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over heating

4K views 29 replies 12 participants last post by  55_327 
#1 ·
Hey guys this is a problem I've been fighting for a while. I have a 35 Ford with a 327 sbc stock with 350 turbo. It runs over 200 degrees no matter what I do.2 fans one pushing one pulling,walker rad,170 degree therm,50-50 mix,I'm at a dead end,need some help.Thanks Big Doug
 
#2 ·
What pump are you using??

What diameter crank pulley??

What diameter water pump pulley??

Current fans are both electric??
Pusher fans often get in the way rather than help

What are their diameters??
Is the puller shrouded, or just a round fan mounted to the radiator core??

What is your initial ignition timing at idle?? What is it at road speed, 2500-3000 rpm??

Are you using a vacuum advance on the distributor??

Will it sit and idle forever and not get hot, or will it get too hot even just sitting??
 
#5 ·
It's been my experience that overheating correction is a battle of a degree or two and NOT a silver bullet. By that I mean good coolant mix...2-3 degrees, clean coolant system/block...2-3 degrees, a way for the air to get out from the engine compartment...2-3 degrees, puller fan with shroud...5 degrees, etc. A pusher AND a puller fan could be your biggest problem (along with no shroud). A '35 Ford has a tight engine compartment which doesn't help but inner fender louvers will help.
 
#6 ·
35 & 36 Fords have a little less engine bay space than earlier and later models. It’s challenging to cool them and getting anything to fit between the motor and radiator is next to impossible. On my 36 I only have about 3/4” between my water pump pulley face and the radiator. Push & pull fan combinations sometimes negate themselves and hamper cooling more, especially if they are opposing each other.

I’m using two Derale HO 16924 pusher fans on mine. But beware, they draw a lot of current (25 amps each) and require electrical upgrades.
https://derale.com/product-footer/e...h-output-rad-pusher-fan-2014-08-14-718-detail
I have them stacked, with the upper fan doing most of the cooling and the lower one coming on only as needed and with the A/C. If you have A/C make sure your condenser is spaced about 3/4 -1” away from the radiator and perimeter of the condenser sealed otherwise the air will not flow well through both.

Also make sure your timing is correct (retarded timing = heat) and your heads are in good shape, a small combustion leak (head gasket or crack) can add an incredible amount of heat to the cooling system.
 
#17 ·
As I said in my earlier post, cooling the 35 & 36 fords can be challenging at best. On mine, because of the tight engine bay with the A/C and alternator mounted high (to clear hood sides), it leaves no room for mechanical or electric puller fans. Add to it my hood sides are shaved (no louvers), I had to get creative to cool mine.

My cooling arrangement consists of Flowkooler (flows more water at low speeds) short water pump (no clearance for long pump), the bottom hose has a stainless spring in it to prevent the hose from collapsing (more output equals more suction), Wizard Cooling aluminum radiator with 1-1/4” tubes (replaced Walker), 2 - Derale HO 19625 pusher fans (yes pusher can work), 14# pressure recirc cap and a recirc tank, 50/50 coolant with a 190 thermostat and a Dakota Digital fan controller (operates the two fans independently). Keep in mind high output fans draw a lot of current which may need electrical upgrades (larger alternator and wire sizes).

My SBC 383 runs consistently at 200° (205° at idle with the A/C running on hot days), a little less on cold days. I can idle with the A/C on and not worry about over heating.

And as mentioned earlier, correct timing along with correct AFR and overall motor condition can make a huge difference in cooling as well as performance.
 

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#8 · (Edited)
Everybody has this problem with these. The single pass vertical flow radiator typically used couldn't cool the old flathead, a modern engine especially with an automatic is nearly hopeless to run under 200 degrees.

Some helps are:

- Run only water with a rust inhibitor and water wetter. Water is a better heat transfer medium than 50/50 coolant which has about 80% of the heat transfer reduction of water to that of straight ethylene glycol. Rust inhibitor because water rusts and corrodes metals which impedes heat transfer. Rust inhibitors are included in coolant so your just running the corrosion chemistry without the coolant. This is seasonal you can't park it overwinter with this stuff in it without serious cooling system damage. Water wetter is a non foaming detergent that breaks down waters resistance to saturating surfaces so you get a tighter molecular association to the surface needing heat removal. Its effectiveness depends on how little coolant is in the system, less coolant more effective the wetting agent, how corrosion free are the surfaces as corrosion is an insulator.

