Big Block Dart Cooling

Big Block A body Tech

  1. dart4forte

    dart4forte FABO Gold Member FABO Gold Member

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    Took the Dart out this afternoon. Drove about 40 minutes on the freeway to the Pavillions in Scottsdale, AZ. Temp gauge got up to 210 by the time I got there. Guess it's time to address the cooling issues. outside temp when I left was 90 degrees. Been windy the last two days and today I had a slight headwind. Drove the car no faster than 60 MPH.

    1968 Dart GTS
    383/TF
    Carter 625 w/the metering rods stepped up two sizes
    Electronic ignition
    Timing at 36-38 total degrees
    Motor is .040 over
    Stock two core Rad (2898033)
    Stock fixed fan
    Stock Fan Shroud
    440 Source water pump
    3.91s (but will soon update with 3.55s
    Stock Big Block A body pullys
    Running 50/50 coolant

    Open to constructive suggestions
     
    Last edited: May 23, 2016
  2. Jlcaptain24

    Jlcaptain24 Well-Known Member

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    -Do you have a 440 source water pump HOUSING?? Heard some casting are restrictive.
    -If it's cooling in stop/go okay, I wouldn't mess with fan/shroud. Maybe radiator is too small?
     
  3. AJ/FormS

    AJ/FormS 68 B'cuda fb, Form S clone ... 367/A833/3.55s

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    If your temp is climbing at speed, You have at least one of three issues; 1) the rad cannot get rid of the heat fast enough, and 2) your engine is generating more heat than the rad knows what to do with, and 3) the coolant itself is unable to affect the heat transfer to the rad material, and from thence to the airflo.
    As to #1) make sure that all of the rad's surface is exposed to the incoming airflo.Or at least as much as possible.Also force that 60mph wind to all go thru the rad, and not around. Also make sure it can pass freely through the rad and over the fins, and out the otherside to exit the underhood area.If you have an auto with a hi-stall, you need an auxilliary cooler, to take the load off the main rad.Make sure the rad is physically big enough. A 26 incher works for me, at over 400hp. I wouldn't think of a 22
    As to #2) The 3.91s are cranking up the Rs which is putting a lot of heat into the system. When the 3.55s go in, there will be about a 10% reduction in heat due to internal friction.
    Then since there will be only 90% as many explosions per mile, that adds up to another 10 % less fuel being burned in the chambers, which adds up to that much additional heat not being generated, in the first place.
    As to #3) Water is a far superior coolant than antifreeze.Since your cooling system is very nearly adequate now, I would simply switch to 100% water (with an additive pkg), at least until the 3.55s go in.After the 3.55s are in you can re-access the situation.

    Additionally;
    You say you are running a fixed fan.But make no mention of the type or number of blades.
    If you also have issues from idle to about 30 mph, then,IMO, you might benefit from a large diameter,all-steel,7-blade,OEM type fan, mounted on a Thermostatic clutch, and situated correctly in the shroud. This set-up moves tons of air. This will eliminate heat issues below about 30mph.As soon as air-speed comes up from the car moving through it,and the exit temp falls, the fan will begin to slip, and eventually freewheel.Whatever you choose I highly recommend to stay away from small diameter fans with flexible riveted-on blades.
    Once you get your heat issues under control, I have found that the hotter the engine runs, the more everything you get. More power,more mpg,more torque,longer cylinder wall life. I stopped at a minimum engine temp of 205*. That leaves a little wiggle room, for emergency situations.I don't know where the benifits stop. My little 367 has over 100,000 miles, and still does not smoke, and seems to make full power. Course this is now more than 10 years since I last opened it up.
     
    Last edited: May 22, 2016
  4. 383Scampman

    383Scampman Well-Known Member

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    Do the easy stuff first. Back timing down 2* at a time and see if it helps. If that doesn't work try a clutch fan. Be aware that crank driven fans don't function above 35-40 mph. Next, pull a spark plug or two to see if engine is lean. Could need to flush cooling system. Maybe the rad is not up to the task. Lastly, I would purchase a direct reading temp gauge. Moon equipment sells them through " Speedway", liquid filled, $35.00 mount on the water pump housing to see what's happening at the outlet. This happens all the time with A-bodies BB. Stick with it, you can solve this. Good luck, Tom
     
  5. dart4forte

    dart4forte FABO Gold Member FABO Gold Member

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    I've heard the same thing on the housing. I'll be tearing down the motor's front end this summer so that may have to go in favor of another housing. A Flowcool pump will replace the 440 Source unit.

