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Event Coverage Just The Facts... Overheating SBCs

Discussion in 'The Hokey Ass Message Board' started by Crazy Steve, Aug 19, 2020.

  1. While I understand why they did it, doesn't it amount to more-or-less the same thing? Poor cooling (which by definition means overheating) limited compression ratio, they needed to reduce/eliminate the 'hot spots' to support the higher compression.
  2. bobkatrods
    Joined: Sep 22, 2008
    Posts: 666

    from aledo tx

    I have had many sbc motors in my 55 years of driving and building cars,never had a problem with cooling even when we were running 12 and 13 to 1 compression,,I have 392 Hemi 32 roadster with alum.radiator and electric fan on 100 deg days it will get no higher than 200,,have a BBC 468 4 speed in a 66 truck with air. 0n a 100 deg day if in stop in go traffic it will creep to 210.I think it is all being able to move air and overkill on radiators bigger the better to a point
    tractorguy likes this.
  3. Every small block Ford I've owned has overheated on me regardless of what it was in. And both Cad powered cars I have run hotter than I like... And I've never heard of the sbc crowd having many issues with overheating.
    Montana1 and tractorguy like this.
  4. One of the issues I have seen with friends SBC's was timing... when they had the timing off, it would over heat when given the situation it normally would not have. At least one had the advance bound up, but he didn't know it and set initial timing with it like that. :eek:
    BigDogSS likes this.
  5. BigDogSS
    Joined: Jan 8, 2009
    Posts: 881

    from SoCal

    Not really. If SBC had poorly designed cooling systems, they would not be the most successful engine in the world for hot rodders and motorsports. And they are still making them 65 years later.....
  6. Apache Albert
    Joined: Nov 8, 2018
    Posts: 82

    Apache Albert

    I'm with DDDenny. Air inflow through the radiator and out of the engine bay is almost as equally crucial. I think its too often overlooked when adding a larger engine to a system. I've always heard SBCs were inherently cool. Plus, if there are additional cooling additives in the system, it sounds like cooling was already problematic.

    GET RID OF FLEX FANS. I ran one on my old 84 ford 300 L6 and it ran much hotter.
  7. scoop
    Joined: Jul 4, 2001
    Posts: 1,281


    I agree with this.
  8. fastcar1953
    Joined: Oct 23, 2009
    Posts: 2,317


    My model a runs cool with a sbc. Never over 180 in traffic.
  9. ekimneirbo
    Joined: Apr 29, 2017
    Posts: 1,619

    from Brooks Ky

    I think the answer is pretty obvious.........making horsepower is the conversion of fuel to heat energy. The Chevies simply produce more horsepower than Ford's.:D:D:D

    Actually since the engines ran fine before they were put into Street rods, I would be looking at what all of the Chevy installations have in common. Start with displacement and compression ratio. Then alum heads or not. Brand and type of radiator and flex fan or not. Shroud or not and alternator output and single wire or not. I say that because at or near idle it is my understanding that some alternators don't produce sufficient output to keep flex fans up to speed. Every one of those cars could have an individual problem, but I bet similarities in how they are installed is where the answer lies.
    Then I would ask the smart Ford guys to tell you what is different in their cars.
    Murphy32 and BigDogSS like this.
  10. A big part of it is probably 302 CI vs 350 CI; 50 less producing cooling system heat. I wonder if they would have the same trouble with a 307....
  11. David Gersic
    Joined: Feb 15, 2015
    Posts: 2,302

    David Gersic
    from DeKalb, IL

    I have an SBC in a 37 Chevy. Not a lot of grill area there. Does not overheat, will run down the highway at 200, or idle in traffic for hours, with or without the A/C running. Spal fan makes a lot of noise, but moves a lot of air. Brassworks radiator does its job.

    If anything, I suspect it’s just that damn near everything gets an SBC stuffed in to it. Some are well done, others are not.

