Starter won't crank when engine is hot, and on a hot day/

Discussion in 'General IH Tech' started by Big Dog, Aug 9, 2020.


  1. Big Dog

    Big Dog Farmall Cub

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    I have a puzzler for you. I have a 75 RWD scout that I've owned for just over a year. The 304 engine was professionally "rebuilt" about 2 years. I say "rebuilt" because the former owner advertised it as repainted not as rebuilt. It came with dozens of photos of the process, and it is clear that the engine was dismantled, cleaned, etc. prior to painting. My assumption is that the basics were tended to, but there was no machining done, etc. The engine and compartment are pristine, all new cables and hoses, battery etc. The one non stock feature that was added were headers. I had a Hamilton EFI install by the same shop the did the engine work. The engine runs great. Here's my puzzler. I was driving on a hot day, engine running fine, temp on the idiot gauge was just left of the mid point, where it typically runs. I stopped for an ice cream cone and shut off the engine while I ate. I was parked on asphalt. When I went to start it up, the starter wouldn't crank. With the key in the "on" position, gauges came on, I could hear the electric fuel pump run, everything was normal until I turned the key to start it. Then I had nothing, not a click, not a feeble attempt to turn over, nothing. I checked my battery connections, and they were clean and tight. a scout wizard that I called told me how I could bypass the ignition on the chance that it was bad. I ran into a nearby store to grab a screwdriver. When I returned to the Scout, it was roughly 20 minutes since I had turned off the engine. At that point, the headers were cool enough to touch. I tried the key again, and it started perfectly. Again, the starter sounded like it always sounds, strong, solid. Battery seemed like a brand new battery. I spoke with a mechanic friend, and he suggested that since the headers curve around the starter, the heat from the tubes might be warming the starter and or solenoid to the point that it overheats (or whatever), and when it cools, it works fine. I wrapped the starter in a Versa Shield heat shield wrap, and that seemed to do the trick. That said, I didn't do a lot of hot weather driving for the remainder of 2019. Now, the problem seems to be back (if it was ever really gone). I've had the same issue twice this week. Hot engine, warm day, all is right with the world until I turn off the engine, and then try to start it within 115 minutes of shutting it off. In both of those instances, I was parked on asphalt. Oh, BTW, I just finished a long drive, and parked in my garage (concrete floor, not asphalt). I tried starting it up about 10-15 min after shutting down, and it fired right up with no issue. I'd welcome anyone's thoughts. Should I buy a better heat sheath for the starter? Should I wrap the headers with heat tape (I hate to do that for no other reason than I like the way they look).
     
  2. George Womack

    George Womack Y-Block King

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    Common problem with GM type starters. Search "Ford solenoid". I consider it a must-do modification for Scouts. Some will disagree, and they are entitled to their opinions, even if they are wrong. :) Here's a commercially made version:
    http://www.madelectrical.com/catalog/st-1.shtml
     
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  3. mallen

    mallen Y-Block King

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    Maybe the starter is overheating from the headers and the solenoid is sticking. But first, check all connections with a meter. First, the obligatory warning, dont crank for more than 20 seconds or so with a 30 second cool down between attempts or you can damage the starter.

