I got a mechanical temp gauge sunpro and put it on the 52 F1 flathead 239 to see what the temp really was and this is what I came up with using a laser gun. 91' outside with a 30 minute run ideling mechanical gauge read about 197' with it in the left head. Left head read 197, 194 middle and 206 in the back. Right head read 209,213 middle and 212 in the back. Radiator in the middle read 183 while the water pump on the left side read 200 and the right one read 208. Thermostat housing on left head read 192 and on the right head 185. This is with straight water in the radiator and no coolant or wetter water.

Took the mechanical gauge off the left head and installed it on the right head and this is the readings I got off of it. Mechanical gauge after running 30 minutes ideling outside temp 86' read about 197. Right head read 222, 214 middle and 213 in back. Left head read 200, 220 middle and 214 back. Thermostat on right 185 on left head 195. Water pump on right side 207 while left side was 204. Radiator in the middle read 185. My question is this normal readings and what a flathead should be running?

After I took the machanical gauge back off and installed the water sending units back up the electrical gauge after 30 minute run idealing was completely on the H and I didn't take any readings.

My question to you Julie is where should I twik the electrical guage to where it reads about 197 like the machanical gauge. Or should I do anything to it? If I don't how will I know if it is running a little hotter than normal. I know you said you would leave it up to the flathead buddies people but you can tell me what to do with the electrical gauge.

To All: Today I drove the truck about 10 miles round trip to fill her up with gas and the electrical gauge was on H (we all know that already.) After I got gas and drove back home the truck stalled and I could not get it started again till it cooled down for a while. What could that be for a problem? Does any of this make any since. I hope it does.

Thanks for the advice and information in advance:

 

Ok well, I guess that answers they mystery about whether the truck is actually running to hot - it is - way too hot. I believe, and Ross is more qualified to answer this, but, I believe that engine should be running about 165 to (maybe) 180 degrees under normal conditions.

And yes it makes perfect sense. The truck overheated and came close to ceasing up.

I wouldn't drive it any more until you get the driving temp down where it should be.

With the temps up about 210, the electric gauge is indicating correctly - it should be on "H." With the truck at 170 it should be on the center mark - or close. I'd leave the gauge alone - it sounds like it is operating correctly.

Now it's up to the flathead guys to help with those temps.

 

Did you ever get either of the water pumps pulled off? It would be strange to have two duds, but if the engine sat in rusty water for a long time, the impellers could be about gone. Check that the impellers are tight on the shafts, and look inside the block to see how much crap there is.

 

I think you'll find 195 degrees after idling for 30 min on a 90 degree day is actually pretty good for a flathead. If I am reading you post correctly that you took the reading after truck sitting and idling for 30 min. It should drop to about 170 to 180 after a couple blocks at road speed. Flatheads were noted for being borderline hot when idling in traffic.
When the truck stalled and you tried to restart did the engine turn at a normal speed and not start or turn slowly.
If normal turning speed and no start likely a weak coil.
Good luck
Larry

 

When your motor quit after running it for the trip down town it is quite possible the fuel system vapour locked. I remember having this problem continuously with the flathead in my 53 Victoria back when I was a kid. The motor would run really hot and seem to evaporate the gas in the line before the carb and in the float bowl.

Just a thought that came to mind while reading the posts.

 

I have not pulled the water pumps off as of yet. That was going to be my next question to you all if I should or not. You answered that question for me. When the truck stalled it turned over at a normal speed and wouldn't start. I even pulled out the choke a little and no start. After it sat for about an hour and a half it did start up again. If you think it is the coil what kind of coil should I try and get a high blast coil or just a normal coil? Should it be 12 volt since the truck has been converted to 12 volt system. I didn't change the coil when I went to 12 volts but the wires that run to the coil run through a reducer ceramic type on the fender. the negative wire from the coil goes to a ceramic reducer and from the other side of the reducer a wire goes to the bottom of the distributer. Is this right?

 

Oh this just keeps getting better and better!

So, you've converted it to 12 volt negative ground..... You're sure?!

But you still have the 6 volt coil on it.

You've got a ballast resistor with the 6 volt coil.

And you have the ignition power that goes through the ballast resistor going to the negative post on the coil and the positive post of the coil has the distributor wire on it, right?

12 volt battery and 12 volt negative ground electrical system? Right?

(Help me Lord! )

Ok, if I remember correctly these engine will run too hot if the timing is off or the wrong spark plugs are in it, right Ross?

Do you think (Ross) having the wrong voltage coil, a 6 volt, with a ballast resistor, and hooked up backwards will effect this engine? Well, it's not helping.

12 volt - negative ground, right?

