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FORD 302 ELECTRONIC IGNITION PLUG GAP????

Discussion in 'Off Topic Hot Rods & Customs' started by ALLDONE, Aug 19, 2025.

  1. ALLDONE
    Joined: May 16, 2023
    Posts: 3,976

    ALLDONE
    Member

    i GOT A CHINA VIRUS DIST OFF EBAY... they advertise coil @ 45k... and say gap the plugs at 45....since putting this dist in..runs like a ****d ape mid and top end...but shakes like a dog ****ting razor blades at idle... could it be the cheep coil is less than advertised??? and 45 gap is too much???could it be spark blow out??? should I re gap the plugs to 40 or even 35.. I would guess wrong plug gap is gonna be the most noticeable at idle?????... did a lot of searching... only to find too many answers..... some say never go bigger that 35???? other than reading the box... how would you see the 45k volts on the coil??? what would you do or try... throwing in the towel for today... started a 3am and it 8 pm now... enough is enough.
     
  2. jimmy six
    Joined: Mar 21, 2006
    Posts: 17,170

    jimmy six
    ALLIANCE MEMBER

    You can go down to .020-.025” to make it easy on the system to check.
     
  3. onetrickpony
    Joined: Sep 21, 2010
    Posts: 863

    onetrickpony
    Member
    from Texas

    Is the timing jumping around at idle? If the mechanical advance system is not working right, it can cause those symptoms.
     
  4. ALLDONE
    Joined: May 16, 2023
    Posts: 3,976

    ALLDONE
    Member

    I have a back to zero timing light...timing is steady, and have it set @ b34 all in... could maybe be in the valves...maybe not seating at idle?? I loaned out my compression gauge...and I always tell others... no better time to check compression as when you already have the plugs out.. I guess i'm like most others here... I don't listen to me either....lol... my wife says I never listen,,,,I say if I never listen... that means I don't hear you say I never listen... any way... I feel like Ray Charles playing darts.... some one needs to point me in the right direction to even get started..

    another thing.. the exhaust is split ..with no cross over.. doing a hand test at the tail pipe the left side is weak compared to the right... soooo.. either the left is not firing,... or valves not right??? could be the valves are too tight from the rebuild???... anyway... nothing seems to easy at my ford barn...
    I have a back to zero timing light...and set the total at 34.. with the va***e advance hooked up... no tach but it's at the 34 wot...idle it is smooth at the timing mark...could be internal.. like sticky valves??? loaned out my compression gauge so need to get it back...maybe even bent or not seating valves...I feel like ray charles playing darts , some one needs to point me in the right direction to even
     
  5. mustangsix
    Joined: Mar 7, 2005
    Posts: 1,549

    mustangsix
    Member

    A big gap is sometimes useful if you have an engine that's tuned to run lean. Not really necessary if you aren't concerned with idle emissions.

    Try closing it up to .035. If it's a gap issue, that should show it. Next suspect would be the initial timing too high or low, then the coil.
     
    ALLDONE likes this.
  6. TrailerTrashToo
    Joined: Jun 20, 2018
    Posts: 1,484

    TrailerTrashToo
    Member

    Maybe a quick trip to Harbor Freight for a compression gauge? Might save hours of guessing.

    Russ
     
    ALLDONE likes this.
  7. ALLDONE
    Joined: May 16, 2023
    Posts: 3,976

    ALLDONE
    Member

    went looking in my old harley tool box.... found a compression gauge.... from somewhere in the 1970 era,,,, trusty...the things you don't wanna find when you go looking...got up this morning and said... I'm gonna start over... from scratch ... getting a bald spot from head scratching...with all the plugs out, and valve covers off.. I started over... my quest... find out whats wrong,,

    so compression test... all is going great... started with 5-8 (left side) all between 150 and 155... go to the right side 1&2 same... put the gauge in # 3... ahh ooh... sum ting wong.... I hear compressed air coming out of #4 and it only has 60 #'s...know i was done... I just had to know for sure..hooked up #4... same 60 lbs,,, so there you have it... like said... start with a compression test and save a lot of time... the last thing I needed the first thing this morning.....
     
