Over heating issues

[usra43]

My S.S. keeps over heating everytime. I have a moroso pump, water wetter, new radiator, no leaks or internal leaks. I took the front air ducting out cause i put it on dirt. I had a electric fan on then went to a mechanical. Didn't change, so i put both on now. I noticed the water neck had a thermostat that was gutted out. Could that be it? Do i need to just have no restrictor????? It just gets hot right towards the end of the race. I'm talking 250 degrees.

[TBSSS01]

Probally too much water flow

[Truck99]

Good ducting from the nose to the radiator is very important. If you took that out, I'd put it back in. Take the thermostat out (wide open water neck).

 

What jets and timing are you using?

[usra43]

36 degrees timing and 76 jets.

[KISS_Racing]

Chase you beat me to all 3.

 

Jason,

 

Are you running a 6AL? Verify the green and purple wires if you are. Although if they are swapped it would run like poop... Chances are it isnt it.

[usra43]

Yes i run the 6AL box. The wires are right. I was told by others to take out the bottom of the front air box so it gets air under the car to the radiator because of the small lower opening in the front of the nose piece. It is a dirt car now.

[KISS_Racing]

I heard of water pumps caiitating? You got me... How long did the car sit before you started racing it? Asphalt to dirt that is. With new radiator and water wetter you should be fine. Have you pressure tested the system?

 

Maybe belt slipping? Man I don't know...

[jwmbishop]

Gutted thermostat is no good. Run 5/8 to 9/16 restrictor in the water neck. Anything else I have ever tried did not work well - cavitation (which is like a huge air bubble wrapping around the water pump impellor) occurs when the water flow is unrestricted. Also when unrestricted the water does not make a good conductive contact with the casting (the steam bubbles create a layer of "air" and air does not conduct heat as good as water). Anytime the pump head pressure is below system pressure (for example if the pump makes 16 lbs of head pressure and the heat makes the system run at 18lbs (cap rating)) - you WILL have cavitation - and it increases with temp causing the temp so just keep creeping up!!! The only way to increase head pressure to above system pressure (and maintain high conductive contact with the block and head castings) is to decrease restriction opening size in the water neck - that in turn DOES decrease water flow so pulley speed then may need adjustment. (I have heard but never tried that a thinner gasket at the water pump back plate will reduce potential for cavitation)

 

Spin the water pump at 4000 rpm max. size your pulley to obtain this - if it runs hot at low RPM (yellow flag) you can always surge (up and down in RPM) to cool it. You want it to reach peak flow at top RPM and let bottom fall where it may.

 

Make sure the fan shroud is larger than the core by about 1/4 to 1/2 inch so as not to pull air around the radiator (air will always take the path of least resistance) - and that the fan is centered and as close to exactly half into the opening as you can get it. I have not noticed much difference in temp removing front duct on tracks less than 5/8 mile - as long as air flow is not encouraged to bypass the radiator (at higher speeds the air compresses in front of the car and the duct becomes more critical to keep the compressed air from going under or over the nose - this starts happening really bad somewhere around 105 MPH and really becomes problematic at around 130). If the air is allowed to go over the radiator between your front brace and hood you are leaving cooling capacity on the table. And the air that comes thru the radiator HAS to go some where. A trans tunnel completely filled with trans in a car 3 inches off the ground can develop a high pressure behind the radiator that impedes flow. Make sure you are "venting" the underhood enough. This can be aided by tipping the radiator back at the top as opposed to standing it straight up and down and trimming some of the fender away behind the front wheels.

 

Make sure you are not sucking the lower hose flat (check this when HOT HOT HOT - A cool hose will have more resistance to collapse). I have seen a hose that would stay open at 4000 rpm at 230 degrees - just touch it and wham it would slam shut! Typically use the shortest hoses possible - and replace as much of it as you can with solid tube.

