| jrbrks | -- 04-19-2026 @ 6:01 AM |
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I have recently purchased a 1941 Ford Super Deluxe. This is my first early Ford V8. The former owner recently had the engine completely rebuilt (approximate 300 miles, since the rebuild). The engine starts easily and quickly, when first starting in the morning. The engine runs smoothly. After running for a short or long period of time and shutting down, the engine will not restart. The engine cranks or turns over adequately, but does not try to fire or start. It just turns over. A second question would be related to the best service manual for this vehicle. I have purchased the "1932-1941 Ford & Mercury Shop Manual" reprint, but I am wondering if there is a more complete service manual option. Finally, the engine is filled with Evans Waterless Coolant. The engine overheats quite rapidly (based on the temperature gauge and use of an IR heat gun). Both sides of the engine record similar temperatures with the IR heat gun. Looking in the radiator, coolant is flowing at a cold start, and the coolant flow rapidly increases when the engine reaches mid temperature on the temperature gauge. I assume the thermostats are opening, but I have not yet pulled the hoses to check their opening temperature. The previous owner had the radiator completely rebuilt/restored. I do plan to flush the waterless coolant and replace with antifreeze/water, but I do not yet know that will fully correct the problem. I do know the waterless coolant has a much lower capacity for heat exchange. I would appreciate any thoughts or advice. Thanks, Jim
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| carcrazy | -- 04-19-2026 @ 7:54 AM |
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The best, most efficient, coolant for you to use depends upon where you live and if your car will experience freezing temperatures! The ideal coolant, provided the temperatures don't dip too low, is distilled water. You will want to use a very small amount "water pump lube" or similar product to prevent cooling system rust and corrosion from occurring. If you have to use any anti-freeze, use the minimum amount to prevent freeze up in the areas where the car will be driven. Check your thermostats to make sure they are functioning correctly. My recommendation would be to use 160 degree thermostats to provide a little more of a "cushion" to keep the temperature of the coolant lower. You never have to worry about Flatheads running to cold! If you have a laser thermometer, you can use it to determine if the radiator is functioning correctly by measuring the temperatures at the top and the bottom of the radiator. A radiator that is working properly will show a difference in temperature between the top and the bottom of 15 degrees F. Hope this helps and that you are able to solve your overheating problem. Remember that it is normal for Flathead fully warmed up running coolant temperature to be about 100 degrees warmer than ambient air temperature.
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| 52flatv8 | -- 04-19-2026 @ 8:50 AM |
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As to the hot restart or not starting, flatheads tend to percolate today's fuels with a negative affect on the carburetor. In some cases causing what some call vapor lock. An electric fuel pump installed near the gas tank can usually help restore fuel & fuel flow. Once running you can turn the elect pump off. You may also have a coil getting too hot and failing. Others here have lots more knowledge on this issue. Make sure your radiator is not over full, you only want coolant just above tubes not up to the top of the tank. Hope this helps. Welcome aboard !
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| carcrazy | -- 04-19-2026 @ 9:33 AM |
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One of the best shop manuals is available from Obsolete Ford Parts. It covers all 1939-48 Ford and Mercury vehicles. The part number is BK-379 https://ford.obsoleteandclassicautoparts.com/catalog/early-ford-v8?qad=44r2qJgN29p3M2yPt3i328v22z3m4Z#page/13
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| pauls39coupe | -- 04-19-2026 @ 7:08 PM |
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Check for a good hot blue/white spark. If you have a fail to start situation after a 5 min to ten minute drive, it is probably the condenser. If it fails after 15 minutes look at the coil. 90% of "vapor Lock " problems are electrical. My bet would be to replace the condenser. They are cheap and easy to change.
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| jrbrks | -- 04-20-2026 @ 4:06 AM |
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Thank you, everyone. I will give these suggestions a try. I appreciate the advice. Jim
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| juergen | -- 04-20-2026 @ 6:50 AM |
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To check for a fuel problem, take off the air cleaner, look down the throat and use the throttle to see if the accelerator pump squirts gas. If not you have a fuel problem.
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| carcrazy | -- 04-20-2026 @ 9:12 AM |
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If the engine cranks over normally after a hot soak but the engine refuses to start, spray some starting fluid into the air cleaner to see if you can get the engine to start and run. If the engine won't even try to start with the starting fluid, the ignition system is not working and you have no spark. The most likely cause is a bad coil that fails when hot. Is the ignition system on your engine completely stock? Does it still have the coil that is mounted to the top of the distributor? This coil uses a resistor that is mounted on the passenger compartment side of the firewall under the driver's side of the instrument panel. This resistor may be failing when hot.
