Plug life

[BR3W CITY]

Plug life.....not to be confused with thug life.

I've been running the tr55 NGK's since my swap, since they seem to be the most popular "regular" plug in the ls series. My question is, how long should they last?

I ran mine for about 12-15k, over about 2-2.5 short summer seasons of driving, a mix of 9hr road trips and city cruise ins. I started to notice a light part throttle miss, so naturally I turned to the ignition.

I had a shady plug wire (crimp-on tip kept popping off), which was a simple fix. Coils, grounds, injectors and their wiring etc, all looked good. I did have a short period with an exhaust leak causing me to dump rich a bit, but it was for less than 5-600miles.

The plugs were a somewhat even burn; the plugs weren't wet, they had no oil on them, the color is a mix of gray/tan, but there are a few salt and pepper speckles.



Is the 12-15k plug life normal for a "performance" oriented/tuned engine (assuming things like no cats, larger injectors, and a tuner that I trust implicitly). With the plugs and one wire replaced, the truck felt normal.

Thoughts?

[Jon01]

Need to see the gap to see if it's opened up.
If it has, they're worn. If not, your wire was causing the issue.
I'd bet it was the wire.

Salt & pepper speckles are an indication of detonation. Better revisit your tuner and have him pull a little timing.

FWIW, I put NGK's in all of my modded LSx stuff. My GTO had them in it from ~800 miles till I sold it with 14k. H/C/I and not a problem. SS had about 8k on them when I sold it but again, no issues.

[BR3W CITY]

Originally Posted by Jon01

Need to see the gap to see if it's opened up.
If it has, they're worn. If not, your wire was causing the issue.
I'd bet it was the wire.

Salt & pepper speckles are an indication of detonation. Better revisit your tuner and have him pull a little timing.

FWIW, I put NGK's in all of my modded LSx stuff. My GTO had them in it from ~800 miles till I sold it with 14k. H/C/I and not a problem. SS had about 8k on them when I sold it but again, no issues.

The wire was definately AN issue, I'm just curious if there might be something else to look at since, I'd have to go from memory, but for the most part all 8 looked similar.
I put about 120miles on this set I'm going to put a few more miles on this new set (tr55's stock gap) before I take another read. I had a period where the collector flange gasket was leaking and throwing off the 02 sensors (thusly everything else too), and I hadn't changed or read the plugs since that.

Hopefully everything should be ironed out. I had run some seafoam through the injectors in case of it being a fuel side problem, but again since all 8 are similar I can probably rule that out. I'll pull the fuel filter as well just to see that there isn't a starvation of flow there.

[Jon01]

Originally Posted by BR3W CITY

The wire was definately AN issue, I'm just curious if there might be something else to look at since, I'd have to go from memory, but for the most part all 8 looked similar.
I put about 120miles on this set I'm going to put a few more miles on this new set (tr55's stock gap) before I take another read. I had a period where the collector flange gasket was leaking and throwing off the 02 sensors (thusly everything else too), and I hadn't changed or read the plugs since that.

Hopefully everything should be ironed out. I had run some seafoam through the injectors in case of it being a fuel side problem, but again since all 8 are similar I can probably rule that out. I'll pull the fuel filter as well just to see that there isn't a starvation of flow there.

Are you still chasing a miss or did the plug/wire swap fix it?
If it's fixed I'd quit chasing.
Does your truck have headers? If not, I'd stick some on it, bet you'll see a huge performance increase.

[BR3W CITY]

Originally Posted by Jon01

Are you still chasing a miss or did the plug/wire swap fix it?
If it's fixed I'd quit chasing.
Does your truck have headers? If not, I'd stick some on it, bet you'll see a huge performance increase.

The miss cleared up immediately with the new plugs and replaced wire. I guess what I'm confused at is; is the 12-15k that I got out of them below average?

I do understand that the plug is a resistor plug, and I as well understand that parts books list an iridium plug; however on the advice of my tuner, the tuners's in-house engine guy, and more sub 11 second cars than I can count, I gotta stick with the ngk's. Truckdude, I don't doubt your advice, but I think its coming from a "traditional repair" perspective vs the "hot rod" perspective, and I don't mean that disrespectfully. I have yet to find a brand or series of iridium plugs that has the needed variety of heat ranges, is widely available and *gasp* doesn't cost $8 per plug.

And On a funny note about the "ford needs Motocraft".....when I worked for NAPA/UPG I sold NGK's to everyone for everything. Maybe I'm just overly brand loyal?

[truckdude239]

I run the ac delo iridium plugs 100k mile garrantee
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[truckdude239]

Just an fyi the tr55 ngk plugs are a standard resistor plug and will burn your coils or wires out you need to run a platinum or iridium plug as they have a lower resisting raiting and will make you a hoter spark your losing alot of ignition power with those plugs. I ve seen it at least once a month at work.
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[Jon01]

Originally Posted by truckdude239

Just an fyi the tr55 ngk plugs are a standard resistor plug and will burn your coils or wires out you need to run a platinum or iridium plug as they have a lower resisting raiting and will make you a hoter spark your losing alot of ignition power with those plugs. I ve seen it at least once a month at work.
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Completely false.

[truckdude239]

Originally Posted by Jon01

Completely false.

If you say so i work on these things everyday and know what i see and fix on them the most is burned out plug wires from running a resistor plug in them i even pulled a set of e-3 out of a tahoe that where new and it had a bad skip at idle. But everyone has there own opinion.
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[Jon01]

That's fine, I've been building them for 10+ years, running resistor plugs in every one and haven't had an issue yet.

[truckdude239]

No worries i guess i am a biggie on running what the manufactor called for like running motor craft in fords champion in dodge ac delco in gms and ngk/denso in most imports. Im a big fan of running what they call for plus for a stock build you cant beat a 100 k plug.but your right too ive know people that have run regular resistor plugs and never had an issuse i just seem to get the weird ones i guess lol. But in answer to the ops question thlse look quite good
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[yossarian19]

Spec'ed interval for the spec'ed plug is 100K. YMMV depending on what you're running (both engine & plug side). Most other motors I've worked on, built 86-99 or so, spec a 30K plug interval. They last longer the newer the design, generally.