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Technical Flathead 8ba dry fouling plugs

Discussion in 'Traditional Hot Rods' started by JJ305WA8BA, May 16, 2021.

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  1. JJ305WA8BA
    Joined: May 16, 2021
    Posts: 12

    JJ305WA8BA

    Thanks ahead of time for any thoughts! My Dad and I are trying to prep for the summer shows with his '30 coupe, but are having a problem with carbon fouling a set of champion H10-C plugs. We have a 8BA flathead, Isky Max cam, Offy heads and manifold with 2X super 97's (45 main jets) and progressive linkage from Speedway. Dizzy is a Mallory with Pertonix 1 ignitor and flame thrower 1.5 ohm coil, wires are spiral wound 7mm and Fuel at 1.5-2.0 psi running non ethanol fuel.
    We've checked timing (4* btdc) wont idle under that. Changed wires and cap on dizzy, tested coil, replaced 97's main jets to 43's. But continue to carbon foul plugs. Tried NKG plugs ( direct replacement) gapped @ .030 but with the same fouling. Idle jets look fine, starting at 2 turns out rough idle smooths out around 1500 adjustment doesn't seem to help significantly. Any thoughts? We're scratching our heads! Maybe hotter plugs? Your help please!
     
    Last edited: May 16, 2021
    stillrunners likes this.
  2. Budget36
    Joined: Nov 29, 2014
    Posts: 6,739

    Budget36
    Member

    I’ve never heard the term “dry foul” before.
     
  3. JJ305WA8BA
    Joined: May 16, 2021
    Posts: 12

    JJ305WA8BA

    Sooty instead of fuel drenched fouling.
     
  4. JJ305WA8BA
    Joined: May 16, 2021
    Posts: 12

    JJ305WA8BA

    [​IMG] carbon fouling or dry fouling
     

  5. karl share
    Joined: Nov 5, 2015
    Posts: 107

    karl share
    Member

    Shitty Fuel ??
     
    stillrunners likes this.
  6. clem
    Joined: Dec 20, 2006
    Posts: 3,406

    clem
    Member

    Have you done a search on the super 97 here on the hamb ? Might be some helpful information.
    Why are they set up progressive, is one a true primary and the other a true secondary ?
    Sounds like it’s running too rich ?
     
    dana barlow and ydopen like this.
  7. clem
    Joined: Dec 20, 2006
    Posts: 3,406

    clem
    Member

  8. rusty rocket
    Joined: Oct 30, 2011
    Posts: 4,236

    rusty rocket
    Member

    I have just about the same setup but using 94’s. I’m encountering the same problem, idles fine but dead spot off idle. Had a guy look at it and he rejet it and changed advance springs in the distributor. Still runs like shit, thinking we need a valve adjustment and drop the springs down to the lightest set. It’s been super aggravating.
     
  9. Glenn Thoreson
    Joined: Aug 13, 2010
    Posts: 211

    Glenn Thoreson
    Member
    from SW Wyoming

    Can you post a picture of the plugs? Folks in the know are able to tell much by what the plugs look like.
     
  10. JJ305WA8BA
    Joined: May 16, 2021
    Posts: 12

    JJ305WA8BA

    Non ethanol fuel, costs more not to add something in!
     
  11. JJ305WA8BA
    Joined: May 16, 2021
    Posts: 12

    JJ305WA8BA

    Thanks Clem, yes one is primary and the other secondary,
     
  12. JJ305WA8BA
    Joined: May 16, 2021
    Posts: 12

    JJ305WA8BA

    Will post asap this morning when I get back up to his place!
     
  13. JJ305WA8BA
    Joined: May 16, 2021
    Posts: 12

    JJ305WA8BA

    Champion H10-C carbon fouled
     

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  14. JWL115C
    Joined: Jan 28, 2010
    Posts: 202

    JWL115C
    ALLIANCE MEMBER

    Power valve leaking?
     
    Truck64 likes this.
  15. solidaxle
    Joined: Jan 6, 2011
    Posts: 555

    solidaxle
    Member
    from Upstate,NY

    If you're using the little air cleaners try running without them.
     
    X38 and wandi harry like this.
  16. JJ305WA8BA
    Joined: May 16, 2021
    Posts: 12

    JJ305WA8BA

    Haven't checked yet, we haven't gotten on the 4 lane yet to test it.
     
  17. JJ305WA8BA
    Joined: May 16, 2021
    Posts: 12

    JJ305WA8BA

    Found that out a few years back, in the trash pile. We're just using screens right now.
     
