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Hot Rods Where to begin?

Discussion in 'The Hokey Ass Message Board' started by Bob Watts, Nov 12, 2018.

  1. Bob Watts
    Joined: Nov 9, 2018
    Posts: 6

    Bob Watts

    Hi all I posted this in the intro board and then got to reading some of the guidelines and got to thinking this car might not even be what HAMB is about if that's the case please advise.
    My car is a 40 Ford Coupe/small block Chevy Hot Rodded a long time ago by unknown persons which I've been trying to get in a reliable state and failing for some time now.
    This is what's happening any ideas gladly appreciated, when driving it heats up then when you get to stop and go traffic it surges and dies and needs about 20 minutes of cooling down before it will even turn over . The starter doesn't even click when it's recovering.
    The most recent instance left me stranded after exiting the freeway in the middle of a very buy highway
    I originally thought it must be vapor lock so I took out the Walker radiator and had it rodded and the radiator shop said it looked fine. I also put a new Edelbrock water pump on trying to improve the flow
    In addition we (various repair shops) have changed the ignition to electronic and I watched the timing set with a strobe, had the Holley carb rebuilt put insulation on the fuel line and installed a new air conditioning unit , new battery , new starter motor .
    I haven't done a compression test but it runs strong right up until the problems start.
    I think it's a 2 part problem that when you run the a/c is when it really heats up causing the surging which could be vapor lock.
    But I'm pretty sure it over heated and died before the new a/c unit as well.
    I have no idea why the starter wont turn over when its hot . It has a mechanical fuel pump and new braided fuel line . I've considered putting a electric pump on to see if that will cool down the fuel by keeping it off the block but that won't stop the engine from overheating of course.
    I've just been throwing money at the problem with no luck and my skills are more simple Model A / Flathead V/8 diagnostics. Thanks, Bob
    40 eng compartment.jpg
    chryslerfan55 likes this.
  2. squirrel
    Joined: Sep 23, 2004
    Posts: 44,633


    Put a flathead in it.

    But if you have a temp gauge that shows the engine is heating up in traffic, I'd first try putting a fan shroud on it.

    Then find a better looking air cleaner!

    neither of these suggestions will help the starting issue, since I don't have enough info about what is going on.
    flatford39, chop job, brad2v and 5 others like this.
  3. Gman0046
    Joined: Jul 24, 2005
    Posts: 5,834


    The cooling rule of thumb, runs hot at low speed - not enough fan. Runs hot at highway speed - not enough radiator. No starter - starter heat soak. Common SBC problem.

    flatford39 and alanp561 like this.
  4. LM14
    Joined: Dec 18, 2009
    Posts: 1,860

    from Iowa

    What's your temp gauge read?
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  5. sevenhills1952
    Joined: Mar 14, 2018
    Posts: 883


    Just curious, something that wouldn't cost much. Replace thermostat with a restrictor, basically looks like a thin washer...a gutted thermostat. And an electric fan on radiator. If you have a fan blade of course pulling air front to back through radiator, electric on front side pushing air same direction...then you have constant coolant flow, constant air flow through radiator. Add Wetter Water we used to use in our drag car.

    Sent from my SM-S320VL using Tapatalk
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  6. AngleDrive
    Joined: Mar 9, 2006
    Posts: 720

    from Florida

    You need a better fan, preferably stock steel, it needs to be closer to the radiator or a fan shroud needs to be added. Like GMan said starter is heat soak. Carb might need spacer to keep gas from boiling.
    flatford39, 56shoebox and alanp561 like this.
  7. alanp561
    Joined: Oct 1, 2017
    Posts: 919


    What AngleDrive said. My 46 Merc doesn't have a shroud but the fan has only 3/4 inch clearance to the radiator. Runs 160 all the time.
  8. treb11
    Joined: Jan 21, 2006
    Posts: 3,341


    Fan shroud, fan closer to radiator. If we can see the fan in the picture in spite of the angle of the shot, the fan is too far away. Is the block grounded to the rest of the car? A poor grounding path is a sure cause of hard starting, as the starter is trying to ground back to the battery. Get an infrared thermometer and check the temp of the carb, including fuel bowls after various driving scenarios. Today's alcohol laced fuels boil (vapor lock) at lower temps than fuels of years past. Get a phenolic heat insulator to go between the carb and manifold as well. That is the most direct heat path from the engine to the carb. If a header pipe or exhaust tube is near the starter, shield the starter and/or insulate the pipe(s). Also, more flow (faster) is not necessarily better. The coolant (water) has to stay in the radiator long enough to shed the heat before returning to the block and heads. HTH
    Last edited: Nov 13, 2018
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  9. guitarguy
    Joined: May 26, 2008
    Posts: 276


