Cooling systems and operating temps

[Leviathan]

Need some help here, trying to get an idea of Regal cooling efficiency:

What do you run for a cooling system (fan/rad/trans cooler) and what are your operating temps? If you can post some about the engine combo too that'll help.

I'm debugging the new engine and it's pretty warm on first run. They dyno numbers were good and clean so I know the machine work was spot on.

I currently have a 26" 4 core triple pass rad with electric fans and it's not cooling well at speed or at idle (shut down when temps reach 210 oil 220 water). Never had this problem before with less rad and the mech fan...

...going back to a mechanical fan and 160* thermostat this weekend...

Any ideas are appreciated!

[regal_84]

I'm not sure if mine is where its supposed to be or too high but here's what I got...

70 350 stock bore

4 core radiator with dual electric fans, no trans cooler yet.

I run between 205* to 210*

[dloyd]

i have an 84 regal with a 455. i use a summit 31x19 2 core
aluminium rad with a 7 blade clutch fan and a 160 therm.
i use an external tranny cooler. it runs so cool i somtimes have trouble
getting it up to operating temp. hope this helps.

[Stage1 Jeff]

my 82 regal has a .030 over 430, TA Stage1 SE aluminum heads, SP1 intake
aluminum radiator, large electric fan (from '96 T bird) 180* T stat, painless #30103 electric fan control
185*on, 170*off

[87GN_70GS]

Do you have a high-flow thermostat or regular t-stat?

[Leviathan]

...all good info so far guys, keep it coming.

I only put in a 180* standard flow thermostat so that is on the suspect list.

I'm diagnosing it in this order:

1. Drive it around again at 50 MPH to rule out an airbubble. If I see high oil/water temps at this speed then there is not enough rad or flow through the rad.

2. Change the thermostat to a 160* high flow unit, repeat #1.

3. If we've still got a problem at speed - buy a new 28" summit aluminum rad. and repeat #1.

4. If no cooling issue shows up at speed then we move onto whether or not the fan is too low... I'll drive it in stop and go and see if it starts to creep up.

5. Change back to a mechanical fan, repeat steps 1 & 4.

[Vern]

I take it these are good factory salvage fans or quality aftermarket fans not cheap weak supplemental fans that they have in the partstores. Does your fans and shroud pretty much cover and seal the back of the radiator. Might be something else entirely blocked cooling passage timeing etc.

[Stage1 Jeff]

Do you have a high-flow thermostat or regular t-stat?

I have a high flow 180* T stat

[austingta]

The 455 is best cooled by, in this order,:


proper ignition timing
7 blade 18 inch stock metal blade fan
known good high quality thermostatic fan clutch
correct BBB shroud
aluminum radiator
known good stock water pump
either 160* or 180* t-stat
external trans cooler, bypassing radiator

http://i2.photobucket.com/albums/y30/austingta/1970%20Wildcat%20Convertible/DSCN3001.jpg

[Leviathan]

Timing was dialed in at the dyno, no problems there :TU:

The fan is an electric 15" 9 bladed unit from Cadillac Norstar v-8. It is very well sealed to the rad - better than the mechanical fan shroud in fact. I can run the electric fan with the engine off and feel it suck air in through the front grille.

...however...

Even if the fan was crap, at 50-60 MPH the system should run around 180-200* with a 180* thermostat. Until i get the at-speed resolved, the fan is off the table.

[v8regalowner]

my regal has the stock 307 radiator and shroud, a flex fan, external tranny cooler, 160 regular tstat. motor is 71 455, stage 1 heads, 290-08h cam, sp1, stock water pump. sitting at idle its right at 185-190 deg

[Buick]

Normally 180-190 for mine. 160 stat, F-Body radiator (Autozone $109 out the door), single GN/fiero fan, no shroud or air deflector under car. After a romp and then sitting in traffic at BG it got as high as 212; I switched on my aux pusher fan in that case. Combo is same as below, but with Edelbrock heads now.

Ditch the 4 row.

That Fbody rad looks way to small to do any good, but it actually works. I bet with your fan set-up, and being in Canada, it'd be a perfect solution.

[Leviathan]

Ramin that setup is pretty close to mine so maybe I'm not too far out. I suspect the 180* thermostat at this stage. The 3 pass 4-core needs a high flow rate and I tend to think that the thermostat is not fully open until 190-195. It neatly explains the high-speed problems (I have an air deflector). It looks like I'll have some time to tackle this on Saturday - I'll be sure to post the results.

[Stage1 Jeff]

I tried My electric fan thermostat yesterday, it came on at 185*,and went off at 170*,as it was supposed to. I have a 180*stat also, I'm very happy with my setup

[Buick]

My therostatic fan comes on, but never goes off.

