Running Hot ?

[Msaby]

I spent several hours yesterday searching and reading posts regarding overheating but is there a way to determine if the engine is running too hot? I recently flushed the cooling system, replaced the hoses, and waterpump. I have refilled the cooling system with water with a small amount of anti-freeze. I think I might have overfilled the radiator but after about 10 min. of driving if spit out some coolant out the overflow. I don't want to damage anything by overheating the engine especially since I just got it running really good.

I have read several post regarding ignition timming casuing the engine to run hot. I have set the point gap at .020 and then set the timming using the test light making sure the rotor is turned properly. Could I be driving with the spark lever too far advanced?

Thanks
Mike

[WTSHNN]

How much water is coming out of the overflow and for how long of a period of time? A lot of people mistake overflowing for overheating (sometimes they are related, sometimes not).

Go buy an infrared thermometer at your local hardware store, get your engine to do what you describe above and then shoot different places on the radiator noting the temps and then report back.
-Tim

[Jim Brierley]

Once it has spit out a small amount like yours has done it should not loose any more. If it doesn't spit any out as you are driving, especially uphill in hot weather, it is likely OK. You could beg, borrow or steal a hand-held thermometer-gun (I think they use infra-red technology?) and check the temp at the top of the radiator, it should read 180 degrees or less.

[700rpm]

I thought my coupe was running hot, so after returning from a good long drive I took a digital meat thermometer (the kind that has a probe you stick into the meat) and took a reading in my radiator water: 178 degrees. That was reassuring, but I'm still going to run the vinegar and back flush the system.

[TinCup]

Radiator should just be filled over the core to cover the tubes. Next to rear main leaks I think this is the second most discussed topic on the barn. Lots of posts to search thru. 30 dollar infrared laser thermometer from harbor freight is a nice tool to have in the box. How about a picture of where your overflow is placed? Do you have a baffle in the radiator?

[Purdy Swoft]

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Retarded timing causes overheating, not advanced timing. The use of a test light only tells when the points open. If clockwise backlash remans at the rotor tip after tightening the cam screw, the timing will be retarded the amount of the clockwise backlash and will cause overheating. I drive at speed with full advance at the spark lever. I retard the spark lever at low speed or in situations that cause strain and lugging of the engine. If it pings or bucks , retard the spark just enough to cushion out the ping or buck, or down shift, or both. Plain water cools better than antifreeze. If the GAV is run too closed, it will also cause overheating. I run my model A Zenith carbs with the GAV about 1/4 turn off the seat, to the left, after warm up.

[TinCup]

What Purdy said!

[Msaby]

My radiator does have the baffle installed. You must have read my mind about the Harbor Frieght IR temp. tool. I hope to stop tommorrow and pick one up, even though I hate to purchase any of those inferior products.

When I set the timming I did in fact turn the rotor to remove the backlash before tighten the screw down. I am using water with just a small amount of anti-freeze but the coolant is primarily water.

It sounds like I am using the spark advance lever correctly. I might be running a little bit lean then with the GAV basically turned in. I am using a Tiltson carb though.

Thanks
Mike

[BN]

“ …. is there a way to determine if the engine is running too hot?”


A radiator needs to be sized to handle the heat load of the engine when it is pulling full horsepower on a reasonably hot day without exceeding a specified top tank temperature.


To test your cooling system, grab your IR thermometer, crank up your “A”, drive it around a while to get it warmed up, and find a long hill somewhere. Hopefully, the hill will be steep enough to require full horsepower to climb and long enough so that the water temp is not still increasing at the top. So, the steeper and longer – the better.


When you get to the top, stop and quickly take the temperature at the top tank and various locations on the cylinder head with engine idling. They should all be within a few degrees. This is the “Top Tank Temperature”. Now, record the ambient air temperature. The difference between the Top Tank and the Air temperature is the “Water to Air Difference”.


Example:
The Air temperature is 70 Deg F, you have decided that you never want your Top Tank Temperature to exceed 190 Deg F, and the Top Tank Temperature you record at the top of the hill is 160 Deg F. So, the Water to Air Difference is (160 – 70) = 90 Deg F. Then, the highest ambient Air Temperature you can drive your “A” (while pulling full HP and without exceeding 190 Deg F Top Tank Temp) is
[(Top Tank Temp) – (Water to Air Difference)] = (190 – 90) = 100 Deg F.


Let us know what your readings are.


Hope this helps.

[columbiA]

TThe rad will always spit out excess water until it finds its level which is just above the tubes.I add water until I can just see it on the bottom of the baffle.I use plane tap water-have been for 60 years-& add a cup of soluble oil for rust protection-cheaper than buying WP lube & the same thing.As stated,water cools better than Anti Freeze.

[Mike V. Florida]

1) Fill the radiator, drive it.
2) Measure the amount you need to top it off and drive it again.
3) If you need the same amount of water as in step 2 then your A is just finding it's own level and you don't have to worry.

[Purdy Swoft]

If its loseing water out the overflow tube, the two main causes are over filling the radiator or the water pump is over pumping. A stopped up radiator or a two row radiator can't handle the flow and will cause the same problem. If steam is also coming out the overflow tube, its running hot!!!

[Msaby]

Okay I can finally update this thread. Unfortunately my car developed a fuel leak and I was unable to drive it. I drove the vehicle today in 95 degree temp. low speed uphill idling etc. When I checked the temp of the top tank on the radiator I had a temp of around 180 degrees. When I shut the engine off it did spit a little water out though. Thoughts?

[Kurt in NJ]

How full is the radiator now---if the level is above the baffle it will probably spit out more, on my car if you can see the coolant above the baffle it will spit it out, when I bother to fill it I won't put more in than just laps at the lowest part of the baffle.

[BILL WILLIAMSON]

Just drop a loose fitting, large head nail in the top of overflow tube to prevent splash over from water rushing into top tank at road speeds, ooooold proven fix!!! If you're a purist, use a stainless or a brass nail. LOL I've typed this at LEAST 27 times!!! I should get a RUBBER stamp! Bill W.

[Ed Saniewski]

Msaby, the water in the engine is still hot when you shut down, without the water pump to circulate the water through the radiator it will continue to expand out the overflow tube for a short while. If you have a motometer you can watch the temp rise quickly, if you start the car and idle the temp will go right back down.

[BILL WILLIAMSON]

Isn't it an odd fact that water volume expands when heated, and also expands when frozen!!! Bill W.

[Jason in TX]

Originally Posted by BILL WILLIAMSON

Just drop a loose fitting, large head nail in the top of overflow tube to prevent splash over from water rushing into top tank at road speeds, ooooold proven fix!!! If you're a purist, use a stainless or a brass nail. LOL I've typed this at LEAST 27 times!!! I should get a RUBBER stamp! Bill W.

...PS That's the trick I'm using!