- Seperate cooling functions for the transmission, put the ATF through its own stand alone cooler with fan somewhere out of sight.

- If need be plumb pipe clamped to the frame to add coolant capacity and use the frame as a heat sink.

- An engine oil cooler hidden like the tranny cooler with its own fan takes a big load off the radiator.

Another path is to follow the aircraft engines of WW II and run straight glycol and accept the high coolant temp. This allows a big reduction in system pressure which is sure easier on hoses and radiator cores because pure ethylene glycol boils at 350F at atmospheric pressure. This pretty much ends nucleate boiling so all the metal is wet all the time, this is the principle idea behind Evans Waterless Cooling.

Bogie
 
#30 ·
Water is a better heat transfer medium than 50/50 coolant which has about 80% of the heat transfer reduction of water to that of straight ethylene glycol.
Exactly. A 50/50 mix lowers the coolant freezing point to -37 degrees F. You certainly don't need that much protection in the summer, and probably not in the winter. I frankly have to wonder if 50/50 is a myth perpetuated by antifreeze manufacturers, similar to the 3,000 mile oil change interval recommended by motor oil manufacturers.

For starters, I'd try 100% distilled water along with an anti-rust additive, as suggested by BogiesAnnex1. If that works to lower your temps this summer, then take a look at this chart to see what you need in the winter.



Finally, engines may be more efficient at 210 degrees, and they do a better job of ridding the crankcase of moisture, but they're more prone to pre-ignition and certainly don't make more power. I think a series of dyno runs would confirm that.
 
#9 ·
Have you pulled your freeze plugs? The amount of sediment that accumulates can add up over the years. Cleaning this out by pulling some plugs and hitting the thing with a hose to flush out that is a good practice. Your heater core can also be a restriction and after cleaning that out it can serve to increase your coolant capacity. Aside from extreme weight reduction the more coolant capacity you have the better.

I run as large of a radiator as I can fit then adjust the glycol to water ratio so the thing warms up to 210 within 5 minutes of driving on a 50 degree day.

You want your engine above 200 but below 220. Hotter engines make more power and having a hotter engine allows condensation to be removed from the oil keeping the oil in better condition.

I try to have air flow through and out the engine bay. Either with louvers, a cowl hood, or vents.

Check the function of your clutch fan. If possible run a 7 blade with thermostatic clutch from 80's (454) truck. Then run a 2 piece shroud a inch around those blades with the fan blades just fully within the shroud.

The 7 blade with clutch is highly recommend if you can fit it even if a short waterpump is required. You will hear the thing kick on. With a proper shroud, a 7 blade, and some escape routes for underhood heat to vent your temps will drop.

From there you get to expermenting. Run a 180 degree thermostat and straight gycol to start. Jump in the thing and drive it hard doing stupid driving for 20 minutes. The fan should be kicking in and keeping that thing 180-190. From here you install a 195 thermostat and go beat on the thing again with hard throttle, energency stopping, and high revs down a secluded area.
Then add water a little at a time until your running a constant 200-210. Most of my summer rides run around 200 with 70% gycol. It should not matter if your running 3500 down the highway or driving stupid with full/no throttle city(highway congested) driving that thing should get up to 200 fast and stay near 210 all day. If it does not search around to find why not.

Check the pressure in your system to make sure there is no air being introduced or your cap is bad. Running a 16lb cap works in most cases. But only if that cap is working and sealing tight.
Many high dollar diesel/big block gas engines have died because the owner did not do maintance on a radiatior cap costing less then $10.
 
