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383 Stroker Running HOT


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Vette Powered: That is a very big condenser for the air conditioning. It appears the temp sender is on the LH side of the engine screwed into the cylinder head. This is where the cooler water is coming up from the block into the cylinder head. Therefore this water has yet to pass through the cylinder head and get heated MORE. Just curious if you tried a somewhat fine spray of garden hose water into the front of the radiator when hot to see if it cooled down and what the results are.

 

Of course it's going to cool down! Spraying 70 degree or less water on a 190 degree radiator?!?! Seeing as how water transfers heat 25 times faster than air I don't see the purpose of spraying the rad. Especially when it's hot and he's in traffic there is no hose to spay it with. What's the point? Radiators are designed for Air cooling not water cooling. That is really pointless IMO and you'll learn nothing about what the problem is. He needs to get proper airflow and it sounds like he's about got it. Having the sensor in the proper place isn't all that important either. Nothing will happen to that engine as long as the coolant stays in the rad. If you pop the rad cap, it's over. If not, it's ok. Circle track engines run between 230 and 250 degrees all the time, even in Nascar. It's oil temp that you have to watch.

 

What is the point about the condenser? It impedes airflow and adds heat to the overall energy balance. Since about every car on the road has one I don't see the relevance. It's pretty simple. Efficient radiator, proper water flow, adequate air flow. It is as simple as that. The more HP you make the bigger the cooling area or radiator you need, or the more air flow you need. Simple high school physics.

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Dr Hunt: Don't get so upset. Just pointing out the facts. Disagree on location of the temp sensor. He is likely not running Circle Track nor NASCAR. In NASCAR the engines are likely rebuilt after ONE race. What is the justification for running 230 to 250 degrees? Oil is not the PRIMARY cooling medium. The condenser is not MODERN and looks to be oversized for the application. Understand efficient radiator, proper water flow and adequate water flow. Pointed out a DIRECT experience with undersized GM type water pumps. The suggested source for VERY GOOD water pumps was IGNORED. Need more?

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Posted by Doc Hunt

Of course it's going to cool down! Spraying 70 degree or less water on a 190 degree radiator?!?! Seeing as how water transfers heat 25 times faster than air I don't see the purpose of spraying the rad. Especially when it's hot and he's in traffic there is no hose to spay it with. What's the point? Radiators are designed for Air cooling not water cooling. That is really pointless IMO and you'll learn nothing about what the problem is. He needs to get proper airflow and it sounds like he's about got it.

 

Spraying the radiator can help diagnose the problem by isolating where the heat transfer is lacking. If the system is running at 230 and you spray the radiator, then the radiator cools down but the motor doesn't, it's an excellent indication you have a coolant circulation problem. I was helping a buddy with a overheating problem on a dirt car, which would peg the needle after a few laps. He had bought a used radiator, and the guy he bought it from threw it in a box, covered it with foam peanuts, and shipped it. Some of the peanuts got in the inlet side of the radiator and just about stopped it completely up. We would spray down the radiator and it would quickly come down to 150 or so, but the motor stayed hot, so obviously there was a coolant circulation problem.

 

Spraying the radiator can also show a airflow problem if the whole system cools when the radiator is sprayed. Braap stated it very well earlier in this thread:

 

Played with the car sitting still at home, allowed it to warm up and get up to approx 210 degrees, then lightly misted the radiator with garden hose, temp came right down! Let it warm up again, blowing air across the radiator from a distance with an air nozzle, (don't get too close or the air blast from the nozzle will deform the rad fins). Temp came right down. Ahh haa...

With that I started to make changes in air flow through the radiator. Not having any of the info from the wind tunnel, I was going at it blind, so only made few changes and they ALL helped, making noticeable difference.

 

So, there is definitely a benefit to spraying the radiator, if the results are properly interpreted.

