BBC overheating

[Gimmie1965]

Ok I know a lot of you have put big blocks in these truck. What have you done to keep them cool??? I dropped in a 77 454 about 3 months ago and have fighting with since. I have a aluminium 4 core rad that I got off of Amazon. It's a oz cooling. It can with a shroud and electric fan. Did some researching and found out that fan was only 1700 cfm. Didn't cool at all. I've replaced it with a 3000 cfm fan and that helped alot. Still runs 230-240. I have put a serp setup from a 89 burn with a hiflow milodon water pump and hiflow 160 tstat. Dropped temps to around 220. I've ordered a zirgo ultra hiperformance 3600 cfm fan. Should be here next weekend. I've looked at several pics here on the forum of bbc trucks. Some look like they are still running stock rads. Is anyone running a us rad or have any info on them. Have been looking at their hiperformance and optima rads. They are very expensive but I'm sure they are worth every penny. Do I need to be looking harder in that direction. Any suggestions would be greatly appreciated.

[geezer#99]

Changing the rad likely won’t help.
Your shroud design seems to be blocking off a good portion of the air flow. The air tends to not want to turn corners. Creates dead air spots.
Maybe double fans will work better.

[Gimmie1965]

Thanks geezer#99. The shroud is what came with the rad. The only thing I did was replace the 1700 cfm fan with a 3000 cfm. Any suggestions on a different shroud. I have very limited space. The fan motor is about 1/4 in from water pump pully. Actually had to offset the fan a little to clear it

[b454rat]

I put a healthy 454 in a 79 Malibu I had. Used a 3 core aluminum radiator from a street stock. I used a Ford Taurus fan, no shroud other than what was on the fan, and cooled it effortlessly. At a stand still, I could turn the fan on and watch the temp go down. If moving almost at any speed, didn't need the fan, there was enough air moving thru the rad to cool it. 10-1 motor with iron heads.

[geezer#99]

Eliminate the shroud, keep the fan.
Get a couple lengths of flat iron and mount the fan to your existing bolts.
See if that helps.

[Gimmie1965]

I was just thinking that. When I first put the motor in I still had the original 3 core with a mechanical fan and no shroud was to scared to leave it that way lol. If I remove the shroud that will give me close to an in extra space. That would make me really happy

[Gimmie1965]

Ok got the shroud removed and fan reinstalled temporarily. Didn't account for the bolts for the on the new brackets so back to Lowe's lol. Test drive soon and I'll let you know what happens

[64shortbox]

That new fan will most likely be worse than your previous one. You're only pulling air air where the fan is mounted. The sides top and bottom of your radiator isn't getting any air flow at all at idle. The Mark VIII electric fans work Great on these trucks. Taurus fans too but I liked the Mark VIII fan better myself. I bought both during 1/2 days at Pick-N-Pull. I used a Volvo relay to trip the fan Here's a link about the Mark VIII fans: https://www.fordmuscle.com/archives/2006/10/Mark8Fan/

As a side note - do you have a radiator overflow tank? Check out the Mercury, ford explorers & F150 Pickups the radiator overflow/windshield washer combos are a perfect fit for our trucks. I also later added an aluminum radiator to my truck but went with a 2 core because each core was 1 1/4" across this gives More cooling surface area than a 4 core. Mine is only a small block but I set it up to tow a 28' travel trailer. The cooling worked great when towing BUT the the trailer was too much for a C-10

[Gimmie1965]

Ok finally got the fan recounted securely and went on a 20 mile drive. Temp ran 205 out and back. Went up 210 when I turned around. Went back down within a min of getting back on the highway. Went to 210 once I got back into and driving on the back streets at 35mph. The last trip I took it 220 on the highway and 230 in town. So this is a great improvement in my book. I'll keep working on it. Would like to see about another 10 degree drop on the highway.

[geezer#99]

Another heat maker is timing related.
Late timing to be exact.

What’s your initial timing set at?

[Gimmie1965]

I originally set it at 12. Was talking to a local guy and he told me I needed to set it at 16. I think it's still set at that. It starts right up and doesn't diesel when I shut it off

[geezer#99]

That sounds good.
Are you up for a crazy idea?
My 70 SS396 I had back 30 years ago tended to run a bit warm too. Around 210 on the highway. I read about mounting an air dam directly under the rad behind the bumper. I retrofitted (with a couple mods) a dam from a 75 nova. It hung down about 2 inches below the bumper if you looked from the front.
It worked great. Dropped my highway temp down 15 degrees.
The theory behind it is the dam creates a low pressure area behind it and the hot high pressure air from the engine compartment escapes more readily into that low pressure area.
Better air flow thru the rad is the result.
I’ve made them on other trucks from some strap iron and a length of plexiglass.
Just something to experiment with.

[Gimmie1965]

It's worth a try. I'm almost to the point of selling it. Setting it up to pull our 33ft 5th wheel. It pulls it just fine but I've only pulled it a couple of miles. Basically to go dump the tanks

[wcstory]

Make sure you radiator hose isn't collapsing on the intake side. Don't ask me how I know

[Paul Y]

I had a similar challenge with my BBC 56 Chevy.

