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Hot Rods Grounding battery to header bolt

Discussion in 'The Hokey Ass Message Board' started by F1 Ford, Dec 18, 2020.

  1. F1 Ford
    Joined: Jul 26, 2013
    Posts: 40

    F1 Ford
    Member
    from California

    Out of curiosity: Is that ever an issue for folks? I've had some intermittent hot start issues. Is this generally not a good spot for a ground? I've never really had to put this much thought into a hot start issue before (i.e., everything worked before or the fixes were pretty straightforward). 350 Chevy Small Block, HEI ignition. Car came with the ground in this location with this problem.
     
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  2. Mr48chev
    Joined: Dec 28, 2007
    Posts: 32,131

    Mr48chev
    ALLIANCE MEMBER

    That may not be the total cause of the issue but I'd say it is a contributing factor. I've never seen a Header bolt that doesn't get a bit of rust on the threads and depending on what the header is coated with you may not have the best conductor. I'd go with bolting the ground to either a bolt hole on front of the head or maybe one of the holes that normally are used for Tri 5 motor mounts down on the front of the block. scrape down to bare clean shiny metal and then go get new Heavier gauge battery cables. No matter what the self styled experts say those skinny oem size cables don't carry the amps like fatter cables will, That helped my OT big block in my Dualie as much as putting the Ford starter solenoid on.

    Running one of the Ford solenoids does help a lot though. No fancy kit needed just a regular old off the shelf solenoid for a 60/70 something Ford and a copper cable terminal with a 3/8 hole that you flatten, trim and drill a hole in the right spot for the S post.

    Still clean, bare and shiny connection points are your friend..
     
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  3. ^^^ Great advice, and don't forget your star washers and a dab of di-lectric grease to minimize corrosion^^^
     
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  4. My ground is on the block at the bellhousing. I used a bolt that links the engine and tranny next to the starter. I figure the closer the ground to the starter the better.
     
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  5. Truck64
    Joined: Oct 18, 2015
    Posts: 5,325

    Truck64
    Member
    from Ioway

    A lot of people ground the battery neg terminal directly to starter bolt, or near it, for that reason.

    It isn't just the gauge of the cables that matters, there are a lot of crap generic electrical parts out there and battery cables are right up there at the top. Those generic blister-pac replacements are junk.
     
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  6. Your headers get hot, the heat transfers to the copper and hardens it adding resistance to the wiring.
    Move it to the bell housing or another spot.

    it will “ work” off a header bolt but definitely not ideal.
     
  7. I use a Ford style solenoid on my SBC, a holdover from my stock car career. For a general negative cable ground I go with a stud on the water pump. I also add a ground strap from the rear of a cylinder head to the firewall.
     
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  8. Petejoe
    Joined: Nov 27, 2002
    Posts: 11,610

    Petejoe
    ALLIANCE MEMBER
    from Zoar, Ohio

    A lot of hot start issues are associated with too far advance timing. Retard it a bit and see what effect it may make.
     
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  9. F1 Ford
    Joined: Jul 26, 2013
    Posts: 40

    F1 Ford
    Member
    from California

    Thanks for the replies. I always appreciate your responses, 48 Chev. I did the remote Ford solenoid move. Dropped to 2 gauge battery cable. Checked the timing. (It is for a Tri-Five, incidentally.) I was just thinking last night that the ceramic coated header wasn't the best spot, for some of the reasons mentioned here. I'm going to relocate the ground. Thanks again.
     
    Last edited: Dec 18, 2020
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  10. Boneyard51
    Joined: Dec 10, 2017
    Posts: 6,107

    Boneyard51
    Member

    We have found out in the Firetruck industry that star washers can cause problems and are now not recommended! I personally have had problems using star washers allowing moisture to collect in them causing rust on the cleaned frame and breaking connections. Granted a fire truck sees more water than the average vehicle, but a problem is a problem. Just my experiences.








    Bones
     
  11. BamaMav
    Joined: Jun 19, 2011
    Posts: 6,028

    BamaMav
    Member
    from Berry, AL

    I never use the star washers, if I use anything it's a split lock washer, but I always try and use the di-electric grease. That stuff is great! Not only keeps corrosion at bay, also acts as anti-seize to help take the bolt out later!
     
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  12. TOD1940
    Joined: May 29, 2011
    Posts: 13

    TOD1940
    Member

    You can do a quick check of the grounding circuit by connecting your voltmeter between the Neg post of the battery to the case of the starter. Crank the engine and read the volt meter, it should read 0.1V or less while cranking.
     