    Deutscher likes this.
  8. jimmy six
    Joined: Mar 21, 2006
    Posts: 17,170

    jimmy six
    ALLIANCE MEMBER

    Don’t loan tools…..send your friends to HF.
     
  9. ALLDONE
    Joined: May 16, 2023
    Posts: 3,976

    ALLDONE
    Member

    I loaned it to my son, he's the one thats gonna fix this truck. he said bring it down and let me pull the head...might get lucky and just need a gasket.... I said... like the T bird that I had to buy a new motor???
     
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  10. ALLDONE
    Joined: May 16, 2023
    Posts: 3,976

    ALLDONE
    Member

    my other gauge was a leak down...only leak down I'm doing is on the tree in the back yard
     
  11. 6sally6
    Joined: Feb 16, 2014
    Posts: 2,936

    6sally6
    Member

    "Maybe" a little shade tree trick to try sometime.......To see which cylinder ain't firing.... get the engine warm and then squirt each exhaust port on the manifold with a squirt bottle full of water ! The one that DON'T sizzle....is the weak one.
    Beats pulling each plug and examining it. ('Specially if all sorts of special ranches are needed to pull the plugs with...)
    6sally6
     
  12. slowmotion
    Joined: Nov 21, 2011
    Posts: 3,707

    slowmotion
    Member

  13. ALLDONE
    Joined: May 16, 2023
    Posts: 3,976

    ALLDONE
    Member

    thanks ,.. I use a temp gun...and I have the tool for the spark plug that lights up when it fires..
     
  14. ALLDONE
    Joined: May 16, 2023
    Posts: 3,976

    ALLDONE
    Member

    ^^^^^^^^^^^^^^^^^^^^^^^^
     
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  15. ALLDONE
    Joined: May 16, 2023
    Posts: 3,976

    ALLDONE
    Member

    sooo other than that, I'd say my diag is spot on... can't think of anything else it could be....????????????????????
     
  16. ALLDONE
    Joined: May 16, 2023
    Posts: 3,976

    ALLDONE
    Member

    Today,or in the next few days I'll get the head off and see.... again... any other ideas??? kinda deja vu of the 55 tbird... ended up with a new motor......hope thats not the case and I can just replace the head gasket
     
  17. MAD MIKE
    Joined: Aug 1, 2009
    Posts: 965

    MAD MIKE
    Member
    from 94577

    Before yanking heads.
    Squirt oil in the sparkplug hole and see if it increases compression. That would point to cylinder/piston/rings issue.
    If no change, pull valve cover off and use a straight edge across valve stems.
    If one of the valves on suspect cylinder is lower than others it could be from a tight fit, bent valve or a failed spring.

    I've had weird compression results when a spiral lock failed on a full floating pinned piston.
    It was notable during compression check, rather than e.g. ~60>90>120 normal jumps, it did 20>35>135 compression jump.
     
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  18. ALLDONE
    Joined: May 16, 2023
    Posts: 3,976

    ALLDONE
    Member

    thanks for posting... when I put the compression tester on #3 50 psi. and it blows out #4 and same thing when I do #4,,, it blows out # 3... if it was valves... it would blow out the carb or the exhaust.. both 3&4 have 50lb
     
    SS327 likes this.
  19. ALLDONE
    Joined: May 16, 2023
    Posts: 3,976

    ALLDONE
    Member

    Sooooo.... got the head off.... sorry to say I was right...

    77904289259__EE6B9151-E8B8-4565-ABA7-20BC181CCF48.jpg


    I'm going with bad torque.....????
     
  20. ALLDONE
    Joined: May 16, 2023
    Posts: 3,976

    ALLDONE
    Member

    anyway... got this truck back together , hitting all 8 now... what a difference...when I pullup to a light I have to look at the gauges to see if it's still running... purrs like a kitten till the lake pipes roar... IMG_5445.jpg IMG_5447.jpg
     
    Mike Lawless and onetrickpony like this.

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