Overheating

[Guest robbie]

Hi guys, its me, Robbie, finally back on track with my sub k running again.

You may recall the problems I had with rebuilt twin 40s on a rebuilt pinto 2l, it wouldnt fire up.

Finally tracked part of prob down to faulty spark plug.

Anyway, she's goin again just needing some tweeking and fine adjustments. So onto the next prob, overheating.

 

Now I know this topic has been covered many times, but I want advice on this particular setup.

The radiator is barely warm and the water wouldn't make a descent cup of tea, but the hose from the inlet manifold to the pump is almost untouchable as is the inlet manifold itself. Can anyone tell me how to approach this problem and ensure the coolant system is doing its job properly.

Thanks guys!

 

Robbie

[Guest Russler]

sounds like the head needs chemically cleaning or the thermostat is stuck. Try removing the thermostat or replacing it.

[steve in stockport]

sounds like your thermostat is either duff or fitted the wrong way round.

as the pinto warms up the water is circulated round the pump, head, inlet manifold and heater( if fitted) til the water is hot enough to open the stat, it then goes round the whole system.

just a little heat on the rad side looks like water struggling to get through the stat for one of the above reasons.

 

steve

[Big Jim]

thermostat is fitted the wrong way round.

My money's on that!

[Guest Guy]

I had a problem when I first started my engine after it had been standing for a long time during the build, the trermostat got stuck shut. It overheated lots then suddenly it cooled and worked fine with no more problems, it's been fine ever since.

[Guest robbie]

Ok guys here it is.

I stuck in a new thermostat (checked both were working and ensured right way round etc) ran up the engine and the radiator seems to be warmer and overflowing as temp increases, perhaps I need to fit expansion tank?

I am still concerned with temp of inlet manifold on twin carbs. I have no means to accurately measure the temp but I am just about able to hold it without burning myself. After a while the carbs splutter and spit and the engine stalls, I think it is due to this overheating but perhaps you know different?

The hose from the manifold to the water pump is also very hot, particularly compared to the bottom and top radiator hose, although this may be acceptable.

Just intereseted to see if you have any further ideas and as to wether or not I have the plumbing right, particularly from the inlet manifold to water pump. I would have expected the temp to similar all over the system.

If I have this right, the water is pumped from the bottom of the rad, through the engine, out of the inlet manifold, returned to pump? With overheated water opening the stat and going to radiator?

Whada ya think?

 

Thanks Robbie

[steve in stockport]

the water is pumped out of the bottom of the rad, through the engine then out of both the top hose to the rad and the inlet manifold, through the heater and back to the top of the water pump.

sounds like you have very little circulation, so if your stat is new, tested and in the right way around the thing that gives you circulation - the pump -is the next place to look

 

steve

[Guest robbie]

Yes Steve, I believe you are right, circulation is the problem. You say:

"the water is pumped out of the bottom of the rad, through the engine then out of both the top hose to the rad and the inlet manifold, through the heater and back to the top of the water pump."

In my set up there is one connection from the inlet manifold direct to the pump? Not sure that is right?

I have no heater connected and didn't intend to unless it can help the cooling situation, in your suggestion, if we forget about the heater, water can return from the engine to the water pump via the inlet manifold without passing through the radiator. This is the way I have it at present but thought it would all need to circulate through the rad. As far as I can determine the flow in the inlet manifold pipe may be preventing the flow of coolant thro the rad (path of least resistance and all that!)

What you think?

 

Ta Robbie

[Guest Russler]

When I was running twin carbs I had exactly the same setup as you, the inlet manifold does stay cooler. You mention that when the engine warms up the carbs splutter and it stalls, as the manifold temp changes different fuel atomisation occurs and so always setup the carbs on a warm engine. A good method is to screw in the mixture screws one at a time, you will find the carbs start popping, this is when it is too lean, so wind the screw out till this stops and then go 1/4 -1/2 a turn more to be sure.

[steve in stockport]

yes, if you're not running a heater the pipe from the manifold will go back to the water pump.

once it returns there it mixes with the remainder (majority) of the coolant to be pumped through the rad then back into the bottom of the engine.

so if your pump works there is a continuous process where cool coolant enters the engine through the bottom hose, passes through the waterways in the block, head, manifold etc picking up heat as it goes.

the heated coolant then passes through the pump to the radiator where it is cooled as it drops to the bottom hose, then it all begins again

[Guest robbie]

OK so do you think the temperatures are normal or should I look elswhere for solution? Does anyone else expirienc similar heat build ups?

 

Thanks Robbie

[Big Jim]

Hi again Robbie,

You're right about the engine not running as good if it gets too hot etc. "7" type cars have always had problems with overheating, but it can be cured. you need to check that each individual part of the system is working as it should.

first of all, the water pipe through the manifold to the water pump is a red herring, it's in a closed loop along with the water in the engine, so whatever the engine temp is, so will the water in that pipe be, and so in turn will your inlet manifold. That water comes out of the manifold, and back into the inlet side of the water pump, so doesn't go through the rad.

The thermostat decides just how hot you are going to run that engine, you can get a number of different temparature stats, the common one for Fords is 82º, or 87º (I think!) but if you look on our web site, you can get one that opens at 76º unfortunately this stat is not one that you local motor factor will hold in stock, he'll have to get it for you on order, and it's around 3 times the price of an "ordinary" stat.

OK, you've checked the stat, filled with water, and started your engine. Let it tick over without the rad cap on. Watch the temp gauge, as it gets to the middle of the gauge, (whatever your stat is at) you will probably get expansion of the water in the rad, as you see the warm water start to flow in through, then it will stop, until in a couple more minutes it will flow again, if this is happening, put your rad cap on, as everything is fine.

If it's not flowing, and starting to overheat, then we are back to either the stat or the water pump. So you can take out the stat and try it, but it will take much longer to get to overheat, if it does, then it's got to be the water pump. (new w/pump is about £14 I think)

Once the system is in full flow (so to speak) say after a drive, then the top hose should be red hot, along with the hose from the manifold, with the bottom hose slightly cooler.

A running engine will expand the water in the system building up pressure, once the pressure reaches the level on the rad cap, the spring of the rad cap will lift, allowing the water to escape out of the overflow until the pressure drops below the cap denoted pressure. On the pinto engine, it will throw out a quantity of water (guessing, around a pint) and you'll find that once the system has gone cold again, there is barely water covering the tubes of the core inside the radiator. An expansion bottle / header tank, although 2 entirely different things, allow the excess water to flow into the expansion bottle, and then returning to the radiator as it cools down.

If you find that your engine is throwing out a lot more water, but it's flowing OK, then suspect the head gasket, if it's not flowing OK, were back to the water pump.

The biggest problem is not usually the workings of the system, but the lack of cool air through the radiator, but this is covered on another thread.

 

I apologise if this seems like "teaching Granny to suck eggs" but it's just pretty logical.

 

good luck with it, and let us know how you go on.

Jim