Temperature

I need to know at what temperature most Zephyrs run. We are testing my recently rebuilt 37 engine right now and after making a short drive test and then letting it sit and idle for a few minutes the gauge was posted over on the hot side. Then we scoped it and the reading was 190. My mechanic felt this was too warm for a flathead running without thermostats. Now, as we did not have any instructions, we might have put the water cooling baffles in wrong, or maybe 190 is what the car would run on a day when the temperature was 96. Any ideas, information or numbers that could help us make a judgement on this? By the way, the engine is running very smooth, very quiet.

Ace Collins

Ace -

I'm sure others like Bill and Dale will have more informed opinions, but that doesn't sound out of line at all to me -- especially for a freshly rebuilt engine, sitting idling on a very hot day. As I recall, the stock thermostats are set to be completely open at 180, which should give some indication about where the operating temp should be.

Thanks. Anyone else have any input to go with my friend's Cecil's? CB, I really do appreciate your thoughts and I think you are probably right. I believe my old flathead V-8 used to run around 160-170, but, it has been 25 years since I sold it and I just can't remember. I know it did heat up on very warm days and spit some from the radiator.

Ace

Dear Ace,I think that sounds like it is in the ball park for a fresh,tight engine.Just a thought,i am going to send my water pumps to SKIP to have improved impellers installed so they move more water,and also add a wetting agent to the coolant,gotta believe every little bit helps.If you can reduce the normal operating temperature 10 or 20 degrees think how much longer the whole power plant will last.diz <img src="http://www.aaca.org/ubbthreads/images/graemlins/laugh.gif" alt="" />

I agree with the previous posts in that a new engine will run hotter than an older broken in engine and especially on a 96 degree day. All Ford flatheads should be run with thermostats. Thermostats act as a restrictor in the system and prevent the water pumps from building a postive preasure in the top of the radiator tank and blowing the coolant out the overflow. As to normfal temps, I have several thermostats that are stamped l76 degrees and have always felt that that seemed like an ideal temperature.

Bill

Bill,

Thanks for your input. I believe you are right as well. I visited with Roy Thorson via the phone today and he told me that he puts a truck radiator coolant in his car and it works very well to bring down the temps by 10 to 15 degrees. The additive is called Nalcool. I got online and discovered that it is being used by many who restore vintage British sports cars as well as those with prewar flathead V-8's. I am going to add the thermostats tomorrow and find and add some Nalcool as well. Adding to my eduation in this area I discovered that tap water runs about 15 degrees cooler in a car engine than a 50/50 mix of water and modern antifreeze. That would account for the old cars running hotter now. Back in the 30s everyone was running straight water in the summer, so engines would have been cooler than using what we use today. I think what I am going to do is add a gauge that will accurately measure the temperature so that I can keep tabs on it the first few months I drive it. It is funny, I have a 200 CID six in my 65 Mustang with a three core radiator and it runs incredibly cool even on the hottest day of the summer. My 57 Ranchero has a 292 Y-block V-8 and never overheats, but it runs between the middle of the gauge and hot all the time. I am going to have to get the LZ figured out, get a feel what the gauges read and the best way may be just driving it.

Ace

Too late now, but when you rebuild an engine have the block dipped at a rust removal firm to not only clean the grease and oil from the block, but also to remove all rust scale from the water jacket. When you get the block back it will look like a brand new casting and can't help but run cooler with the rust scale gone.

Don't believe what your temp gauge tells you. Get a thermomoter that reads up to 212 and read the true temp and note where the needle is on a fully warmed up engine. These gauges are only for approxamations.

Bill

We have been shooting a real mechanics gauge into the water each time we run the car. Today, after a few minutes out in the Texas heat the real temperature reading was right at 200. Have been told that an additive, used to be called Nalcool and is now knows as Pencool, we have found it via Napa as Napacool, used in large truck, will bring the temperature down from 10-15 degrees. Also, figure putting the thermostats in place as sort of restriction plates will slow down the water and bring the temperature down a bit as well. Roy Thorson told me about the coolant additive and logic holds on the thermonstats which have not arrived yet. In my study of auto heating, I discovered that tap water runs 10-15% cooler than antifreeze and water mixed. I am guessing that cars in the 30s ran straight tap water in the summer and therefore ran a bit cooler than those same cars do today with the mixture of fluids. Anyway, I will keep you all posted when we get the additive and themostats in and thanks for all you advice. This is a new game for me, so I need all the help I can get.

Ace

If any of you want to email me directly with any information, please feel free to do so.

ace@acecollins.com

I have had the same cooling problem in my newly rebuilt V12 in my 48 conv. coupe. I have 16- thermostates in it new water pumps and the brass baffels, it runs 180-200 on real hot days 105+ in stop and go rush hour traffic here in calif. it doesnt get over 200 but I have had it vapor lock. I am using a 6 volt electric fan to help cool it in traffic and am thinking of adding an oil cooler. But after reading the posts here I am heading to napa to get some napacool before adding the oil cooler. Also have a fan shroud being made, cant wait to get that installed. As far as the guage, mine was way off, I used a mechanics thermomiter and a 2amp 100 ohm variable resistor to get the guage to read where it should at the right temp then read the ohms and installed a 1 amp 80 ohm resistor parralle to get everything reading correctly. now at 170 its right in the middle of the guage at the normal reading. Anything you can do to make these engines runs cool will make them last longer.

Thank you for your insight. I deeply appreciate any experiences that anyone can share in this matter. The thermostats and coolant additive should go in today and we will try it again. As the weather is still extremely hot here, we will get a really good test situation as well. I am hoping I don't have to add an electrice fan, but will if I must. We are going to work with the gauge to get it right on the money and probably keep the extra added temperature gauge up and running as well.

Ace

We appear to be cooling. We took the baffles out and it idled at 190 for ten minutes and only hit 200 on the highway. As the temperature today is 102 with the thermal heat index over 112 and the sun is as bright as it can be, that is probably not bad at all. Danny, the shop owner, is driving it right now to retest it. He has screwed a digital readout into the block and is watching it as he drives it in the heat. If it remains below 200, I think I will finally give it back to me. My guess on the baffles is that they were upside down. There was no diagram and Alan (the man who rebuilt it) and I guessed when we stuck them in. Finally, Danny is going to put a carb kit in tomorrow and test it one more time. Tomorrow's high is supposed to 107. So, if it does not overheat then, I think we will be fine. Also, did not vapor lock even when it was running close to 220 with the baffles still obviously wrong. That is a good sign as well. For now I will probably leave the baffles out until I can visit with someone who has them in their car and the can show me how they work.

Ace Collins