It's not how it advances....manifold vacuum keeps the timing more advanced at idle (when your problem occurs (if it is working correctly)) which causes the engine to run cooler at idle. Normally a stock 34 radiator will cool most SBCs The kicker here is how much it has been chopped.
Overheating at idle is not enough air flow through the radiator. Overheating at speed is not enough radiator capacity...all things being equal. I'm using a Stock 32, 4 cylinder radiator to cool my blown DeSoto with a Summit 5 blade, 15" fan, no vacuum advance, and Stock DeSoto 175 degree thermostat. Cools beautifully...stays at 175/180 idle or highway. The engine being fully exposed probably helps a bunch, too...
getting your temp reading off front or back makes a difference ,i always got better average reading of front of cylinder head . this position for sending unit is the one most used it makes a difference in gauge reading on most after market guages . the calibration is different from front to back . this it what i have found . does not effect the engine temp. but does effect the guage reading
Certainly not the fix, but something you may want to try anyway- Add a bottle of "Water Wetter" to your coolant. They claim it will lower temps by 20 degrees. It lowered temps in mine by about 10. Chopped down radiator may not be allowing enough water circulation in the radiator to cool it properly. Better fan may help, or try some water wetter.
Yep. Pictures. Speculation is moot. Above idle it's cooling, you've already said that. To answer your question; You can draw more air; #with different fan, #optimum fan clearance, #efficient shroud, #increase fan speed(if for some reason you're underdriving it now for some reason?). Using that house fan you'll need a loooooooooooong extension cord. Can't see your shroud. Can't see your fan. Yep. Need pictures.
actually that bring sot mind my buds car that was being tuned for a turbo set up he had on it and my boss that was tuning it was amazed at all the timing the engine was taking without it moving the needle so he kept on adding timing and adding timing until he blew the headgasket and it wasnt till them my buddy told him the guage was broken so he glued the needle to where it was supposed to be. i know it has no relavance but it does make sense to make sure you use another source of checkijng temperature to know for a fact your guage is reading correct. to me the ultimate place to get the best engine collant reading is right as close to the the thermostat as possible cause remmeber the water comes out of the top of the motor cools on its way down the radiator and back in throw the pump from the bottom. so the best place is the hottest which is right out the thermostat in my honest opinion. i agree with some pics. there could be so many different variables involved some pictures would defenitly help out.
Placement of the fan in the shroud also affects air flow. Too far into the shroud the fan will cavatate, just stir the air in the shroud. Too far out it will not pull enough air through the core. The fan should not be over a quarter to half inch into the shroud.
Ok I read most and glanced over some so if this was asked I missed it . What are the dimensions of the radiator ? Have you have a flow test done to make sure you don't have any blockage in the block and cooling system ? Now you can hide an electric fan on a pusher on the front side of the radiator . Do you have sides on the engine compartment or is it open with no hood ? That will make a big difference in the way the air moves . Header wraps will help with heat also . Remember when the temps go that high so does your trans fluid if hooked up to the radiator and not a standard shift . Are you running HOT firing spark plugs ? That will make extra heat also . I would consider an alum radiator too . Maybe you can find someone that will let you borrow one to try out to see if that helps at all . As for the alt pulleys and so on , like someone said ONLY the crank pulley will change anything else ! You can change any pulley you want to and nothing will change unless you change the drive pulley ! All I can say , if the electric fan makes a difference , then install one ! Engines are too costly for the sake of not running an electric fan for looks . Just my opinion . Retro Jim
thanks for all the help....sorry no pics,the radiator core is 17 x 18 4 row, plus the stock 34 tanks,new recore buy a good shop......i have the fan about half way in the shroud. the fan will hold a shop rag . i have a 6 blade fan rigid from speedway..the shroud is air tight , added duct tape for now....i do see some air bubbles in the radiator but i cant make it leak under presure ie head gasket cracked head. i ,did a block test, clean there too....i removed the fan belt and stat housing ran it and no movement or bubbles in the stat hole.....pulled the e plugs hot, pressurized it cranked it over no spray...... what else will cause air bubbles ??? again with the extra fan it will idle forever at 185.... kicking my ass ....thanks for the help
Did you check to make sure your temp guage is accurate? I would check that first with an IR gun and put it right on the t-stat housing at temp. You would be surprised what your actual temp is.