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| kevinshea | -- 04-20-2026 @ 1:00 PM |
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I agree with Pauls39... check your spark, disconnect a spark plug wire and drape it near the block.. DO NOT HOLD IT. .. look to see if you have a nice blue spark jumping a 1/4 gap.. if it is white and weak, it is likely electrical .. check your charging system to see that you are getting full charge out of the generator, then look into your distributor (points/coil/condenser)... also, check your plugs to see of any are fouled as that may point to bad spark also. how long had the car sat after the 300 miles? if these old cars sit for a while, weird things can happen.. corrosion, rust, things get stuck, etc
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| jrbrks | -- 04-24-2026 @ 1:49 PM |
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Another question: Is it possible to drain the coolant from the block of the 1941 Ford V8 by removing the radiator hoses on both sides at the water pump?? The pipe plugs in the block seem very tight, and I do not want to bust off the head. Will the water pump prevent the block from draining? Thank you Jim
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| pauls39coupe | -- 04-24-2026 @ 5:35 PM |
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Yes you can drain the block by removing the lower radiator hoses. Not a fun job if they are old and hard.
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| nelsb01 | -- 04-24-2026 @ 7:44 PM |
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If you have replacement hoses --- a hacksaw can be your friend.
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| marko39 | -- 04-25-2026 @ 4:56 AM |
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is there something wrong with your radiator petcock?
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| RAK402A | -- 04-25-2026 @ 8:34 AM |
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I fought the hard starting when warmed up thing for years. I learned what was causing it from this Skip Haney and this forum. It was a combination of things... 1) Voltage drop from dirty connections-especially the ground straps to the firewall and starter cables. 2) Repro coils-even when brand new, when combined with the voltage drop from the bad connections these had trouble providing enough voltage for a good, blue spark when the car was fully warmed up. Once these items were corrected, the car cranks briskly and will start when fully warmed up with no problem. I live in Southern California, where it gets very hot and it is still not a problem. I take a Dremel tool with a soft wire brush to all the battery connections and grounds every two to three years now. I will only use re-built coils from Skip Haney-no more repros! As others have mentioned, a bad condenser can cause problems too (repro condensers can be bad even when brand new). This message was edited by RAK402A on 4-25-26 @ 8:36 AM
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| jrbrks | -- 05-02-2026 @ 4:36 AM |
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As a new owner, I am not certain the best procedure for replacing points, condensers and/or coils on the 1941 flathead V8? Should the distributor be fully removed? One of my older "MOTOR" manuals recommends this. If so, what is the procedure? Are there specific "watch-outs" for removing the distributor? I understand there are three bolts holding the distributor in place? As previously mentioned, the engine starts normally after sitting for a period of time. After running the engine, it will crank normally but it will not "fire" or restart, even if the engine has been run for only a minute of two. Spraying starting fluid into the carburetor has no effect, and the engine will not restart. I will go through the suggestions and checks mentioned previously, but I suspect I will be changing the condensers and/or the coil. Thus, I would like to better understand how to work on the distributor of this engine. ______________________ Also, I remain concerned, regarding fully removing coolant from the engine block and doing a thorough flush and cleaning? I have sprayed the drain plugs in the block, with PB Blaster multiple times, but the drain plugs refuse to move. I am concerned to not bust the ends of these drain plugs with a 3/8" open ended wrench or crescent wrench. Is there a better approach to removing the drain plugs, e.g. purchase a pipe plug socket set? Is there another approach that would effectively drain the block and permit me to better flush and clean the entire cooling system? When I clean the system, I am thinking to use the CRC Thoro-Flush product. Does anyone have thoughts, positive or negative, related to this product? The system currently has Evans Waterless Coolant, and I want to return to a typical mix of green antifreeze and water. The engine currently overheats very rapidly. I am hoping a thorough flush and system cleaning will help. I appreciate everyone's advice, and I will be working through suggestions over the next couple of weeks. Thanks again, Jim
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| carcrazy | -- 05-02-2026 @ 1:29 PM |
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I will answer your questions in the order that they have been presented in you last post. 1.) Yes, remove the distributor from the engine before attempting to do any work within it. 2.) Use the original bolts to replace the distributor on the front cover of the engine. Use of longer bolts can foul the camshaft timing gear and break it. 3.) Three bolts hold the distributor in place. 4.) My recommendation is to use a quality modern tubular, internally resisted, coil with a coil adapter kit that mounts on the top of your distributor. These adapter kits are available from VanPelt and several other vendors. They typically come with a new condenser. 5.) This distributor is fairly complicated to work on to set the points and timing correctly. It is best to send it off to a professional distributor rebuilder to have the new points installed and set up on a distributor machine. 6.) Your spark plugs may be totally fouled out if the engine won't start with starting fluid. 7.) To remove the drain plugs from the bottom sides of the engine block use either a 6 sided (hexagonal) box wrench or socket wrench if the plug has a hexagonal head. If the plug has a square head you will have to use an open end wrench of the correct size. You can heat the plug with a propane torch to help loosen it. Heat the plug until it is red and let it cool before trying to remove it. Once the plug is red hot you can place a beeswax candle net to it on the threads where they go into the block to get the melted bees wax into the threaded area of the block. When the bees wax melts, it will have an extremely low viscosity appearing like water. You may have to do several heat, bees wax applications, and cooling cycles before the drain plugs can be removed. 8.) If your car has a hot water heater, you can buy and use a Prestone Flush 'N Fill kit to backflush your cooling system. These kits are available from your local Wal-Mart and other auto parts stores. With this kit you use your garden hose to back flush the cooling system through a tee fitting you install in your heater inlet hose. 9.) I don't know anything about the CRC Thoro-Flush product. Prestone also has a product you can use.