  13. F1 Ford
    Joined: Jul 26, 2013
    Posts: 40

    F1 Ford
    Member
    from California

    Good suggestion. Thanks.
     
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  14. Boneyard51
    Joined: Dec 10, 2017
    Posts: 6,107

    Boneyard51
    Member

    I think 48Chevy answered all your questions. I would never ground to a header bolt for two reasons. 1: Header bolts tend to rust and the severe heat cycles promote poor contact. 2: Looks tacky! Lolo_O







    Bones
     
  15. 1971BB427
    Joined: Mar 6, 2010
    Posts: 7,806

    1971BB427
    Member
    from Oregon

    My biggest concern with using a header bolt is heating and cooling. It's not uncommon for header bolts to loosen over time from expansion and contraction, so anything that sees that much heat is a poor place to ty to make good contact.
    Additionally the headers have a gasket, which is a soft point, and allows the connection to be less solid. I'd use the block, heads, or bellhousing bolts for a better connection.
     
  16. jaracer
    Joined: Oct 4, 2008
    Posts: 1,832

    jaracer
    Member

    Excellent reply, that test confirms the condition of the ground. You beat me to it.
     
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  17. Truck64
    Joined: Oct 18, 2015
    Posts: 5,325

    Truck64
    Member
    from Ioway

    0.2 volts in the ground circuit is considered the acceptable limit, though the lower the better. For some reason the positive side will always read a little higher - maybe 0.3 volts. Anybody know why that is, exactly?
     
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  18. I also use the grease on the battery terminals, and don't use star washers.
    Bob
     
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  19. Paul
    Joined: Aug 29, 2002
    Posts: 15,963

    Paul
    Editor

    also consider a hot conductor has more resistance than a cool conductor.
     
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  20. MAD MIKE
    Joined: Aug 1, 2009
    Posts: 719

    MAD MIKE
    Member
    from 94577

    Dielectric grease is an insulator.
    Do not use it if you want better conductivity.
    We use it on spark plug boots to improve insulation, remove the possibility of carbon tracking(grounding) on plugs and boots to maintain ignition performance.

    Ox-Guard/Noalox or other similar anti-oxidant compounds aid in improving conduction while reducing galvanic corrosion between two dissimilar metals. Mostly on specific aluminum alloys but also a good idea to used anywhere there is a possibility of water intrusion, a connection is exposed to the elements, or if in a corrosive environment.

    A proper main ground/bonding connection shall be single purpose.
    Fastener used to connect the main ground/bond should provide clamp load, it should not be the conductor itself. Cable end(terminal) to body/block/frame connection is the electrical connection, not the fastener itself. Much like a lug not does not hold the wheel on, it provides the clamp load to hold the wheel on.

    Using a header bolt is probably one of the worst ideas. Not only is it a high heat area(increase in resistance), but it is also usually partially insulated(gasket), and undersized for a solid bonding connection as fastener sizes go. It's fairly volatile as mechanical connections go with expanding and contracting due to heat. As noted the heat will anneal and harden the copper, which will affect its ability to conform(cold flow) and increase it's available surface area to make a connection. Not good at all for a desired solid electrical connection.

    Starter bolt is also not a good spot.
    It's great for the starter motor, if the connection maintains clamp load, but not so much for the entirety of the electrical system.

    Main ground connections should be made in a way that they will not be regularly molested during maintenance. 'Set it and forget it'. It should be a connection that will be ignored outside of inspection.
    A cylinder head stud-bolt is the best solution, easy access/inspection. Doesn't require molestation unless major engine service is needed. But is unsightly on most hot rods/customs.

    When it comes to SBCs the most common spot I see a main ground wire connection is usually at the upper right front engine mount hole. The same hole that is usually not used on later models for anything except to plug the oil pump pushrod hole. Great spot as you would normally not use it for anything else. Just make sure that if you need a longer bolt, it does not interfere with the fuel pump pushrod.

    If you are using front mounts and the block has side mount bosses, use the unused side mount bolt holes as a main engine bond. Clean out the threads, clean the machined surface where the mount would normally rest against, use an appropriate length bolt and hardened washer to compress(cold flow) the terminal with a proper clamp load.

    If you don't care about seeing the main bond/ground, on later model engines, just bolt it to the side of the head using one of the ancillary bolt holes. For a cleaner install, use the firewall side holes to hide it.