Read the whole post and a few things that come to mind: I agree that air flow is almost always the culprit, you confirmed it with the house fan trick. Speeding up the water pump with a smaller pulley on the pump and/or a larger one on the crank can help this. Is the fan the correct one for the rotation of the water pump? Is the water pump being turned the correct direction? Some pumps designed for reverse (serpentine belt) will work when installed in a V-belt style system but at low speeds, suffer in movement of water volume. Does this have a viscous clutch? Is it the correct rotation and in good working order? Cavitation of the pump, usually shows up on high speed but if your pump is a re-manufactured unit, there could be a possibility of an incorrect impeller for the housing. Thermostats should be checked for function before installation. Pot of boiling water and a candy thermometer is all you need. Thermostats that fail to open can sometimes make themselves know with a bang, I have had three in my lifetime fail to open and you get a water hammer sound from your system, scary shit! Bubbles in the system can be a few things. Most likely trapped air in the heads and block. Just takes some time and patients to bleed it out properly. leaky heater cores, bad manifold gaskets or bad head gaskets can cause this.
thanks ,two water pumps, two fans, two temp gages, as for bleeding it out, i swear it was cured once ,bubbles were gone no extra fan was needed . ran at 185. any tips for bleeding the system ????
Say what? My eyes are burning from my attempt at reading your post. But if I understand what you are trying to convey, changing the water pump pulley in this instance does not change the RPM of the crank or affect the "overall" system speed. A belt on a 6" diameter pulley spinning at 1000 RPM has a speed of 1570 Feet per minute. Changing any other pulley in the system does not change that belt speed. The diameters of the other pulleys will determine what RPM those driven objects will be. BTW, I have cured more overheating problems by removing the parasite pusher fan from the front of an otherwise satisfactory cooling system than I have seen been cured by doing so.
Best I can suggest for bleeding the system is to get the front of the car/truck as high as you can. I know you are frustrated with changing parts. I have run into a series of crap parts from ball joints to thermostats, went through several before I got a good usable one.
Now i need you to pay attention to what i am telling and to think . I can bring it down by bringing the RPMs up. You said that i did not but I understand. What is happening when you raise the RPMS. The fan is turning faster and the water pump is turning faster. Not a lot faster either Ill bet. So what can you do? Change the pulley diameters. A bigger bottom pulley or a saller top pulley ir a combo of both will completely eliminate your problem. It doesn not take a huge change to ake a big difference. On BB Mopars which is my specialty this exact problem can often be solved with a 1/2" reduction in water pump pulley size which speeds up the pump and fan. A trip to the local old car wreckers with the current pulley in hand for comparison of both diameter and back spacing will be time well spent. Just so you know I did this on my own classic too. A 63 Dodge max wedge car clone. Now it doesnt even threaten to overheat. At frst it was a problem. I have done it for several customers. Usually i have to as all their friends have other ideas and try to discourage them from trying it. Usually it goes like this. "Give me the dang pulley, shut up and get in my truck." An hour later after we're back and it is installed and working perfectly i get to say "now What the heck is wrong with that?" It doesnt take a lot to cure this particular problem when it only overheats at idle. Try it youll like it. Don Don
Anybody read the fact the guy is not even driving the car? All this speculation is being done in the driveway
Ive been having the same issues. As in running hot. I changed my stat to a 165 it helped but still running 215 -220. Where is the correct or best place to run the temp gauge sensor for an aftermarket temp gauge?
I did notice, fresh engines are tight and prone to running hot-er. Still he has had it run cool before the rebuild. Just have to solve what went wrong. The range your thermostat opens has less to do with cooling and more to do with the minimum temp your engine runs at. Make sure you thermostat flows the correct amount in the minimum temp range you want to be. Temp sending units should be close to the thermostat. Yup, just have to solve that.