I might just try a cut-up thermostat to use as a restrictor orfice and see how that works. I'd love for the temps to be closer to 160 for drag racing.

[Leviathan]

Well, some results just not good ones...

-Eliminated all air bubbles - no change.
-I tried it without a thermostat (can't get a 160 high flow just now) - no change.
-Something nobody mentioned yet, but I changed to a larger drive pulley and smaller waterpump pulley. I have not tested it at speed but it did not help the idle condition.

...it goes like this:

Water temp goes to 190 then drops to 180 (thermostat opening)
Holds at 180 until...
Oil temps come up to 180...
Water temp starts to build to 200
Oil Temps follow 5-10 degrees behind water temp.
Shutdown at 210-220 water temp.

...next up: the pulley tested at speed, back to the mechanical fan :( and changing out to a remote transmission cooler...

Anybody think i should try the oil cooler?

[87GN_70GS]

I would try this first, it's quick and cheap. Take the guts (spring, copper pellet, supports, etc.) out of a standard thermostat and use that. It will act as a restricter.

I'm not hopeful that this will work, but it's so easy that it's worth a try. If you had a single-pass core I would guess that it's possible for you to have too much flow. But a 3-pass acts like a restriction anyway, so it might be that it's already too restrictive and that you need more pump flow.

Other thought:
Does your water pump have the cast impeller or stamped (like the fins on an alternator)? Do you recall how many fins on the impeller and how far did they extend towards the outer edge?

[Leviathan]

Interesting idea Scott, I was thinking the same thing about the 3 pass. It actually looks to be flowing kind of slow with the rad cap off. (didn't check this after the pulley swap though).

I ran it initially with no thermostat and it was overheating so i tend to discount that. I picked up a high flow 160* and a bottle of water wetter yesterday. I'll try them one at a time and see what happens.

Water pump is one of those brand new units. I don't recall the exact number of blades but it was less than the full-blown impellers I've seen pics of.

[87GN_70GS]

From stewart components site:

"Double pass radiators require 16x more pressure to flow the same volume of coolant through them, as compared to a single pass radiator. Triple pass radiators require 64x more pressure to maintain the same volume. Automotive water pumps are a centrifugal design, not positive displacement, so with a double pass radiator, the pressure is doubled and flow is reduced by approximately 33%. Modern radiator designs, using wide/thin cross sections tubes, seldom benefit from multiple pass configurations. The decrease in flow caused by multiple passes offsets any benefits of a high-flow water pump."

[Leviathan]

Glad you posted that Scott... this is a rant I've been wanting to do for a while, hope this get5s some fuel on the fire...

Full article can be found here:

http://www.stewartcomponents.com/tech_tips/Tech_Tips_5.htm

I read that before I bought this rad :TU: their analysis has got a number of problems.

First, pressure losses (or head losses) for turbulent flow in pipes is proportional to the length of the pipe, not the square of the length. Check out the Darcy-Weisbach Equation for this. The length increase is added, not geometrically multiplied. Making 2 or 3 passes is NOT a geometric loss as they postulate. That 16X 64X is pure fiction.

Don't take my word for it:
http://www.pipeflowcalculations.com/pressuredrop/index.htm using calculator number one, enter an L (length) value of 1000 and you get a pressure drop of 548.35. Now increase the length by a factor of 3 for the triple pass and you get 1324.83...looks linear to me!!!

Second, their reduction in flow rate is meaningless unless you calculate out the COOLING capacity. If you work this out in detail for an actual fin-tube cross flow heat exchanger (facy terms for a radiator) you find that tripling the distance of the cross flow rad amounts to a pressure loss of about 35%, but more importantly a cooling capacity increase of about 28%!!! This translates to about a 10% reduction in outlet -vs- inlet temps assuming you run at 180-200* Who cares about the flow losses if the cooling is increased??

Third, (and if Ken is reading this post he'll agree) arguing the theory is pointless in a complex car situation. You have to do tests and see what works. The test should back up the theory if the theory is correct...

These guys tested it: http://www.usradiator.com/testing.htm

...and found a 15% reduction in outlet temp:

http://www.usradiator.com/options.htm

...just what the correct theory predicted.

OK. How about a home test. If you have a heat gun, shoot the rad at the top of the inlet tank and the bottom of the inlet tank. If the temp drops then you can prove that the tank is not circulating the coolant through all the tubes evenly. I tried this with a typical rad on my 1978 Century and found a difference.