 

New or not the radiator must be able to handle the therms. There are several things that effect this (tube wall thickness, fins per inch, tube inside surface to outside surface areas etc). As an example I put a four row radiator with electric fan in the truck (replacing two row and mechanical). It overheated. Hmmmmm come to find out the radiator transferred TOO MUCH heat. The thermostat would open and close so fast that the electric fan did not even have time to come on - this started a cycle that by the time the fan WAS able to come on and stay on the overheat was already emminate. I then set the fan to stay on all the time and it would not open the thermostat. Finally solved by putting smaller pulley on wp (street veh so never sees over 4000 RPM anyway) and its now happy with both fan and thermostat working together. Yes racing is different - but the principals of mechanics are the same! Make sure you are using the correct radiator - call the manufacturer!

 

A restricted exhaust can elevate temp. Make sure you have no kinks in the pipe from banging on the trailor etc.! (and it doesn't hurt to wrap).

 

Sometimes its just the hand we are dealt - I built a .030 over olds 455 once that overheated every time no matter what we did. Prior to boring we had no problems with it (final 4 weeks of a season) After 6 weeks of problems in the new season we relugated it to a tow vehicle (54 ford) and never could keep the truck cool either. After we retired it the guy I gave it to had the block sonic tested to see if he could take it to .045 over to run in a river boat. The casting was so thin half way around four of the cylinders that not only could it NOT be bored any more - it was deduced that it was just transferring heat faster than the water could absorb and dissipate at the radiator - so would never be usable for anything (which was a shame as in our incarnation of it it was a VERY strong runner and a high nickel content that made for some real purty machine work).!

[usra43]

Thank you everyone with the info. I will consider every idea. Next i will put a new water pump on. I got the used Moroso from a buddy. Maybe its failing?

[KISS_Racing]

Thank you everyone with the info. I will consider every idea. Next i will put a new water pump on. I got the used Moroso from a buddy. Maybe its failing?

 

 

Jason,

 

Do as Mr Bishop mentioned and look at the hoses closely. If one of them is closing off there is your restriction. Good call Mr B.

 

Mark

[Ford27]

Jason, I dont think it was the waterpump cause at thr we could see the water moving in the radiator . If the thermostat was gutted it could possibly be that the water is not staying in the radiator long enough to be cooled off. You might consider a restrictor. Its also the cheapest. let me know if ya need help.

[lbeaver087]

usru43 you may need to check to see if the fill is higher than the thermostat housing if it is lower it can cause an air pocket

[rpfan]

The same thing happened to us when we went dirt a month ago. We took the electric fans off and put a 6 blade metal fan on, no flex fan. Our other car we put a 4 blade fan on. The 6 blade car runs 220 still and the 4 blade runs 180. The 6 blade will be changed to a 4 blade before the next race they pull much more air. If you put one on just stand behind the lt front tire and lean over and crab you some throttle and you will fell the enormous amount of air it is pushing at you from the radiator.

[jwmbishop]

The 6 blade car runs 220 still and the 4 blade runs 180.

Next time you want to play scientist and conduct an experiment - try this. Place your hand in the airflow of the fan and run the engine up to 3000 rpm. Then (after shutting down the race car) get in your passenger veh and run up to 45 mph and hang your hand out the window. Which has more air flow force? the passenger car wind at 45 will push against your hand a heck of a lot more than the fan's air flow at 3000 rpm. What does this show?

 

Simple - above 45 mph the fan actually can RESTRICT the air flow if it has more blades with less pitch than a 4 blade with steep pitch. A 6 blade fan is generally for trucks and tow vehicles. More blades DOES equal more air flow at lower speeds/rpms for cooling under lower speed higher LOAD heat demands. however fewer blades with more pitch equals less restriction once there is more air coming thru from vehicles speed than from the fans work. At 70 mph my truck goes up to 195 - I override the electric fan and it goes down to 190. At 45 its just the opposite - with the fan it runs 190 without it it gets to 200 REAL fast.

 

That is also why a clutched fan will run cooler on the highway than a solid. Once the fan is maxed out it can only allow more air by coasting - or spinning faster than the incoming air. I don't see any fan being able to make a 75 mph air flow! This is the main theory behind a flex fan - not just to unload the fan at higher RPM for more engine power - but to allow the air to run past it at a greater volume once the veh speed is greater than the fans air speed. If you were at a miniature golf and trying for the hole under the windmill - how many shots could you make between the blades at a slow rpm vs how many at a faster RPM? the golf ball is representative of the air molucules.

