I have been battling overheating problems on my 1950 Ford Sedan and have tried just about everything. I am in the process of taking it apart to replace the temp sending units and the electric fan which means emptying the coolant. And so here is the crossroad that I have reached. In Bill Sinclair's book, Thunder Road Flathead Guide, he talks a lot about cooling and mentions in his book a modification that he performs on the stock flathead waterpump . He drills a 1 1/16" hole below the impeller and plugs the top 1/2" hole with a freeze plug. He says it works great with a modern pressurized type system. Has anyone tried this modification? I am several bolts away from pulling the pumps off and trying it but is it really worth it? I am pretty sure the new fan is going to fix it with the minor tweaking of the engine sheetmetal to help the hot air exit but with a flathead, any extra help is a bonus. I am including a picture of the books picture so that you can see the modification if you don't have the book. Posted using the Full Custom H.A.M.B. App!
I would go with water pumps from Skips and of coarse a good clean cooling system and a mechanical fan plus a good shroud. Gary
I believe that what you are considering is an attempted shortcut that some will hope will solve an existing problem. The Ford engineers had the cooling thing all figured out by 1950 (I have a 1951 V8 that has not run over 185 in the last 25 years I have owned it.) The first thing you should do is to make sure the cooling system is working as designed. Is the radiator clean? How about the rest of the cooling system. Is the block clean? Make sure you have the right thermostats in it. With a flathead, improper ignition timing can cause overheating problems. If you haven't already done so, take the radiator out and have it checked. That's probably the main problem (it was with my '51 for the first 6 months I owned it, when I had it recored.) Things like no thermostats, "flow restrictiors", and changing the cooling flow like you are suggesting are only band aids to get around a fundimental problem in the system. Do a search; check and see what the other guys are doing (running vinegar to clean the system and other methods). Get it clean and operating to factory specs and you will be happy.
I have new speedway pump that have been in there for just over a year, new radiator, cleaned the block several times, running thermostats, have tried 4 different types and ratings settling on 180 that have been checked and matched on a stove, have a new Bubba's Chevy distributor, etc.,ect...... no manual fan or shroud can be used since I have A/C but I have been having problems since I got it with all the original,.as I got it at least, leaking coolant components on it. All the original sheetmetal is installed. I have done the searches and tried all the tricks and still I battle it. Save from putting in a new block or acid dipping the one in there now, everything has been done, with little improvement but still not quite enough. so please only comment if you have heard of or have tried this modification. Posted using the Full Custom H.A.M.B. App!
If you have a flathead that doesn't overheat then congratulations. You haven't had to deal with all the frustration that comes with one that does overheat. So by telling us that you have never had a problem with yours but can tell me exactly what we need to do is kinda like a slap in the face. Especially when in my first post I said that I have tried just about everything. I know you are only trying to help but please read the post before offering such a generic response. Posted using the Full Custom H.A.M.B. App!
When I built the engine in my '40 Ford I did the exact thing to the water pumps that you are talking about. I got the idea from a book perhaps the same one you mention. It just made sense to me to try it. The flatheads dump their cooler water from the radiator right onto the exhaust ports from the front cylinders before they even cool anything. If the water can bypass this exhaust port it should be beneficial. All I can tell you is I have not had any cooling problems with my engine for 14 years. I do live in Canada though where the weather is a little milder than say Southern California. It certainly will not harm anything. Why not try it?
I assume that you have confirmed that there is no compression leaking into the cooling system(cracks). When does it overheat??? at idle in traffic or on the highway at cruise or all the time? The combination of an a/c condenser in front of the rad and an inadequate electric fan with no shroud could be your trouble. A shroud is a must if you want to keep it cool in stop and go traffic. The only time the 8ba in my roadster goes over 185 is in 90 plus weather and I am pushing it at 70 plus mph. I am sure that my problem is an undersized rad, the rad just runs out of cooling capacity. Most flatheads do not run hot if everything is set up properly. Good luck. pm me if you want any additional info
after you try the mods on your pumps do you have room for a shrould if so make or buy one. one more thing i did on my 51 merc was put a sheet of stainless or tin or thin steel between the radiator and the hood latch base. top of grille to top of rad. what that does is force all the air through the radiator. that helped the merc alot hope you get a handle on this it can be frustrating.
The new electric fan going in is a Cooling Component fan that has the shroud built in. Posted using the Full Custom H.A.M.B. App!
Thanks Ol' Blue, finally someone that has some real world experience with the modification. Posted using the Full Custom H.A.M.B. App!