So far I can't fault the radiator. It might be what is wrong due to losses at the critical airflow/coolant flow point. It may be junk, but nobody has proven that to me yet.

...any thoughts?

[Leviathan]

Stupid cooling systems.

Tried each of these one at a time and failed:

-Increased drive pulley size, decreased water pump pulley size.
-160* high flow thermostat + water wetter.
-Added baffles, air dams and plugged up everything around the rad.
-Removed Vacuum advance

...it's still building heat at 210* water temp and 220* Oil temp running at about 50 MPH (80kph)

Next up, delete the electric fans and if that fails I'm throwing out the triple pass radiator.

The only good news is that it does a darn nice burnout...:3gears:

[Leviathan]

...maybe I missed something.... anyone see the problem?

[Leviathan]

Some success... it cools at speed now. Water temp holds at 160-180, oil temps hold at 220-225.

IChanged to a mechanical fan - no joy, but another backyard guy suggested I look for air bubbles - the only thing that makes sense. Reburped the car by jacking it up tot he point that the rear bumper was nearly on the ground and then "blurp"... "glug". ran fine at speed after that.

However... the idle temps climb steadily, shut down at 230 water, 220 oil. Even with the mech fan on there - no clutch. The should never seals as well with a mech fan, hoping that's all it is. I've gotten hold of twin merc fans that pull 25 amps (old fan pulled 5 amps) and it seems to have more air than the mech. Going to try an even smaller water pump pulley and these fans next.

[bigdawg70]

Im not sure but i havent seen it posted what the set up of your motor this may be a determining factor. How much compression? What kind of gas you running? Did you try drilling a 2 or 3 small holes in thermostat so to allow small flow at all times? Compression could be a possible determining factor i have a 11:1 motor that is real touchy wit gas it will only run cool on quality grade 93. What octane fuel ers you running? Have you tried switching fuels? Also from that pic you posted that fan may not put out enough cfm4 you motor. How old is the radiator? Did you try flushing the radiator? Heres a simple yet overlookd prob do you have a good temp guage? sum guages go bad also where are you reading temp from out of the head front or back of intake all the spots may read diff. It sounds like your finding isues just thought these might be sum more for you think on.

[Leviathan]

...all good ideas, keep em coming...

Compression is 10.25-1 at 4300' altitude. ...engine ran at 180* on the dyno.

Hmmm, I have not checked the fuel but it's running on 93 octane with no pinging

Thermostat is a Mr Gasket 160 high flow with a single bypass hole.

There are 2 temp gauges (oil and water) both calibrated using a thermocouple.

The fan was definitely too small for this engine. I replaced it with a mechanical (1/3 out of shroud) this weekend just to be safe. Now that it is cooling at speed (found a stubborn air bubble) I can focus on the idle. Event he mechanical could not do the trick. Upping to 2800 CFM twin fans this weekend if all goes to plan...

[Vern]

Strong twin electrics generally due better than clutch fans at idle. Timeing often seems to be a factor with cooling problems. I did not have much luck with water wetter but on an older semi clogged up system RMI-25 worked wonders. I have been useing it on all my stuff for 5 years. A truely clean to the metal system transfers a lot more heat and makes your system as efficient as it can be. They have an excellent informative site.

[Stage1 Jeff]

I tested the fan thermostat I put in my car. it came on @ 185*,and went down to 170* worked flawlessly

[Leviathan]

...another week, another test.

I tried a set of twin electrics from a 94 mercury that pulled more than the lousy mechanical fan and had a nicer shroud.

Good news - temps finally hold at idle
Bad news - they hold at 225* Water, 240 oil* :af:

...onto the transmission cooler upgrade.

Maybe I should just carry a bucket of water around with me?

[Stage1 Jeff]

heck, 14k would talk Me out of My car

[Leviathan]

heck, 14k would talk Me out of My car

Sweet! Couple conditions though so that it matches the Wagon. I'll need you to drive it to Inuvik and Rio Gallergos. Also, weld on a Wagon tail end and arrange for me to live in the car while attending a university for a couple months. I'll also need to test drive the car across Canada at least a dozen times.

...let me know and I'll get a check cut :TU:

I honestly think it would be easier to crush the stupid thing and make it a coffee table. :blast:

your setup is not far off of mine though....are you running an external trans cooler? Which AL rad... 26" or 28"?

[alec296]

where do you have your fans get power from,
i suggest off alternater post with a relay to turn them on
maybe your not getting enuff electricity to them
alum radiators help.is your radiator old? it might be plugged
check your hoses when hot to see if they are collapsing .
is your andtifreeze a premix or are you adding water, you might have to much
ratio of antifreeze .
what size over bore on pistons? if 50 or 60 over it could be a problem

[bigdawg70]

another problem could be carb to small or not tuned right. Forget all that it was tuned on a dyno stuff real world is that a car doesnt have tha air to move around and a dyno isnt ran for a hour or two

[Leviathan]

...nuther weekend, nuther failure.

