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Old 06-25-2007, 10:41 AM
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350 chevy small block over heating?

my car idles at 180 190 and when i start driving its up to 210 220 is that to hott? and if so what could cause it i put no stat in it and i have a 3 core radiator and i disconnected the heater core pls help
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Old 06-25-2007, 11:03 AM
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What car is it? Automatic or standard? Power options? What year? No 210 or 220 is not too hot, especially if it's a relatively late model.

Vince
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Old 06-25-2007, 11:35 AM
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350 over heating

its a 1979 small block and i have headers on it i never really let it run longer then 20 25 mins before turning it off (me thinking its over heating ) so you think 210 220 is a good temp to run at thanks for the info because i was running out of ideals
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Old 06-25-2007, 11:37 AM
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350 chevy

its a 1988 cutlass salon power windows and doors and its a auto matic if that make a difference i hope my car is fine so i can start driving it it is summer you know
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Old 06-25-2007, 12:12 PM
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Quote:
Originally Posted by xxxtonyrusxxx@yahoo.
my car idles at 180 190 and when i start driving its up to 210 220 is that to hott? and if so what could cause it i put no stat in it and i have a 3 core radiator and i disconnected the heater core pls help
This is typical for insufficient flow thru the radiator as speed/rpms pick up. The cause is usually a plugged radiator that doesn't allow full flow thru the core. The plugging is either or both corrosion within the radiator itself between dissimilar metals, brass, copper, and solder for instance or between the radiator and block in the case of aluminum cores and cast iron engines. Or can be from rusting of the block caused by water without coolant or hard tap water used in the cooling system.

There are other issues like too slow a pump speed, ie changed to underdrive pulleys or wearing of the pump's internal clearances; an intake hose that collapses; lack of an external bypass connection.

Bogie
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Old 06-25-2007, 12:20 PM
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Did you say there is no thermostat? You found the problem. The thermostat acts as a restrictor, if there is no thermostat the coolant can`t stay in the radiator long enough to cool it, so when the engine speed is picked up, the water pump turns faster, the coolant moves faster, and the coolant that just entered the radiator hasn`t cooled hardely any and it`s going right back into the engine so it runs hot. Install a 180 degree thermostat, NEVER run one without it. If it continues to run hot let me know, I have a 86 Cutlass, and I battled every type of cooling problem on that car you cam imagine until I got it completely figured out, I know the cooling systems on these cars front to back.
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Old 06-25-2007, 12:36 PM
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Missed the fact that it has no T-stat. I agree with Doublevision, put one in, it needs it.

Vince
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Old 06-25-2007, 02:49 PM
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heater core disconnected?

You say it's "disconnected". How exactly did you do it? My truck had an issue where I needed to connect the one heater hose to the other to allow it to flow. That fixed my problem entirely. i chased and chased only to find out that was the problem after all (after I installed a Vintage Air A/C unit).

But, I have run SBC before with plugs installed in the intake and water pump.

BTW, I had run the truck with no t-stat to see if it would help - and it did. I, myself, do not believe in the theory of the water moving too fast through the rad. I have been wrong before, but I think Thermodynamics would tell us that it shouldn't matter.

But I shouldn't open that can of worms. What I noticed is that your motor will take a long time to heat up, and then if the weather is cool it might not heat above 140. And that IS bad. You don't want to run a motor too cool.
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Old 06-25-2007, 03:50 PM
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With or without the fan running? Mine is setup with an electric water pump so flow is the same all the time, no tstat "yet" and it runs 180 - 190 but will hit 210 if I get on it hard. But turn on the electric fan and it will pull it down to 170 in a short time if I stay off of it. Im using a stock V6 radiator that came in the car. My SBC is not stock.
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Old 06-25-2007, 04:28 PM
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The rule of thumb is, any thing over 35 MPH you do not need a fan. So air movement is not the problem. If your motor runs cool (and 180-190 is cool) at idle, but heats at speed, indicates not big enough radiator or a radiator that is not dissipating heat well enough. The radiator shops will tell you, if it is not pucking, its not hot. That said the OEMs are running 220-240. They say, to burn unleaded better???? In our shop we put a 3/4 washer in place of the stat, some will say, you can move water over the radiator to fast. ?????
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Old 06-25-2007, 04:38 PM
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Moving the water too fast is not true! Think about this...why would they make hi-flow water pumps? If floing too fast they would make low-flow water pumps! Just an old wives tail!

