Strange overheating issue

[Ben Bruce aka First Born]

Flowing only 26 percent.  Wow.  How did someone manage that, Ed?

 From MANY years of experience, I believe most "overheating" problems are "under cooling"  due to plugged radiators or too small radiators. Easy to check. 

 

  Ben

[AL1630]

On 10/14/2019 at 6:26 PM, 19tom40 said:

Incorrect spark timing can cause poor mileage and overheating.

 

Have you checked your point dwell at various speeds? Worn distributor bushings can cause the dwell to vary and change the timing. Worn timing gears or a stretched timing chain will also cause the timing to vary.

 

If your timing marks are on the vibration damper, it is a good idea to check that the TDC marker is correct. Some vibration dampers can slip on the pulley and give you an incorrect indication of TDC.

 

I got a dwell meter and hooked it up, and when I gave the engine gas, the dwell dropped by 10-15 degrees. I think I may have finally found the culprit (Or a big one anyway). The tachometer on the dwell meter also said that the engine is idling way too fast-I think that my throttle isn't returning all the way to idle, even after I replaced the spring.

[Larry Schramm]

AL1630, 

 

It sounds like you might have a problem with the distributor, maybe a worn bushing. 

 

Once you fix that, you might want to try timing the car an old fashioned way to be sure the timing is not retarded too much causing the over heating.

 

To do that, get the car up to temp, remove the vacuum hose from the distributor and connect it to a vacuum gauge, and slowly move the distributor increasing the advance until the RPMs increase.  You can also look at the vacuum gauge to see the vacuum increasing.  When the vacuum reaches a maximum and/or the RPMs stop increasing back the distributor maybe 5degrees, hook up the vacuum advance hose and check the timing with a light to see where it is.  Test drive the car and let us know how it runs.

 

 

[AL1630]

Thank you, I'll look into getting the distributor rebuilt. I'll also try the vacuum timing.

[AL1630]

This weekend I put in a thermostat, 180 degrees. Driving this morning with the ambient temperature about 25 degrees, the engine didn't even get up to temperature on my 10 minute drive. This afternoon, it's been about 60 and the temp gauge would get well above the middle especially when idling.

 

As I mentioned before, my gas pedal doesn't return all the way, and if I pulled it back to the right idle speed, the temperature would drop, but as soon as i started moving it would rise again. Turning on the heater also dropped the temperature.

[FLYER15015]

Reading this last post, it sure sounds like a lazy water pump to me.

 

Mike in Colorado

[studeboy]

I once had what looked like a perfect water pump on the outside. it was sitting for 50 years with coolant in it. When I opened it up the blades of the impeller had disintegrated. It wouldn't move much water.

[AL1630]

I would hope it's not the water pump, I've already replaced that with a NOS one.

Edited November 5, 2019 by AL1630 (see edit history)

[pmhowe]

If you haven't solved the problem already, I'd recommend you contact the AMC Club https://www.facebook.com/AMCRambler

 

You may find it is a common problem with a well-known solution, or find a colleague who has had the problem and figured out a fix. 

 

I have a 1966 Morgan that had the same symptoms. For that car it was a design flaw: The water flow rate through the radiator was too high, so it didn't have a chance to cool adequately. The solution was to put a partial plug in the bypass hose. 

 

Please post the solution for your car, once you have it.

 

Good luck,

 

Phil

[RansomEli]

Yes, I'll double-up on pmhowe's request. I'm a Rambler fan and want to see how everything works out. 

[ted sweet]

he never verified the guage is accurate

[pmhowe]

3 hours ago, ted sweet said:

he never verified the guage is accurate

 

Good point.  The gauge is fluctuating under different conditions. Is the car actually overheating? My criterion for overheating is boiling over with some steam. I have had several cars where the temperature gauge fluctuated from cool to normal to hot and back gain, depending upon whether I was driving uphill, downhill, on a straight, or at a light. (Actually, every one of them was British - seven '50s - '60s Jaguars, three '50s - '60s Morgans, one '59 MG). Even my current 1966 Morgan fluctuates in temperature as the thermostat does it thing in response to driving environment.  My 1935 Cadillac is rock solid in its behavior: no fluctuations at all. But then, the Cadillac has enough water in its system to drown several Morgans.

 

Phil

[AL1630]

The car has only officially overheated and boiled over once, after pulling a hill in summer. When it did that, the needle was above the top mark on the gauge, which i believe is 260 degrees. Now with a 180 tstat and 50 degrees ambient, the gauge stays around the middle. This leads me to believe it works, but I've never really tested it.

[JACK M]

It may have been suggested before but a battery powered digital laser thermometer thingy is a pretty handy and not that expensive tool.

You will find all kinds of other things to do with it after you figure out if your car is or is not in fact over heating.

 

The Jeepster that I just restored has an electric temp gauge and it will easily peg on a hot day when the engine is running at 200 degrees.

Its hard to ignore but if it aint broke ,,,, Oh I need a correct sender.

[AL1630]

If I shoot the thermostat housing with the temperature gun, should it read about the same temperature as the gauge if the gauge is accurate, or would it be different? The T-stat housing is where the temperature sending unit is located.

[JACK M]

Yup. Logic would dictate that it should be the same.

But take its temperature other places as well.

Follow the water jacket front to rear and low and high on the block.

This way you will have a lot of info to consider.

Don't be to far away from your targets.

Probably want to do this when its acting up as well as when it seems normal.