Hello, I need help with over heating problem I have a 468 bbc with 8.9 cr with a 871 blower with 15% under drive I'm running a electric water pump Miezer 55gpm with thermostat housing and a restrictor to slow water down the radiator is a 4 core 11/16 cores monster two pusher fans and one puller fan timing is 29 deg. and running a little rich at idle merlin block only 4.310 and has enough meat to go to 4.625 heads are also merlin and copper head gaskets to match Idling around 1200 rpm and takes 20 minutes to get to 195 at thermostat housing and 210 on front head surface. Anything you can think of would be appreciated thanks Ed
Is it truly overheating or is the gauge "reading hot"? Some times people rely on the gauge... If it is truly over heating, I suspect something is plugged. The pusher fans combined with a puller fan also troubles me a bit. pushers are notoriously inefficient, and may be limiting what the puller can accomplish.
Willy, I used hand held pyrometer to check gauge and it is high but readings that I posted are from meter. I ran pushers first without puller and know that I think of it with shroud the pushers would do a much better job on puller side I will try it I don't know why I never thought of it before. And to answer. Big Duece I have more pics and I will try to add them soon also if you look on youtube and search Ed Beaumont corvette g***er you will find a video from hot rod reunion from inside of car maybe you will like
electric water pump,dose not pump enough GPM to cool a 470 in. motor.............................. 12v pump going down the drag strip it will,but not around town
Dana, The pump I have puts out 55gpm static and runs around 35gpm though the block the factory pumps around 18 to 20 I had to run a restrictor plate in the thermostat housing to slow flow down to allow time to cool I think the pumps of the past may have been limited but the more expensive pumps of today kick **** I was curious about flow and direction so I took one of my small lines off number 6 size and it shot across the room before restrictor plate it would **** down the return side of the radiator tank with cap off of course any other thoughts thanks Ed
OK,thanks good to know,but got to admitt I'm old an have not tryed newer 12v pumps. Don't see how a new 12v pump can do that much gpm though,cus it takes like 2hp+ to do that and that would kill hell out of a battery fast and el motor should be real big around. Other factor that gets me is your gpm on stock pump is find for idel [18/20],but not at 5000rpm+ were big heat is made fast,just saying my thinking there,I'b using a stock drive pump set up,could other stuff too. I maybe just too old to help,have not played with any high $ stuff for years now.
We have a 468 BBC,871 blown motor in a 64 Nova and it does good, we don't have a thermostat in it at all, no restricter. Sounds like you have more radiator than we do also. Easy to try pulling your restricter out and see.......................
I've never figured out how a guy can see 195/210 temps as "hot" on a big blown V8 engine. If that is all it's getting up to I'd say it is running pretty much at operating temperatures. If the temp drops right back down in the range you "think" it should be in nothing is wrong. Running hot is puking coolant out the overflow every time you get caught in traffic or for a race car not cooling back down in a reasonable amount of time after a hard run. Also it's been proven time and time again that coolant moving too fast through the system doesn't get time to transfer heat at either side. It doesn't soak up the heat from the block and heads efficiently nor does it transfer the heat to the air through the radiator all that well.
Ed, 195 @ stat is not overheating. if that is a good reading then I would not sweat it. Your heads are going to show hotter than the stat.
Any way to slow the idle down to like 900 or less? I also think you are doing alright at those temps given the combination.
I agree with you on the first statement. As far as slowing the water down to give the coolant time to transfer heat is absolutely not true. I used to install hydronic heating systems and I can tell you the slower the flow from the pumps the faster the boiler is going to come up to high temp and kick off. A motor is no different then a boiler, it's just a heat source. In fact the hotter the water going through the radiator the better. The lager temperature differential between the ambient air and the coolant temp. the better it's going to transfer BTU's. As far as restrictors and thermostats those are for getting the motor up to operating temperature not for cooling. For the OP, I run a N/A 582 BBC with a normal front mounted radiator and a auxiliary one in my bed. I run a 195 stat and my motor likes to run at 210. In fact in runs like **** until hits 200 anyways. So you got nothing to worry about.
The restrictor is not there to get the engine up to temp quicker. It's there to build block pressure, which eliminates steam pockets and DOES improve cooling of the METAL by pressing the coolant more tightly against the water jackets. As far as slowing the flow down not improving heat transfer: Try this simple experiment. Heat up a burner on the stove, then brush your hand across it quickly. Not likely you will get burned, but try pressing your hand down on the burner and it will cook you good. It's the SAME HEAT. The only difference is contact time... Think about your logic on the boiler comparison. You were actually making the opposite point. The boiler kicks off quicker because the slower flow allows the water to absorb more heat, which in turn kicks the burner off, right?
put a thermostat in it. drill a small hole near the center to allow any air to bleed thru and see what happens.
