I have listened to the fast vs slow flow for years. If it flows fast, it picks up a little heat often. If it flow slow it picks up a lot of heat less often. Either way it’s a wash. Some engines don’t even have water pumps and depend on thermal transference to circulate the coolant. I have several that work that way..... very slow/low flow. Cummins engine experimented with a “ low flow” cooling system a few years back. The big Diesel engine had radiator hoses the same size as a heater hose! It worked, but Cummins abandoned the idea after a few years, going back to a high flow system. It’s kinda funny that some aftermarket people sell high flow pumps and over drive pulleys, then folks try to “ slow” down the flow, with restrictions. It you are not running a thermostat, your radiator is working 100% of the time trying to cool your engine the best it can. If you are running 190 degrees with out a thermostat, your radiator or air flow is probably suspect. These are just some of my observations on the subject I’ve had over the years. Bones
Im with Mr. Squirrel on temp. approaching 240 is the danger zone a vette low speed cooling fan will come on at 226 and shut off at 219. The high speed fan will come on at 235 and shut off at 226. These are subject to rpm, speed and AC signals sent to the team of engine management specialists located in the PCM. The stock stat for these is rated at 212. The race guys will use a 160-170 stat to replace it. Im guessing the demands of racing will keep the temps normal? My ride operates around 210-215 during the summer, no issues other that vapor lock on hot days when engine will see 220 sitting in traffic. It has yet to purge any coolant.
I'm getting antsy if the temp starts to creep up past 195. Basically 15 degrees over the thermostat is going to cause me some alarm. I look at it this way; if the thermostat is 180, that was the temperature at which that engine was designed to run. In my mind, the car should be able to sit and idle at that temp even on the hottest of days. A good fan with more than 4 blades, and a shroud, is the most basic of places to start.
My Merc with a 302 has a 3 row aluminum rad and a flex e lite fan. Around town and stuff it is 185-190ish. When sitting at DQ trying to get the kids a blizzard it hit 230 then back to 190 when we got out of line and moving. I am assuming it is the fact that there is no fan shroud. Will need to make one and see if that fixes it.
Sorry Guy's enough is enough. The HAMB is being turned into Facebook on Steroids. There are more Drama Queens on here lately then on day time TV Soap Opera's. Nobody can enter an opinion without being confronted or somebody impling the posters a dumbass. Count the number confrontations on this one thread alone. It seems like everyone is trying to seperate fly shit from pepper. It never used to be this way. Somethings gone bad wrong. I personally would like to see things get back to the way it used to be without all the back biting and get back to helping others solve their problems. Just my opinion.
Big difference between a modern engine made with modern metallurgy and machining technology, and modern fuel injection and engine controls, and a 50's - 60's era carbureted engine, made with 50's - 60's era metallugy and manufacturing/machining tolerances, and with zero controls other than a throttle linkage/cable. At 230 the difference between being OK, and not, can happen in seconds. Another way to view it is, if an engine runs at 230 all day, every day, never gets any hotter no matter what, well OK then, it's pretty stable at that temp. A big difference from an engine that normally runs 210 - 215, but under some circumstances the temp creeps up, and will get up to 230 before conditions change and the temp comes back down. If you have faith that it's going to only go up to 230 and not any higher, OK go for it. If you don't, it's pretty hard to just watch the gauge and not be worried. At what point do you shut it down? Let it go till it boils over? Let it go until the pistons start swapping metal with the cylinders? Shut it down at 240? Man, that final 10 degrees can happen in an instant.
for my 350, i guess 225-230 is when I will shut it down. Haven't had to yet. the 235 ran 200-210 all day long. the only issue I have ever had with overheating was the 302. Boiled over without the thermostat, ran hot with the 180 t-stat at idle. I personally don't think running below 190 is healthy
Pretty much has to be an air flow problem. I believe he said little T-Bird and the air flow in these cars is a problem. My stock 312 will run pretty hot with long idles in traffic, but cool down once you get moving.
I didn't forget, I thought that should be obvious. The thing is you have to consider that the engine is one entity and the radiator is another entity. A radiator of any size will eventually be able to transfer 100 btus if the coolant moves "slower" when passing thru it. So a radiator can remove a specified quanity of heat if you let the coolant spend more time inside it. I don't think you can argue that statement. So how does someone increase the time the coolant is in the radiator? You either slow the coolant down OR you increase the size of the radiators area.........effectively allowing the coolant to remain at the same speed but travel for a longer time. Again, I don't think you can say that statement isn't basically true. ( This is considering that whatever air flow being used isn't altered and we can just consider it as a constant for both cases.) But let's consider the other entity in this system......the engine. While we want to assume that the engine gets a free pass, a limited supply of water may not be sufficient to cool it and may actually need to spend more time inside the engine. That's why fins or risers exist inside heads,to increase the transfer of heat. Also, the placement of the holes in the block and the head and the head gasket determine how quickly coolant moves thru the head. Take a close look at the head gaskets on many (All?) and you will see that not all of the passages coming up from the block pass water to the head. The head will often (Always?) have much smaller holes and then there is the gasket itself. The gasket may completely block some of the holes and allow coolant to only pass thru certain holes. On the Cadillac engines I am beginning to work with, some of the more advanced builders are experimenting with increasing the flow in the heads......rather than increasing radiator size. I looked up what Felpro had to say about blocking some of the coolant holes and they specifically stated that they do so to keep the coolant from passing thru the head too fast. Maybe an oversimplification for Mass consumption, but I tend to think Felpro knows what they are talking about. The point here is that everyone wants to say someone's radiator is too small while we could just as well make changes to the engine which would lower heat production .......possibly without the loss of any power, but most certainly by the use of different materials. Remember the reverse cooled Chevy engines with aluminum heads and how they could run more compression. The point is again that while you can push coolant at any speed through 1 object and correctly absorb heat, it can still only move through the heat exchanger at a speed that allows it to give up that heat to the atmosphere. Call it too small a radiator or too large an engine........they still have to work together. While you can move the coolant through both entities at warp speed, what may not be too fast for the engine may be too fast for the radiator to transfer it to the air. So what ? It's semantics on how someone wants to look at it.
Think of it like this. Your coolant is a reservoir.......whether it is contained in one container or in a series of components comprising a system. In the case of a large container, with plenty of volume and surface area, you may not need any movement of the cooling fluid because it has sufficient area for the volume of fluid to absorb all generated heat and transfer it to the air. That's how the electrical transformers mounted on your power pole outside your house work. They are large containers filled with oil. You could attach a pump and create motion of the fluid but it could still only transfer heat at the same rate to the air because the air can only work on the area available to it.
Put a Stant High Flo 160 degree thermostat in the block.. If you normally use regular try 89 or 94, then advance the initial timing a few degrees. If the generic factory setting is 12, try 18 or 20.. If you get part throttle ping, unplug the vacuum advance and block the vacuum opening. If you get full throttle ping or knock, immediately back off the timing!
Another winner! I advanced mine 12-17 or so with 93. Was set BTDC ... bad. Took 20 degrees off probably.
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