sbc cooling issues (1 Viewer)

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cruiserlad

cruiserlad

Joined
Oct 14, 2004
Threads
23
Messages
84
Location
Meridian, ID
I'm running a sbc 383 with a Taurus fan. I know, I know, it was an iffy proposition in the first place. Particularly since I'm running an original radiator. Any recomendations on a different radiator. Changing to a mechanical fan is out of the question due to clearance problems.

Here's a pic of my rig moving under it's own power for the first time in 15 years.
first drive.jpg
 
How /when does it over heat? What does your shroud look like?
 
It's a Taurus fan mounted on the stock radiator. Taurus has it's own shroud. The electric fan will keep it at 202 degrees, but runs all the time which sucks down the battery even with the engine running. At 45 mph on the road the fan still runs. I've got a Dakota Digital controller controlling the two speed fan. I've set the low speed to come on at 205 and shut off at 200. The high speed comes on at 215 and shuts off at 207. I've got a 192 degree thermostat. I'm thinking that the radiator just can't keep up. I can get it to stay at 190 degrees if I play around with the fan operating temps, but this is just at idle. Any suggestions?
Cooling left.JPG
Cooling right.jpg
 
My 350 was overheating also.
Changed the thermostat(195) and took the rad out and flushed it out at both ends.Saw alot of crud blocking the tubes when I took the rad cap off to drain the coolant for the Tstat replacement.
Made a big difference.

I also added some fiberglass blankets to my header primary pipes.HUGE-mongo difference in underhood heat.I didn't use the tape wrap but rather used the cut-to-size wrap from Summit and loosely covered each pipe coming off the head so they could breathe a bit.
 
Do you happen to have an underdrive pulley on your V8? That could be a factor if that is the case. You know if you're running a bit lean at all?
The shroud looks fine and I'm sure you checked to see if the fan was pulling the right direction. If you haven't flushed the block and radiator properly, I would do so ASAP with a new T-stat, rad cap, and 3-4 bottles of redline water wetter. If that doesn't work, a bigger radiator, smaller water pump pulley, and maybe even a new water pump would be the answer.
 
flush that rad , possibly get it turned into a 4 core .

my 350 with a taurus fan has the opposite problem , i have the fan set to low and it overcools . doesn't even come on at highway speeds .
 
Get a oversized aluminum radiator is the start of the short answer. At any speed over 25 my fan never kicks on. If you stay electric get a high output low RPM alternator that can keep up with the fan and all the electrical doodads. Buy a good one and hopefully buy it once.

Here is how mine is going/gone.
SBC-warm 383-ramshorns- single exhaust down drivers side - tube fenders with no "liners"-high volume water pump - high flow 180* thermostat

With a generic aluminum 2-1"core radiator 19x26 (AFCO $200) and a MKVIII fan and the 180* thermostat the fan will keep the temp on the thermostat (if you set it to come on at 180) in the Florida heat. I have a couple small holes drilled into the thermostat to allow a little flow at all times and the fan will actually cool the motor below the thermostat if the fan is turned on manually and left on. It is quite a draw on the electrical system though. With the headlights off the alternator can keep up at idle, but with other electrical stuff on it slowly loses ground. I had a "no-name" high output alternator but it died, switched to Autozone lifetime warranty one and it did better. I have still went through a few of those though. Everything is grounded with #2 cables from the alternator, to the block, to the batteries, to the frame. I may try a mean green but I'm going to experiment with a 7 blade flex, 7 blade fixed with clutch and see how much volume they will each pull through the radiator compared to the MKVIII first.

Even with the MKVIII my underhood temperatures are too warm for my taste, I may try the blankets mentioned above to help with that. I put a small mechanical fan along with the electric to help move a little air even if the electric wasn't on and it helped a little, but not quite enough.
 
Shouldn't have put on that sq bezel. Looking good. Have to meet-up for breakfast end of Oct.
 
Things I've done.

Thanks all, I'm running rams horn manifolds so wrapping them is not an option. I'll look around for an undersized pulley for the water pump. That may be a problem as I'll need a three belt. I bought a 180 degree thermostat yesterday and I'll try to install today. I was looking at radiators on Summit and one of the details of an aluminum said to use an 18 to 22 lb. radiator cap. Hmmm. I've watched my rad blow coolant into the recovery tank and literally over fill and blow it on the floor. So I may need a bigger tank as well.

Plowboy, ready for breakfast anytime, let's go wheel'n! :D
 
I forgot to mention that the radiator is brand new as is the engine. No blockages!. As far as running too lean, well, yes for now. I'm in the process of tunning my TBI with a MegaSquirt controller. Whew! Man, have a learned a few things. Thanks again for all the help.
 
cruiserlad said:
Thanks all, I'm running rams horn manifolds so wrapping them is not an option. I'll look around for an undersized pulley for the water pump. That may be a problem as I'll need a three belt. I bought a 180 degree thermostat yesterday and I'll try to install today. I was looking at radiators on Summit and one of the details of an aluminum said to use an 18 to 22 lb. radiator cap. Hmmm. I've watched my rad blow coolant into the recovery tank and literally over fill and blow it on the floor. So I may need a bigger tank as well.

