Welcome to Club Hot Rod!  The premier site for everything to do with Hot Rod, Customs, Low Riders, Rat Rods, and more. 

  •  » Members from all over the US and the world!
  •  » Help from all over the world for your questions
  •  » Build logs for you and all members
  •  » Blogs
  •  » Image Gallery
  •  » Many thousands of members and hundreds of thousands of posts! 

YES! I want to register an account for free right now!  p.s.: For registered members this ad will NOT show

 
Like Tree42Likes

Thread: Spark Plugs
          
   
   

Reply To Thread
Page 1 of 2 1 2 LastLast
Results 1 to 15 of 28
  1. #1
    Msgt Luttrell's Avatar
    Msgt Luttrell is offline CHR Member Visit my Photo Gallery
    Join Date
    Jun 2016
    Location
    waldron
    Car Year, Make, Model: 1986 IROC Z28
    Posts
    47

    Spark Plugs

     



    Hey guys, I have a new 383 Small block chevy, 10 to 1 compression, aluminum high flow heads, roller cam shaft with .528 Intake .536 Exhaust lift, 221 Intake / 226 Exhaust duration @.050 and a 110 degree lobe separation; running a Holley 750 cfm carburator and a HEI Distributor. It has long tube headers with 2.5" dual exhaust, with Flowmaster Super 10s on it. The engine dynoed at 426 HP at 5700 rpms and 452 ft lbs of torque at 4300 rpms. The issue I'm having is that I'm running the cold racing spark plugs that it was dynoed with (Champion 792), gapped at .045", getting spark through a new HEI dizzy and sometimes during cold start I have a spark plug that will have an intermittent miss that goes away completely as soon as the engine starts to warm up.

    This only happens after a few short trips in the car, where the engine doesn't get a chance to warm up all the way and doesn't get driven at cruise speeds. I'm wondering if I should step up to a little hotter spark plug, or maybe even extend the spark plug gap out a little to help with the issue.

    I have a motorcycle that's the same way and you simply don't start it unless you are going to take it out long enough to warm it up completely and cruise it for a while at highway speeds. I'm just hoping that I can make the engine a little more street friendly with a little hotter plug; any suggestions or advice on the issue will be appreciated.

  2. #2
    Msgt Luttrell's Avatar
    Msgt Luttrell is offline CHR Member Visit my Photo Gallery
    Join Date
    Jun 2016
    Location
    waldron
    Car Year, Make, Model: 1986 IROC Z28
    Posts
    47

    I should add that the only thing I reused on this new engine is the spark plug wires, they are around a year and a half old and since they've been running behind headers for that long it's possible that I've cooked one or two of them by now enough to cause issues during cold start and high humidity situations. So I just went and ordered me a new set of 8MM wires from Select, hopefully that'll take care of the intermittent miss on cold starts.

    That said, I'm still wondering if I can or should run a hotter spark plug for the street, especially when colder weather returns?

  3. #3
    34_40's Avatar
    34_40 is offline CHR Member Visit my Photo Gallery
    Join Date
    Sep 2007
    Location
    New Bedford
    Car Year, Make, Model: 34 Ford 3W Coupe Replica
    Posts
    14,606

    UMmmmmm... YES!


    Have you a loupe? Are you experienced enough to read plugs? Changing your heat range should be no big deal. Same with the gap. Both easy tuning tools provided you can read the plugs. On my stroker, I found dropping the gap to .040" really smoothed out the cold starts. No other changes, just dropped the gap by .005" smaller made a lot of difference.

  4. #4
    techinspector1's Avatar
    techinspector1 is offline CHR Member Visit my Photo Gallery
    Join Date
    May 2003
    Location
    Zephyrhills, Florida, USA
    Car Year, Make, Model: '32 Henway
    Posts
    12,423

    Heat range is read by where the color change is on the ground strap. If the color changes out near the tip of the strap, then the plug is too cold. if the color changes back by where the strap welds to the plug body, the plug is too hot. If the color changes at about the halfway point, the heat range is correct for your tune.
    Wallace Racing - Spark Plug Reading

    .
    PLANET EARTH, INSANE ASYLUM FOR THE UNIVERSE.