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| ford38v8 | -- 05-02-2026 @ 3:08 PM |
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Jim, As your car had a waterless coolant when you bought it, I would say it had overheating issues for the previous owner, who resorted to that tactic that also didn't work. Start from scratch here, remove all hoses top and bottom, remove both water pumps, and fish the lower end with long screwdrivers wire coat hangers, etc, ((((Use plastic saran wrap or similar to prevent water from entering your distributor fo the flushing!)))) flush from the top end, watch for debris exiting the lower end. All flatheads will benefit from this procedure, some more than others. Don't bother with your drain plugs, you won't get debris out those small orifices anyway. The condition of your water pumps may also be a factor, someone may have removed or modified the fins, or the pumps may be frozen, not turning at all. Fan belt may be of an incorrect type, not providing enough friction to turn the pumps. Incorrect or improperly installed thermostats can certainly be a problem. Check the functionality of stats in a pot of boiling water, ensure that a small bypass hole exists in each stat, and that they are installed in a manner that prevents binding or turning sideways during operation. Depending on your local climate, a simple water pump lubricant can be added to your water, nothing else, unless a possibility of freezing exists. Now for your ignition, do not remove your distributor, as it has proven capable of working properly. Your coil and condensor though, are HIGHLY suspect. Old coils tend to heat and short out, thereby failing to produce a spark until allowed to cool down. Easy to diagnose, next time the no-start after warm-up happens, check your spark at a plug, a very quick and accurate diagnosis. Never buy a new or old stock coil, both are bad. Skip Haney in Florida rebuilds original coils that last forever. Do not install a rinky ding adapter plate on your distributor, as while it may initially work, it is short lived and will draw polite smiles as observers walk away shaking their heads. I repeat, Skip Haney is your go-to man for coils, and use his advice on condensors. As you state that starter fluid is no help, I'll skip advising you on fuel delivery issues, an entirely different subject. I'll simply say don't mess with your carburetor, you know it works in the morning now, and shouldn't be radically different after warmed up. Alan This message was edited by ford38v8 on 5-2-26 @ 3:11 PM
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| pauls39coupe | -- 05-02-2026 @ 5:31 PM |
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Tackle one problem at a time. When the engine will not start, pull one of the spark plug wires and look for a bright blue/white spark about 1/4 inch long. If you have no spark the problem is electrical in nature, spraying tons of starting fluid will do more harm than good as it washes oil off the cylinder walls. Change the Condenser!!!!! it is located next to the coil and is held in by one of the distributor bolts. Easy to change and you don't need to remove the distributor. If that does not solve the problem I would have Skip Haney rebuild the coil. Do the easy stuff first. If you must remove the distributor it only goes back in one way. It has an offset tang that fits into the end of the camshaft only one way. If you don't get it back in place correctly you will break the mounting flanges. If it does need to be rebuilt send it to Skip or one of the other pros to do it. This is not something for the average tinkerer to work on. One long shot, it is possible that someone has set too much Advance or Retard into the distributor. This would cause the engine to run hot. Look at the timing tag on the side of the distributor, there is a large screw holding it in place. Normally the screw and timing tag will be near the center of travel. If it is at either extreme the timing would be either too far advanced or too far retarded. The correct way to set this is with a distributor machine. I agree with the others flush the cooling system. You won't believe how much rust and core sand remain in the block. Also retorque the heads to be sure the gaskets are sealing. Let us know how you solve the problems.
