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  1. #1
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    I need help-bigger RAD needed for 64 Olds F-85, some fabrication will be required

    Guys, finally got this 1 of none 64 F-85 on the road however, long story real short runs to hot in the Texas heat. 64 Olds F-85, Cutlass's came with a V-6 or a small block 330. Currently has BB Olds 400E with a 330 small block Champion 3 row aluminum rad that fits the 1 year only core support with VERY little room left between the Flex-a-lite dual 2500 cfm dual PULLER fans and the water pump pulley. This rad is rated to support up to 600 HP?? I don't think so. At this point my idea was to cut off each side of the core support and drop it about 3 inches, weld it back using C channel steel I already purchased. That will allow to drop in the larger 65 442-GTO rad-which is about 3 inches deeper-442's came out in 65 with BB 400E. Either way, max width is 25.5-26 inches by 22.5 tall down flow type rad. Couple of considerations is I would like to try another brand of rad and different dual fans. At some point I'm going to pull the 400E and build it 475-500 HP range , so I'm thinking I only want to do this 1 more time! I have learned that the CFM ratings are with nothing in front of the fan. A lot of trail and error on this over heating problem ( drove me nuts) and the parts are new. Timing, Q-jet, 160 degree Robert Shaw thermostat, Flow-Kooler water pump, is all in check great. So I decided to remove the condenser in front the rad and bingo the 2,500 CFM rated fans could NOT pull in enough (weak motors?) air in 100 degree Texas heat. BUT dang it still would eventually tip over 200 degrees in traffic with 95-100 degree ambient temps. So this is where I'm at , need a larger cooling capacity rad and maybe a 4000 CFM rated Derale dual fan set up if I can make another 1/2 of room between the fans-shroud and water pump pulley. Is there any cross flow rads that will fit that space?, 2-row or 3? Should I try a larger rad and re-install the Flex-a-lite fans first before I lay out more $$ or just get a higher 4000 CFM rated fan set up with bigger motors? Please note: this is my hobby, I don't build cars like most of you guys here so any assistance will be greatly appreciated. The pictures of the core support is not mine, but that's what I thinking to do. Thanks.
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    64 F-85 post car Resto-Mod project-my RV when I retire

  2. #2
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    Couple of suggestions.

    A two row radiator with 1” or larger tubes will cool much better than a three row.

    Flexalite fans are overrated imho. Go with a couple of big Spal fans.

    Don
    1969 Camaro - LSA 6L90E AME sub/IRS
    1957 Buick Caballero - huge project
    1959 El Camino - Ironworks frame
    1946 Chevy pickup patina project
    1956 Cameo - full C5 suspension/drivetrain

  3. #3
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    I second Don on the Spal fans. They're the supplier for many OEMs.

    I'd try C&R for your radiator. They could probably build you one to fit your stock location and be able to cool your current and future setup.

  4. #4
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    Good info, I will start looking into these suggested replacement parts..
    64 F-85 post car Resto-Mod project-my RV when I retire

  5. #5
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    A couple of thoughts that might help you, as I used to design cooling systems for long haul Semi's. When automotive radiators claim a HP they can cool, that is spec'd at high RPM with the waterpump pushing lots of coolant, the fan CFM at max, and vehicle speed usually above 55mph. The radiator you have may be just fine for your power level, but other areas of the system may be causing issues at lower vehicle speed.

    When your idling in traffic you need all the CFM and pump flow you can get.
    My first opinion is underdrive pulleys should never be used on the pump unless you've got a seriously robust cooling system that can make up for the lost performance. Coolant flow at idle is only a few GPM, and reducing it with pulleys can easily tip the balance to overheat. I don't think you mentioned one, I'm just sayin in general is all.

    If you plan to keep the flex fan, make sure the shroud is as tight as it can be to the fan tip within a few mm. If you happened to have a 13'' stock fan , but went to an 11'' flex fan, there will be excessive clearance between the blade and shroud which drops that much needed CFM at idle. Nice tight shrouds generate good CFM, poorly fitting or lack of a shroud will drop fan CFM significantly. On big rigs, we find the difference between an 8mm gap and 6mm gap can be the difference in maintaining performance at full tilt.