    On Tri-5s IIRC they are similar to the '54 and earlier cars, which is kinda a garbage bonding setup. Especially if you are now using electronic equipment.
    Short Negative wire to the battery tray/fender and another short connection between engine and body. Which normally that would be OK, but since fenders are not always the most permanent of parts and fasteners loosen up, the main ground/bond is not the most secure(electrically). A proper ground/bond wire should go to the block, and a smaller ~10ga wire from the battery terminal to the body, followed by the grounds between engine and body.
     
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  21. The ceramic coating on the header would also be a factor in not being a good ground.
     
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  22. Truck64
    Joined: Oct 18, 2015
    Posts: 5,325

    Truck64
    Member
    from Ioway

    Silicone grease, petrolatum, axle grease, they all do the same thing though some are better than others - protect the electrical connection from corrosion due to road spray and salt.

    The idea is that the underlying metal "plows" through the grease and makes the connection, it doesn't act as an electrical insulator, it excludes the air and moisture. If it did act as an insulator there wouldn't be eleventy bazillion corrosion preventive electrical compounds that are applied to grounds, cables, connections, SAE connectors, cannon plugs, block connectors etc..
     
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  23. As several posters have noted, heat increases resistance. It doesn't matter if the heat is applied externally or generated internally, connecting to a point that gets hot will increase your voltage drop. The other issues matter too, but this is the big one that can't be fixed. How much? Well, a common example is the 1157 brake light filament; if you check resistance though the lamp 'cold' (deenergized) it will measure at about 2.2 ohms. That increases to about 6.1 when 'hot', a 270+% increase or almost triple. While you probably won't see such a dramatic increase in a conductor, even a small increase can have a big effect in a high-current circuit. An additional .1 ohm of resistance in a 10 amp circuit will drop just 1 volt; increase the current to 200 amps (a typical starter draw) in the same circuit and that skyrockets to 20 volts, or more than is available in a 12V system. If the heat increases the resistance by only .01 ohm, that's still a 2V drop or 16%, more than enough to cause problems. Add in the fact that if a motor sees low voltage, it will draw more current in attempting to do the same work which only increases the drop further.
     
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  24. If a connection is sub-standard you might be able to inspect it for arching pits or other tell-tales.
    In a very general way, I'm a believer in more than one ground cable...... not a spider web all converging on the battery, but maybe a simple daisy chain, ie: chassis to block - block to main ground point. I wouldn't go looking or 'imagining' trouble or trying to fix something that isn't broke. But if I had a project from scratch, such as new gauges, I might run their ground to the cleanest, most direct path that presents itself.
    In my racing days, back in the previous century, somebody I can't remember put a bug in my ear that it might be a good idea to ground the heads for the sake of the sparkplugs. We all overthink something sometimes. Maybe I'm doing that about grounds. (?) :rolleyes:
     
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  25. I am not an expert, but when I wire a car I always ground to the frame and then ground the engine/trans to the frame in more than one place. I like lots of ground points.
     
  26. Boneyard51
    Joined: Dec 10, 2017
    Posts: 6,107

    Boneyard51
    Member

    Mad Mike, I was right there with you all the way...... til you said to use a head bolt! I don’t think that’s a good idea, for several reasons. There are better places available on the block, some actually made for the ground.
    Also, I kinda like to put the ground in an easily accessible place so that I can check it easy.
    Other than that, man, I’m in your corner!










    Bones
     
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  27. Boneyard51
    Joined: Dec 10, 2017
    Posts: 6,107

    Boneyard51
    Member

    I prefer to go directly to the engine with the ground, then ground the frame from the engine. In most cases, the biggest load is the starter, there should be the primary ground!






    Bones
     
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  28. Yep, that's the best method. Compared to the starter, all the rest of the loads are peanuts.... Just don't use the exhaust!
     
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  29. I use gaskets with headers and never seize on the bolts so that would be a no for me.
    Don’t know if ya lose anything with the never seize.
    I like a ground to chassis, then a ground from the chassis to the engine block. But I understand the vice versa.
    I worked on a lot of new cars that had the ground to body(unibody stuff). The engine would have a couple grounds from engine to body.
     
    Last edited: Dec 18, 2020
  30. Not going to really help your hot start problem like the Ford solenoid will (or mini starter/newer GM starter), but you can never have too many grounds (without being cartoonish). Ground from block to frame, body to frame and battery to frame and all minimum of 4 gauge. I usually go to a engine mount bolt (if side mount bolt holes are there) or the holes on the lower front (and NOT the fuel pump rod hole).
     
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