    I also have a clutch fan with a multi blade fan. While the rad is out I'll take it in for a rodding and a good boil.
    ding and a good boil. It's the original numbers matching rad so I need to take care of it.

    The hard water down here is really hard on cooling systems. I may try using distilled water only with a good additive. Doesn't get cold here to warrant a heavy use of antifreeze.
     
  6. Bad Sport

    Bad Sport HALF A BUBBLE OFF Staff Member FABO Gold Member

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    210* IMO, isn't 'hot', but it doesn't leave any room for error.

    You didn't mention what stat you have in it.

    Maybe adding some water wetter will help.
     
  7. dart4forte

    dart4forte FABO Gold Member FABO Gold Member

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    Good call, forgot to add that I have a 160 stat in the car right now. Need to change that out for a good 180
     
  8. AJ/FormS

    AJ/FormS 68 B'cuda fb, Form S clone ... 367/A833/3.55s

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    Actually, for cool-cruising, the engine wants mega-timing.I hope you have a functioning vacuum advance. I have seen good results with cruise timing well over 40 degrees. Sometimes over 50*(but not at your rpm).

    How much will yours like?
    Well heres a cheap test.
    Hook up your Vcan to a long hose that you can suck on from the driver's seat.Tee a vacuum gauge into it where you can see it.Find a clamp that will pinch the line off and maintain the vacuum.
    On your next trip, run the car up to speed and lock the pedal there.Then apply full vacuum to the can. Run it like that for several miles and record the exact vehicle speed. Then dump the vacuum, and repeat with Zero vacuum. Record the exact vehicle speed.Record the difference.And whether the no-vacuum speed was higher or lower than the full-vacuum speed. Repeat with as many different vacuum settings as you care to,to find the maximum speed obtained.
    Of course terrain,slope,load,and wind, will all need to be minimized or standardized,so as not to skew the results. Here in MB, we don't have terrain and slope problems.And I have no rear seat,and the car is always empty during testing.
    If the best results were obtained with the most vacuum applied,then stop, crank 10 more degrees into the dizzy and repeat the testing. Continue this way until the speed begins to fall from too much advance. There will be a plateau of around six degrees where the speed variance will not be perceived, cuz the speed-o just can't read that finely. So your cruise timing at whatever cruise speed you choose, needs to be on that plateau. Pull over. Put the light on it. Crank the rpm up to whatever Rs you were cruising at, and pull the vaccuum up to whatever achieved the plateau. Read the timing. Return to idle, and exit the vacuum.Return the timing to the pre-trip amount.
    That timing number you saw, is what the engine wants at that particular rpm and mph; and no other.
    Then you can repeat the tests at other rpms and mphs to see what it wants at those. Eventually you will have several data points, and then you can graph them. From the graph, you can extrapolate other points.
    Then you can mod your dizzy or Vcan, or both, to try and hit the targets.
    OK, so thats the hard way.
    If you really wanna know, I bought a dial back timing device,adjustable from the driver's seat, and with a 15 degree capability.I mapped my mechanical advance to a graph, and same with the Vcan. I installed a permanent vacuum gauge in the cab. So from the cab I know exactly how much the timing the engine is working with at all times, just by cross-referencing the chart.I then installed the DB device in it's midrange, so that I can add about 10 degrees advance or subtract about 5.
    Then instead of having to suck and clamp a hose,Plus time and re-time my dizzy, I just twiddle the dial. I also installed a 2-step return spring on my throttle arm, so I can always cruise at whatever speed I have it set to.
    FWIW, my 367 at 2100, likes nearly 50 degrees. This is 16 initial, 9 in the dizzy at 2100 and 24 in the can.This is on the plateau. Here she runs cool and gets the best mileage.Occasionally I still twiddle the dial, but it usually comes back to the initial setting which I have indexed on the dial.
    Yes I have O/D.
    Your results,of course,will vary.
     
    Last edited: May 22, 2016
  9. hangn0ut

    hangn0ut Well-Known Member

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    When you say the rods were stepped up you do mean rods thinner by two sizes or steps?
     
  10. dart4forte

    dart4forte FABO Gold Member FABO Gold Member

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    Stepped up meaning two steps richer. The next step would be to change the jets and the rod
     
  11. dart4forte

    dart4forte FABO Gold Member FABO Gold Member

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    As far as running lean it is not. Pulled some plugs today. They are all medium brown in color, not wet. Also, the exhaust tips are medium brown as well. So, I think I'm on the mark in terms of air/fuel. The next step will be the timing. I have a Fire Core Plug N Play and the appropriate coil. Problm I have is I think I punctured the rubber diaphram while I was adjusting the vacuum advance. Not matter what I do in terms of adjustment it surges at light throttle. I unplug the vacuum advance and the surging goes away. I also need to change that T state to 180 as well.

