Changing Ignition Components...Need help selecting spark plugs

Discussion in 'Engine Topic' started by Millwright, Jun 2, 2019.

  1. COPO

    COPO Veteran Member Lifetime Gold Member

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    I use AC R43S and R45S depending on my driving habits. I've also tried NGK XR5 3332 which worked well.
     
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  2. jeff swisher

    jeff swisher Veteran Member

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    I have not had any issues with champions.
    I ran them in my double humps that I ported..I picked a hot heat range spark plug but my engines ran very cool. 160 to 180 F on coolant temps.
    Timing was optimized as were carbs.
    I ran RJ18YC.
    The R45s or the R46S ran just as well.
    Autolights were down on power in the upper RPM range.
    I never cared for fine wire stuff in my old V8's.

    Worst spark plug ever was the splitfire spark plugs this was 20 years ago.
    Engine would only rev to a bit over 4,000 rpm then start popping out and not rev any higher..no matter the gap or timing I dialed in. Junk spark plug for my engine.
    Buddy used them in a stock 185HP 350 and they did fine.
    But any clean spark plug would have.

    AC had just came out with a Rapid fire spark plug and it did quite well.
    No platinum on it, just had a center ground that had splines in it.
    I drove tens of thousands of miles a year, I had 11.9 compression and I liked to test things.

    11.9 compression and over 7000 rpm will surely show you which parts do not work well.
    Like a stock 10 bolt rear end.
     
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  3. 1980RS

    1980RS Veteran Member

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    We used to call those spit-fire plugs. This year I will stop using the AC Delco plugs as another racer said because of the dark color of the outer shell they are to hard to read. I guess I have to agree after what he showed me.
     
  4. jeff swisher

    jeff swisher Veteran Member

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    I read the strap for timing.
    I play with jetting and figure out what it likes best when i drive it.
    But if it is a track only car you do not get much seat time.
    I get a lot of seat time.

    I did add some 110 octane the other day.. felt like it gained some power.
     
  5. G72Zed

    G72Zed Veteran Member

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    Ah, the first "Rapid Fire's" , that brings back memories LOL.

    I did some R&D testing with those "new" AC's back then vs what was out there including cut backs. All AC #1 1st edition (1996) and again as they changed over time. It's interesting what you learn on the dyno/track, and how GM changed over time.

    Here's a pick for reference. Pic5.jpg
     
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  6. jeff swisher

    jeff swisher Veteran Member

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    Very nice! I have not ran them for a very long time. I just use the old school AC plugs now


    I had friends that worked at Oreilly parts store way back then and he wanted me to try all kinds of spark plugs and tell him which ones were best.
    AC rapid fire and second was the Champion RJ18YC.
    That was a brutal SBC .028 piston to head clearance 245 psi cranking pressure.
    It would show a weak spark plug.

    OH I may have cheated on my plugs back then as I would cut the ground strap back like the racing plugs.
    Did it make a difference..Yea it did, in the fact that it made me sleep better at night.

    Did not make the car any faster but did not slow it down at all either.
    I even took the rotor bug and filed the square flat tip a bit more pointy.

    My thought there was that wide tip would dwell the spark for a longer time than a narrower tip and if it was narrower i could saturate the coil longer.

    I never seen that trick in any book but I thought of it and I had to try it. I bet others have thought of it.
    No idea if it worked better or not. would have been nice back then to have test equipment.
    All I could do is make sure I won the races i got into.
     
    Last edited: Jun 4, 2019
  7. Millwright

    Millwright Member

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    Well tonight I got the MSD ignition wired in and the car fires up no problems. I do have a yellow wire that was connected to the coil that I can't identify.....
    Not sure if its my imagination but the car sounds different....better.
    Got the new coil wire made up. New plugs and fab up the new wires will be tomorrow night then take it for a test drive.
    I am optimistic that this will really change the way the car drives. I know you normally don't see hp gains with this but I think with the issues I was having this will bring some better numbers.
     
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  8. COPO

    COPO Veteran Member Lifetime Gold Member

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    I noticed a big difference with these 40 ohms/ft wires I installed on my 70 Z28 especially while hitting high rpms. Note that the factory wires resistance increases the higher the rpm which is what you DON'T want.
    39524575625_ac2171b241_k.jpg

    39709558754_087758d5c7_k.jpg
     
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  9. jeff swisher

    jeff swisher Veteran Member

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    Those wires look nice.
    I have never bought ready made "expensive" plug wires but I have bought the bulk spools of the wire and made my own.
    I purchased Belden wire.
     
  10. Millwright

    Millwright Member

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    So this has become a fairly major ignition upgrade.

    MSD 6AL Ignition box
    MSD Blaster 2 Coil
    MSD Superconductor Wires
    NGK G-Power Spark plugs

    Today I picked up an MSD cap thinking I may as well do that while I am at it. Not sure if that was worth while or a waste of $68.
     
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