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Technical Blue spark plugs

Discussion in 'Traditional Hot Rods' started by 28 Ford PU, May 5, 2017.

  1. 28 Ford PU
    Joined: Jan 9, 2015
    Posts: 408

    28 Ford PU
    Member
    from Upstate NY

    I need some advise with reading

    The photo below shows bluing on the first few threads

    Should I be ok or am I supper lean

    [​IMG][​IMG]

    Thanks



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  2. Jalopy Joker
    Joined: Sep 3, 2006
    Posts: 23,974

    Jalopy Joker
    Member

    what kind of motor & ignition? - possibly overheated
     
  3. Gene Boul
    Joined: Feb 9, 2006
    Posts: 807

    Gene Boul

    Might be overheat...duh! You think?
     
  4. deathrowdave
    Joined: May 27, 2014
    Posts: 2,009

    deathrowdave
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  5. 28 Ford PU
    Joined: Jan 9, 2015
    Posts: 408

    28 Ford PU
    Member
    from Upstate NY

  6. 28 Ford PU
    Joined: Jan 9, 2015
    Posts: 408

    28 Ford PU
    Member
    from Upstate NY

    Not sure what you mean by over heating. My temp gauge reads constant 160 degrees. Sometimes my electric fan doesn't come on.

    I would like to know what you think is causing the heat. I'm running autolites 764 coppers. Should. I go to a colder plug?


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  7. bonzo-1
    Joined: Oct 13, 2010
    Posts: 326

    bonzo-1
    Member

    Is that the correct plug? Are the threads in the combustion chamber?
     
  8. bonzo-1
    Joined: Oct 13, 2010
    Posts: 326

    bonzo-1
    Member

    Looks like a really long reach.

    E6SE and GT40 heads take a 14mm plug with 0.708" reach
     
    Last edited: May 5, 2017
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  9. Truck64
    Joined: Oct 18, 2015
    Posts: 3,859

    Truck64
    Member
    from Ioway

    Plug reading is tricky. It takes a lot of experience to know what you're looking at. It's not anything like what people popularly think it is, the porcelein color is just one thing, and modern fuels don't react the way they used to. The stock heat range plug is usually perfect or near enough, for most uses.

    Extended interstate cruising in the summer, a cooler plug is probably indicated. But a grossly mistuned carburetor, with oily fouled plugs, is not a reason to switch heat ranges. This is very common.

    Wideband o2 sensors aren't being given away yet, but they are worth every cent for carburetor tuning. Still need to look at plugs, but the widebands take a LOT of the guess and by golly out, especially for people who didn't grow up reading plugs.

    Make sure your ignition and ignition timing & distributor advance is all squared away. A strong, hot spark is required. THEN tune the carburetor, get it dialed in, the idle and cruise circuits, power, transition circuits, etc, are all different and will be evident in a different part of the plug. For example, wide open throttle mixture is observed way down inside the plug, where the plug shell transitions to the porcelein. Need a strong light and magnifier. The ground strap shows heat range, and believe it or not, ignition timing and advance. This takes experience. Going too lean under load will nuke pistons, so getting this right is important.
     
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  10. stimpy
    Joined: Apr 16, 2006
    Posts: 3,547

    stimpy

    the plug is too long and in the chamber , check the head number and see what the proper plug reach it should have , if it was too lean it would be ash white with no brown color , and this includes the strap .
     
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  11. 28 Ford PU
    Joined: Jan 9, 2015
    Posts: 408

    28 Ford PU
    Member
    from Upstate NY

  12. 28 Ford PU
    Joined: Jan 9, 2015
    Posts: 408

    28 Ford PU
    Member
    from Upstate NY

    Running plug 764 14mm / .708 reach




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  13. deathrowdave
    Joined: May 27, 2014
    Posts: 2,009

    deathrowdave
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    from NKy

    That is correct plug for GT40P head that you have . I still say lean , your using injected plug on carbed engine, cool it down a heat range and try it , also richer up the carb a bit
     
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  14. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 4,844

    Ebbsspeed
    ALLIANCE MEMBER

    The porcelain on the OP's photo would indicate that the heat range of the plug is acceptable. Colder plug AND richer mix will darken the porcelain quite a bit.
     
  15. 28 Ford PU
    Joined: Jan 9, 2015
    Posts: 408

    28 Ford PU
    Member
    from Upstate NY

    I'm running 3 Stromberg 48s on a early 302 with a tunnel ram.

    Uncle Max suggested open the Jets up a .001. I took all 3 carbs off and got them ready to go back on tomorrow.

    Max is the man I don't question any of his opinions. I'll see what happens over the weekend and I'll let you guys know how I made out.

    I can't believe this site it's full of instant knowledge there is no other place like it.

    Thanks

    I threw a couple picture on of my truck.