    As far as the water pump housing is there a housing on the market that doesn't have flow issues? I did order a Flowcooler pump today. I'll put that on when I change the t state and go with pure distilled water and an additive such as Wetter Water


    All these changes will be done one step at a time so I can keep track as to what and doesn't work.
     
  12. perfacar

    perfacar Well-Known Member

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    if it surges at light throttle, either it's lean or too much timing!!!!. metering rods with smaller middle diameters might help that? why do you want to install higher t-stat?
     
  13. AJ/FormS

    AJ/FormS 68 B'cuda fb, Form S clone ... 367/A833/3.55s

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    You cannot damage the Vcan thru the nipple.
    I would Skip the water wetter. It is very expensive, and I doubt you need more than straight water.
    For the amount of time that the water is gonna be in the system,
    personally,I would skip the distilled water too. If you can drink it, I would dump it in there. It'll be out in a few weeks; when you get the 7-blade all-steel oem-type giant fan on there, with the thermostatic clutch.lol Then you can go back to an antifreeze mix.

    You say you have power-timing of 36 to 38. But you don't say when it's all in by. If it's in early and the Vcan adds it's load early, Then it could all be in too early, and surging is the result. So then you disconnect the Vcan, and then it's all retarded for every circumstance except WOT.Retarded timing consumes more gas than necessary, and that makes more heat than necessary.
    If it surges as you describe, you have too much low speed timing. In your case, I would probably back off the initial and put the Vcan back on to the sparkport. Unless you currently have it hooked direct to manifold vacuum, then I would swap it to the sparkport first, and see how that goes.
    You also don't mention your cam specs, or your compression ratio, or your cylinder pressure;and that is important in determining idle timing.
    I'll go out on a limb and and say ALL your timings are just plain too early, and some are too much.
    I see you are a one-change-atta-time kindof guy.
    And if I were you; I would map out the timings and see where I'm at.Then I would start making changes. One atta time. Well no, I would skip ahead a bit first. I would set the initial timing to 16/18 at idle speed. I would ensure the T-port sync is correct.I would limit the power-timing to 36* for now. I would slow it down so that it is not-all-in until around 3600.I would hook the Vcan back up...to the sparkport. I would measure what it is capable of. I would unwind it's adjustment to allow it to work as soon and quickly as possible.Now I would map the timings out.From the maps I could see how much timing the chambers are seeing for every driving circumstance. Next, I would roadtest it to see where and when changes need to be made.That's my plan.
    I don't know if you are one of those guys who subscribes to the more timing the better rule, but if you are, I gotta tell you, those days are gone. With pump gas, a street car needs pretty accurate timings. That engine is being asked to run and perform under a myriad of different conditions and circumstances, and so it needs a careful choreography of the timings.To that end, it is advisable to sneak up on all the timings. Save perhaps the WOT timing from somewhere in the mid 3000 range to shift rpm, cuz that is more or less written in stone.
    More timing is not always better anymore, and in fact, 3 or 4 degrees less than optimum is very often better than just one degree too much. So my very best advice is to start conservative, and sneak up on the optimum. The graphing of your curves will help make that as painless a process as possible, if you start with a conservative tune.
    IMHO,The low-speed timings for a street car with a conservative TC,are far, far, more important than wringing the last 10 or 20 hp out of the engine at peak power.And if you change the stat midstream, you get to start all over.

    So the order of operations is;
    1) Bring the cooling system up to speed,whatever it takes;make sure it is up to the task.
    2) set the minimum engine temp with the stat.on the conservative side.
    3)ballpark the timing conservatively, for the fuel you will be using.
    4) ballpark the AFRs.
    5)Sneak in some timing and adjust the AFRs as may be required.
    6) repeat 5) as often as necessary;trying to hit as many targets as possible, making as few sacrifices as may be necessary.See note one below.
    7) try a lower grade fuel, and go back to 3) and start over.
    8) increase the minimum engine temp and go back to 1), and start over.

    note 1;
    For a streeter,the targets are; a)low-speed driveability from idle to about 3200rpm, b)idle quality, c)freedom from detonation as throttle is increased, d)fuel consumption, e)detonation-free power, f)and should be in the order listed.
    The sacrifices may be:idle quality,fuel consumption,and/or, cost of fuel.I would sacrifice ultimate power for driveability.
    Detonation and overheat is/are to avoided at all cost.