Ok, [deep breath.......] we're gonna help fix this Larry:

Do this and don't do anything else until you do this. Seriously, no water pumps or thermostats NOTHING!!

1. Go to the local parts place and buy a "Flame Thrower" 12 volt coil and physically mount it on the truck where the old one was. Nothing else, a FLAME THROWER 12 Volt!

2. There is a wire that is attached to your "I" or "IGN" post on your Ignition Switch. Find that wire and hook it to one tab of that ceramic Ballast Resistor.

3. Then, run a 14 AWG wire from the other post of the ceramic Ballast Resistor to the POSITIVE post of the Flamethrower Coil.

4. Connect the small black wire coming from your Distributor to the NEGATIVE post on the Flamethrower Coil.

Once you've done that, run the truck again and check the temps. If it's still too hot, we'll take the next step.



Edit note: WRT coil selection: You are using the FLAME THROWER coil not because I am looking for enhanced performance of your flathead, but because 50% of all NEW oil filled coils are bad coming off the shelf. The flamethrower is EPOXY packed and will be good/stay good.

 

Yes the coil should be a 12v "for use with external resistor", and use a ballast resistor with it. Blaster coils are a total waste on a flathead with 7:1 compression. I'm using a NAPA $12 universal coil, have never had any problems, either using a ballast on 12v or with my MSD distributor.

When you get a 12v coil, you need to hook it up with (+) coming from the ballast via the ignition switch, and the (-) connected to the distributor. Yours is still connected the way a positive ground system would be.

Edit: Julie's typing faster than me, appropriate, huh?!

Could the coil be causing the heat problem? Seems unlikely. If the coil is firing, timing is what matters. POSSIBLY unburned gases are in the exhaust, but I would expect all kinds of backfiring and misfiring if that were the problem.

 

Julie I don't know if it has a 12 coil on it or not as it came that way with the truck. I just assumed it was 12 volt since some of the truck was wired already before I got it. We didn't mess with the coil wires when we changed to 12 volts or at least put the ez wire kit on the truck. It is a negative grounded to the engine from the negative post on the battery and the positive hot wire goes to the starter. I checked the timing with the vaccume disconnected from the distributer and put it right on the mark on the bottom pully. I don't know what kind of spark plugs are in the truck I have never taken one out so I don't know if they are to hot for the engine or not. What kind of spark plugs are suppose to be in the truck if you know a number for the plugs please tell me and if they are a different number I will change them too. Tomorrow I will go see if I can find a 12 volt flame thrower coil and put it on the engine. Nothing else will I do before this. The wire that goes from the coil to the distrutor is white. I have had some back fires or sounds like the engine is misfiring sometimes but not all the time. I am going to take all the wires out of the wire looms so I can be sure to get the right wire to the ignition with no mistake.

Thanks Julie and Ross for the information. I will do what you have said and let you know.

 

Lbrauer
Yes you could have a bad coil. A coil many times when it fails will stop firing when hot and resume firing when it cools down. Your coil hooked up backwards will not cause your engine to overheat. You do not need a expensive coil to make your flathead run and be dependable. It is likely you have some bad plug wires if you get missing occasionally, or a sticking valve. Flatheads are bad about slightly sticking valves causing a miss especially accelerating at low speeds in high gear. I can leave my mercury in high gear and accelerate from going around a corner (12 15 mph) and it is smooth but if you have a very slight miss you will notice it at that speed.
Mine is the older style engine (1946) but I drive it about 10,000 miles a year. It will run toward hot if I get tied up in traffic and have to wait 10 minutes or so in traffic and not move. Thats perfectly normal and not too likely you gonna stop that. About 3 or 4 minites after I get back to speed it will cool right back down to normal and run 180 degrees at highway speed in 100 degree weather. They make all kinds of high flow water pumps, water wetter and a hundred other things to help cool these old motors. If your radiator is good and not partly stopped up, your block clean and not fill of rust and other crap, water pumps good you will be able to drive your truck and it not get hot. Don't get excited and throw a bunch of money for stuff without knowing if you have a problem and what your problem might be.
Some other flathead guy might have different experiences but from mine your truck was not running too hot if it sat in your drive and idled 30 minutes on a 90 degree day and registered 197 degrees. I would have liked to have seen you leave the mechanical gauge hooked up on one side and seen what your temp was during your trip to the gas station. If you engine turned over at a normal speed when you tried to start it after it stalled it did not quit running because it was over heated and about to seize. It likely stopped running due to a bad coil or very unlikely vapor lock. Unless your fuel line is very near your exhaust it was not likely vapor lock.
As always I am sure opinions will vary
Larry

 

FWIW, I'm going to agree with Larry and say that if your engine will idle for 30 minutes without issue and your water temp is 195-197F when it's 90F outside, you don't have a problem. That is a perfectly normal engine operating temperature. You should have left your mechanical gauge installed when you went for your drive. That would have given you an indication of how your cooling system is working under load and with air moving through the rad and over the engine. I think you're confusing iron temperatures with water temperature by taking all those readings with the ray gun, and freaking yourself out for nothing. Both sides seem to be operating evenly, too, giving more indication all is better than you think.