Plowboy, ready for breakfast anytime, let's go wheel'n! :D
Click to expand...


For a street application you will want to stay on the low side of that 18-22 psi range, probably lower. I am running a 17psi with my radiator and it works perfectly with a fj60 overflow tank.

rad
Griffin Thermal Products 1-85222-T - Griffin Aluminum Circle Track Radiators - Overview - SummitRacing.com

cap
Griffin Thermal Products KM84 - Griffin Radiator Caps - Overview - SummitRacing.com
 
X2 it is not the taurus fan that is your cooling problem. I run a SBC stroked 406. 400 SBC are worse for overheating than the 350's ever were. I have the Taurus fan but with the Delta Controller. I olny have the high speed side of my fan connected. The Delta slowly ramps up the fan speed as needed. I use to have problems with over cooling. I do have a HD Chevy oversized radiator that I had recored from the PO. I have tired to find what it came out of but Advance or Autozone can't figure it out. I wanted to know so if I had to replace it would be an easy swap. Now my fan olny comes on when I am sitting in traffic or when I run 75 to 80 on the interstate. This is due to the Factory 3 speed tranny. NV 4500 swap sometime in the future. I have been lucky to never have a cooling issue. Also x2 Redline Water wetter it is an excellent product. I have a friend that swears by it in his strip car.

cruiserlad said:
I'm running a sbc 383 with a Taurus fan. I know, I know, it was an iffy proposition in the first place. Particularly since I'm running an original radiator. Any recomendations on a different radiator. Changing to a mechanical fan is out of the question due to clearance problems.

Here's a pic of my rig moving under it's own power for the first time in 15 years.
Click to expand...
 
73fj40lc said:
X2 it is not the taurus fan that is your cooling problem. I run a SBC stroked 406. 400 SBC are worse for overheating than the 350's ever were. I have the Taurus fan but with the Delta Controller. I olny have the high speed side of my fan connected. The Delta slowly ramps up the fan speed as needed. I use to have problems with over cooling. I do have a HD Chevy oversized radiator that I had recored from the PO. I have tired to find what it came out of but Advance or Autozone can't figure it out. I wanted to know so if I had to replace it would be an easy swap. Now my fan olny comes on when I am sitting in traffic or when I run 75 to 80 on the interstate. This is due to the Factory 3 speed tranny. NV 4500 swap sometime in the future. I have been lucky to never have a cooling issue. Also x2 Redline Water wetter it is an excellent product. I have a friend that swears by it in his strip car.
Click to expand...


I am running the FK-50P delta fan controller and really like it so far. Do you have the led status indicator? I do and it lights up green when the fan is not running, just trying to confirms the way it should light up:
green = fan off?
yellow = 10% to 49% speed?
red = 50% to 100% speed?
Not sure if this is correct or not. I am running a 180 t stat and the fan controller says it is adjusted for a 180 t stat so I haven't adjusted it yet.
 
More about my rig.

The engine is a sbc 383, four bolt main. It's mated to a NV4500. I'm running a 3 sp xfer case. The rear is a Toyota Elocker from an FJ80. I've got 4.88 gears front and rear. It is spring over with BFG MTs 35s on 15" rims. Got about 6 degrees caster on the cut and turn. It tracks straight and true. I've just ordered a set of Rancho 9000s which should complete the package.

Now if I could just solve the cooling problem. I'm not using a high performance cam, just an RV cam. I do have heads from a 92 350 which my engine builder says has a better swirl pattern than earlier ones. By all that I have read on this forum the rad and fan combo should have worked. I'm going the cheap way first. Radiator cap of about 18# and a thermostat of 180 degrees. I will re-tune the fan controller and maybe take the 2 speed out and just run with the high. The Dakota Digital controller doesn't have LEDs, but a display that can tell you the temp and other settings. It is working right.

Thanks again for the advice and sources. I'll let you know what happens!
 
Have you played around with your timing? Over on the Hotrodder's Bulletin Board (Hotrodders Bulletin Board - Engine) the CW is that 80% of SBC cooling issues are timing related, especially if you have anything other than a stock cam. Over-retarded timing increases heat buildup. An engine like yours can take quite a bit of base timing, maybe up to 22* or so.
 
I'm running a mild 350 with the stock radiator and an 18" Flex-A-Lite metal fan, without a shroud. No cooling problems.

Since you have a new radiator, and the cooling fan setup you have has been proven to work for others, I suggest looking elsewhere for your problem before altering the existing cooling system.

One thing that can lead to overheating is having the ignition timing too far advanced. Often this results in pinging, but not always, thus the absence of pinging is not a reliable indicator of the timing being too advanced. Make sure your timing is set properly.

Overheating can also be caused by the fuel mixture going way too lean under cruise conditions.

Timing explained: http://www.type2.com/library/electrip/timex.htm
 
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