    All the best to you
     
    Last edited: May 23, 2016
  14. dart4forte

    dart4forte FABO Gold Member FABO Gold Member

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    Engine is basically stock. The CR is calculated to be at 9.1 CR. To be honest I haven't touched the timing since we set everything when the engine was first fired and broke in. Using a dial back timing light with the initial set at 14 degrees and the Firecore settings internally we have approximately 36 to 38 coming in at 1900. The vac advance is connected to the vacuum port on the carb. Timing is probably the first culprit I need to tackle.

    Down here in the SW the water is super hard. In fact it's almost corrosive to aluminum. That requires the use of distilled water if you want your aluminum water pump to survive. Right now it has good clean Washington State water 50/50 antifreeze.

    As far as Wetter Water goes it's a give or take in terms of using it.

    As far as the fan goes I'll have to take some measurements to insure it's compatible with my shroud.

    As far as fuel, I'm using pump premium. I'm finding that the fuel down here in Arizona is pretty good.
     
  15. dart4forte

    dart4forte FABO Gold Member FABO Gold Member

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    I should add that according to the Firecore timing curve chart the timing starts coming on at 1200 RPM and is totally in at 2800 RPM for a total of 25 degrees. This is with 2 silver springs. Adding initial I'm running at 39 total. This is without the vacuum advance hooked up. With the 3.91s I'm cruising around 3100 RPM at 60 mph. Maybe I should back the timing off 2 degrees on the initial and see what happens.
     
  16. mguner

    mguner How many is too many?

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    Definitely need more radiator and running a 195 T-stat is also a very good idea. Sounds funny but it really works.
     
  17. dart4forte

    dart4forte FABO Gold Member FABO Gold Member

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    Yeah, you are right on the T stat. Going to a larger rad is not an option. I don't want to make too many changes given that this car is stock. I'd like to keep modifications to a minimum.
     
  18. dart4forte

    dart4forte FABO Gold Member FABO Gold Member

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    What's going on in Armarillo? Did the members of that Mopar club kiss and make up? I'm still wanting to get more information on my Dart. I may call Jimmy Scharber later this summer. He's suppose to know a mechanic that worked at Hodgecoke back in the day.

    I'm also looking for a Hodgecoke Motors license plate frame.
     
  19. mguner

    mguner How many is too many?

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    Now it is called Mopar rollers of the High Plains or some such.... It is on Fakebook but I dropped that a couple of years ago.
     
  20. dart4forte

    dart4forte FABO Gold Member FABO Gold Member

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    Too bad, I was just getting more info on my car when they disbanded and dropped their site
     
  21. 1969383S

    1969383S FABO Gold Member FABO Gold Member

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    Your car should have the 033 radiator. That is a 3 core unit.

    I have a new 033 in my 69 cause the correct 065 are extremely hard to get. Run the stock 7 blade fixed fan and shroud with the correct spacer and pulleys. (All Stock)

    I had similar issues and put in the FlowCooler pump and high flow 185 Milodon t-stat. Got my timing all sorted and she will hold her temp cruising or idling. I am running an 800 AVS and have blocked the vacuum advance, 20 degrees initial and 35 total all in at 2500RPM. I run 50/50 mix.

    That was with 4.56 gears. Just went 3.55 and have not cruised much yet but intend to this weekend.
     
    Last edited: May 23, 2016
  22. yellow rose

    yellow rose Overnight Sensation FABO Gold Member

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    Take the Tstat out. It is just a restriction and its there to facilitate quicker warm ups and to make sure you have enough temp to run the heater.

    You need more flow. Make sure the water pump is turning at a MINIMUM of crank speed. If it's more than crank speed that is better.

    You could use more initial.
     
  23. dart4forte

    dart4forte FABO Gold Member FABO Gold Member

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    Actually the part number of my rad is 2898033 which is correct for a 1968 A body with the 383/440. My car is completely original with the numbers matching engine and transmission. I have the complete documentation for this car This is why I want to keep any modifications to a minimum.
     
  24. 1969383S

    1969383S FABO Gold Member FABO Gold Member

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    Sorry mistyped that, yes 033 which is a three core unit.
     
  25. dart4forte

    dart4forte FABO Gold Member FABO Gold Member

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    Looked at your pics. Looks like the makings of a real nice resto
     
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