    Sent from my iPad using The H.A.M.B. mobile app
  12. lippy
    Joined: Sep 27, 2006
    Posts: 5,153

    from Ks

    You guys sound like politicians. LOL. Lippy
  13. jimmy six
    Joined: Mar 21, 2006
    Posts: 7,663

    jimmy six

    Personally I think the gasoline formulated today adds to what ever you already have. I use an additive, 1oz, in every fill up. Depending on how “trick” your under hood panel configuration is also hurts some.
    I had a idle in heavy traffic heat problem that was solved by a smaller water pump pulley. Seems not much was moving thru the radiator at idle. It’s nice not to worry. Seems like all the 20’s-30’s cars had side hood vents or louvres.
    Montana1 likes this.
  14. gene-koning
    Joined: Oct 28, 2016
    Posts: 2,121


    I have to think a lot of the overheating may not have been entirely the car, but the people inside of them also played a part in the decision to go home. If your not used to mid 90s, it take a toll on the passengers as well as the cars. Its easier to blame the car then to tell the other guys "My wife says its too hot and she wants to go home to the AC."

    Then we can add "The car is running hot, its over 200 degrees and has never been that hot before."

    When the car and the people inside of it are not used to being in high temps. the old saying: "If you can't stand the heat, get out of the kitchen." Or in this case, get out of the cruise. Gene
    Driver50x and BigDogSS like this.
  15. My father formerly had a '32 Tudor with a SBC/TH350, solid hood sides, aftermarket radiator, and a shroud. It never overheated. My brother has a '32 Tudor with a mildly hopped-up Flathead, 3 speed, stock louvered hood sides, stock fan with custom shroud, and he has had numerous problems with it getting hot. These two cars were even driven on the same trips, so the weather variation argument wouldn't be valid.

    The issue isn't the SBC itself.
    Baumi and tractorguy like this.
  16. fortynut
    Joined: Jul 16, 2008
    Posts: 1,038


    As Sherlock Holmes might say, "Dr. Watson, I would suggest turning the question on its head --- in order to return to the scientific method: Did the excessive heat in the environment, potentially compromised cooling systems, and coolant, cause the Chevrolet's First Series Small Block Engines in the modified automobiles to overheat?" From The Case of The Misunderstood Application of the Laws of Thermodynamics.
    tractorguy likes this.
  17. Automotive Stud
    Joined: Sep 26, 2004
    Posts: 4,145

    Automotive Stud

    Those small block chevy's are junk, that's why nobody uses them. /s
    Baumi, Montana1, tractorguy and 2 others like this.
  18. lcfman
    Joined: Sep 1, 2009
    Posts: 244

    from tn

    I went to Louisville last year and the hot rods were backed up of the main exit as far as you could see. Almost all of them had their hoods up or pulled off to the side. There were all kinds of car makes with overheating problems.
    I suspect that hopped up engines and poor cooling system design was at the root of the spectacle.
  19. ccain
    Joined: Jun 13, 2009
    Posts: 428


    Okay, this might sound crazy, but, here goes. Now that I think about it, the water pump might be their problem. There is a difference in SBC pumps depending on whether or not the vehicle used a v-belt or a serpentine belt. Other than that the pumps look very similar.

    Given that Chevy did make reversed pumps for serpentine belts, is it possible that the owners of these cars have accidentally installed water pumps with the reversed impeller? That would account for the overheat.

    I seem to remember something along the lines of having to pay close attention as to which side of the pulley the belt rides on the later model pumps. I mean if this was like the first long cruise for these cars, they may have never put enough miles on the car at any given time to heat 'em up to normal temp, let alone overheating.