 

Its always a give and take with engineering. To get a gain somewhere you give up something somewhere else. The fan is only there for lower speed cooling. With a street radiator this is usually 35 - 40 - with a racing radiator (with more fins per inch) this is around 45-50.

[1-Crew]

The 6 blade car runs 220 still and the 4 blade runs 180.

Next time you want to play scientist and conduct an experiment - try this. Place your hand in the airflow of the fan and run the engine up to 3000 rpm. Then (after shutting down the race car) get in your passenger veh and run up to 45 mph and hang your hand out the window. Which has more air flow force? the passenger car wind at 45 will push against your hand a heck of a lot more than the fan's air flow at 3000 rpm. What does this show?

 

Simple - above 45 mph the fan actually can RESTRICT the air flow if it has more blades with less pitch than a 4 blade with steep pitch. A 6 blade fan is generally for trucks and tow vehicles. More blades DOES equal more air flow at lower speeds/rpms for cooling under lower speed higher LOAD heat demands. however fewer blades with more pitch equals less restriction once there is more air coming thru from vehicles speed than from the fans work. At 70 mph my truck goes up to 195 - I override the electric fan and it goes down to 190. At 45 its just the opposite - with the fan it runs 190 without it it gets to 200 REAL fast.

 

That is also why a clutched fan will run cooler on the highway than a solid. Once the fan is maxed out it can only allow more air by coasting - or spinning faster than the incoming air. I don't see any fan being able to make a 75 mph air flow! This is the main theory behind a flex fan - not just to unload the fan at higher RPM for more engine power - but to allow the air to run past it at a greater volume once the veh speed is greater than the fans air speed. If you were at a miniature golf and trying for the hole under the windmill - how many shots could you make between the blades at a slow rpm vs how many at a faster RPM? the golf ball is representative of the air molucules.

 

Its always a give and take with engineering. To get a gain somewhere you give up something somewhere else. The fan is only there for lower speed cooling. With a street radiator this is usually 35 - 40 - with a racing radiator (with more fins per inch) this is around 45-50.

 

 

More info (taken from an earlier post - search is your friend.. )

Antifreeze (ethylene glycol) does not cool any better than water alone but it does raise the boiling point (and lower the freezing point). It is simple chemistry, any mixture will freeze at a lower temperature than either of the two components of the mixture. The same is true of boiling where the mixture will boil at a higher temperature than either of the two components of the mixture.

 

In a typical automotive cooling system, the enemy is something called "nucleate boiling" which occurs when a localized hot spot develops and allows boiling to occur at that point even if the overall system temp is lower than boiling temperature. Once nucleate boiling begins, there are trapped steam bubbles in the system that quickly work their way through the system, lowering cooling efficiency.

 

The other problem common to automotive cooling system is boiling that occurs at the water pump. As the impeller of the water pump moves, it creates a low pressure region behind each blade. Water boils at a temperature proportional to the pressure so if the water is close to the boiling point, the lower pressure behind the water pump blade can be enough to initiate boiling. This is commonly referred to as cavitation but is really boiling at a low temperature. The end result is the same, a sudden reduction in coolant flow (since steam is compressible), with a resultant increase in engine temp. The purpose of a thermostat and/or a fixed restrictor, is to allow the water pump to build pressure in the block. With increasing pressure, the boiling point of the water in the block increases. This is the real effect of the restrictor, it has nothing at all to do with "slowing the water down" or "keeping the water in the radiator longer". The equations covering heat transfer to air (from the radiator) are independent of the fluid flow but very dependent on air flow (see above post).

[j.j.&s.racing]

when im behind cars i meen right up there bumper mine now is going to 230.i used to have a fsr tripple pass and it did not do this i put a tripple true china brand now it does. the reason i changed to it was a wreck. i have a gutted out thermo,30 degree reduction belts high doller water pump.water wetter,the old one weghts more than the new one maybe better material. plastic flex fan could it be worn out??