I think you're kind of saying the same thing I am but in a different way. The boiler like a motor makes X amount of BTU's per hour. When they make those BTU's they need to get out of the heat source. Which means the water needs to be flowing through them to pull the BTU's out. Then the BTU's are transferred to the baseboard, radiant floor or in the case of a car the radiator. If you stop that flow or slow it down, the quicker either one is going to get hotter. You increase the flow and it's going to start pulling more BTU's again. That is if the radiator can expel those BTU's. Which then comes down to airflow, radiator size, and ambient air temp. I'm not trying to argue, but I think this is a complete myth. Think about it this way. Why did they start putting water pumps on cars in the first place? If cars didn't need more flow to keep cool wouldn't car makers left the cooling systems work off convection like Model T's? As far as building pressure with the restrictor. I don't believe car water pumps build pressure. The pressure comes from the water expanding. Wouldn't that be why you can pull the cap before the system gets near boiling. As far as your stove experiment. I believe the difference would be water molecules would be in constant contact with the heat source. Where as you hand just swipes by once. I'm just guessing on that.
I was once miffed for a log time with a wicked overheating problem on the SBC in my five window Model A years ago. I tried everything and just couldn't keep her from running hot (198-200 I don't care what people say - 185 is tops for me). At that time, I even thought that I had a crack in one of the heads I got so crazy over it. One night , my good friend is junking a Feiro and he brings it by my house before taking it to the yard for weight. I pulled the fan up front b/c they had the fan and rad in the front nose with an air dam and the v6 engine in the back of the car, and they ran so damn hot they caught on fire, hence- Firearo. Anyway, long story short, I don't recall the cfm , I did know it at one point after the problem was solved; but that damn stock Pontiac fan pulled that engine down to 178 all day long. I had a stock water pump- shorty, and a 4 core custom fabbed br*** radiator. The motor was hot 1 to1 stupid lift cam, etc. It may not be the case with your deal, and I would have never believed at that time that that stupid fan whould make any difference, b/c I had a ****py electric fan on the damn thing already; but it just didn't have enough CFM. Check it out' worst thing is that it doesn't help ou? Best thing is with a dam and a freat solid wind maker- you drop 10 to 15 degrees, right?
More flow only works up to a point. Those of us who have run race cars have found out the hard way. Most of us tried running without a thermostat or restrictor and have faced the overheating issue. We learned that high revving engines flow too much coolant and a thermostat or restrictor plate slows that flow down. It certainly increases the pressure in the block. It's one of the ways to tell if a cooling system has lost too much coolant. We ran two pressure gauges. One on the radiator and one on the block. We played with restrictor plate sizes and found that about 4 lbs higher block than radiator pressure seemed to cool the best. Radiator pressure raises the boiling point of the system. Increased pressure in the block raises the boiling point even more to keep hot spots from turning the water into steam. Rules required us to use only water for coolant. If you're involved in hydronic heating, you should be familiar with head pressure. If a pump doesn't have enough head pressure, it overloads. If a pump doesn't increase pressure, water from the heating system in the ba*****t wouldn't pump up to other floors.
Wow I just got a look at all the replies thanks for all the feedback having a group give you that much advice is great! I will take it all in and try some things tomorrow I want to have it ready for the spring. God Bless
Big Duece I'm glad you liked the video it has been very helpful to me if I play it on my flat screen tv I can see all the gauge values while running down track
Automakers started using water pumps as the energy level in gasoline went up. Power makes heat, and more heat meant more steam, which is totally useless in cooling the engine. Even with a non-pressurized system, the water needs to circulate to keep it from flashing to steam. Water pumps DEFINITELY build pressure. Ever seen a water pump improver kit? It's designed to close up the tolerances inside the pump to increase pressure. ANY sort of restrictor or thermostat is going to limit the flow through the engine, so a "high flow" pump is about the most useless thing you can buy for the cooling system... As far as the experiment: When you boil water on the stove, does it happen the instant you put the pan on a hot burner? No, it takes TIME. That is the water absorbing the heat. The cooling system obeys the same laws of thermodynamics....
It's still amazing that every time a question like this comes up we get self styled experts who disprove their theories right in what they write. The issue is still heat being transferred from the block and heads to the air. To do that the coolant has to circulate through the block and heads and through the radiator/heat exchanger into the air and be carried off. The variables: The amount of heat the engine creates and when it creates it. How well the coolant absorbs the heat in the engine and then transfers it to the air in the radiator. The speed that the coolant flows through the system, fast enough to flow max coolant but slow enough to absorb and transfer max btu. The amount of air flowing through the radiator at a certain time. On that particular body can you get air in and out well? Can air flow be improved? By? Better fan? Better flowing inlet with less restriction? Better airflow on the back side to reduce restriction of air flow? And for the "former" and I understand why it's former heat/avc guy the reason the boiler shut off with the slower movement of the fluid was because that allowed the heat to transfer to and from said fluid to the air in the room quicker and the thermostat on the wall shut the boiler off. Pretty damned simple when you think about it.