  5. #5
    Msgt Luttrell's Avatar
    Msgt Luttrell is offline CHR Member Visit my Photo Gallery
    Join Date
    Jun 2016
    Location
    waldron
    Car Year, Make, Model: 1986 IROC Z28
    Posts
    47

    Thanks for the advise guys, I am a retired USAF aircraft mechanic with 30 years of wrenching on just about anything with wings or wheels, but while this engine isn't radical by any standard, it's probably the the most radical I've daily driven. I think my plan of attack on this will be to first swap out the wires with a new set, if I still get some misfire, I'll look at the plugs and try setting the gap to .040". Like you mentioned reading the plugs should give me a hint of where I'm at on the heat range.

  6. #6
    rspears's Avatar
    rspears is offline CHR Member/Contributor Visit my Photo Gallery
    Join Date
    Sep 2007
    Location
    Gardner, KS
    Car Year, Make, Model: '33 HiBoy Coupe, '32 HiBoy Roadster
    Posts
    10,989

    I've evolved to NGK plugs.
    Roger
    Enjoy the little things in life, and you may look back one day and realize that they were really the BIG things.

  7. #7
    NTFDAY's Avatar
    NTFDAY is offline CHR Member Visit my Photo Gallery
    Join Date
    Aug 2003
    Location
    Springfield
    Car Year, Make, Model: '66 Mustang, 76 Corvette
    Posts
    5,333

    I'm running E3's in both the Vette and the Dakota and so far, so good.
    Ken Thomas
    NoT FaDe AwaY and the music didn't die
    The simplest road is usually the last one sought
    Wild Willie & AA/FA's The greatest show in drag racing

  8. #8
    Msgt Luttrell's Avatar
    Msgt Luttrell is offline CHR Member Visit my Photo Gallery
    Join Date
    Jun 2016
    Location
    waldron
    Car Year, Make, Model: 1986 IROC Z28
    Posts
    47

    Ok guys, this is what I did and what I found. I bought some new wires and was going to change them out this morning when the engine was stone cold, but I got bored last night after dark and wondered if I could see any arcing under the hood after dark. I didn't see any arcing, but what I heard under the hood sounded like I had a header gasket just starting to blow out on the passenger bank of the engine, so I shut it down made a mental note to chase down the header leak in the morning and called it a night.

    Got up this morning and over my cup of coffee I wondered if the leak I heard could be from a loose spark plug, so that's where I started this morning and I found the #8 plug was loose and leaking compression. It wasn't loose enough to wiggle around, but it was almost a turn from seating on the washer. I inspected all the wires and they all look good and since I saw no arcing last night I put the new set on the shelf in the man cave for later on sometime. I also checked all the header bolts and intake bolts and they were all good, so I'll drive it a few days and hopefully the miss is gone for good.
    34_40 and 40FordDeluxe like this.

  9. #9
    Rrumbler is offline CHR Member Visit my Photo Gallery
    Join Date
    Jun 2004
    Location
    Las Vegas
    Car Year, Make, Model: Sans hot rod, sold the truck.
    Posts
    1,207

    Good catch. Sometimes - heck, quite often, really, educated curiosity, and just sitting down with a cuppajoe and thinking for a while is good. Hope this did it for you.

    .
    Rrumbler, Aka: Hey you, "Old School", Hairy, and other unsavory monickers.

    Twistin' and bangin' on stuff for about sixty or so years; beat up and busted, but not entirely dead - yet.

  10. #10
    techinspector1's Avatar
    techinspector1 is offline CHR Member Visit my Photo Gallery
    Join Date
    May 2003
    Location
    Zephyrhills, Florida, USA
    Car Year, Make, Model: '32 Henway
    Posts
    12,423

    Yep, always keep a chair in the garage, so you can just sit and think about this or that.

    .
    40FordDeluxe likes this.
    PLANET EARTH, INSANE ASYLUM FOR THE UNIVERSE.

