Cooling a 66 Nova

[Fuelie Nova]

I have a 66 Nova, 406 SBC/550 Hp with A/C. I drive this on LONG trips and need to keep it cool. Currently I run a BeCool cross flow that is a direct replacement for the 66 with Spal dual 11" fans and Stewart stage 2 pump, also have the correct pulley ratio according to stewart.
Normally this does ok until I get caught on a hot day idling (90 - 100 degrees) and then it is marginal at best.

I want to come up with a setup that will make me forget about watching the temp gauge on hot days. I have above average fab skills and have been considering a universal radiator that is wider than the current 25.5" overall length of my BeCool. I am willing to modify my radiator support, fab new mounts, whatever it takes to cool the Nova!

Anyone got any suggestions? I have been considering a RD setup with the dual 12" fans but am even concerned about that.



HELP
Tom

[SparkyRnD]

If overheating at idle, then it's possible your fans aren't moving enough air or your radiator is a little small for your setup. We make a crossflow for the Nova here: http://www.rndfabrication.com/Nova.html

On your BC version, what are the dimensions of the core and dimensions of the tanks? And are they using dual 1" thick cores? Last, what is your current timing and fuel mixture? Have you put an air-fuel ratio meter on it to verify the fuel mixture level?

[Fuelie Nova]

BC deminsions are:
26 1/2 W X 19 H X 2.5 Thick Overall
17 H X 22W Core
1 3/4 X 3 X 18 Tanks

The motor is tuned great. I do have a O2 sensor in both pipes but haven't hooked them backup since the dyno session. Plugs read great, I would also have to get my timing light back out. I havent retuned since motor was tuned by reputable local dyno tuner.

My feelings are that the radiator is marginal in size and so are the fans. The shroud is tight to the radiator and sealed so all air is being pulled thru radiator and not leaking around the shroud.

Most problems are only when stuck in traffic on warm summer days. Normally running down highway temp is ok. I have had a couple of warm days when I drove the nova down to Atlanta and the motor started getting up around 205 at 70MPH but this is very rare. Still it seems to tell me something.

I only want to do this once and do it right. I am tired of worring....
Tom

[SparkyRnD]

Understood. The core size is decent, but probably a hair on the smaller size for that motor. Tuning on the timing and mixture are key to keeping it cool, and the $100 or so for an air-fuel mixture meter is money WELL spent. For the fans, what type of controller & relay kit are you using? Have you measured to make sure they are getting full power (amps) when running?

[Fuelie Nova]

Just some thoughts.... I do tune with good equipment. I am certain the fuel mixture is good by reading the plugs. I cut the threads off and read the whole plug. I could try and get a pic. Patrick at Pro Systems does my carb work and setup. I normally time for power on the dyno, I am certain it is not retarded. By the way, I also had this same prob with my 383 I just pulled out, I ran fast XFI with that and AFR was 13.9:1 at idle and transitioned to 12.5:1 @ WOT.
I had an itch to go back to a carb for now. Power level on the 383 was close to the 406 ( actually a 400). This is a fresh motor with a new Dart block and Pro-Filer heads so I know the cooling passages are good.
For the fans I use a time delay relay to bring them in 3 seconds after start for the first one and then another two seconds for the second one. They are wired thru a 50 amp relay directly to the 1/0 battery cable. They run all the time. I did not have time to do a controller. Will install one when I do cooling updates this winter.
I am also running a Robert Shaw high flow thermostat 180* Yes I am confident on the wiring, I do industrial control work for a living, I also have a 140 amp Power Master alternator for the electrical system.
Tom

[SparkyRnD]

Sounds like you have all the bases properly covered (without knowing you or your background on the previous posts, I like to ask the most basic questions first to make sure something wasn't overlooked). Since you have all of those items covered, then it does point to the radiator either being too small, or the fans being too small, or a combination of the two. For similar sized radiators with near stock V8s, we use dual 12" fans. I would consider a larger radiator and if there is room, dual 12" fans or a larger single fan to keep it cool.

[Fuelie Nova]

What kind of delivery times do you have if I order a wider radiator from you?
Tom

[SparkyRnD]

right now, we're on about a 2 week turn around (finishing up some other prototypes and SEMA car radiators).

[Fuelie Nova]

What I really want is a 32W X 17H with a slight angle on the bottom of both tanks. Dual 1" tubes. I also want a shroud to mount two 14" fans.
Can you build this?
Tom

[anthonys 69]

I know dart is a great block and has better cooling passage ways then the old gm 400 block. On the old 400 if you changed the cylinder heads you would have to drill steam holes in the cylinder head and use a head gasket for the 400 sb. I would double check with dart to see if that still the case. good luck

[Fuelie Nova]

Thanks... problem solved. Replaced the radiator and fans with Ron Davis setup, everything works great now even on hot days with the A/C on.
FWIW, I am running the dart block with Pro-Filer heads with NO steam holes. I know this is a big debate sometimes but mine cools fine now w/o the holes. Most street engines I have tore apart have the holes plugged with junk anyway. I talked with Dart and Pro-Filer, both agreed holes were not necessary.
Tom

[Randy67]

I only have the lower 3 steam holes drilled on each head (Victor Jrs), per Edelbrocks instructions. No problems with running warm. This is on my 377 (400 block) btw. I had a BeCool crossflow radiator as well in a 67 El Camino, it never got hot, but the temp did go up when idling, no higher than 210 degrees though. I used a Flex-a-lite 16" S-blade fan (3000 cfm) which worked well. I did have 25% underdrive pulleys which affected the idle temps, less underdrive would probably have worked better.

[BADDRIDE II]

Thanks... problem solved. Replaced the radiator and fans with Ron Davis setup, everything works great now even on hot days with the A/C on.
FWIW, I am running the dart block with Pro-Filer heads with NO steam holes. I know this is a big debate sometimes but mine cools fine now w/o the holes. Most street engines I have tore apart have the holes plugged with junk anyway. I talked with Dart and Pro-Filer, both agreed holes were not necessary.
Tom

Did you end up with the size radiator/fans you had posted or another "bolt in app"?
Did you get transmission cooler as well?
If you do not mind me askin'....how much for this setup?
One last ?....can you post pics of this radiator? (sounds like its killer)

Thanks!

[Fuelie Nova]

Sure I can post pics this evening when I get home. This was RD's direct replacement radiator for a 66 Nova. I run a separate stand alone transmission cooler so this one is not for auto trans. I thought I would save the $40.
Total cost for system was $1013, radiator, shroud and fans. IT looks killer!
Tom

[BADDRIDE II]

Sure I can post pics this evening when I get home. This was RD's direct replacement radiator for a 66 Nova. I run a separate stand alone transmission cooler so this one is not for auto trans. I thought I would save the $40.
Total cost for system was $1013, radiator, shroud and fans. IT looks killer!
Tom

Nice, appreciate it as I am in need of a radiator soon and was thinking of RD as an option. My Dad runs a 64 Nova (similar to your drivetrain) with a RD radiator that has been in for over 10 years and is still cooling! I will check back this evening!

[Fuelie Nova]

Hope these help. Not the greatest pics but the build quality is second to none!
Tom

[BADDRIDE II]

Wow, very very nice! money well spent. Thanks for sharing pictures. I will have one soon.