You're right more flow is only going to expel more BTU's to a point. You're going to run into velocity issues at some point. Also the radiator can only get ride of so many BTU's. That makes sense about the restrictor. If a pump is oversized for an application and doesn't have enough head pressure which will create cavatation basically the pump losing it's prime, and stop or slow the flow. I think this just proves my point. The motor needs more flow to get rid of added BTU's. I'm not even arguing this point. But you didn't answer the question. Why can you pull the rad cap on a running engine? You have to look at it the molecular level. The water NEVER losses contact with the block. As the molecules go by they gain heat in the block and lose that heat in the radiator. The faster the flow the more molecules to pick up and drop the heat. I wasn't even sure if I was going to debate you. I don't see any reason for you to put me down or call me names. But this isn't to convince you, I couldn't care less. This is for the people who want to learn something. First off I never claimed to be an expert. But I do have training and real world experience in how heat is transferred. So what makes you more knowledgable then me? Give us some facts not your theory. What is the formula for this "correct" flow? It doesn't exist. But here's the formula for figuring Flow for Hydronic heating. GPM = BTU's/500 x Delta T. Lets do some math. We have 100,000 BTU boiler and we are going to shoot for a 20 degree delta T. Because I would think that we can all agree a hotter temp at the radiator with put off more BTU's, correct? I won't have to tell you want Delta T is right? But for those who want learn. Delta T is the drop in temp from Outlet to Inlet of the heat source. 100,000 BTU/(500 x 20 Degrees)= 10 GPM Ok lets do it again with a 200,000 BTU's boiler and the same delta T. 200,000 BTU/(500 x 20 Degrees)= 20 GPM Wow look what happened the flow doubled! What this shows us is it takes double the GPM's to transfer double the BTU's. Lets try again with a higher delta T. Lets say 40 degrees. Like we said before higher radiator temps = higher BTU's expelled. And now we just dropped our radiator outlet temp 20 degrees. 100,000 BTU/(500x40 Degrees) = 5 GPM This is where radiator size and air flow would come into play. If we are using the same size radiator as our first example and it's just big enough or air flow is not sufficient. We are not going to not be able to expel all our BTU's because we have lower the rad temp 20 degrees. More flow= More BTU's lost. We would now need a bigger radiator or more air flow to get the same amount of cooling. This is fact not theory. Good point about air flow, but I have to ask if we slow the water down for more contact time, why not the air. Wouldn't there the be a perfect air speed? If it's too fast how does it have enough "contact" time? Let me answer for you. Water and air are both fluids and there is no perfect "contact" time. You can flow as much air as the radiator will handle. Former heating guy, nice put down. But your explanation is laughable!! In my example of the boiler shutting off I was talking about WATER temp not room temp. The room thermostat is still calling for heat, so the pump is still running but the burner has shut down because the boiler is cycling on and off. Which would mean, there's not enough flow to get the BTU's out of the boiler and into the room. It's really quite simple! Let me tell you why I don't do installs anymore. I'm still in the Plumbing, Heating, Well and Septic industry. I've working on the wholesale end for 19 years. I did installs on the side and made damn good money doing. I still have people call me even though I quit 2 years ago. The reason I quit because I have 2 kids and Wife that I like to see on the weekends and after work. Also I make enough money with day job that I don't have to do it anymore. Click on this link and check out Fig. 8-30 and 8-31. But maybe these are just self styled experts. http://books.google.com/books?id=-E...ormula for hydronic heating flow rate&f=false
Remove the restrictor and plumb some water to the intake manifold byp***. Should take care of the air. 240 is hot, anything else is warm.
Aright guys I think I've got it with your help of course I put two ten inch puller fans on engine side of radiator and installed 17 or 16" fan on front for pusher I installed a 5/8 restrictor in thermostat housing keep in mind the thermostat housing it remote due to blower intake old school cragar next I hooked all fans to adjustable thermostat switch at 165 I can now run car for a solid 20 minutes and get no hotter than 170 at thermostat housing and no hotter than 185 on heads this is a considerable difference the shop I tested was some where between 65 and 70 deg does this sound doable for a drag car and occasional cruise and before you ask why only ten inch fans its because in a corvette that radiator sets on a approx. 30 deg angle there is no room do to old school race frontend thanks tell me what you think about run time Ed
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