 

jt

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Update... Water hose test brought temp down right away although I've not have a problem with high temps since weather has been in the high 80's. So, it looks like I need a air box and better flow through the cooling system. The a/c is blocking almost all the rad. Up front and I think this is a problem. Does anyone know what's a solution for this? Is anyone out there using a Vintage a/c system? Thanks...

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Update... Water hose test brought temp down right away although I've not have a problem with high temps since weather has been in the high 80's. So, it looks like I need a air box and better flow through the cooling system. The a/c is blocking almost all the rad. Up front and I think this is a problem. Does anyone know what's a solution for this? Is anyone out there using a Vintage a/c system? Thanks...
I have a Vintage A/C system and my condensor covers the same area as the radiator. I think this is pretty typical and probably not the source of your problem. I think you need to make sure that all the air is going through your radiator by sealing it to the front of the engine compartment and closing off any other openings that allow air to pass through.
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Dr Hunt: Don't get so upset. Just pointing out the facts. Disagree on location of the temp sensor. He is likely not running Circle Track nor NASCAR. In NASCAR the engines are likely rebuilt after ONE race. What is the justification for running 230 to 250 degrees? Oil is not the PRIMARY cooling medium. The condenser is not MODERN and looks to be oversized for the application. Understand efficient radiator, proper water flow and adequate water flow. Pointed out a DIRECT experience with undersized GM type water pumps. The suggested source for VERY GOOD water pumps was IGNORED. Need more?

 

Fact is that 230 or even 250 doesn't kill the engine as long as the water stays in the block, pertains to everyday vehicles as well as nascar. That is my point. If you run a 22-24lb cap on your daily driver then it'll run 250 or 260 without hurting anything which can be mighty handy if you don't happen to see the temp guage or temp light come on right away! Oil looses it's lubricating ability if it gets too hot and will cost you an engine, which is why most top end road race cars monitor engine oil temp. But in this case the poster doesn't run the engine at that temperature for any extended period of time, in fact quite the opposite.

 

An engine typically lives longer if the operating temp is 180 to 200 degrees but closer to 200 which is why the manufacturers use 195 thermostats. Less temp typically makes more power because the engine heats the incoming air in the intake and heads, which is the primary reason for having temp readings at the intake rather than the head, although either is fine but the water at the neck area is exiting the engine and is the hottest of the two.

 

You can mod a stock pump for more flow by riveting or welding a circular plate on the vanes, been there done that and back in my days we rebuilt water pumps, starters and alternators. Actually the gasket for the back of a water pump is in a full gasket set for those of you who want to try that mod. A lot of attention is being given the pump, but no attention given to the drive mechanism. You can overdrive or underdrive the pump which is usually more cost effective than buying a $150+ pump. I have found that option much more effective both temperature wise and cost wise.

 

Stock pulleys overdrive the water pump and there are two sizes for the sbc long style pump, non a/c and a/c and come in v-belt and serpentine belt options. The a/c version is larger diameter and drives the pump faster for more coolant flow and is typically installed on vehicles with A/C and/or two package and is often seen in newer vehicles with aux. electric fans as well. There may be others as well offered from the factory that I am unaware of and there are many offered by the aftermarket. I personally underdrive the water pump by 80% using the Moroso 3 inch diameter crank pulley on all my race cars and I have no problems with cooling since most water pumps flow way too much to be effective. Yes, that is right you can have too much flow and not enough residence time in the rad, especially in an aluminum radiator!!!!

 

The serpentine belt offers superior belt gripping ability over the v-belt design. Both have their advangages and disadvantages. v- belt slippage can contribute to heating problems as well, but multiple belts offer a safety in case some road debris happens to take one out. Redundancy is the key there and is my point.

 

I see your point and agree for testing for a plugged radiator which is basically your suggestion, but brings to mind the thought of doing it right the first time or skimping and using used parts of unknown quality and serviceability. Not sure it's all that applicable to the poster of this thread since he didn't state that he bought a used radiator off ebay, but a valid point nonetheless.