#10 ·
I'm not so sure about the comment that "hotter engines make more power". Hotter engines are more efficient, but everyone at the track is always doing what they can to cool the engine between runs for a good reason. ICE's are terribly inefficient. Every btu of heat they emit whether it's through the cooling system or the exhaust or anywhere is wasted energy. Plus any and all means to cool them is wasted energy also. So the less you cool an engine, the more efficient it is, to some degree anyway. (no pun intended)
 
#13 · (Edited)
Best to keep your engine as close to 210 as possible. Having it as hot as possible without (having the gauge read) 220's increases the efficiency and allows for more pressure. Ideal gas law and thermodynamics can help you get around that track faster.

https://www.khanacademy.org/science...ory-ideal-gas-law/a/what-is-the-ideal-gas-law

Automotive Engine - Physics and Mechanics


Point is if your running or think that running 160-180 is the ideal temperature your leaving power on the table. That being said if that 160-180 engine swings into the 210-220's under hard breaking or sitting in traffic due to a undersized cooling system then your forced to run the cooler temps(by having a thermostat that opens earlier)to avoid boiling.


Find someone with a infread thermoter. You dont need a imaging one just something that shows temp at a specific area. Run the engine and point the thing around to see if some area of your block/radiatior is hotter/cooler then the other areas. If so there is a blockage or damage somewhere.

This HF one is cheap and works good for this.
https://www.harborfreight.com/121-Infrared-Laser-Thermometer-63985.html


As far as cleaning goes. The type of cleaning I am talking about is scale rust which I clean with pressurized water within the block using a pressure washer inserted into one freeze plug having the stuff exit out another freeze plug. I have broke up blockages over 1/3 the diameter of the cooling passages using this method.
Some guys who tank blocks can chime in here on what kind of fun they find over the years when someone has a head gasket leak which they try to fix by pouring in several cans of "leak fix".

The radiator or heater core you can disassemble and run a wood dowel roughly 1/2 the size of the tube down the tube a few times to clean out the thing. Depending on how popular the radiator or heater core is. Just replacing things may be a better option. Maybe you can find a "slightly used" "high performance" unit for some change locally.

If you simply pull your radiator, put the cap on then flip the thing so the cap is on the ground. Then taking a garden hose and stuffing it into the former lower hose the amount of stuff that comes out of the upper hose can be staggering.
Simply flipping your heater core hoses (in to out and out to in) using a garden hose on that lower hose to push things up out the upper hose can also get good results or have you find that you have a non flowing blocked heater core.
 
#11 ·
Looking at the Walker radiators pictures for that vehicle it appears that they are a single pass, 2" unit?


Unless the unit is new, I would start with making sure that the radiator is completely clean and not starting to block any tubes. With that out of the way, I would remove any fans on the front of the unit. Keep the rear fan(s) to draw air through and do whatever you can to channel air from the grille to the radiator opening. Even a small spoiler at the bottom of the radiator mounting might help to deflect some air into the radiator. I am assuming that the stock small block is correctly tuned, not leaning out and not crazy on timing, remember too little is just as bad as too much. It probably wouldn't hurt to reverse flush the engine while the radiator is out too. I believe you are fighting a small capacity radiator first off and air flow issues secondly. I am not sure if anyone makes a double pass unit for your car but it would be something to consider if the above doesn't move the gauge down.
 
#14 ·
While a 212° coolant temperature may be considered ideal for modern ICEs. You must also take into consideration that these modern ICEs are computer managed. Timing, AFR and coolant temperatures are constantly adjusted to maintain optimal operating conditions, even with lesser octane fuels. As coolant temperatures rise toward ideal levels, fuel efficiency (and maybe even slight horsepower) increases are available, but at the risk of denotation and other BAD forces if not managed properly.

While these forces are greatly kept under controlled in modern ICEs by their CPU management systems, it can be CATASTROPHIC to and older non CPU managed ICE. Adding to this danger is the lack of knowledge about tuning older carbureted ICEs and detonation's adverse effects. Older high performance carburetor ICEs require regular hands on tuning to prevent these conditions.

For the majority of those that do not race or have a firm grip on tuning of the average street driven older muscle/hot rod type ICEs, a 200° coolant temperature (along with safe tuning margins) is a much more realist goal…

JMHO
 
#15 ·
The hot in terms of temperature is another from the history of military piston aircraft engines. Yes it's effective to reduce heat loss to the cooing system especially with an aluminum engine. Smokey Unick was messing with this idea for NASCAR engines talking about 400 degree coolant temps. But all of this crashes on materials and manufacturing processes. In spite of building blocks and heads from exotic materials using forging and billet machining it just proves to be impractical to do. I'm not aware of anybody that's been able to take this idea outside the experimental lab and get it to work in the everyday even in the highly managed environments of military aircraft or highly exotic race cars.

