Spark plug wire routing

Discussion in 'Tips 'n' Tricks Topic' started by Dennis Wilkie, Sep 22, 2020.

  1. Dennis Wilkie

    Dennis Wilkie Veteran Member

    Messages:
    176
    Likes Received:
    16
    Joined:
    Mar 17, 2020
    I was attempting to break in my new cam and apparently my #7 & #8 plug wires shifted and laid on the headers, and #8 caught on fire. So, before I buy another set of wires, are there any sets with a little more length or better angles to run them under the tubes? Or am I gonna have to go ahead with the sleeves? It's got ZZ4 heads, so the plugs are angled, which does me no favors on #5 - 8, and i've got a set of looms, but never used them because there really wasn't enough room or length on the wires.
     

    Attached Files:

  2. biker

    biker Veteran Member

    Messages:
    2,159
    Likes Received:
    777
    Joined:
    Dec 7, 2014
    Location:
    Canada
    Nice looking engine.
     
  3. Bills69

    Bills69 Veteran Member

    Messages:
    193
    Likes Received:
    14
    Joined:
    May 28, 2018
    I use Taylor wire looms , vertical or horizontal type , nice clean look
     
    Zstar likes this.
  4. Twisted_Metal

    Twisted_Metal Administrator Staff Member Lifetime Gold Member

    Messages:
    28,285
    Likes Received:
    1,678
    Joined:
    Feb 26, 2004
    Location:
    Bloomington, MN
    Since you need to buy a new set anyway.... Use a couple of the longer wires from the new set for those two plugs and route them differently.

    You may still need the sleeves to keep the plug boot off the headers with the angled plugs.
     
  5. Dennis Wilkie

    Dennis Wilkie Veteran Member

    Messages:
    176
    Likes Received:
    16
    Joined:
    Mar 17, 2020
    What do you all think about header wraps? Are they worth the trouble? I've read that they don't last and are a pain to put on right
     
  6. Zspoiler

    Zspoiler Veteran Member

    Messages:
    3,723
    Likes Received:
    342
    Joined:
    May 6, 2012
    Location:
    Federal Way, Washington
    I use MSD wire looms with custom fit MSD 8 MM wires ,I use a a heat sleeve on #5 and#5 since it runs really tight .And with a supercharged small block I never had never had an issue,I learned from experience over the years .
     
  7. xten

    xten Veteran Member

    Messages:
    3,750
    Likes Received:
    2,563
    Joined:
    Sep 24, 2014
    Location:
    Pittsburgh, Pa.

    Attached Files:

  8. 73 Z

    73 Z Veteran Member Gold Member

    Messages:
    1,115
    Likes Received:
    65
    Joined:
    Jun 9, 2007
    Location:
    Los Angeles, Ca
    Angle plugs here, I found it better to run them under headers. Had a top mount metal rail before but it gets real hot from rising header heat and dry's them out on the bottom although the top of wires looked visually good.
    spark 1.jpg spark 2.jpg spark 3.jpg spark 4.jpg
     
    Coadster32 likes this.
  9. Dennis Wilkie

    Dennis Wilkie Veteran Member

    Messages:
    176
    Likes Received:
    16
    Joined:
    Mar 17, 2020
    I was running them under the headers until #7 melted & #8 caught on fire. But I just finished the break-in for the cam, and I had to get it up to 35° advanced before the headers stopped glowing red this time...and the # 5 melted from the boot, about 5 inches up, and the plastic wire separator melted between 1 & 3. I used a spring to hold the throttle while I stood over it and supervised everything with the plugs running upward on this attempt. I ordered some sleeve boot protectors that'll be here tomorrow, but I really don't think these should be getting that hot only running at 2500-3000 rpm for that amount of time. Even though they've been on it since I bought it, i'm starting to think this style header is gonna continue to be a problem. But the good news is, both sides were glowing pretty even this time, and once I dropped it to like 2700 and below, you could barely tell they were hot by just looking
     

    Attached Files:

  10. biker

    biker Veteran Member

    Messages:
    2,159
    Likes Received:
    777
    Joined:
    Dec 7, 2014
    Location:
    Canada
    Glad you got it broken in. Some headers may use thicker tubing than others, so thinner ones will glow more easily than thicker ones. Something to look into maybe.
    I think your cam has way more duration than stock. So, it could be creating a mixture/timing condition that the TBI and computer dont have the calibration to compensate for. Might have to get some TBI tuning done?
    Edit: the more I think about it, that cam probably needs more fuel at that rpm than the TBI can provide. Being that lean at that RPM will jack up the exhaust temp as well.
     
    Last edited: Sep 25, 2020
    Scaleytail likes this.

Share This Page