    Well, we start off with some basics. No one has mentioned timing. So i'll ask, what is it (Initial, full advanced). That can have an effect on cooling. As can the tune on the carb. What temp thermostat do you have in it? I always run a 180/185 degree T-stat----usually a hi-flow version. Never had issues doing so.

    Do you know how old the radiator is? Is it Copper/brass or aluminum? What condition are the fins in (still attached to the tubes or coming loose/ corroded). I have perfectly good looking older radiators that were clear inside, with good fins, no leaks and they just couldn't cool any more---had to replace.

    And what Jim said is dead on too---get a fan shroud of some sort on that thing--It can make an AMAZING difference. And when you get a shroud, seal it to the radiator with foam strips (see heating and cooling section at Lowes / Home Depot for the foam) The fan blades should be approximately should be halfway in the shroud. You need to pull air through the radiator to extract the heat. With no shroud, all your doing is moving air in the engine compartment around. What kind of fan blade is that also, is it plastic?

    As mentioned, the starter (more specifically the solenoid) is probably getting to hot and failing. If you don't have a mini starter on it, get one and heat wrap it (DEI and other places make starter reflective insulation). The starter can be from any newer (90's) GM 5.0/ 5.7 truck---be sure to get the bolts for it too, they are different than the older bolts on the shank portion. If you still have issues, run a remote mounted solenoid (Ford Style).

    Yes, running the A/C will not help the issue as the heat coming off the condenser will just aggravate the heat going into the radiator assembly. Get it cooled first without the A/C before turning that on.
    flatford39 likes this.
  10. I agree with replacing the fan with a multi-bladed steel fan, also look at your pulleys, your water pump pulley needs to be smaller diameter than the crank shaft pulley.

    These are things I did when my 40 sedan ran hot and it made a huge difference. HRP

  11. The Shift Wizard
    Joined: Jan 10, 2017
    Posts: 1,757

    The Shift Wizard

    If it runs okay at highway speeds but heats up for "stop and go traffic", that points a big neon arrow at the fan not doing its job.
    Put another vote in Add a Fan Shroud. :cool:

    This is especially important when dealing with homebrewed cars that have had the bodywork messed with and higher power than original engines put in. It's a basic law of thermodynamics, more power makes more heat.
    Last edited: Nov 12, 2018
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  12. Mr48chev
    Joined: Dec 28, 2007
    Posts: 26,218


    I'd agree on an airflow issue at low speeds. If the temp drops right back down when you hit 35 or so and continues to drop down to it's desired level at road speed you can be sure that the air flow or lack of it at low speed is the main issue. I have that on my truck in my avatar because of lack of room for a proper fan.
    On the starter I would say heat soak is the issue here. There may be issues with the starter such as worn bushings that are letting it drag some but heat soaked Chevy starters are a common issue. Making sure that the starter is in top shape with good bushings and brushes is one step. Getting a heat shield for it like the one from Mr Gasket is a must do. That helped more than anything on my work truck. I put this one on mine.
    Doing the Ford solenoid conversion also helps and isn't hard to do.
    The other thing and this should be first is making sure all of your connections on your cables are clean and tight especially the ground connection to the engine. I've seen too many guys fight starting issues where they just didn't have a good connection between the ground cable and the engine.
    flatford39 likes this.
  13. RR
    Joined: Nov 30, 2008
    Posts: 94


    I would check the fuel pressure while running and keep an eye on it- see of the car will have the problem while you watch the fuel pressure. I had a weak mechanical pump that would run the engine fine for a while then it would vapor lock. Just could not keep up with prolonged engine RPM. The lean condition that was caused when the fuel bowl was low caused the engine to heat which made the situation worse. While it did not happen to me, the starter could be getting so hot it won't engage. Just a thought.
  14. F-ONE
    Joined: Mar 27, 2008
    Posts: 1,918

    from Alabama

    Let's see...
    What cools an engine?
    A problem with any of these will cause it to run hot. A weak link somewhere in the three will upset the balance....thus overcoming the other two. It's a balancing act. There may be an issue with all three...two of three...or one of three.

