Are You Exhausted?
Last month we talked about lazy or inefficient cooling systems, and as promised, this month we will talk about ways to make life a little easier for your cooling system.
First, however, I need to clarify some of the points from last month. I hope I didn’t leave the impression that all radiators need a new core. What I meant to say is that if it needs a new core, then go to a high-efficiency core.
I also miswrote about not needing a fan if you never drive over 45 mph. What I meant to say was that if you only drive over 45 into a wind, you probably wouldn’t need a fan.
The best tool for cleaning and flushing your block is the one that uses a mixture of water pressure and air pressure. Air pressure by itself won’t do much.
Also, I still stand by my recommendation on distilled water, regardless of other opinions. This matter was verified by a metallurgist from the Colorado School of Mines.
So much for last month– let’s go on to the problems of your engine generating more heat than even the best cooling system can dissipate effectively. Heat itself comes from two sources in your powertrain; fire or friction.
The outside air temperature is very minor in comparison to fire in the cylinders and friction of moving parts. At 3,000 rpms or about 60 mph, you have about 12,000 explosions per minute inside your engine. That boils down to 200 per second. Each of these explosions must have the right mixture and at the exact, precise instant.
The key to the timing factor is exact. If your timing is too soon (advanced), the explosion in each cylinder comes before the piston is ready to go down on the power stroke. The piston is then fighting the explosion instead of using it.
If the timing is too late (retarded), a lot of your usable power is going into the exhaust instead of pushing the piston down.
Either way, you will generate too much heat. Check your manual for precise timing. A poor or weak spark in the spark plug will give a weak, uneven, or slow explosion.
Here again, a lot of your power goes out the exhaust in the form of unused fire, again generating more heat.
The first thing to do is keep good spark plugs gapped properly and evenly. Again, check your manual for proper setting. The distributor and coil work together to generate a good clean hot spark. The distributor, with its points and condenser, feed spurts of low voltage current to the coil, which converts it into spurts of high voltage fed to the distributor cap and the rotor, which directs these spurts to each of the spark plugs.
Any improper adjustments in this process can cause your engine to overheat. You would be surprised at how many heating problems originate from faulty ignition.
We mentioned earlier about having the right mixture for the explosion. This is the job of the carburetor. It mixes air and fuel in the proper ration for the most efficient explosions.
Too much air make a leaner mixture that generates much more heat then the cooling system can handle. Too much gas for the amount of air results in too rich a mixture, which results in less powerful explosions, wasting fuel, makes the engine work harder, overheats the exhaust system, and blows black smoke out of your exhaust. A well-tuned carburetor can greatly reduce the heat your engine generates.
Worn, burnt, improperly adjusted or sticking valves can generate a lot of excess heat by causing the fuel mixture and exhaust gases to mix in the manifold. Frequently, this will cause backfires and loss of power. This problem requires more than minor adjustments.
Earlier we mentioned friction as a source of heat. If somebody could produce a friction-free engine, fuel economy would skyrocket and heating would plummet.
The moving parts in your engine generate friction heat from either being too tight or insufficient lubrication. The oil in your engine acts as both a lubricant and coolant. Use good oil in the proper amount.
A freshly rebuilt engine will usually overheat from friction until the parts “break in;” usually these frictions will adjust themselves during “break in.”
A good way to tell if you still have “overtightness” in your engine is to remove the spark plugs and feel how hard it is to turn the engine over by hand. Occasionally, a cause of overheating will be from dragging brakes. A good brake adjustment will take care of this.
Many of the things we have mentioned are reasonably obvious. One of the biggest culprits in causing overheating is generally the hardest to detect and the most overlooked. We mentioned it briefly last month—that’s right—the exhaust system!
Most of the unused heat in your engine is sent out through the exhaust pipe. Your engine breathes in through the carburetor and exhales out the tailpipe. If it can’t exhale it can’t inhale, but it tries hard and generates excessive heat.
A simple law of physics tells you—if you take any gas, vapor or liquid and raise its temperature, you increase its volume. The hot exhaust comes out of the cylinders into the exhaust manifold, from there to the exhaust pipe, then through the muffler, where most of the sound of explosions are quieted and then out the tailpipe at the rear of the car.
We talked about the exhaust pipe between the manifold and muffler last month insofar as the much-needed insulation. This also needs to be the proper size with smooth bends, and without unnecessary bends. These can have hidden kinks from improper installation.
This brings us to the muffler. All of the critical parts of the muffler are hidden and sealed inside. Many things can hide inside the muffler and make “breathing” more difficult.
Carbon buildup, oil residue and rust...this is even more prevalent in our old cars that spend long periods of idleness. I took a muffler off a car awhile back and it was heavier than the transmission—it was packed with crud.
While talking about mufflers, be sure when you replace the muffler, it is one designed for your car, although it is important that the length and pipe connections are the right size. It is more important that it has the right capacity. Just because it fits doesn’t make it right. The tailpipe is easily inspected and can easily be bent on low centers. Remember, any extra restrictions will cause instant overheating.
Another tip: When you replace any of your exhaust system, it is not much more expensive to replace it all. Many of our suppliers sell the systems in a complete set at a lot less than the individual parts. If your car runs well, starts easy and for the most part in good condition and tune, but it still overheats, it is a good chance the problem is in the exhaust. After all, how well do you run when you can’t get rid of your hot exhaust gases?
See ya next month.