    Test the positive battery cable by putting the positive lead in the center of the post , not touching the terminal, and the negative lead on the terminal. Have a helper try to start the vehicle. If the voltage jumps way up then you have a poor connection. Now move the negative lead to the lug on the battery cable on the starter. (Not the bolt, but the metal lug crimped onto the cable.) Crank it. You should see a larger voltage drop, but if its really huge then theres something wrong in the cable. Now put the negative lead on the bolt that the cable is attached to and repeat the test. Next, put the negative lead on the negative battery post and the positive lead on the negative terminal. Crank it. Next put the positive lead on the lug on the negative cable where it connects to the block. Crank it. Now put the positive lead on a bare spot on the engine where you can make good contact. Clean it off with some sandpaper if necessary. Crank it. Now find a clean spot on the starter housing where you can put the positive lead. Crank it. This test is looking for weak connections between the battery and the starter. When large currents flow though a poor connection there is a large voltage drop and it registers on the meter. If you find anything suspicious clean or repair it. It may help to wiggle a suspect connection and see if it changes the reading. Next check the bulkhead connector. Be careful that you dont strip the screws. Make sure the terminals both on the dash harness side and the engine harness side are crimped properly to their wires. Look for signs of heat damage. Poor connections often get hot. Melted insulation or melting of the plastic connector shell indicate something wrong. Disconnect the battery positive terminal before continuing. These connections are are always hot. Clean the contacts on both sides of the high current loop through the dash with sand paper. If the screws are striped carefully drill them out a bit larger and use some small brass screws and nuts to hold them. I guess you could re-tap the holes but by the point the threads fail the contact has probably been softened by 30 years of heating and cooling those contacts annealing the metal so they probably wont hold.

    Other things to try. Immediately after it fails to start, tap the starter solenoid with the handle of a screw driver or a wrench. If it starts the solenoid is probably sticking. Replace it. While you have the starter out, pop off the top and check the brushes. The parts store probably wont list them for your starter. These are the part numbers.
    Standard Motor Products RX60 , 1114 (package of 4 brushes)
    Ac Delco D746 (packaged as single brush, require 4)

    Here's a limk to the useful part numbers thread post i made some years ago. http://www.binderplanet.com/forums/...ful-part-number-list.8030/page-8#post-1035540
     
    Last edited: Aug 9, 2020
  4. scoutboy74

    scoutboy74 Lives in an IH Dealership

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    I agree with George's assessment. It's most likely typical starter heat soak, commonly solved by the remote relay process. It doesn't hurt to check for and eliminate any other potential weak links in the chain as outlined by Mallen, but where it seems to be very temperature sensitive, your best bet at solving it is with the remote relay.
     
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  5. mallen

    mallen Y-Block King

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    Your best bet is always to follow diagnostic procedures, and know exactly what the problem is first instead of guessing. You only fix problems youve diagnosed when at all possible. (Sometimes its impractical for example , if diagnostics require tearing a huge amount of dissasembly or you lack expensive equipment)

    But just throwing a relay in isnt a good place to start. If there's a large voltage drop in the main loop or in the wire from the ignition switch to the starter, then the solenoid may not engage. So you put a relay in so the wire from the ignition switch carries less current and it works. But all you really did is put a band aid on it to cover up the problem. Eventually on old vehicles the entire thing just grinds to a halt under the weight of all the bandaids and it ends up a wrecker. The starter circuits worked just fine for 40 years without that extra relay. Its a better idea to find the fault and fix it properly. If at the end, you find that theres a problem that is just impractical to fix, then the band aid might be appropriate, but only after you KNOW what the actual problem is.

    The reason I suggest going for the electrical issues first, is because they are easy and cheap to fix. Its so old, your likely to find a few. But they are simple to trace down and cheap to fix. So you look for those first rather than spending money throwing this and that at it. I can't say enough times, always diagnose first before throwing parts at it if possible. How many stories do we hear about people who tried this and that and it STILL doesnt work. Now they spent a ton of money, made a bunch of modifications and not only does it not work, there are four NEW things that may be contributing so now, even if you fix or have fixed the original problem, it still wont work. (And when I ignore my own advice I end up with an extra 50 buck ignition coil in the parts box because I was so SURE that must be it. So I just ran out and bought one. All to avoid a simple visual inspection of the bottom of the duraapark box where my nose and eyes would have spotted the burned box, because I was so sure it was almost certainly the coil. Diagnose FIRST)


    While I say go for the wiring first, my best guess is that the real problem is the heat from the headers. The starters overheating and the solenoid sticks. Maybe if you put a relay in that extra half volt ot volt ot whatever will kick over solenoid. But the starters still being overheated. The fist thing Id try after checking the wiring is a halfass insulator made from from some fiberglass insulation wrapped in aluminum foil. Hold it to the starter with some bailing wire. Maybe a sheet of ptfe or silicone could be in order if its too near the wiring. (Wear gloves and some old clothes you can throw away when handling that insulation Its terrible when it gets in your skin) If that makes the problem go away, you have discovered the problem. If your careful in making it, it could be a permenant fix. Perhaps get some of those metal wire ties off ebay.
     