Long time ago----Some guys experimented with this problem. If everything has been done as above, here's another suggestion, remove every other blade in each pump, this will slow down the rate of water returning to the hot top of radiator & give it a chance to cool before recirculating.
The speedway pumps say that their impellers have been redesigned so that mod doesn't need to be done. The removal of the blades was normally done when the thermostats were removed back in the day. No thermostats meant faster than normal flow so they slowed it down by removing the blades. I have the thermostats in place so it might slow the flow down too much and affect idle or slow engine cooling.
AND you have checked the timing??? A defective vac diaphram will retard the timing to the point of over heating????
DUDE!!!!! I have one of your Chevy conversion distributors in there!!! Posted using the Full Custom H.A.M.B. App!
Stock 8ba motor with the exception of an aftermarket intake with a tuned and jetted 4 barrel and a Bubbas Chevy distributor. Posted using the Full Custom H.A.M.B. App!
Exactly what are your cooling problems? Around town, on the highway, everywhere? Does the radiator puke coolant or is the temp gauge just reading high? Is your pressure cap holding?
Here's a couple things to check: Is your timing adjusted correctly? Just because the distributor is good doesn't mean the thing is stuck in the engine at the right degree. Does the block have plugged water passages? Just because you cleaned it by backflushing or vinegar doesn't mean it's really clean. We had our block sandblasted in the passages when it was bare and now it only gets above 170 when sitting still in hot weather. And it's bored to 3-3/8", so there's not a lot of cylinder wall there. All that rust stuck to the walls is hampering the coolant's efforts. Do you have an AC condenser sitting in front of the radiator? If so, can you remove it to check if the problem goes away? Blocking air flow is a major problem with cooling old cars. Especially if there's no shroud to pull the air through.
. I have never tried that modification and think that it's a waste of time. This may not qualify me to comment. However, I will anyway. Two things that I would do. First of all grab hold of that Bubba distributor and give it a twist to the left.. Secondly, slow down the rate of coolant exchange through the radiator. ....Peace!
Sorry, but slowing down the coolant flow will only cause more overheating. More flow equals more heat transfer equals cooler engine.
I have the book and that pump modification is one of the few things I have doubts about. The hole is cut into the suck side of the pump allowing the pump to pull and recirculate some portion of the hot block water instead of drawing all from the radiator. I'd want a better explanation of the theory, if it does work, before trying it. Working on the better fan should be enough.
back when everybody raced with flatheads, one cure was to run tubing through the block so it would direct coolant directly to the cylinders. barney navarro swore by it!
Back to the question...I haven't tried it and wouldn't do it. Thousands of flatheads are running well without that modification. Your searching for something you've overlooked. Want a good pump. Skips pumps increase volume and pressure with his impeller design. Proven by many people... Even with a small block in there you will struggle to keep it cool in that old car if your obstructing airflow with a A/c condenser. That A/c pump is also stealing horsepower and adding stress to the old flatty. Want heat? That will sure make it. One of GMC bubbas Chevy converted distributors does not have advance. Does yours?? Have you verified you are getting correct advance? How did you do that? A lean engine will get hotter than hell. Have you verified this is not the case? How did you do that? Also Answer the questions of others above of your exact symptoms and knock that chip off your shoulder. Like ..Exactly when does it overheat, Exactly what did you do to clean it? Is your cooling system pressurized? Is the radiator overflow tube in the neck of the radiator after the cap? We just might be able to help you find the issue.
I don't know why I bother but I put those washers in my old bomb to slow down flow as the water was running through the radiator so fast it wasn't exchanging the heat....look it up.
Absolutely!! The guys that say to slow coolant flow drive me crazy! Why does slowing the coolant flow down but speeding up air flow make sense to some people? The more water molecules flowing through the core the more btu's you can get rid of. Just like increasing the air molecules flowing over the core. Why would the thermostat close as it cools. To slow the flow to bring the temp back up. The same reason it's wide open when it's at operating temp. To increase the flow to keep it at operating temp. Posted using the Full Custom H.A.M.B. App!
I looked it up, here ya go. Here's the formula for figuring flow for a hydronic heating system. The same concept as a car cooling system just in reverse. Plug some numbers in. So 10,000 btu divided by a 20 delta t or temp differential x 500 equals 1 gpm. Now double the btu to 20,000. Now it's 2 gpm. It now takes double the gpm to dump double the btu's. GPM=BTU/deltaT x 500 Posted using the Full Custom H.A.M.B. App!
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