"If it overheats in the driveway it will overheat on the streeet." Not always the case. many engines in hotrod form only cook when stopped in trffic or idling. Once there is airflow through the rad (Fan does nothing above 30 MPH but suck HP) the problem disappears. Typically there are three main types of overheating problems I have had to deal with for customers. There is this one which i wont go over again. Then there are cars that run fine slow but overheat when pushed . These are often rad related but are sometimes also pressure cap related. Raising the pressure cap value raise the boiling point. When the coolant boils it makes steam .Steam expands and does not cool. Little by little as steam is produced there is more steam and less coolant touching the metal surfaces. It also pushes out coolant into the overflow tube. (Ie if i drive my car hard it pukes) And there is the ones that overheat all the time which is often related to insuficient cooling capacity. Somerimes before we reach for the mega buck rad though a test and little experiment with rad caps will solve what seem to be an insurmontable problem. It is easy to surmise and discuss but as a tradesman when a customer came here i had to fix it if I wanted to get paid. I do not reacall ever having failed at the challenge in 41 years of turning wrenches. You sit down and analyze what is going on and when. You figure out what it wants to cure it and do it. There is no mystery no black magiic. Cooling systems obey the laws of nature. Always without exception. In most cases the probalem can be solved easily for a few bucks and a bit of time. The biggest obstacle to overcome is getting people to do it. That was always more work than solvng the actual problem. You get "well so so says this." And that so and so might be a traffic cop. Then you hear "the guy at the parts store says." Well then why is he selling parts instead of fixing cars? The difference $ wise per hour is huge. And then there is "My bother in law says" stories and on and on. The car doesn't give a hoot about all that. If the engine is sound it needs more rad capacity or flow or a properly working rad cap or a bigger fan or a faster moving fan and water pump as in this case. A little testing and sound thinking coupled with an understanding of how it actually works will usually bring about a swift and permanent cure. Don I am surprised at how many answers are not related to finding out what is wrong or missing and curing it. ???????????????
I have the same~ish problem in my '49 Ford. Stock radiator, unknown cap pressure, no thermostat yet....overheats at idle with electric puller fan set to kick on around 165. I am installing a 180 thermostat soon, replacing my intake gaskets and double checking the timing.
Get it so you can take it for a spin, right now you are proposing changes on something that you haven't even test driven.
Spend the bucks on a flow cooler pump. It makes all the difference in the world. Make sure that the fan shroud is sealed well to the radiator so that the air you are pulling has to pass through the radiator. Try a fast acting T stat. I use a Mr Gasket fast acting T stat in my 350. Works way better than the off the shelf T stat from the auto parts. Double check your timing as has been suggested. Although I have never really had a problem with timing making one run hot I know it can affect the operating temp on some motors.
I am very weary of electric fans, period. I have two high end Spal fans on my truck run by a Variable Speed Controller and it still gets warm on those 115 degree days. Because of the configuration of my radiator, steam was pushing out the coolant regularly. My solution was a DE-GAS bottle similar to what you see on modern cars like the Mustang. Still runs warm (220ish) sitting in traffic for 10 minutes, but it never pukes. Most of the relatively inexpensive fans barely pull 1800 CFM and that's just not enough for the average V8 around here. The Spal VA33-AP71/LL-65A Fan (16" HP) is one of the only fans I have used that truly pushes past the 2000 CFM mark in normal use. http://www.spalusa.com/store/main.aspx?p=itemdetail&item=30102082 If I have the room and the budget for it, I really like the Lincoln Mark VIII fans. Vintage Air sells them too, PN: 32018-VUF and they do really pull close to the advertised 3700 CFM. http://vintageair.com/catalog10/2010 VintageAir Catalog printed_ (Page 80).pdf You can source one from the auction sites or your local junkard. The last one I did was on a Studebaker truck. Guy accidentally left the truck running in his driveway with the air on on a 105 degree day for an hour plus while he took a phone call. When he remembered what he had done he rushed out to expecting to see his truck melting down, instead it was idling nicely at 175 degrees.
Probably the best fan out there. Pricey, but worth the money. I have different customers from hot rodders to road racers to high end exotics and the guys building the very be$t stuff will only buy Spal. And I agree with Tman. Sounds like you are pulling your hair out over something that might not even be an issue. If you get stuck in traffic keep the RPMs up... or shut it down.
and if you have bubbles in the system and no headgasket leaks you might just have air in the system. if you are running a heater core make sure the valve for it is open. i'd let it idle with the rad cap off and let it bubble up till it doesnt anymore. just maintain your eyes on the temp guage and if it gets to hot shut it down. i had that with a customers car last week and i swore i had goten all the air out of it but it would creep at idle. took the car home to make sure it wouldnt overheat and once i got home and let it sit for a while i was able to open the rad and top it off. most of the time i can just let is sit there and open the heater core valve and make sure all the air is out but sometimes like in this case i had last week i had to drive the car for about a few miles to make sure it did actually get all the air our of the cooling system.
I need to change the intake gaskets this weekend anyways...as I also have a vacuum leak causing my idle to creep all over the place. Knowing that, I think the majority of my problems have come from the intake gasket. Once I get the gaskets replaced, I can re-time it and hopefully that clears up my cooling issue. Also, on these older radiators, how many pounds of pressure will they take? I am leary of getting a 16 pound cap on a stock radiator...and I have no idea what my cap is. At high RPM's, I know it pukes a little...the only reason that sucks is cause I dont have a catch can for it yet...or a hose to direct it downward...
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