    What heats an engine?
    Internal combustion...

    Going through all this...

    What coolant is used? What's the status of the water pump? Is it correct? Is it turning the right way? What's the status of the block? Does it need flushing? Is it full of scale? Could there be an issue with gasket....head compatibility? Is there enough water? (sometimes there's a bubble) Is the water reservoir big enough to adequately cool this engine? (remember flathead radiators were massive and made of thin brass which transferred heat better than thick aluminium.)
    What oil is used? Do you have enough? Do you have good pressure?....
    High volume pumps can pump nearly all the oil up top before it drains back down. If you have a high volume need a high volume reservoir....oversized pan.
    I think this may be where the issue lies. It's the one you can do the most about.
    Thick metal holds heat....thin metal sheds heat. This can be good ...this can be bad.
    If the cylinders are over sized, they'll shed too much heat..thus over coming the balance. This is an internal problem but first lets look at the bolt on stuff.....
    Cast valve covers will hold heat longer. Tall cast covers hold heat longer and restrict air flow. Stock sheet metal type covers shed heat faster...are smaller....thus more air is around them to absorb that heat. The more doo-dads and accessories added the more air flow is restricted.
    Cast small air cleaners hold heat as well and restrict air. Big sheet metal air cleaners and their big filters have more ability to cool incoming air and shed heat from the engine....
    Tube headers shed heat but they really have an opposite effect as far as cooling a tight engine compartment. Iron manifolds hold heat but mainly they allow the high heat to exit into the pipes instead of transferring into the engine compartment.
    Is there enough cooling air going around the engine? Fords had all kinds of shrouds and sheet metal to direct air around the engine. The top of the radiator was shaped to meet a air dam in the hood. Is the air directed through the radiator?....or around it?
    Fan shrouds help here. Use your head in directing airflow. It's possible that you can actually restrict it instead of free it with the wrong choice.

    Internal combustion.....
    Incorrect timing can cause too much heat. Too thin a cylinder can overcome the heat transfer of the block. Scale rust gook from stop leak can hold heat in the jackets.
    The only thing you can do for a "bored out" engine is a bigger radiator and better air flow.

    Starter.....Old trick was a sheet metal shroud to protect the SBC starter.

    In Conclusion......
    Remove and replace things that can hold heat or restrict air.....Valve covers....cast headers
    Add things that cool air, direct air and shed heat......Big air cleaner.....low profile thin metal valve shrouds....seals above and around the radiator....
    Make sure your oil system is right.
    Make sure it's tuned right.
    Make sure the block is clean and not restricted with sediment and goo. Do a good flush.
    Make sure the radiator is adequate for the job. You may need bigger. Aluminium holds heat more than brass so an aluminum radiator may need to be bigger than a brass counterpart.

    A little does make a difference. Think about it....
    Sometimes a car run can fine at 50 degrees ambient temperature. At 90 degrees ambient temp it over heats. That 40 degrees is minimal yet it overcomes the system.
    All the little stuff adds up.
  15. 56shoebox
    Joined: Sep 14, 2011
    Posts: 1,106


    Is that a flex fan? If so, get rid of it and replace with a steel fan and add a shroud as suggested.

    As for the starter issue, are you using an early, full size style sbc starter? If so, replace it with a mini high torque starter.
  16. Bob Watts
    Joined: Nov 9, 2018
    Posts: 6

    Bob Watts

    Thanks so much for the advice I will be definitely put that to use.
    A little more info-
    It has a new Edelbrock water pump and recent oil change with Castrol GTX 10/40.
    The coolant didn't look dirty but was changed when the radiator was removed with Prestone and distilled water 50/50 and also a bottle of water wetter.
    The temp gauge needle is in the hot area when the problems start
    It has a 6 blade fan that pulls air with about 1" between it and the radiator which also has an 18" electric fan that pushes air which does work.
    The Walker radiator is probably early 90's vintage and has brass tanks and the fins look good a radiator shop opened it up and said it's all clear inside but it has a trans cooler built in and the a/c condenser covers almost the entire radiator.
    Some questions please,
    If this fans no good what would you recommend?
    Could someone guide me to a shroud link?
    Also what radiator would you advise for replacement and with or without the trans cooler?
    Thanks again, Bob
    40 electric fan.jpg 40 fan.jpg
    Last edited: Nov 13, 2018
  17. F-ONE
    Joined: Mar 27, 2008
    Posts: 1,918

    from Alabama

    That electric fan may be hurting more than helping.
    Shroud.....You'll have to mock one up or modify a factory one....a half shroud may do...
    Going by all the rusty stains around the cap, I think a good drain and engine flush would benefit you.
  18. Moriarity
    Joined: Apr 11, 2001
    Posts: 16,949