The next issue is why did the engine stall? Something you did? It just didn't shut off by itself, did it? And again, as Larry asked, what did it do when you tried to restart it? Did it turn over slowly, grunting? As in; ahruh....ahruh...ahruh... or did it spin normally and nothing happened? The answer to this question is most important for a proper diagnosis.


Edit; OK Larry was posting his above note while I was typing. I didn't just copy him. lol!

 

I have seen timing issues that also cause overheating on a flattie. Check that also. Good luck.

 

kinda fighting some of your issues myself right now with my 52's quitting after she's run awhile , and it seems to be vapor locking . have to yet once again pull the fuel lines and check again for blockages in the tank , had a bad coil so all the ignition components got replaced , and i think we have stuck thermostats . running that hot is gonna be a number of things the guy's have mentioned . i myself am going to replace the pumps on my truck , and quite possibly the ones on the 52 { so happens i have a set for it laying here } just for safety's sake . did you use sealant on the head bolts ???? maybe you got some seepage past them ??? do you / did you have a larger than required pressure cap on the system ???? sposed to have a 4lb cap . i popped a radiator seem and caused some other issues when without paying attention i put a larger cap on it laying on the bench and paid no heed to it's rating . how about blockages in the system ??? heard of lots of crap being in the systems , and actually flushed a hack of a lot out of mine upon first re-firs years ago ............ just more ideas coming to my feeble mind early in the am ...........

 

My concern with the Flamethrower coil is not expense or power. I'll say it again, it's reliability. This poor guy needs to strat dividing these problems out and conquering, not creating more by buying an oil filled coil that has a 50% chance of being bad off the shelf - third time I've stated this.

The truck is obviously running. But if these things are this sensative to different spark plug heats or timing being off, then it is equally likely that it is sensative to very weak spark (which might affect/impede timing/firing right) - which a 6 volt coil with a ballast resistor will cause. And yes guys it could be contributing. Although again now we really don't know if it's a 12 or 6 volt coil - or a 12 volt coil with an internal resistor and an regular resistor. We do know it's cross wired. So lets get it fixed.

And try to remember that the problem here is a percieved overheat problem. That's where the focus needs to stay.

Lastly, on an earlier post he gave us these same temperatures and everyone said it was running too hot. It's kind of funny, but in my original note about the temps where I got the lower numbers in a PM and said they didn't seem too high, some of you jumped on his revised numbers - almost identical to these now - saying "oh yeah those are too high!" Now that I'm seeing these numbers and saying it seems high, you're all "no that's normal." I think some of you are on a mission here that has more to do with trying to discredit certain people rather than trying to help someone with a problem. Too bad. Ross thinks it's hot and that's good enough for me.

Larry, my advice is to buy the flamethrower and install it as I told you. Then go from there, see if it helps. If nothing more, it will be reliable, wired correctly and elliminate any question about that being a problem for you. Divide and conquer.

In one of the Star Trek Movies they were searching for a pair of boots. At a loss to find them Mr. Spock orders the search to be continued. His "logical" approach was that if you could not find the boots by looking directly for them, then eventually you would find them by elliminating every other place they were not. So, if there's no direct answer to this overheat, you just start to elliminate the possibilities of what it could be and eventually you'll find the answer.

Finally, the guy drove the truck 10 miles - not just sitting at idle - the temp gauge was pegged. I sent him this gauge. It was tested, and calibrated to read 170 degrees while on the center mark, prior to my sending it - and it's fine. So baring anything else out of order - like having the temp gauge wired to the gas tank sender, I believe the gauges (both the mechanical and the electric) are functioning well enough to give a reliable indication, that yes, the truck is running hot.

There is also the distinct possibility that the overheat is a compilation of small things - weak spark, water pump impellers are worn, no fan shroud, fan too far from the radiator, full moon - who knows. So as I said above a good approach is to ensure all these things aren't contributing by making sure they are functioning properly.

Please read the posts guys! It really helps.

So, Larry, take care of the coil and miswiring and we move on to the next possibilities if the problem persists. Be sure to check the timing again after you install the new coil.

 

Julie and Ross I was wrong when I said we didn't hook a wire to the coil because after looking at 3am this morning and not sleeping I do see a new wire hooked to the positive post. I tried to post some pics I took of the coil and how it is hooked up but can't seem to get them uploaded this morning.