    Recirculation: depending on your setup(baffles, lowered stance..etc), in traffic and 110F+coming off the blacktop, you may be getting fan re-circulation. Even small zones that are sucking in fan blast can start to increase coolant outlet temps pretty fast. Having the bottom of the radiator sealed off to the forward portion of the bumper can make a big difference in traffic. This goes for the sides and top of the radiator, that there shouldn't be a path for engine bay air to sneak by and re-enter the radiator at all. While hot Texas summers of 110F are definitely brutal, fan blast can get upwards of 200F+, so you definitely don't want that mixing with the "fresh" air coming in.

    Thermostats: There generally about a 20F spread between the Start to Open (STO) and Full Open point. When aftermarket manufacturers sell a 175F thermostat, that is when it just barely cracks off it's seat and lets some flow into the radiator. Full waterpump flow to the radiator(and at idle that's still not a whole lot) is given to the radiator at 195F.

    If you go to electric fans, you need to make sure that the Fan comes on about 15-20 degrees after the thermostat is fully open, and turn off about 5 degrees above fully open. this way, the thermostat stays open the whole time and the fan is not driving it back closed and cycling it(this can happen with strong electric fans and poor fan strategy. Being Carb'd you probly want to maintain a narrow range in the 210F coolant temp zone. Now, I'll say as an engineer that having coolant temps maintained in the 220F zone is fine, but I can't personally bring myself to even run that way because I like a little margin to notice temps climbing before they get away lol. I keep mine in the 205-210 zone.

    I hope this was helpful. I know the easiest answer is big ass spal fans and a BeCool 4 row aluminum radiator, but all of these tips still apply to those when you start pushing the limits of their capability. I would think your current rad is up to the job, might just need some teaks to the overall system to get it back inline. Good luck man.

    1969 442 6.0L LQ9 T56
    Fab9 w/ custom 3 Link conversion
    FAYS2 Watts link
    Thanks to Mark at SC&C for his honesty and passion for the sport, and Ron Sutton for the wealth of knowledge that has helped shape so many of the cars on this site.

  6. #6
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    Now here is someone who knows what they are talking about. Very good points and thank you for the info.

  7. #7
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    Thank you for taking your time to write. Current running a FlowKooler 1775 water pump, Robert Shaw 160 degree thermostat, 3 row aluminum radiator and Dual electric fans.
    64 F-85 post car Resto-Mod project-my RV when I retire

  8. #8
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    Quote Originally Posted by jetmech442 View Post

    If you plan to keep the flex fan, make sure the shroud is as tight as it can be to the fan tip within a few mm. If you happened to have a 13'' stock fan , but went to an 11'' flex fan, there will be excessive clearance between the blade and shroud which drops that much needed CFM at idle. Nice tight shrouds generate good CFM, poorly fitting or lack of a shroud will drop fan CFM significantly. On big rigs, we find the difference between an 8mm gap and 6mm gap can be the difference in maintaining performance at full tilt.
    He’s not running a flex fan, he’s running dual electric Flexalite fans. Flexalite cfm ratings are “creative” in my experience.

    Any comments on dual row with big tubes versus three and four row radiators? Everything I have read and experienced says dual row with big tubes will cool better.

    What sort of calculations and analysis go into designing an OEM cooling system?

    Don
    1969 Camaro - LSA 6L90E AME sub/IRS
    1957 Buick Caballero - huge project
    1959 El Camino - Ironworks frame
    1946 Chevy pickup patina project
    1956 Cameo - full C5 suspension/drivetrain

  9. #9
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    DHUTTON X2 your spot on. I have learned that CFM's are rated with nothing in front of them-the rad, AC condenser-like mine. The current Flex-a-Lite 410 dual puller rated at 2,500 CFM is not capable of keeping the BBO 400E under 200 degrees in 100-plus ambient temps-fan motors are not strong enough. Removed the AC condenser much BETTER. I also believe that the 3 row Champion rad is also contributing to this issue. So as the picture from my previous post above,a fellow Olds Club member cut, lowered the core support about 3inches and welded back up. I now have the bar stock but have not got started yet. There is a single Flex-Lite 16" fan rated at 3,000 CFM that is thicker about 4inches deep that if I mounted it off center it should clear the water pump pulley- I dont know if this is a good idea. I cannot find a Spal or other brand that will fit. The 410 dual fans covers 95% of the rad and only have about a 1/2 inch space between the fan motor shroud and the water pump pulley.
    64 F-85 post car Resto-Mod project-my RV when I retire

  10. #10
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    Quote Originally Posted by dhutton View Post
    He’s not running a flex fan, he’s running dual electric Flexalite fans. Flexalite cfm ratings are “creative” in my experience.

