keithb7 Posted July 3, 2022 Report Share Posted July 3, 2022 (edited) I have been doing a little more investigation into engine cooling issues. Over the past 3 years I have been working to get my car back to spec. I have done all the things I can to address my cooling system. I've rebuilt the engine. Complete hot tank of the block, all sediment removed. New brass water distribution tube. New water pump, rad cap and 170F thermostat. All new hoses and belt. New water pump. Rad re-cored. As mentioned earlier I have learned that my stock temperature gauge is inaccurate. With my fresh new 237, I am not babying the car. I work it now more than before it was rebuilt. Including my recent 300 mile hi-way trip. Over and back a mountainous pass. Yesterday I removed the stock temp gauge capillary tube from the left rear of my head. I installed a new capillary type gauge. I proceeded to work my car hard. Get it really heated up until I notice the oil pressure drops a few pounds. This tells me the oil is good and hot now too. Then go climb some big hills. Long hills with steep grades. I am talking 15-20 minute climbs with your throttle wide open with the ambient air temps above 80F. So your car is just able to maintain 35-40 mph with all she's got to give. A winding steep 2 lane road. Not a hi-way. This indeed tests the limits of your cooling system. The old cars with no fan shroud, with a belt driven fan, rely on air flow from the car in motion, to help cool it. When you are working the engine hard, a good load, burning lots of fuel on a steep long hill, airflow becomes an issue. You are traveling slower now. You are making a ton of heat. The engine fan is possibly turning slower depending what gear you are in, dictating engine RPMs. The 80F ambient air is not helping very much. The cards are all stacked against your cooling system now. Most of these old cars did not utilize a shroud around the rad. An open fan is much less efficient than a fan with a shroud. I have read up to 38% less efficient. The fan draws air from all around it, not necessarily from in front of it. Yes some air comes through the rad, not all, efficiently. In addition to that the outer edges of your rad, outside the span of the fan blade, those fins get little to no air moving through them at lower speed travel. At stop and go traffic, none. A fan shroud could help tremendously depending on your driving conditions. A shroud controls the air movement by the fan. It has to come through the rad. A venturi effect is also is created, pulling air through the rad at a higher rate of speed. At low speed, high-load hills, your car could really benefit from a shroud. The stock system in these old cars was adequate in most all situations. Moving at speed really helped a lot. Yet as each part of the cooling system weakened with age and lack of maintenance, the system may not keep up. Unable to cool adequately in all scenarios. Band-Aids are available. Electric fans. Larger rads. Larger pulleys etc. My 1938 Plymouth cooling system is not stock. The 23" engine was removed. A 25" 237 is in the car now. A different rad was installed so it could be moved forward in the nose cone and accommodate the longer 25" engine. The fan on my engine is not as close to the rad as I'd like to see. The 237 likely creates a bit more heat than the stock 201 engine. I am seeing temps a little warmer than I'd like on the long hills. I am not boiling the coolant. It is 50/50 water and glycol, pressurized with a 7 psi rad cap. The 237 performs awesome in this car. The increased torque and power make it a pleasure to drive. Yet, i am convinced it makes more heat. I suspect I would benefit greatly from a fan shroud. Building a spacer to to get the fan blade a little closer to the rad. There are limitations as the crank pulley and generator pulley must all line up. Moving the rad closer to the fan, would be a good benefit. Hmm...Things to consider. Edited July 3, 2022 by keithb7 Quote Link to comment Share on other sites More sharing options...
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.