 

Personally flow testing, especially aluminum radiators is a mute point as they significantly outflow any copper cored radiator hands down due to larger tube cross sectional area. Although packing peanuts would significantly impact that flow characteristic, but allowing that to happen seems rather inconceivable except in rare instances considering how much money a person typically invests in an engine. It's a healthy investment in an engine that should last for years and taking chances on used radiators is aking to shooting oneself in the foot, which is another point. Things cost money and it is troublesome to watch inexperienced people invest heavily into the engine only to have problems such as overheating. I am sure any advice is great, especially if it directly pertains to the situation at hand, and even if it doesn't directly apply to the thread.

 

I think there is alot of information provided here by alot of members and should be compiled and made a sticky by someone other than myself. Seems a good idea overall. Perhaps one our new admins will be up to the task.

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I have a Vintage A/C system and my condensor covers the same area as the radiator. I think this is pretty typical and probably not the source of your problem. I think you need to make sure that all the air is going through your radiator by sealing it to the front of the engine compartment and closing off any other openings that allow air to pass through.

 

Yah but how about when the car is sitting in traffic?? That's my big problem!! Sitting still...

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Fact is that 230 or even 250 doesn't kill the engine as long as the water stays in the block, pertains to everyday vehicles as well as nascar. That is my point. If you run a 22-24lb cap on your daily driver then it'll run 250 or 260 without hurting anything which can be mighty handy if you don't happen to see the temp guage or temp light come on right away! Oil looses it's lubricating ability if it gets too hot and will cost you an engine, which is why most top end road race cars monitor engine oil temp. But in this case the poster doesn't run the engine at that temperature for any extended period of time, in fact quite the opposite.

 

An engine typically lives longer if the operating temp is 180 to 200 degrees but closer to 200 which is why the manufacturers use 195 thermostats. Less temp typically makes more power because the engine heats the incoming air in the intake and heads, which is the primary reason for having temp readings at the intake rather than the head, although either is fine but the water at the neck area is exiting the engine and is the hottest of the two.

 

You can mod a stock pump for more flow by riveting or welding a circular plate on the vanes, been there done that and back in my days we rebuilt water pumps, starters and alternators. Actually the gasket for the back of a water pump is in a full gasket set for those of you who want to try that mod. A lot of attention is being given the pump, but no attention given to the drive mechanism. You can overdrive or underdrive the pump which is usually more cost effective than buying a $150+ pump. I have found that option much more effective both temperature wise and cost wise.

 

Stock pulleys overdrive the water pump and there are two sizes for the sbc long style pump, non a/c and a/c and come in v-belt and serpentine belt options. The a/c version is larger diameter and drives the pump faster for more coolant flow and is typically installed on vehicles with A/C and/or two package and is often seen in newer vehicles with aux. electric fans as well. There may be others as well offered from the factory that I am unaware of and there are many offered by the aftermarket. I personally underdrive the water pump by 80% using the Moroso 3 inch diameter crank pulley on all my race cars and I have no problems with cooling since most water pumps flow way too much to be effective. Yes, that is right you can have too much flow and not enough residence time in the rad, especially in an aluminum radiator!!!!

 

The serpentine belt offers superior belt gripping ability over the v-belt design. Both have their advangages and disadvantages. v- belt slippage can contribute to heating problems as well, but multiple belts offer a safety in case some road debris happens to take one out. Redundancy is the key there and is my point.

 

I see your point and agree for testing for a plugged radiator which is basically your suggestion, but brings to mind the thought of doing it right the first time or skimping and using used parts of unknown quality and serviceability. Not sure it's all that applicable to the poster of this thread since he didn't state that he bought a used radiator off ebay, but a valid point nonetheless.