Overheating comes from, not enough air flow across the radiator, not enough radiator, timing out of adjustment, carb being set wrong, air pocket in engine, clogged radiator, restricted flow, colasped hose. I think I got most of them....oh blown head gasket...any more????
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Old 06-25-2007, 04:39 PM
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Quote:
Originally Posted by Jake_Dragon
With or without the fan running? Mine is setup with an electric water pump so flow is the same all the time, no tstat "yet" and it runs 180 - 190 but will hit 210 if I get on it hard. But turn on the electric fan and it will pull it down to 170 in a short time if I stay off of it. Im using a stock V6 radiator that came in the car. My SBC is not stock.
I have done a lot of S10/15 conversions to an SBC and found out early along that in spite of professional recommendations to the contrary, the V6 radiator including the 4.3 90 degree V6 radiator for air-conditioned models is absolutely insufficient for an SBC from 305 inches up.

I never use electric water pumps on street engines in my builds, I have yet to see one of these things that can keep up to extended period, high power demands on the cooling system. By definition, they only put out one rate, usually around 40 gallons per minute. This is too much at low speeds and not enough at WOT. You need a high flow thermostat which at low speed supplies sufficient restriction that the engine warms in a reasonable period of time and opens sufficiently when hot so as to not interfere with the marginal maximum flow capability of an electric pump at high engine power and RPM settings. A simple restrictor is not sufficiently clever to accomplish this requirement. You need to shop for a high flow thermostat like Mr. Gasket supplies. But the basic problem is that the faster and harder the engine works the more cooling it needs, constant flow electric pumps can't meet that criteria. This is the primary advantage of a crank driven pump, that is the amount of coolant delivered is reasonably proportional to the demands of heat transfer. Under drive pulleys on street driven engines have much the same short coming, in that they short the engine of coolant somewhere if not everywhere in its RPM cycle. If you operate constantly at 6000 RPM and above there can be an advantage as at these RPMS a fixed vane pump reaches a point where it's beating the coolant to froth, so slowing it down a little will increase effectiveness and reduce power losses. But that's going to take something a lot more clever to accomplish than current designs. But if you don't drive for extended periods with the engine running on its red line, this also is a useless if not dangerous practice. This is a closed system with resistance to flow from both the radiator and the engine's coolant passages. Once flow is maximized any further spinning of the pump and any further use of WOT across time overheats the engine, period! If you monitor engine side coolant system pressure and temperature, you'll see this point on the gauges. Pressure will increase till flow is maximized, then temperature will climb beyond control.

The big horsepower absorber in OEM pump shaft driven designs is the fan. Elimination of the fan is a great power advantage as well as taking a lot vibration load off the pump shaft and bearings. Basically a pump driven fan is working its hardest at the point where it's least needed, high speed. The ram airflow at speed thru the radiator is more than sufficient for heat transfer. The problem is low speed and idle stopped air flow which without a fan is insufficient. An electric fan that's properly shrouded so that it's drawing air thru the total core area of the radiator provides plenty of low speed air and gets out of the way when not needed.

For your installation the first thing to correct is the radiator, there just ain't enough of it.

Bogie
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Old 06-25-2007, 06:10 PM
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I know of high flow meaning flows more water, water pumps, but I don`t recall them increasing the speed of the coolant any unless we change pulley sizes. The question here isn`t based on size or flow or speed when it comes to T stats, it comes down to time, the radiator has to have time to cool the coolant that just came out of the engine, and if there is nothing there to restrict it, the coolant that just came out that`s still hot is going right back in it, if the coolant doesn`t stay in the radiator anymore than 20 seconds it didn`t cool it anymore than what 5 -10 degrees? that`s not enough to keep the engine cool, that`s why it`s called a radiator, it`s job is to "radiate" off heat, if the coolant don`t stay in it, it don`t have time to cool it. again, time comes to mind. take a regular radiator, place a water hose in the top bung with the cap on, see how long it takes for the water to get to the bottom bung, it gets there very quickly and that`s the same thing that happens if there is no T stat in the system on the vehicle. sure, we can move water in high flow, and we can move it in high speed and the cooling system will work better, but if the radiator doesn`t hold that coolant long enough in the radiator to lower the tempature of the coolant what good did it do?
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Old 06-25-2007, 08:08 PM
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With all due respect Double Vision I offer the following information taken from another forum. Here is a link to this discussion. Cooling Problems

