Air in 914 V8 cooling system, Need advise.... Options

[boxstr]

Today after installing front Konis on the V8 914 , started the car and the water pump hose clamp was loose so it puked out a fair amount of coolant. Added a 50/50 mix. ran the car until warmup and drove the car, cold and rainy weather, so it didn't really get hot. @ 160-170.
Any suggestions that I should do as far purging out any air that might be in the system. Or maybe I don't need to do anything.
TIA
CCLINV8CANTWAIT

[BIGKAT_83]

This is from a drag race site that I go to. Some real good info on cooling
Sorry for the length.



Cooling system basics.

Let’s start with a few of the known facts about cooling and examine them a little closer. We all know that air in a system creates heating problems. The reason why is simple. Water that is heated and allowed to expand uncontrolled will rise in temperature uncontrolled. That is why starting in 1901 car builders pressurized the cooling system. The second principal is: air can compress much more than water. This would mean air in any location in a closed cooling system will allow the water to expand uncontrolled and the temperature to run away. Worse yet would be if that air was trapped at the impeller and caused cavitation.

Let’s first look at the most common myth about cooling systems: I have to fill it from the highest point in the system. Many companies make “tall” water necks to help you accomplish this. Some make the necks so high it will be higher than the horizontally mounted radiator above the transmission. The ironic part is; most of these companies put in a sight glass or sight tube so you can see the water level. Some even recommend you only fill to a certain point. The fact is; the only place that you can replace the air with water is in the low pressure area of the cooling system. In a normal street car that location is: at the radiator cap directly above the suction (lower) hose. To prove this point, you can open the cap and look at the coolant level drop when you rev the engine. As the engine RPM increased, and the water pump speed was increased, the pump will now pressurize the water jackets inside the engine. The water traveling over and around ports, between the cylinders and anywhere else the air was trapped, displaced the air. The displaced air moved to the low pressure (suction side) area of the radiator and this is why you noticed the coolant level drop. What this shows is: 1. a system that is gravity fed can appear full and still have trapped air until the water jackets are pressurized. 2. If the water pump you are using can flow enough water, it will pressurize the water jackets and push the air to the low pressure area of the cooling system. 3. No mater how high the point of filling takes place unless you are pressurizing the system (pump pressure) you can’t displace that air.

If you open the system (with the pump on) at a high pressure point (such as at the intake manifold) a good pump will be pushing water out. The higher flow pumps on the market will sometimes push water up a tall water neck so hard that the cap starts to by-pass. Needless to say you would never be able to fill from there with the pump on.

This brings us to a cross roads of the types of cars we race. If you have a door car and the top of the engine sits above the radiator most people feel they have to fill from the high point. This is wrong. As long as you have the water level high enough that the pump does not lose its prime you can fill from the radiator. In some cases a restrictive radiator may create problems with filling. I have had many people cure their over heating problems by just getting rid of the fill neck, going back to a stock type water outlet and filling from the radiator. I also make a point of having them exchange the “catch tank” for a recovery tank.

For the dragster guys, life isn’t so easy. The radiators are often installed in low and/or horizontal positions. They can be found in front of the foot box or over the transmission. Getting to the low pressure area is almost impossible in these cases, until now. Meziere makes the reservoir tank pump for big and small block Chevrolet as well as big MOPAR. Logic dictates and testing has proven there is a low pressure area directly before the impeller of the water pump. The tank above the impeller allows for continuous priming to feed the impeller and separate the air and water at the same time. This is a complete departure from all other systems on the market today. There is no “snake oil” here. The research was done at Los Angeles County Raceway in the heat of summer (pressure altitude above 6000 feet). Every test we performed clearly showed the end of run temperature reduced. The smallest reduction was 15 degrees and the highest was 60. No matter the radiator position, this pump has the ability to push the water to all points, and returns any trapped air to the reservoir. As you continue to fill, you will in a matter of a few minutes get all the air out of the system. Not only does this make filling the system much easier, it is self priming as well as self bleeding. Once full, cap the system (using a closed system style cap) set the coolant level in the recovery tank to half and run the engine through one or two heat cycles.

The recovery tank will allow the coolant to expand and contract as necessary. Once two full heat cycles have been done, the system needs to have the level in the recovery tank (only) checked and set. This system: the reservoir pump, recovery tank and standard type (non-fill short) water neck will make your dragster cooling system as reliable as an OEM system. This system is truly a fill it and forget it system. You will not need to maintenance it. If you are curious you can look in the recovery tank to see where the water level is, but you will never need to open the cooling system unless you are having an engine problem. This system works so well it is guaranteed.

The next most common myth is: I have to slow the water down to help it cool. If this is the case; some is good more is better. Just stop the water. As silly as this sounds there people that suggest you do exactly that. Remember what you are cooling. You are not cooling the water you are cooling the engine. A running engine develops a lot of heat. The exhaust temperatures on well tuned race engine can be at 1300 degrees. On the other side of that exhaust port is a water jacket. If the water was to move too slow or be stopped, it would take no time at all for the heat to be transferred to the water. The best coolant and the best pressurized system will still have a boiling point below 300 degrees. Temperatures this high will mean that a steam pocket will develop and continue to grow until the heat source is removed or a large amount of coolant is brought to the area to soak up the heat and resultant steam pocket. This is the reason I tell anyone who drag races to not use a thermostat. If the water is stopped while you are at full throttle, these hot spots will cause detonation. Even though you can’t hear detonation on most race engines, your time slip will reflect it. If you find yourself saying “my car ran 3 to 4 off for no reason” this may be your answer.

The higher the water flow the better for cooling. Remember a water pump’s job is to move the hot water out of the block to the radiator. The radiators job is to remove the heat from the water and pass it into the air stream. If you get a 15 degree drop across the radiator at 20 gallons per minute and a 10 degree drop at 50 gallons per minute you cooled more water at the higher flow. During a drag race, (short burst at full throttle) if the heat exchanger (radiator) can’t keep up, very little or no degrade would be noticed. If the tables are turned; the water pump can’t keep up, your ET and consistency will suffer greatly. The reason is, if the water temperature increased from 170 to 190 in 9 seconds, this would stay well within the tune up on the engine. If the water pump was not pumping enough water the metal around the combustion chamber may go up several hundred degrees. When Meziere started building pumps for pro stock teams, a very famous P/S engine builder said “one cylinder pre igniting for one power stroke costs .005 of a second. Two pings would be .010 and five would be the difference from number 1 to DNQ. Give any good bracket racer or super class racer .025 off and he will own you.

To recap the high points: You have to fill from a low pressure spot in the system, not the highest location. A good pump will push the water above the pump level and remove the trapped air. Trapped air causes more problems in a cooling system than all other malfunctions. Don’t stop or slow the water flow. Always use a high flowing water pump. Always use a recovery tank with your system. Just make sure it recovers to the low pressure area of the system. A recovery system will not return the water to a high pressure area correctly.

Here are a few quick tips. Clean out your cooling system. Small particles can create big problems for cooling systems. Plain water will transfer heat better than anti-freeze and water mix. Water is the best “low cost” coolant. Use an anti-corrosive and water. This is a reprint of the

Feb Technical Article on DragRace Results.com