  6. scoutboy74

    scoutboy74 Lives in an IH Dealership

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    I wasn't contradicting you, rather I'm looking at this from a cut to the chase standpoint. The relay is inexpensive. It's not like we're talking about throwing a new camshaft in the engine. And the relay modification is more than just a bandaid. It's a time tested solution to a very common problem that has vexed a multitude of vehicles from this era that use the Delco starter motor. We've all agreed so far that heat is a major contributing factor. If he was having starter performance issues all the time, then I'd be more apt to jump on the electrical issues bandwagon. And again, I'm still not telling the guy that he shouldn't look for obvious electrical problems also. I can't state that point any more clearly than I've already done multiple times.
     
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  7. mallen

    mallen Y-Block King

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    I think insulating is the first thing to try. Its cheapest and i bet thats the problem. The relay wont stop the heat from causing more damage.
     
  8. winchested

    winchested Y-Block King

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    New solenoids are literally 10 bucks, put a new one in. I used the standard motor parts one made in Mexico. Works every time I turn the key and my engine bay is always hot when wheeling.

    Then put a stainless steel heat shield around it like there was from the factory and I'm sure all your issues will be solved.
     
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  9. Ron A

    Ron A High Wheeler

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    At the very least you need the factory style heat shield on the starter. FWIW I am running 1 gauge cables on mine, a Thermo Tech starter blanket and a remote solenoid, in addition to the factory heat shield. If you have those cheesy battery cable repair ends I would replace the cables. Double check the ground at the engine block. I know it works most of the time but check and clean it anyway. The already suggested remote solenoid is worth doing. It can help fix this problem, but the best thing is does is get your other wires out of the heat and up on the firewall where they are better protected and you can get to them.
     
  10. Kurt_M

    Kurt_M Farmall Cub

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    I have an 89 Chevy with 454 that had this problem constantly. But on it I could always crawl under the truck and short the battery cable to the solenoid terminal with a screwdriver and it would always go. So on it wasn't voltage drop in the battery cable or the solenoid sticking it was heat related voltage drop in the wire from the solenoid to the key switch. I just put a cheap universal relay in the solenoid wire, mounted it to the back of the alternator, got my hot from the alternator bat terminal and all is well.
     
  11. Big Dog

    Big Dog Farmall Cub

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    Gentlemen, I appreciate all of your input. Time for me to get on it.
     
  12. MrKenmore

    MrKenmore Y-Block King

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    I recommend the rewire with a Ford style relay. Works great. Check my signature for a write up. I did this on my Terra (2WD just like you) and my 75 Travelall. I'm only sending juice down to the starter in the "crank" position.
     
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  13. 1975IH200

    1975IH200 Y-Block King

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    Part number ST-124 is the "heavy-duty" solenoid.
     
  14. RinTX

    RinTX High Wheeler

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    Waaaay back when I was young and had a VW bug - this was a common problem and the screwdriver start was well known. On those things the battery was under the rear seat and it was a long way in an undersized wire fwd to the ignition switch and then back aft to the starter. Place ignition/key in “run”. Crawl under with screwdriver and she starts right up.
    Wish I knew about remote start relays back then...
     
  15. 1975IH200

    1975IH200 Y-Block King

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    Just an FYI.........
    I have seen stories on the TV where people have started their trucks in that manner.
    However, they inadvertantly left their manual transmission in gear and the vehicle started and drove over their body causing major damage to them. One guy had brain damage and was lucky to have lived.
    So be aware of the danger in doing this procedure.
    It is better to use a remote start button as sold in auto parts stores, Sears, etc. to start the vehicle when needed for maintenance, etc.
     

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