With back-up information from a seminar;

Cooling System Basics for Spark Ignition Engines
SuperFlow Advanced Engine Technology Conference, December 7, 1992

EMP Stewart Components

With all due respect... we have had these discusions before and there should be alot of old threads with plenty of examples and physics discusions on this very subject. Rick has it down believe me! The reason I am chiming in here is that I have fought long and hard over the last 12 years to fight these myths about cooling and debunk them with explanation and physics on sites like these....no disrespect meant. Just alot of misinformed folks out there with this subject. I would like to respectfully try to offer some education on this subject... as I ususlly do.

There are alot of engineers here as well with alot of knowledge on this very subject and Rick is one. I put myself in that category as well with years of design experience with heat exchangers (mainly nuclear cooling mechanisms) and moreover of late, custom automotive radiator design. I also have done real world testing with radiator/cooling system designs (specifically for aftermarket applications and racing) and have the lab data and references to prove it. I also have written countless articles (professionally) for both web based and periodicials on this subject as evidenced by some of the links I have provided herein. Now I really didn't come here to wave my flag here....there are many folks here as versed on this as I am.... but, just offer some education on this subject that will debunk the "less flow is better" myth. Without going into some long boring diatribe that is already in thread storage here.. I will try to keep it pithy.

First, let me ask some basic head scratching questions that make you think? Why do you think high flow/performance water pumps where invented? The answer.. more flow!!!.. more heat gets exchanged and thus can handle more horsepower on the same cooling system parameters. Just upgrading your waterpump will in fact increase your capacity to cool more btus and make the overall system more efficient (with the same parameters other than the water pump capacity) notwithstanding potential issues in the "stock" system.

Also..based on "slowing the flow"... doesn't this mean that completely stopping it will be the best strategy for cooling whereas WE ALL KNOW that HEAT TRANSFER is linear? No heat transfer book OR CLASS that I am aware of...at least where I went to school or thereafter... supports that theory. Also, I saw a post here saying that if high flow worked.... then you should just eliminate the radiator completely??? Huh? Flow has nothing to do with the radiator per se. First, we never said anything about removing the heat exchanger for heaven's sake?? The radiator design stands by itself in the "cooling system" but, EVERY RADIATOR WORKS AT HIGHER EFFICIENCY RATES WITH THE MORE FLOW THRU THEM! Or in other words.. cools better. Because the automotive system is a closed-loop system, doesn't slowing the flow leave coolant in the engine sitting getting dispropositional hot? The answer is yes...yes...yes! And this is problematic. First, the bigger delta (difference) between the coolant and heat transfer surfaces (this could be the radiator or engine surfaces) the higher the efficiency of the system. So, as the coolant sits in the engine it's ability to absorb heat diminishes as it approaches it's corrected vapor point (boiling at pressure X?).

Here's a great experiment for trying to convince you of more flow is better. IF you had a hot piece of metal and wanted to cool it under the tap would you ...A. Dribble water across the surface giving more time and less coolant ...or.. B. Run the faucet as fast flowing as you can with abundant cooling? While this is NOT a closed-loop system.. the principle is the same. I think you know the answer. Same thing with the radiator exactly!

Restrictors are another subject all together. And, moreover just like your anecdotal experience what seems to be (the slowing the pump in your words SEAMED to be better?) may in fact have other cause and effect solutions and/or the conditions may not be the same... simply put tooooo many anomolies to monitor and figure out.
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Old 06-25-2007, 09:14 PM
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350 chevy

well the guy up at nanpa told me my car should run 212! i dont know if thats true i never let it get over 205 i always turnned if off i put a stat in it today and im gonna see what happens tomarrow i reconneted the heater i blew threw it so i dont think its cloged well i hope everyone is right becasue im gonna take it for a cruise tomarrow and see how hott it gets i hope nopt over 212
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