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| TomO | -- 05-03-2026 @ 12:24 PM |
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Jim, Good advice from Alan and Paul. I am concerned about the fact that you say you cannot start it after running for just a minute and that it will run for a long time normally. This is unusual. Can you drive the car for 10 miles with no problems? Here are my suggestions to try to isolate the problem. Failure to start after running is usually an ignition problem caused by weak spark but can be because the engine is flooded due to carburetor problems. I would not wait until the engine fails to start to do some diagnosing. Next time you start the engine, test the spark. A weak coil or condenser will not show a good blue spark. With the engine idling, look down the throat of the carburetor to see if you can see any fuel dripping into the carburetor venturi. You could have a flooded condition causing the hard start. Have someone turn off the ignition switch while you are looking down the throat of the carburetor. There should be no fuel dripping in. If you have good spark and no fuel dripping into the throat of the carburetor, the next thing to check is the ignition switch. With the car running, tap the bakelight portion of the switch with the handle of a screwdriver. Do not hit it really hard, just tap it lightly. If the engine sputters when you tap it, your ignition switch needs attention. Tom
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| MG | -- 05-03-2026 @ 1:33 PM |
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I experienced this same problem with a '57 Chevy I once owned. - It would start immediately when cold, but after warm-up it would not start until it got cold again. It was tricky to find the cause, but it turned out to be a faulty resistor in the ignition circuit. Seems the resistor got so hot while the engine was running that the voltage drop across it increased to the point where there was not enough voltage to the coil for ignition during start-up...
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| pauls39coupe | -- 05-04-2026 @ 7:26 AM |
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Good advice from all. I think MG hit on something with the resister. I have had that happen on a Ford tractor. The resister would not cool off quickly went the engine was first shut off. This lead to low voltage going to the coil. When this happens again, try using a wire to jump around the resister to provide full voltage to the coil.
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| carcrazy | -- 05-04-2026 @ 9:16 AM |
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If you use a modern internally resisted coil with a coil adapter kit, you can eliminate the troublesome external resistor from the ignition primary circuit.
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| Barney | -- 05-04-2026 @ 4:57 PM |
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Just curious - Why in the world do we refer those little, silver round things a bit smaller than the size of our thumb that reside in the distributor as 'condensers'? Aren't condensers gizmos that change the state of a gas into a liquid? Shouldn't they be referred to as 'capacitors'? I'll shut up/ Barney
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| MG | -- 05-04-2026 @ 6:19 PM |
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'Condenser' is used as another name for capacitor...
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| TomO | -- 05-05-2026 @ 9:50 AM |
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Barney, look at this topic. It explaines why a capacotor is called a condenser. https://electronics.stackexchange.com/questions/222137/why-was-a-capacitor-called-a-condensor-condenser-in-the-early-days-of-electro Tom
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| jrbrks | -- 09-25-2026 @ 8:18 AM |
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Regarding overheating at idle with my 1941 Ford Super deluxe: The base of my radiator sits on two short, stiff springs. Thus the bottom of the fan blades can extend just below the bottom of the radiator tank as shown in the photo. Removing the springs would lower the radiator about an inch to inch and a half. Is the radiator supposed to be sitting on these springs? Should the springs be removed? Is this likely to help with cooling? I have just had the radiator thoroughly cleaned at a reputable radiator shop, and it is a four row radiator. And, yes, I do have the bottom pan that I will install after reinstalling the hoses, etc. I have just reinstalled the radiator, after returning from the radiator shop. Appreciate any advice or thoughts. Jim
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| jrbrks | -- 09-25-2026 @ 1:08 PM |
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I did find a factory drawing describing how the radiator is to be mounted with the springs and rubber cushions. The previous owner had it mounted incorrectly, and I followed that pattern. I now have the correct installation. Jim
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| carcrazy | -- 09-25-2026 @ 1:40 PM |
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Ideally you would want the fan to be located just behind the upper third of the radiator for maximum cooling efficiency. With the crankshaft mounted fan on the 1941 Ford engine, this ideal location is not possible. The reason you want the fan to draw air through the top of the radiator core is because that is where the hot water from the engine enters the radiator. If you reassemble all of the cooling system components and you still cannot get the engine to cool properly, you might want to consider using an electric cooling fan mounted near the top of the radiator core. The most effective fans available are the puller type mounted on the engine side of the radiator. The best fan to use will have metal mounting straps which attach to the frame of the radiator. One source for a fan of this type is Fifth Avenue Antique Auto Parts - www.fifthaveinternetgarage.com
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| jrbrks | -- 09-28-2026 @ 4:49 PM |
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Thank you for the aftermarket fan recommendation Jim
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