    Any comments on dual row with big tubes versus three and four row radiators? Everything I have read and experienced says dual row with big tubes will cool better.

    What sort of calculations and analysis go into designing an OEM cooling system?

    Don
    Your right Don, thanks for clarifying, I read "flex" and my mind autopopulated the engine driven flex fan, instead of recognizing he's running dual electrics

    As far as tube rows vs daimeter, if they have the same technology(turbulators..etc), then its a balance between which has more total surface area vs total pressure drop. Too much pressure drop and pump flow drops, which is one of the most important inputs. Also affected by this though is airside pressure drop due to the thicker required core, air side pressure drop reduces fan CFM( or in reality exposes any leak paths you have with the shroud and will want to recirculate engine air more. Generally speaking though lol, I'm with you in that for my car I'd rather have larger tubes given aftermarket availability.

    As far as designing OE cooling systems, we generally have a pretty good idea what the engine heat rejection across the lug curve is going to be, give or take a few hundred BTU's. Rad suppliers will provide coolant and airside pressure drops as well as cooling curves for a proposed rad that will fit package. We then run several rounds of heavy, full vehicle CFD to accurately predict airflow. fan blade number, diameter, tip clearance, blade immersion into the shroud are all optimized to get the exact airflow we need at peak cooling(which in our case is not peak power or peak torque). This is done not just with the rad, but the intercooler, condenser, transcoolers, everything stacked up front must meet targets. Fan requirements can get as high as 90HP for a severe service truck just to give you an idea of the airflow required.

    Quote Originally Posted by therobski View Post
    DHUTTON X2 your spot on. I have learned that CFM's are rated with nothing in front of them-the rad, AC condenser-like mine. The current Flex-a-Lite 410 dual puller rated at 2,500 CFM is not capable of keeping the BBO 400E under 200 degrees in 100-plus ambient temps-fan motors are not strong enough. Removed the AC condenser much BETTER. I also believe that the 3 row Champion rad is also contributing to this issue. So as the picture from my previous post above,a fellow Olds Club member cut, lowered the core support about 3inches and welded back up. I now have the bar stock but have not got started yet. There is a single Flex-Lite 16" fan rated at 3,000 CFM that is thicker about 4inches deep that if I mounted it off center it should clear the water pump pulley- I dont know if this is a good idea. I cannot find a Spal or other brand that will fit. The 410 dual fans covers 95% of the rad and only have about a 1/2 inch space between the fan motor shroud and the water pump pulley.
    Your absolutely right that CFM is provided without restrictions in front of the rad(like the condenser), or behind like the engine compartment. Comparing motor power can sometimes be a bit more helpful.

    Are you able to get sub 200 in like, 70F? if not then its the thermostat cycling back down to control that full open temp. In order to get sub 200 in traffic, you'll need a thermostat that is fully open by 180F or so in order to incorporate the right fan strategy. You'll also need a LOT of airflow that is sub 130F (the condenser adds to the air temp going into the rad). But i'm still curious why you need sub 200 in traffic, if its just what you want then I can certainly respect that and we can try to find the combo that achieves that for the least amount of money.

    As far as dropping the core support in order to get a bigger fan...it seems like it's in the right direction. you're still going to have a lot of engine side resistance since it's right on the pump pulley. Is a 16'' pusher fan an option?

    One last question, if in traffic and it starts getting hot, does increasing engine rpm drop the temps back down?

    1969 442 6.0L LQ9 T56
    Fab9 w/ custom 3 Link conversion
    FAYS2 Watts link
    Thanks to Mark at SC&C for his honesty and passion for the sport, and Ron Sutton for the wealth of knowledge that has helped shape so many of the cars on this site.

  11. #11
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    Quote Originally Posted by jetmech442 View Post
    Your right Don, thanks for clarifying, I read "flex" and my mind autopopulated the engine driven flex fan, instead of recognizing he's running dual electrics

    As far as tube rows vs daimeter, if they have the same technology(turbulators..etc), then its a balance between which has more total surface area vs total pressure drop. Too much pressure drop and pump flow drops, which is one of the most important inputs. Also affected by this though is airside pressure drop due to the thicker required core, air side pressure drop reduces fan CFM( or in reality exposes any leak paths you have with the shroud and will want to recirculate engine air more. Generally speaking though lol, I'm with you in that for my car I'd rather have larger tubes given aftermarket availability.

