Forum Discussion

udidwht's avatar
udidwht
Explorer
Feb 14, 2021

24K plugs

Decided to pull the spark plugs after haven been in for 24K. This is in a 1994 Fleetwood Southwind Storm 28ft 454 w/4L80E

Surprisingly they looked very good after 24k miles....

https://www.irv2.com/forums/f22/pulled-plugs-521236.html

I did however break a boot 1/2in from the end off cylinder #8. Darn....replaced those wires at the same time as the plugs. Engine is now at 68,295

Purchased new 8.5mm heavy duty Belden ceramic wires. The old ones were Belden Edge 7mm wires (non ceramic). I also use 1500F heat shield cloths on the wires. The plugs were AC Delco coppers. I replaced them with Autolite coppers.

After 24K miles the gap had only opened barely .001 (from .035) With exception of the distributor itself. Everything in the ignition system I've replaced.
Class A
  • udidwht's avatar
    udidwht
    Explorer
    Feb 15, 2021
    Copper plug change intervals should be....30-35K

    Platinum plugs - 50-60K

    Iridium plugs - 100-120K

    Attaining those intervals depends on how well the actual ignition system items are and how well the engine is running.
  • dodge_guy's avatar
    dodge_guy
    Explorer II
    Feb 15, 2021
    I can show you 100k mikes platnimum plugs removed at 70k miles with no electrode left! The 100k miles plugs are a sales tool to make you think the car your buying doesn't need any maint.
    Plugs with huge gaps from being worn out will make the coils work harder.
    Too make your vehicle last a long time and give you minimal hassles, do your maint far earlier than what the manuf recommends!
  • udidwht's avatar
    udidwht
    Explorer
    Feb 14, 2021
    theoldwizard1 wrote:
    24K is nothing for spark plugs these days ! I'll bet the recommended interval is 100K.

    Those don't look like AC Delco that came out of them.


    Recommended interval of 100K applies to Iridium equipped vehicles. These are standard copper plugs (94 GM 454 TBI)

    These types of plugs are designed with today's ignition equipped systems combined with high CR and lean cruise AFR ratios.

    One other note...

    All spark plugs (Iridium) are copper at their cores. What differ is the tip. A standard copper core has a copper tip coated with nickel.
  • udidwht's avatar
    udidwht
    Explorer
    Feb 14, 2021
    rgatijnet1 wrote:
    Coat the spark plug porcelain with dielectric grease before you put the boots on and they will not stick the next time you want to take them off.


    That was done when wires were installed with Super lube.
  • udidwht's avatar
    udidwht
    Explorer
    Feb 14, 2021
    theoldwizard1 wrote:
    24K is nothing for spark plugs these days ! I'll bet the recommended interval is 100K.

    Those don't look like AC Delco that came out of them.


    Those indeed were AC Delco copper plugs. If you hold left CTRL and press + key you can zoom in real close.
  • wa8yxm's avatar
    wa8yxm
    Explorer III
    Feb 14, 2021
    Modern spark plugs are rated for 100K or more.. This is due to the metal used in the tips. Of course to get 100K out of 'em, you need a good engine, oil burners kill plugs fast. Bad air/fuel mix can do it too. But the proper plug in a well tuned and properly operating engine should go 100K or more.

    6 of mine lasted 15 years the other two had "External damage" (Rodents v/s wires mandated the replacement of 2 plugs)
  • theoldwizard1's avatar
    theoldwizard1
    Explorer II
    Feb 14, 2021
    24K is nothing for spark plugs these days ! I'll bet the recommended interval is 100K.

    Those don't look like AC Delco that came out of them.
  • rgatijnet1's avatar
    rgatijnet1
    Explorer III
    Feb 14, 2021
    Coat the spark plug porcelain with dielectric grease before you put the boots on and they will not stick the next time you want to take them off.

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