I agree with 36 Sedan and others who point out that running street vehicles in the range of 200 to 210 is done with EFI and port or direct injection at that. And that these systems include a lot of monitoring and control in real time for ignition timing and mixture, and in some cases cam advance and retard plus in the case of dual overhead cam's changes to the LSA and LCA angles. This is also a coming technology to single overhead and in block cam's. This is something that the average hotrodder with an aftermarket carburetor or TBI injection simply doesn't have in terms of engine management and probably doesn't want. So running the engine especially an older engine from the 20th or very early 21st century would be and is risky at these elevated temps.

I have run Frankenmouse for years with Evans waterless because I can't keep it under 200 and often 240 in hot weather and stop and go city driving. You can't put enough fans on an S15 to force sufficient air through the core and keep a stock body profile. So the next step was to accept that it will run hot and then becomes the need to disallow nucleate boiling in order to protect the castings from cracking.

The problem in doing that with water/glycol mix coolant is it takes a lot of pressure. After having a couple three spectacular hose and core failures, I switched to the Evans which because of its 350 degree boiling point at atmospheric pressure, I was able to back the system pressure off to using only an 8psi cap.

I've run this stuff for about 15 years in this machine, the engine is now creeping up on 450,000 miles on the bottom end. This truck has been a daily driver, daily parts hauler, occasional racer, home to a lot of cam, valve train, heads, and induction experiments over the past couple decades. Now we're both retired and to my wife's consternation I'm starting a top to bottom rehab.

Bogie
 
#18 ·
Loovering your hood sides will help.

As far as radiatiors go I have always wondefed why no one ever made a V shaped radiatior to sit tight behind the V shsped grill. This would give you a significant increased cooling area, allow for electric fans to be used, and allow for more engine space. You would need to fill it through the upper hose using a center mount fill. But other then that it seems that would allow for a overall larger cooling area.

Break out the tape measure and measure behind that grill. There are several small radiatiors out that may fit behind there.

You will just need to run a sealed radistior, or higher pressure caps, or block off the caps then you can mount the things anyway they fit using 2 common radiatiors. Link the two together to go off the engine to the top of 1 flow through it to bottom, having a hose going from the bottom of 1 to top of 2 then flow through 2 before back to the block.

I am guessing you can fit 2 15x30(ish) radiatiors back behind that grill depending where your rails drop.

A cadilliac northstar 2000-2005 radiatior and fans MAY work and after getting your measurments heading to a yard to confirm may get you the fix you need. That radiatior has a long upper hose which may allow you to connect to the 2nd unit easily while keeping everything non custom.

A 91(ish) jeep cherokee (xj) radiatior is a bit smaller then the cadilliac radiatior and there are more options for aftermarket support which will you to use a larger core if need be.
But your going to need to make your own fan brackets. I would use four 12" fans for the 2 radiatiors.

Electrical wise I would run a single controler turn on a single relay(if not incorporated into the controler). Having that single relay to turn on the 4 relays powering the fans. Then use a audio capacitor to buffer the fans all turning on at once.

Sounds over complicated. But your ending up with a 30×30 "tripple pass" radiatior cooled by 4 fans pulling a combined 3200-4800cfm.

Only issue is where your frame rails come into play or other obstructions which may complicate things.
 
#19 ·
I think this would be a great spot for an electric water pump due to the volume it flows is not tied into the engine rpm's. How to to tie it into coolant temps without any intervention fro the driver would require some minor ingenuity, but could be done on the cheap. But initially running it at maximum voltage should resolve all of the OP's issue.

36 sedan - that engine is a piece of art work!!!!!
 
#20 ·
cerial, that is some out of the box thinking and it just might work for someone!

64nailhead, they make an auxiliary electric water pump that co-exists with the mechanical and it is designed for exactly what say, a good alternative too! And Thank you (it runs as good as it looks).
 
#23 ·
What did you point the magic dot to? If it was shiny then your temp is almost guaranteed to be higher than what the infra red thermometer shows. If you can use some real cheap flat black paint on it you will get a better reading. I say cheap paint so you can wipe it off again.
 
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