Just tried it with the hood off. No difference in building temps or final shutdown temp.

Good suggestions guys...

Fan power is alternator fed with a 50A keyed power relay fan controller.
Fans are drawing 24-28A (factory rating)
Rad is a brand new 4 core 26" triple pass unit.
Hoses inspected visually at speed with a mirror. All fine. Reved to 4k in the shop, all fine.
60% water with 1 bottle of water wetter.
38 overbore.

...carb is an 800CFM quadrajet jetted way rich. I suppose it is possible that the carb or aircleaner are acting as a restriction...but that would cause it to run rich, not lean.

How rich does it need to be before it runs hot?

I think the radiator is now the top suspect. Although its brand new it's the only thing I cannot rule out...

Running out of ideas....wow this is starting to get depressing...

[Buick]

Hi Clint.

What stayed the same with this rebuild as the last one? I remember a while back you had some rod bearings that looked like they had been over heated. I'm just wondering if any problem you have now is somehow related to your problem last year? I'm grasping at straws here.

I agree, try the rad next.

Could your gauge or sender be inaccurate?

I wish I could help more buddy.

Ramin

[Leviathan]

Ramin (and everyone) the advice here helps a ton! Thanks!

You know, I am racking my brain over that exact issue "did i somehow cause all this mess with the installation". I've fried 2 engines in the last 2 years, and I'm the only common thread. The first engine came from a poor shop, the machining was analyzed by 2 separate shops and proved to be crap. The second engine was a stock 1970 I bought dirt cheap that had a rod knock on day 1.

...but maybe I am causing this somehow... :idea2:

The same

-Transmission. Switch Pitch 400...but it does have a new torque converter.
-Headers & exhaust - 2.5" mandrel all the way with x pipe
-Engine bay, rad support, and front cowling are all the same.
-Same distrib, but the builder recurved it
-Gauges... oil and water temp gauges
-Carb - increased the jets, otherwise the same.

Changed this time

-Engine, reputable builder, dynod, rechecked bearings, and dynod again.
-Water pump gasket was bad, had to change it before install. Flows fine...
-Rad - new 4 core triple pass unit.
-1/2" fuel lines
-Added a fuel pressure regulator + return line
-New rear end
-Increased fan capacity.

OK... so here's what's on the table for install troubles:

1. Fuel flow is buggered somehow (see pics). I built this system and tested it out, but could I be restricting flow somehow? I ruled it out before because if I close the choke at cold idle the sucker runs worse (a sure sign of running rich).

2. Vacuum leak someplace. Ruled this out by not hearing any whistling and I've been over the intake 3 or 4 times now.

3. Distributor. Timing set by the builder, but maybe I screwed up somehow? OK I know to take the vac advance off the intake port but I went from the carb anyways. The vac advance is working (it runs like crap at idle with it unplugged) and I tested it at speed with the vac advance off. No joy. Firing order is 18436572

4. Something I don't know or have not though of yet.

...pics of the whole install are attached, let play "what's wrong with this picture!" :laugh:

[Buick]

Use two vice grips to (1) pull the heater core out of the system to force all the coolant through the rad and (2) check the bypass the same way. Maybe the rad is restrictive enough that it's bypassing a lot of coolant back into the suction side of the water pump.

[Buick]

And check the timing yourself.

[Leviathan]

Ramin...good guess man! That got about 20 degrees. She held temperature steady at 200 water and 220 oil.

...that's the good news...

...the bad news is that I heard noise. Pulled the oil.... anyone want to buy a few litres of metallic colored oil? :(

[Buick]

That stinks man. What kind of noise (besides bad)?

[455regal]

Hi!
I'm using a 31x19 aluminum "Howe" rad ,and a oil cooler from a nascar team. Its pretty big! Those guys are great part sources they use stuff once and get rid of it! I never have gone over 185 and it takes about 20 minutes to get the oil temp up to 180 mind you my system uses 12 quarts! I modified the oil pan for more volume.( 8 quarts) Someone at the stock car track was nice enough to throw a rod at the front of a chev canton oil pan so I cut off the sump and grafted it to the buick pan. I figure I'll change the oil once a year whether it needs it or not!
I wonder if your problem is the electric fans? I'm using a 19" flexilite fan and the stock 307 shroud.
hope that helps?
Brad