Help.....Over heating

T

tyler

Senior Member
Just put the car all together last night and tried to take it for a drive today. Goes about two miles and suddenly the mercury shoots up in the motometer. Let it cool down and the same thing happens, mercury comes up so that it's just visable and stays there for a little while then it rapidly shoots up into the danger zone. Car runs well.

What I've done; had radiator cleaned out by a radiator shop, new 5.5 head, new rings, pistons, honed cylinders, new leakless water pump, took up main bearings. Car seems to run well and I'm trying not to advance the timing too much with the h.c. head. The engine is very tight.

Fan belt is turning, water looks good that I've drained out and seems to flow out of the drain with no problem. What could it be? Would too rich or too lean a mixture be my problem? It seems like the gav doesn't affect the running as much as it did before. ?

I'm lost.

Tyler
 
Could be just very tight new engine which if run for a couple of hours with a hose providing cool wtaer during that period will sort itself. Er long shot but is the engine actiually boiling within a couple of miles or is the motor meter causing your concern. Maybe check water temp with a thermometer , or finger? Doubt if marginally a weak mixture would cause a problem of that magnitude within a couple of miles ( esp if car starts ok when cold)
 
John;

Yes, the engine is boiling after only a few miles so I beleive the motometer isn't lying. The engine is so stiff right now that you can't crank start it ( and I'm a stronger than average guy) and my starter isn't the best so I park the car on a hill to get it going. How would you run it with water from a hose, open the drain some?
Thanks for your help, much appreciated.

Tyler
 
How did you set the mains? Star three car and with the moot meter off watch and make sure you have good flow.
 
TinCup;

The old guy that set my bearings has been doing it successfully for over 60 years on T's and A's. I'll check the flow as you suggest. Thanks .

Tyler
 
tyler said:
.... mercury comes up so that it's just visable and stays there for a little while then it rapidly shoots up into the danger zone. ... Tyler
Click to expand...

If there is really this sudden onset, it doesn't sound like normal overheating to me; that should be monotonic--unless you've got a sticking thermostat. I'm wondering if your head gasket might be starting to leak combustion gases once the motor gets to a certain temp. That could have a sudden onset, however, I would expect it to also be accompanied by pretty vigorous boiling over. Simple fix might be to retorque the head.

It's times like these when it would be nice to have a real temperature gauge.

Steve
 
Steve;

Ran the engine just enough to warm it up last night. This morning I re-torqued the head before I started out. No thermostat. I think I'll let it sit untill mornig and re-torque the head again. Thanks for the help.

Tyler
 
Tyler,
Best wishes as you resolve your overheating. This morning a friend of mine that has a Model T suggested that I use a product called Water Wetter in the coolant. The claim by the manufacturer, Red Line, is that it will reduce the temp. by 20 degrees. I purchased two bottles this morning at Auto Zone. Has anyone used this product? If so, what were the results? My friend says the temp was reduced on his motometer.
Tom
 
I had mine rebuilt last winter and it did the same thing. I found that my spark was too retarded. I reset my timing and the problem went away. It was probably a combination of new tightness and too retarded spark.
 
I ask because it sounds to tight. If you can't hand crank its too tight. I did an extensive test on straight water with water wetter vs 50/50 anti freeze. I didnt find that water wetter made enough of a difference to warrant using it. My solution was new radiator but in the process I learned more than I ever wanted to about cooling these cars. Yes too lean can make it run hotter but I never found that it would cause my car to overheat as fast as you describe. After starting open the gav about a quarter of a turn (zenith) half( Tilley) this should be plenty. Drop th advance about 3-4 notches till it smooths out. Open the meter and look for bubbles which can indicate a leaking head gasket this would cause your car to overheat faster. Last but not least how many cores does your radiator have. If it is only a two core radiator it is not enough for the motor you have built unless you live in Alaska.
 
TinCup said:
... If it is only a two core radiator it is not enough for the motor you have built unless you live in Alaska.
Click to expand...
Don't count on that -- We had at least 2 cars (mine included) that overheated on our most recent tour (2-weeks ago). Both are similar equipped as above.
 
Mine would always cool enought in the winter months but come summer it just wouldn't cut it. Love your truck.
 
If you can't hand crank it, it's WAY too tight.
It is going to be worn out before it is normal.
Did you have the block acid stripped before rebuilding?
The water jackets could be full of scale and rust.
A 2 core radiator will work fine if everything is right.
 
I should have explained it better, I can turn it over with the hand crank but not fast enough to start it. I start my Model T with the crank several times a week but this A is way too tight to attempt it, though it did seem to loosen up a little today.

Yes, I have a 2 core radiator but it worked well on the engine before. Also, the car wants to run with the gav opened at least half a turn when the engine is warm.

I'll re-torque the head in the morning, watch for water circulating, take it for a drive and report back. Thanks for all the ideas.

Tyler
 
I noticed you speak of not advancing the spark too much on your HC head. Have you advanced it to where it starts pinging due to pre ignition?
While an HC head should only be advanced around 30 degrees, I feel you shoulld let the engine tell you when to stop advancing the spark. It becomes quite obvious if advanced too much. A Retarded spark will certainly give you the results you are experiencing with overheating.
 
Tyler, I keep an inexpensive dial meat themometer in my truck that I use to check the water temperature. The motometers are nice but not necessarly super accurate. Cheap and quick and you know for sure what the temperature is.
Dave
 
Is the engine any looser after all your various test runs etc? And h/gasket OK?.. If so surely must be a problem with the cooling system that it boils this quick.( back flusk block and then consider re-approaching rad shop rad next ? )
 
Bruce;

I'm glad you brought that up about advancing the spark, it sounds like the engine nocks a little untill I advance the spark further than half way, then the nock goes away.(this is when I'm driving down the road at maybe 30mph) This is just the opposite of what happens with my model T, if I advance too far for conditions it will rap just a little. I know it's hard on bearing to drive with too much advance, especially with the hc head.

I'm heading out now to work on it while the temperature is still reasonable, supposed to hit 90 again today and that's way too hot for me. I'll let everyone know what happens and thanks again to this wonderfull group.

Tyler
 
1crosscut said:
Tyler, I keep an inexpensive dial meat themometer in my truck that I use to check the water temperature. The motometers are nice but not necessarly super accurate. Cheap and quick and you know for sure what the temperature is.
Dave
Click to expand...


Thank you for that tip!!
Shoulda thought of this one myself, especially since I've got a spare one sitting in the kitchen drawer doing nothing useful, but sometimes we need the spark of someone else's genius to spot the obvious...
 
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