    As far as designing OE cooling systems, we generally have a pretty good idea what the engine heat rejection across the lug curve is going to be, give or take a few hundred BTU's. Rad suppliers will provide coolant and airside pressure drops as well as cooling curves for a proposed rad that will fit package. We then run several rounds of heavy, full vehicle CFD to accurately predict airflow. fan blade number, diameter, tip clearance, blade immersion into the shroud are all optimized to get the exact airflow we need at peak cooling(which in our case is not peak power or peak torque). This is done not just with the rad, but the intercooler, condenser, transcoolers, everything stacked up front must meet targets. Fan requirements can get as high as 90HP for a severe service truck just to give you an idea of the airflow required.



    Your absolutely right that CFM is provided without restrictions in front of the rad(like the condenser), or behind like the engine compartment. Comparing motor power can sometimes be a bit more helpful.

    Are you able to get sub 200 in like, 70F? if not then its the thermostat cycling back down to control that full open temp. In order to get sub 200 in traffic, you'll need a thermostat that is fully open by 180F or so in order to incorporate the right fan strategy. You'll also need a LOT of airflow that is sub 130F (the condenser adds to the air temp going into the rad). But i'm still curious why you need sub 200 in traffic, if its just what you want then I can certainly respect that and we can try to find the combo that achieves that for the least amount of money.

    As far as dropping the core support in order to get a bigger fan...it seems like it's in the right direction. you're still going to have a lot of engine side resistance since it's right on the pump pulley. Is a 16'' pusher fan an option?

    One last question, if in traffic and it starts getting hot, does increasing engine rpm drop the temps back down?
    Thanks for the tech. CFD, had to google that one...

    Don
    1969 Camaro - LSA 6L90E AME sub/IRS
    1957 Buick Caballero - huge project
    1959 El Camino - Ironworks frame
    1946 Chevy pickup patina project
    1956 Cameo - full C5 suspension/drivetrain

  12. #12
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    May 2011
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    When the AC condenser was in front of the rad once it started getting over 200 degrees, it would not recover even if you got on the freeway. Now that I removed the condenser in front of the rad a few weeks ago it was 95 out ( not 100 or more outside) no issues with over heating, in fact at 75-85 MPH temp. stayed 175-180 degrees! Pull off the freeway, stop and go traffic temps would go up and down as air flow got past through the rad without the condenser. HAD a Mr. Gasket 180 degree thermostat, changed it over to a Robert Shaw 160 did not make much difference. with the condenser still in place faster RPM at idle did not help reduce temps. Now that it in the 80's here and 60's at night the engine temp will not get above 165-170 degrees ( AC condenser still removed. My plan from the above message should do it. with the lower core support dropped 3 inches I located an aluminum 2 core rad from Engineered Cooling Products that will almost drop in, originally designed for 63-66 Chevy C/10 trucks. I may use a Spal large motor 16 inch 3000 cfm single fan and off set it on the rad to clearance the water pump pulley. Hopefully it should clear the AC compressor on the passenger side. after all said and done if I pull the 400E build it, or build a 455 either one with more power the rad set up should handle it. I mean a stock 350 HP. over heating is something that I never thought would never ever happen on this build. But in 64 the core support was initially designed to cool a V-6 or small block 330. In 65 when the 442 came out with the 400E the core support was 3 inches deeper for a reason? Hey a friend joked and said: just the leave the condenser off and go. My response: I would have never built this car without AC especially at my tender age plus in Texas summer heat-no way. Thanks.
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  13. #13
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    Cooling recommendations

    To keep it simple, for high performance street cars with modern power plants or retro big block power plants it is ALL about as much core face (must be high quality core with the latest core technology MADE IN USA NOT OFF SHORE CORE) you can get in the hole you have and QUALITY fans that are rated with a load, not free flowing. The brushless technology is the way to go but very pricey. I have a 65 Olds 442 with LS3 that I designed a radiator for using stock core support with no modifications. I maximized the core face (~475 sq inches) and used SPAL's 850 watt 4500cfm brushless fan. This combo will have no issues cooling most any motor combo with AC in most any climate in the US up to 800HP. Unlike most we have manufacture our own core in house so we have the ability to maximize core face (make tanks as small as possible). This is just one of the features that separates the C&R cooling packages from most. Feel free to ask me any questions about cooling at any time
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  14. #14
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    +1 for Phil. He helped me design my setup for my car. Countless revisions, lots of valuable input and knowledge from him. He works with all the big name shops and knows a thing or two about these things! Thanks again Phil for your patience and help!