Had a big B Cool rad, twin spalls fans and a shroud, panelled in the radiator so that all air coming in was ducted through the rad, bigger pulleys to make the water pump run slower to ensure thermal transfer to the water blah blah blah - still ran at 220.

Finally worked out that the hot air had no means of escaping as the headers and general Big Blockedness didn't allow for the required airflow.

Tested the theory by driving it with the hood off - trend setter as this was way before Roadkill - temperature dropped to 180 driving and 190 in traffic with both fans running.

Fixed it by louvering the inner wheel well panels and fitting a 2" cowl hood, open a the rear. The heat haze coming through the cowl was amazing and worked very well at stopping the windscreen misting up....


https://lh3.googleusercontent.com/KS...-no?authuser=0

https://lh3.googleusercontent.com/-G...-no?authuser=0


Plus try everything suggested, timing, running lean, etc. Nothing worse than a vehicle that overheats. Takes the pleasure right out of the drive.

P.

[vin63]

I run a dual 12" HO shrouded fan set up from Derale. I used to run dual 12" fans from Perma-Cool, but they couldn't keep up when I went with AC this time around. I set the Derale fans so that the blades are just to the inside of the shroud surface. I can run one fan on the freeway and it keeps my temps to 180-190. In town driving, both fans will keep things around 170-180 even with the AC running.

[Ziegelsteinfaust]

Originally Posted by geezer#99

That sounds good.
Are you up for a crazy idea?
My 70 SS396 I had back 30 years ago tended to run a bit warm too. Around 210 on the highway. I read about mounting an air dam directly under the rad behind the bumper. I retrofitted (with a couple mods) a dam from a 75 nova. It hung down about 2 inches below the bumper if you looked from the front.
It worked great. Dropped my highway temp down 15 degrees.
The theory behind it is the dam creates a low pressure area behind it and the hot high pressure air from the engine compartment escapes more readily into that low pressure area.
Better air flow thru the rad is the result.
I’ve made them on other trucks from some strap iron and a length of plexiglass.
Just something to experiment with.

I have done similar things, but my preference is to use a cowl induction hood with the back end open. Not sealed up against the carb. Also I have used a stylized Mopar Hemi scoop to good effect for a different look.

Either way you increase airflow through the radiator, and allowing removal of heat.

The first time I did it I was very skeptical it would work, and cut wood as long as my hinge. That tampered from a 1" to a point. Drilled holes, and mounted them between my hood+hinges. It made such a difference I got a proper hood.

[61K10]

some say a 160* thermostat won't let the coolant stay in the radiator long enough to cool. Try a 180* can't heart.

[sweetk30]

were is the temp sender ?

what kind of guage and brand ? mech or electric ?

baypass hose from water pump to intake below t-stat ?

water pump for serp belt use ? aka reverse rotation ?

stright water or 50/50 mix ?

make sure fans are puller if behind the rad .

let us know then we can go from there .

[nail pounder]

Originally Posted by Gimmie1965

Ok I know a lot of you have put big blocks in these truck. What have you done to keep them cool??? I dropped in a 77 454 about 3 months ago and have fighting with since. I have a aluminium 4 core rad that I got off of Amazon. It's a oz cooling. It can with a shroud and electric fan. Did some researching and found out that fan was only 1700 cfm. Didn't cool at all. I've replaced it with a 3000 cfm fan and that helped alot. Still runs 230-240. I have put a serp setup from a 89 burn with a hiflow milodon water pump and hiflow 160 tstat. Dropped temps to around 220. I've ordered a zirgo ultra hiperformance 3600 cfm fan. Should be here next weekend. I've looked at several pics here on the forum of bbc trucks. Some look like they are still running stock rads. Is anyone running a us rad or have any info on them. Have been looking at their hiperformance and optima rads. They are very expensive but I'm sure they are worth every penny. Do I need to be looking harder in that direction. Any suggestions would be greatly appreciated.

Are you running ported or manifold vacuum on the advance? When I switched to manifold my SBC ran at least 10° cooler.

[urmyboyblue]

You haven't said if it gets hot idling or running down the road. If it gets hot idling, you have too little fan. If it gets hot running down the road, you have too little radiator. Also, check your timing with the engine around 3000 RPM to look at total timing, not initial. I would check to make sure the distributor is working correctly- you are getting both vacuum advance (check by pulling the vacuum hose to it- timing should change) and mechanical advance (timing should change as RPM changes). I run mine around 32-36 degrees total timing (checked at 3000 RPM. Total timing is more important than initial because it is approximately the RPM the engine runs down the road. Also check the fuel pressure and make sure you are not running the engine lean.

As for cooling, I have BBC's in two trucks. My 66 has a 400 hp 427 that uses a Champion radiator and an HHR electric fan. I drove it 400+ miles a few weeks ago in 90+ degree weather and it never got above 195. This is a cheap fix all around and is easy to fit. My 65 has a 550 hp 489 and uses a cheap chinese radiator that has been custom fit (aka hacked a little) and a high dollar Derale dual fan set up with a radiator controller. It keeps the temps below 200 as well.

I would do the easy things first- check the tune. One last suggestion- make sure the fan is pulling air thru the radiator and not pushing it. Sounds silly, but I have made that mistake before as well.

[sweetk30]

any new info on this yet ?