 

Personally flow testing, especially aluminum radiators is a mute point as they significantly outflow any copper cored radiator hands down due to larger tube cross sectional area. Although packing peanuts would significantly impact that flow characteristic, but allowing that to happen seems rather inconceivable except in rare instances considering how much money a person typically invests in an engine. It's a healthy investment in an engine that should last for years and taking chances on used radiators is aking to shooting oneself in the foot, which is another point. Things cost money and it is troublesome to watch inexperienced people invest heavily into the engine only to have problems such as overheating. I am sure any advice is great, especially if it directly pertains to the situation at hand, and even if it doesn't directly apply to the thread.

 

I think there is alot of information provided here by alot of members and should be compiled and made a sticky by someone other than myself. Seems a good idea overall. Perhaps one our new admins will be up to the task.

 

Thanks for all the help! I am by no means a mechanic but know enough to get by. The rad. seems to move fluid very well and I flushed it out really well. I did not buy it so I really don't know the history behind it. I bought the car as a project although it looks pretty new. There has been alot of talk about the air box which I'm going to build but this is not going to help me when I'm sitting still. The strange thing about it is I've been driving the car all over durring the last few days and it not gotten over 200. The temp. here in Texas has been about 10 degrees cooler and just that alone has seemed to fix the problem.(but I have not been stuck in traffic sitting still for more than 3 minutes or so)

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dr_hunt: Yes, 230 or even 250 F doesn't kill the engine but it sure doesn't help it. Manufacturers chose the 195 thermostat for Emissions purposes. After my experience with high temp Chevy Big Block I only trust one manufacturer that is Stewart Components. Bought a new Edelbrock Aluminum water pump and it leaked out of the box. Not real good quality. NEVER a problem with Stewart Components who make the water pumps for NASCAR teams also.

 

The temperature sender hole on the Small Block Chevy is located IN-BETWEEN the two intake valves in the head DIRECTLY above the coolant passage from the block. This should yield cooler numbers than at the thermostat.

 

Per David Vizard's Max Performance Chevy Small Blocks on a Budget book "Having the oil at a high temperature and the water at a lower temperature is worth a measurable amount of horsepower. Just being able to elevate the oil temperature from 180 to 210 degrees F on a typical 300 horse small block Chevy is worth about five horsepower, and independently pulling the water temperature down to about 170 from around 200 degrees F is worth about six or seven horsepower."

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  • 6 months later...

Has anyone who has done the JTR conversion and followed the cooling recommendations closely ran into this problem? In other words, with the JTR aluminum/plastic radiator, one of the recommended fans, thermostat, etc.

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As a past experience I have had with this type problem. This is what I have done and going to do to my car. 2 things should be done. 1st put a skin from the bottom of rad to the subframe. This helps direct the air away from the radiator preventing a recerculation of the hot air. 2nd, put a air dam, spoiler, something that extends the from the bottom front edge of the radiator. This creates a low pressure area on the back side of the radiator and forces the air through the radiator. Just my thoughts.

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240Z%207.jpg

240Z%205.jpg

 

this looks very typical of engine swap cooling systems

 

flx-440_w.jpg

 

http://www.summitracing.com/parts/FLX-440/?rtype=10

 

personally I think adding twin pusher fans since youve obviously got the room required is a no brainer here!

Id also check the amps and voltage at the pull fan, as its very common for those electric motors to either be less than up to the job of pulling enough air flow or your alternator to be putting out less than the required power levels to spin the fan to its FULL potential, Ive cured several marginal cooling engines that ran electric fans problems with a swap to a 200 amp alternator

 

http://www.db-starter-alternator.com/Items/ho-7888-11-200%20amp?&caSKU=ho-7888-11-200%20amp&caTitle=CORVETTE%205.7L%20200%20AMP%20HIGH%20OUTPUT%20ALTERNATOR%2088%2089%2091%20%207888-

Edited by grumpyvette
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  • 2 weeks later...

I will look into the alternator amp issue. I don't think adding the fans will help. The taurus fan is 4000 cfm on the high side. Plenty of people on here run them with similar set ups with no issues. I think ducting and a shroud will help for sure. I will post results when I get to it.

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