time. I wrote a paper on this joint. I'll look for it.
If you can get those hoses tight and drive 45 mph for 10 min straight, your rad is OK.
jack
Jim Ervin I don't think that clamps are your problem. Drive 45 MPH for 10 full, steady minutes, and if you overheat, and I think you will, your radiator is plugged.. Most of them are and people keep playing with bandaids and fooling themselves. jack
Good stuff, like always, from Jack! Thanks.
Hi Jack,
I'm well aware of the old problems with Model A fan blades breaking off. But as I said, mine was totally reinforced maybe five years ago and I've never had a problem with it, well at least not yet. It's just the rear ring of the pully which broke off, thankfully in my own yard. This morning a friend of mine was able to Mig weld it back on. Now I just have to grind down the welds, give it some new paint and put everything back together and try it out. I haven't heard of that belt load problem but could that be the cause of the rear ring breaking off?
I found my old write-up and will paste it in here. I don't think a bad joint would cause that pully to come apart. Sound like you are all set. jack
Model A tips on the water pump connection to the fan assembly.
The joint between the fan assy. and the water pump shaft has given Model A’er fits over the years. It is a taper fit and it must fit tightly or there will be problems down the road. The design of this joint is not the best. The belt load is about 2 inches aft of the tapered joint. The belt load puts a cantilevered (offset) force on this joint. If there is any movement between the shaft and fan assy., this force will cause a pounding out of the two tapers. This force rotates 360 deg. every time the fan makes a rotation, and it turns faster than the crankshaft. Many people try to fix a loose joint by tightening the nut on the nose of the shaft. This does little to fix the problem and most of the time results in a stripped nut or shaft. Clamping the fan assy. tighter on the shaft can not overcome the forces tending to wobble the fan assy. on a loose fitting shaft.
So what do we do about all this? Check the fit often, and don’t start on a long tour with a loose joint. In time, it will pound out and make noise, and may end up causing damage to the radiator or hood. If you find a loose joint, check the fit with the mounting nut off. If it is loose, replace the fan assy. with one that has the proper taper for the shaft you are dealing with. If it is not a snug fit, it will get worse and the problem will repeat.
I have been successful twice fixing this problem on the road. Not sure why it fixed it, but it got us home. Take a small piece of shim stock and form it into a conical shape and place it in the joint leaving room for the key. You will have to do this a few times until you get it in the correct place to cause a tight fit. Be sure you have bandaids handy because that shim stock is very sharp.
This problem may be a little worse with an altenator. I think we run higher belt tension when we put an altenator on due to the smaller pulley. Keep you belt tension as low as you can. Don’t put anymore load on that water pump joint than you have to.
Jack Bahm 2007
What are you located
would a 4 blade fan help with pulling in more air and help with the cooling??
I have a 31 A model that I've had to install an electric fan to force more air through.
Lee Goins
Sure it would, but you are just adding another band-aid, trying to cover up a radiator problem.
Jack Bahm Hello Jack, the 4 blade fan worked well, but still was running alittle hotter than I liked. I bit the bullet and spent $1100., had a buddy of mine build me special radiator with bigger tubes....everything works like a champ now.
Is this for a properly functioning system as Ford designed? Like, IOW, could a model A not ride for 10 minutes at 45mph without overheating?
It seems to me that any classic car that is going to see the road should have a newly cored radiator and the proper pump in good working condition. From my experience, it is parades that kill classic cars. It's the constant low speed often just stopped and idling that causes the overheating of old cars.
Clean tubes transfer approximately 15,000 btu per square foot of tube surface. And dirty tubes transfer approximately 10,000 btu per square foot of tube.
I want to get a model a truck for daily driver and I live in a very hot desert , can I or do I need to add a better fan or electric fan
I would start with just a new radiator. Most cores are plugged, but the owners never want to admit it. The best you could do is put a three row AA radiator on, but you may be OK with the two row.
Don't think a radiator shop can clear an old core. Most can't, no matter what they say. The only way to clear a core is by rodding it out mechanically, and that is hard to do because of the design of the A core. Good luck.