  11. #11
    40FordDeluxe's Avatar
    40FordDeluxe is offline CHR Member Visit my Photo Gallery
    Join Date
    Apr 2011
    Location
    Prairie City
    Car Year, Make, Model: 40 Ford Deluxe, 68 Corvette, 72&76 K30
    Posts
    7,264
    Blog Entries
    1

    Quote Originally Posted by Msgt Luttrell View Post
    Ok guys, this is what I did and what I found. I bought some new wires and was going to change them out this morning when the engine was stone cold, but I got bored last night after dark and wondered if I could see any arcing under the hood after dark. I didn't see any arcing, but what I heard under the hood sounded like I had a header gasket just starting to blow out on the passenger bank of the engine, so I shut it down made a mental note to chase down the header leak in the morning and called it a night.

    Got up this morning and over my cup of coffee I wondered if the leak I heard could be from a loose spark plug, so that's where I started this morning and I found the #8 plug was loose and leaking compression. It wasn't loose enough to wiggle around, but it was almost a turn from seating on the washer. I inspected all the wires and they all look good and since I saw no arcing last night I put the new set on the shelf in the man cave for later on sometime. I also checked all the header bolts and intake bolts and they were all good, so I'll drive it a few days and hopefully the miss is gone for good.
    Nice catch and thanks for your service too!
    Ryan
    1940 Ford Deluxe Tudor 354 Hemi 46RH Electric Blue w/multi-color flames, Ford 9" Residing in multiple pieces
    1968 Corvette Coupe 5.9 Cummins Drag Car 11.43@130mph No stall leaving the line with 1250 rpm's and poor 2.2 60'
    1972 Chevy K30 Longhorn P-pumped 24v Compound Turbos 47RH Just another money pit
    1971 Camaro RS 5.3 BTR Stage 3 cam, SuperT10
    Tire Sizes

  12. #12
    techinspector1's Avatar
    techinspector1 is offline CHR Member Visit my Photo Gallery
    Join Date
    May 2003
    Location
    Zephyrhills, Florida, USA
    Car Year, Make, Model: '32 Henway
    Posts
    12,423

    Thanks Ryan, for the reminder....
    Master Sergeant Luttrell, thank you for your service to our country and may God love you and keep you safe and well. Without fellows like you, we'd all be peasants and slaves under some pissy little dictator.

    .
    PLANET EARTH, INSANE ASYLUM FOR THE UNIVERSE.

  13. #13
    Msgt Luttrell's Avatar
    Msgt Luttrell is offline CHR Member Visit my Photo Gallery
    Join Date
    Jun 2016
    Location
    waldron
    Car Year, Make, Model: 1986 IROC Z28
    Posts
    47

    Thank you guys for the sentiment, but it was truly my pleasure to serve, I wouldn't trade the experience for the world and would do it all again in a heartbeat.
    NTFDAY likes this.

  14. #14
    Msgt Luttrell's Avatar
    Msgt Luttrell is offline CHR Member Visit my Photo Gallery
    Join Date
    Jun 2016
    Location
    waldron
    Car Year, Make, Model: 1986 IROC Z28
    Posts
    47

    Ok guys, time for a little update, since the car is just a weekend play perty and doesn't get driven that much, I just got around to noticing that I still had a plug or two that were acting up on cold start. So I bought a new set of champion 792s and gapped them at .035" down from .045 I had gapped the other set at, installed them along with the new set of good wires. I believe with the camshaft and 750 Holley I'm running, combined with the higher compression was keeping the spark from igniting the air charge during cold starts. The cold start this morning was much smoother and the throttle response seemed better as well. I just did the 500 mile break in oil change on the new engine last week, I'll get her lined out soon enough.
    34_40 and rspears like this.

  15. #15
    rspears's Avatar
    rspears is offline CHR Member/Contributor Visit my Photo Gallery
    Join Date
    Sep 2007
    Location
    Gardner, KS
    Car Year, Make, Model: '33 HiBoy Coupe, '32 HiBoy Roadster
    Posts
    10,989

    As an (old?) aircraft mech, if you're ever having trouble getting a threaded fastener to "take" that first thread, do you ever close your eyes so that you can "feel" the threads better? I still remember some activities where we had to work "blind", reaching back into a void to set a washer, start a nut, tighten and then torque the nut that could only be seen with a light and mirror.... I often closed my eyes to kick the other senses up a notch.
    Roger
    Enjoy the little things in life, and you may look back one day and realize that they were really the BIG things.

Reply To Thread
Page 1 of 2 1 2 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
Links monetized by VigLink