    Staff Member

    does it run hot at low speed, or on the freeway? If it runs hot at low speed it is an airflow through the radiator problem. If it runs hot at freeway speeds it could be a coolant flow or radiator size problem ( or maybe not enough timing or too lean a fuel mixture) and for crying out loud leave the AC off until the cooling issues are fixed
    flatford39 likes this.
  19. treb11
    Joined: Jan 21, 2006
    Posts: 3,341


  20. Bandit Billy
    Joined: Sep 16, 2014
    Posts: 6,065

    Bandit Billy

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  21. Model A Gomez
    Joined: Aug 26, 2006
    Posts: 1,144

    Model A Gomez

    As to the not turning over when it's hot I had a Chevy pickup that did that and the bushings in the starter were worn out and it would suck the armature over against the coils when it was hot. Would spin great if it had been sitting overnight or all day at work. Wait a little while and it started great, replaced the starter and took care of the problem. Looks like you have plenty of advise on the cooling system. Good Luck
    flatford39 likes this.
  22. jimmy959
    Joined: Oct 16, 2011
    Posts: 108


    I had the same exact problem you have. $18 starter heat shield wrap from Summit. Solved my hot start problem.
  23. Bob Watts
    Joined: Nov 9, 2018
    Posts: 6

    Bob Watts

    Thanks for the advice everyone it's much appreciated.
    Not sure what to make of the shiny bits comment Billy.
    I'm just trying to figure out what to do to solve the problem starting with what my Dad left.
  24. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 4,882


    Definitely get a shroud on it, and as mentioned above the electric pusher fan may be doing more harm than good. A puller fan will do more good than a pusher, especially since you have a full-size A/C condenser in front of the radiator. And get a good steel fan, not that aluminum flexi-flopper that's on there. Also make sure the hot air that the fan (with shroud) pulls through the radiator has room to get out from under the engine compartment. This is usually out the bottom. As another HAMBer mentioned, too much crap in the way under the hood can block HOT airflow, just as too much crap in front of the radiator can block COLD airflow.

    Nope, debunked, and proven by physics. See Newton's Law of Cooling. If you leave the coolant in the radiator longer, doesn't the coolant in the engine stay there longer and pick up more heat?

    Read the following thread, in particular post #23.
    flatford39 likes this.
  25. sevenhills1952
    Joined: Mar 14, 2018
    Posts: 883


    Is it me, the picture, or ? ...but the fan blade looks bent to me. Doesn't it look curled up on the end?[​IMG]

    Sent from my SM-S320VL using Tapatalk
  26. Atwater Mike
    Joined: May 31, 2002
    Posts: 9,865

    Atwater Mike

    No...but that upper belt is twisted on the top of that pulley...
    flatford39 likes this.
  27. sevenhills1952
    Joined: Mar 14, 2018
    Posts: 883


    You're right, looking carefully at that picture it looks like several problems. Blade still looks curled also.
    Sent from my SM-S320VL using Tapatalk
  28. Suggestions without 100% info:

    1.Get a IR gun from Lowes/Home Depot, compare the exhaust manifold temps , intake temps, and radiator surface temps to a car that you have that runs well. We need to see if you are actually running hotter than normal 195F engines.

    2.If you have very high temps and no other reason, maybe the block itself is clogged or bored out too far, retarded timing and/or defective(wrong impeller, impeller on back backwards,) water pump.

    3.your symptoms sound like vapor lock , vapor lock, vapor lock .Bypass the mechanical fuel pump with the cheapo electric one, get a fuel pressure gauge on there, should read 3-5 max psi hot. Make sure the fuel line doesn't run near exhaust or engine or anything real hot.

    4.swap out that air cleaner for either a cheapo disc one or none. That thing might be soaking up heat, restricting air, and adding to your problems. (Looks dorky too. LOL. )

    Would be interesting to see if these issues occur with the hood off.

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