  18. G-son
    Joined: Dec 19, 2012
    Posts: 794

    G-son
    Member
    from Sweden

    Haven't worked on a flathead and don't have any idea what is the right heat range for them, but I've fouled plenty of spark plugs and I can't think of any other causes I've had than too much fuel or wrong heat range. The plug needs to get hot enough to burn the carbon off, if they remain too cold they'll give up sooner or later. Most sensitive to running rich at idle, as little heat is created then.
     
    gary macdonald likes this.
  19. clem
    Joined: Dec 20, 2006
    Posts: 3,406

    clem
    Member

    I think that what he means is that pv may be leaking at low revs and idle, hence the sooty plugs.....
     
  20. Glenn Thoreson
    Joined: Aug 13, 2010
    Posts: 211

    Glenn Thoreson
    Member
    from SW Wyoming

    Dry black soot is a fuel problem. Something is causing it to run too rich. The H-10 plugs should be fine for normal driving. If you make a lot of short stop & go trips you might want a hotter plug. I agree with the opinion on those little air cleaners. Much too restrictive and only good for show. K&N has finally come out with a filter that fits the Holley 94 and Stromberg carb tops. I'm not convinced they're worth the money, though. I'm also not convinced those new Strombergs are worth the money. I've heard from folks who experienced problems with them.If you're going to run Strombergs you may be better off buying used originals and rebuilding them. All parts are readily available.
     
  21. Flathead Dave
    Joined: Mar 21, 2014
    Posts: 3,389

    Flathead Dave
    ALLIANCE MEMBER
    from So. Cal.

    Hope this helps you

     
    Desoto291Hemi likes this.
  22. F-ONE
    Joined: Mar 27, 2008
    Posts: 2,828

    F-ONE
    Member
    from Alabama

    97s have a very small fuel bowl. It seems they can fill and overcome the needle and seat, even with a mechanical pump. This has been a problem with the big 97....dribbling fuel past the needle, flooding, leaking and a rich condition.

    A simple fix was a tiny return line running from out board the fuel pump the fuel pump to inboard the fuel pump. This relieves the excess pressure off the needle and seat. Being a very small line, and plumbed correctly it has no effect on fuel flow. Likely it's probably a fix for vapor lock as well.
     
    34 GAZ likes this.
  23. justpassinthru
    Joined: Jul 23, 2010
    Posts: 329

    justpassinthru
    Member

    My 8BA Offy heads are the 425 version and require a spark plug with 1/2" reach.

    The Champion plugs you are using have a 7/16" reach.
    I am running NGK B6HS which has 1/2" reach, non protruded tip.

    Offy heads for the 8BA are either the 400 version which has a higher compression ratio or the 425 heads which have a lower compression ratio.

    I can't say for sure, but I would think both heads would have the same plug reach.

    Maybe your issue is from the electrode being too far up in the hole, which I would think can't be good.

    Might be something to look into.

    Bill
     
  24. justpassinthru
    Joined: Jul 23, 2010
    Posts: 329

    justpassinthru
    Member

    I also run an Offy regular dual manifold and two Edelbrock 94s. Both carbs are primary (non progressive).

    I spent a lot of time researching the carb setup and the general consensus was to not do progressive setup on a regular dual or super dual manifold due to the placement of the carbs.
    Cylinders will have uneven fuel distribution due to being further away from the one primary carb.
    Progressive linkage should be only on 3 carb setups, with the center carb being primary.

    Just a thought.

    Bill
     
  25. Just to get things straight, are the carbs Speedway 9Super7's?
     
    Hotrodmyk likes this.
  26. start your idle adjustment 1 1/2 turns out each, turn each one in till it starts to run rough then back out 1/2 turn and your done and use a unisyn to calibrate both carbs to each other...............(do this first)
     
  27. So what has changed since it ran good without fowling ? Did I spell that right ?
     
    Stogy likes this.
  28. clem
    Joined: Dec 20, 2006
    Posts: 3,406

    clem
    Member

    fouling.........
     
    Stogy likes this.
  29. cs39ford
    Joined: May 1, 2012
    Posts: 852

    cs39ford
    Member

    I have been running H 12 champions since Next hotter plug would be H 11 Not made anymore Works out well for me Just a thought Also run adjustable Carb jets Also I am running strombergs 97
     
  30. F-ONE
    Joined: Mar 27, 2008
    Posts: 2,828

    F-ONE
    Member
    from Alabama

    Well since you asked... It's fouling.;)
    Fowling is an archaic term for bird hunting. Below is a smooth bore fowling piece or fowling gun.
    [​IMG]
    Sometimes these guns are called fowlers but technically the hunter was the fowler, who hunted fowl, with his fowling piece.
     

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