@@JackBahmlll Thank you so much for your advice ! I don't have a model A yet but have watched nearly all of your videos and I feel more confident that I can maintain the vehicle . You explain things very clear and easy . I absolutely enjoy the simplicity of the model A and how everything is mechanicle. Thank you again for taking the time to teach me .
Good job
I know of a business here in New Zealand who still use antique equipment from the era to make vintage car radiators, maybe what your looking for?
Tell them that there are about 250,000 Model A's over here and there should be a good market for a new, old radiator. They are getting $400 for the ones we have. They fit and look OK, BUT USUALLY HAVE A MODERN CORE IN THEM.
No, my boiling problem is now solved. And it was caused, like I said, from the lower clamp on the upper rad hose which, I believe, needed tightening as well as moving it up a little. After seven months, I think I can safely say that it wasn't a plugged radiator, just one of those little Model A problems of something coming loose.
Was it sucking air or leaking coolant?
@@clockguy2 She had a water leak. After 5 years, I still do recall.
I had a prospect radiator manufacture in Minneapolis for an electrodeposition paint tank. One of the many parameters for an E-coat tank is ... we need to throw 1.3 amps per surface area-square foot of 'work' in the tank.
We calculated the square foot of all the crinkled-up cooling fins plus the tube's outer surfaces times the number of radiators an hour to be produced and concluded that Minneapolis did not have enough available electricity. We would cause a massive 'brown out' and everyone's refrigerator motor in town would fry.
I sketched this back in 1977 as I talked to a prospect about an E-Coat tank. I sketched this so I didn't forget anything. ~~~~ www.finishingtalk.com/community/user-uploads/skip/Electrodeposition%20Painting.jpg
build a fan shroud or find a suitable size one from a junkyard car , it sounds like you need to increase the airflow going across the rad, food for thought
I drive a 1931 Townsedan, heavy car, at 50 mph plus in Houston when the temperature is 98 degrees. Never had an overheating issue and do not have a fan shroud. Ford only used a fan shroud for a few months on the early Model A's. It was abandoned as Ford felt it was not needed. Suggest before you feel you need a fan shroud you find the root cause of your cooling issues. Just saying.
So, if I started making radiators that are similar to the old Model A/T radiators, I could have many customers?
I Invoke My First Amendment Rights There are a lot of good new ones out there that work good as long as there is not much junk going around. You would have to compete on price and market the fact that your core has big tubes for better flow of junk. jack
Brassworks makes a fantastic radiator. They make some that are like the original and some that are more of a modern style. When this video was made these radiators may have not been available. You would have to compete with them. They have a fantastic following and a fantastic reputation. www.thebrassworks.net/shop/index.php?cPath=11_18
Is there anyone out there using EVANS WATERLESS COOLANT? I saw this on Jay Leno' garage. Looks like a quality product used on many antique automobiles. Any suggestions? Thank you in advance!
If your core will flow at 36 GPM, there is no reason to spend the money for it. Just another band aid that people use. Fix or replace your core. Just my opinion.
@@JackBahmlll Thank you sir! You are considered by many to be a guru of everything Model A. I'm learning alot about maintaining the Model A. I haven't found "THE" vehicle for me but living in Phoenix, ya gotta keep 'em cool. Thanks again! Keep the videos comin'!
They sell filters, but once a filter catches the junk, you can remove the filter. I think an old sock would do the job. When you put on a new core, give it a short run with the sock in there, then remove it. Should work. Once the junk is stuck in the tubes, the filter won’t help.
If you can not cool it with 2-1/2 gallons you will not cool it with 3 gallons.
The centrifugal pump slings water uphill through the neck and into the upper tank. It's virtually impossible to flow water through a tube faster than 32 feet per minute. Ford sized their Model 'A' radiators easily on the correct side.
thats very interesting , now ive got a question about a 70s chevrolet cooing stystem and how to descale the iron block and radiator.would it be safe to fill everything up with tap water and add a small percent of sulfuric acid let it run mix well.sit overnite then run again with a garden hose old school flush for awhile? ive descaled other things that way works very well..but would that really get the cooling channels in the block and heater system cleaned out to flow again like it was ment to?
thunderstorms06 Be careful with that acid. It may do things you don't want. People have screwed things up even with bleach. If there is no flow in the tube, the acid won't get there. jack