    Again, probably sounds dumb. Don't blame me, I've had a traumatic brain injury. :D:D:D
    Last edited: Aug 20, 2020
    winduptoy likes this.
  20. texasred
    Joined: Dec 3, 2008
    Posts: 1,082

    from Houston

    Or maybe there were 8 wimps along with all of you tuff and cool running ford guys:eek:
  21. There is no question that the sbf thin wall cylinder design is good for cooling. Maybe superior to sbc.
    In the rod area in addition to poor cooling design by many home builders, they want power.
    So higher compression, more radical camshaft and over carburation are all mods that increase cooling demand.
    A low compression stocker will require less cooling.
    All these things need to be considered in the planning stages of a build. Especially if the rod is actually going to be driven.

    AHotRod, nunattax and i.rant like this.
  22. pragmatist
    Joined: Jul 5, 2010
    Posts: 43


    Sounds like a bunch of raucous teenagers hotrodin around! They should have to run 22r Toyota engines! That'll teach um!!!:eek::p:p:p
  23. it had nothing to do with poor cooling, it was all about keeping the water temperatures even on every cylinder, which as I was told, created more horsepower/fuel mileage.
    ekimneirbo and BigDogSS like this.
  24. fortynut
    Joined: Jul 16, 2008
    Posts: 1,038


    This sounds like the test a teacher once created that had no right answers. Everyone was expected to defend the reason the gave the answer they did, and he spent a great deal of his time trying to keep a straight face and not break out laughing, because if he had the men in white suits with the butterfly nets would have taken him away. Always loved that song: 'They're coming to take me away'. Should be the theme for this study in red (as indicated on the temperature gauge).
    David Gersic and BigDogSS like this.
  25. It's been fun reading all the explanations and I won't deny that there may be at least some truth in most of them...

    But it was still a hell of a coincidence... LOL
    partssaloon and pprather like this.
  26. Budget36
    Joined: Nov 29, 2014
    Posts: 4,839



    Improving a product doesn't always mean there were issues with the previous product.

    I think some get real world experience about heat in an engine, here's my real world experience...I'm sure others can share. I have to go a bit OT, but still a SBC.

    I bought a new '89 IrocZ with a 350. Dual fans, the primary fan was set to come on at 235* F, secondary at 242* F.

    Made me nervous as hell, called the dealer/etc, thought for sure something was wrong with the car. They told me to come in, and to calm me down they gave me a shop manual. Even after explaining to me that my 6yr 60K warranty would cover me and that's the way the engine was set up for emissions, etc.

    So, what is really over heating? GM built my car so when I'm idling in traffic/stop and go shit, to run between 210-235*'s.

    Ya, made my butthole pucker. So being smarter than those that engineered and backed there product with a warranty, I made some changes so looking at the temp gauge I was more comfortable.

    Well, I do have the engine out of (my kids car now) after near 200K on it. So maybe a better cooling design is warranted?
  27. sdluck
    Joined: Sep 19, 2006
    Posts: 2,581


    The number of people that I have worked on there hot rods,wrong pulleys,that don't have vacuum advance,haven't curved aftermarket dist,don't have enough timing because the don't want to run premium fuel is at least 75%. Most heating is tune up or wrong pulley's.
    AHotRod likes this.
  28. sdluck
    Joined: Sep 19, 2006
    Posts: 2,581


    If it is not pushing out coolant is is not overheating.
  29. sunbeam
    Joined: Oct 22, 2010
    Posts: 5,021


    You can run into problems Swapping vortec and nonvortec blocks and heads with out a bypass hose.
  30. enjenjo
    Joined: Mar 2, 2001
    Posts: 2,522

    from swanton oh

    The first thing I would look at is where you are getting the vacuum for the vacuum advance. For the best cooling at idle you should be using manifold vacuum, not ported vacuum. Ported vacuum was invented for emission control in the 70s. That is all it's good for, raising the temperature at idle.

    If you are using manifold vacuum make sure it's working. I have seen many cars that had defective vacuum advance units.

    Outside of the COOL factor mechanical advance is for racing where the engine doesn't have to idle for long periods of time.
    AHotRod likes this.

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