    [​IMG]

    [​IMG]


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  16. gimpyshotrods
    Joined: May 20, 2009
    Posts: 16,502

    gimpyshotrods
    Member

    Some plugs are blue in tint from the factory:
    [​IMG]
     
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  17. 28 Ford PU
    Joined: Jan 9, 2015
    Posts: 408

    28 Ford PU
    Member
    from Upstate NY

  18. Jalopy Joker
    Joined: Sep 3, 2006
    Posts: 23,974

    Jalopy Joker
    Member

    Cool truck - interesting manifold choice to run with those carbs - from a site "The Hot Rod Garage" :heads changed in early '97 - talk about using Autolite 104 instead of 764 w/ .054" gap there is a difference in length of plug - also, NGK TR55 as alternative - the '93-'95 Cobra/explorer GT40 heads were milled to bring it's larger combustion chamber down to size of E7 heads to keep compression up - others say bluing of plug is due to plug itself overheating
     
  19. butchcoat1969
    Joined: Apr 1, 2017
    Posts: 165

    butchcoat1969

    I agree 100% even though ur running what it calls for it will react diff to a carb run motor and it looks a little to LAN to me to, jmo hrh


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  20. Engine man
    Joined: Jan 30, 2011
    Posts: 3,476

    Engine man
    Member
    from Wisconsin

    The threaded portion of the plug should be transferring the heat to the head. Antiseize should help do that.
     
  21. 28 Ford PU
    Joined: Jan 9, 2015
    Posts: 408

    28 Ford PU
    Member
    from Upstate NY

    I opened up the jets a bit and it looks much better. My next move will be an increase in power valve size. I feel real confident with my idle and mid range it's the WOT that still looks a bit lean.

    I love the suggestion of anti-seize on the threads to help transfer some heat. It's quick,cheap,and almost effortless. From there I'll try the Autolite #104's.

    I may be old school and I may be cheap, I've always been a big fan of the Autolite copper plugs. You can keep your $5.00 plugs with the titanium electrode with split ground strap wiz-bang stuff. I think the olé coppers will give you the biggest bang for the buck (No pun intended).


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  22. 28 Ford PU
    Joined: Jan 9, 2015
    Posts: 408

    28 Ford PU
    Member
    from Upstate NY

    Hey, Thanks for the thumbs up and info.

    The Strombergs took a little time to get them March to the same beat but it will idle all day @ 800 rpm now and I have no problem running it on the street. When you hit it,it's instant get-up and go. More so than I have had with any other. Gets a lot of looks too.


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  23. Engine man
    Joined: Jan 30, 2011
    Posts: 3,476

    Engine man
    Member
    from Wisconsin

    It's always a good idea to use antiseize on spark plugs, especially tapered seat plugs that have a nasty habit of not coming out.
     
  24. THE FRENCHTOWN FLYER
    Joined: Jun 6, 2007
    Posts: 2,811

    THE FRENCHTOWN FLYER
    Member
    from FRENCHTOWN

    No offense to your uncle, but I don't think carb manufacturers recommend drilling out the jets .001". Drilling may cause the internal passageway to be left with a rougher surface that original and the rougher surface can reduce the flow thru the jet such that even though you made the opening bigger the flow thru the jet may actually be less.
     
  25. 28 Ford PU
    Joined: Jan 9, 2015
    Posts: 408

    28 Ford PU
    Member
    from Upstate NY

    Let me clarify it a little. The good uncle told me to step it up a bit so I did it the Traditional way with a .047 drill bit

    That's what we're all about isn't it



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  26. alphabet soup
    Joined: Jan 8, 2011
    Posts: 1,353

    alphabet soup
    ALLIANCE MEMBER

    Drilling jets...I think everyone that's fooled with hot rods has done it at least once. Yes from what I can tell it's lean. I would be as worried about black specs on the center porcelain. They mean you are getting things hot enough to flake the top piston ring.
     
  27. lippy
    Joined: Sep 27, 2006
    Posts: 4,228

    lippy
    Member
    from Ks

    Frenchtown Flyer, You are correct. Even as you know jets are so sensitive to hole finish and hole inlet and exit shape and finish. You can buy jets brand new and send them out to be flowed, (like for injection) and even though they are manufactured by the same company and made with precision equipment, they will flow differently. Lippy
     
  28. lippy
    Joined: Sep 27, 2006
    Posts: 4,228

    lippy
    Member
    from Ks

    I read the mixture by the runningboard finish. LOL Lippy
     
  29. 28 Ford PU
    Joined: Jan 9, 2015
    Posts: 408

    28 Ford PU
    Member
    from Upstate NY

    I'm not being a jerk here. Could you explain to me want would sending the jets out to be flowed for a driven show car.


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  30. Falcon H
    Joined: Mar 11, 2015
    Posts: 138

    Falcon H
    Member
    from Waco Texas

    It looks like the sparkplug is tempering from the heat. That color looks like about 550°F to me.
     

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