[jwmbishop]

That is an indication of obstructed air flow! But also make sure your air is being lifted from the ground rather than from the lead cars vaccum area - this is what the front ducting can be used for. The two radiators probably have different surface areas of the fins - and different SHAPE of fin - but sounds like you just need to adapt rather than totally replace (thinking it does cool back down when you run clean - you did not say)

[kingracing76]

My S.S. keeps over heating everytime. I have a moroso pump, water wetter, new radiator, no leaks or internal leaks. I took the front air ducting out cause i put it on dirt. I had a electric fan on then went to a mechanical. Didn't change, so i put both on now. I noticed the water neck had a thermostat that was gutted out. Could that be it? Do i need to just have no restrictor????? It just gets hot right towards the end of the race. I'm talking 250 degrees.

Take a real close look at your pulleys and belts. Very common for the belt or belts to slip trying to start and stop the heavy mechanical fan. The more they slip the hotter and looser they get. causing the temp to climb towards the end of the race. Serpentine setups are great but you have to keep a close eye on pulley wear. Once they're worn and start transferring metal to the belt, replace them.

[jwmbishop]

Once they're worn and start transferring metal to the belt, replace them.

Hmmm - I understand theory - but lack on application. What would one be looking for as an indicator?

[kingracing76]

Once they're worn and start transferring metal to the belt, replace them.

Hmmm - I understand theory - but lack on application. What would one be looking for as an indicator?

Indications of serpentine pulley wear are easy to spot. Ribs first begin to lose their coating and get shiny, then as they wear they lose the sharpness and flatten out the tops of the ribs. Once this happens the belt will slip no matter how tight it is when on and off the gas as in dirt track racing. I've seen it happen in 5 races or less and cause overheating problems that were driving people crazy. With a large steel fan KRC recommends an idler system just for this reason, to keep tension on the belt as it heats and stretches, and prolong pulley life.

[jwmbishop]

Cool thanks, I've seen what you describe quite often - but in street apps where it was inconsequential and thus ignored (until it's actually throwing the belt). Never gave a "percentage of loss to slippage" thought to it. hmmm... Old dogs DO learn new tricks.

[kingracing76]

Cool thanks, I've seen what you describe quite often - but in street apps where it was inconsequential and thus ignored (until it's actually throwing the belt). Never gave a "percentage of loss to slippage" thought to it. hmmm... Old dogs DO learn new tricks.

This old dog just learned it recently himself, the hard way of course! This is a very informative forum.

[Danielsen Motorsports]

The very first thing when it comes to heating issues is pullies. Yes worn belts will slip too but an easy way to check that is grab the fan and try to see if you can turn it. If so then either your belts are worn or your adjustment for belts need to be tighter. If you running a SS motor then your obviously turning up the rpm. You most run one to one pullies and not overdrive the waterpump and fan. One to one pulley basically means the crank pulley needs to be the same size as the water pump pulley in diameter. You can do everything else if they are not one to one you will always have an issue either at low rpms in the pits or at high rpms.

[claybuster]

Didnt read all the responses, but here is what we do, on a DLM on gas.

*1-1 Pulleys V-belt not serpentine, make sure belts are riding on the sides not in the bottom of groove. They will slip if riding in the bottom(pulleys worn out).

*about 3/4" restricter

*4 corner cooling, with water entering the neck at the same direction as flow, not back down into the manifold against flow. Dont know if it matters, I just prefer all fluids going the same direction, not against each other.

*GM 4 Blade fan Part#405442, not the imitations, just go to GM and pick one up.

*No holes in nose, holes allow dirt.

*Everytime Radiator is out of car it is capped and plugged, and soaked in a "kiddie" pool. Even though you rinse it out you will not believe the crap that comes out.

 

Hope this helps.

[j.j.&s.racing]

mine went to 230 in kyle when we were racing tight.had to back off then it cooled down to 220. 210 under coution.iwent to the 4 blade fan,29-31 # cap i was a little lean too.