Other Has anyone else had NGK plug failure (ceramic coming loose from base)?

spork

down with the sickness
This summer I had five or six NGK plugs fail from the insulator coming loose from the base. 750cc sx motor running 180psi on each cyl. I've not done much jetting changes or much of any mod changes and this is the first time i've ever had this happen period. Just curious if anyone else has had this happen or knows for sure why (guesses aren't necessary I can do that). Both plugs look exactly the same as far as burn, and I even went as far as shooting the head with infra red temp gun yet there was only maybe a degree or two difference in temp between the two sides.IMAG0826.jpgIMAG0827.jpgIMAG0828.jpgIMAG0830.jpg
 

Blue

Judging your cheapness
Location
St Cloud Florida
I had it happen a few times. Never found a good reason. The ceramic just blew out of the steel base, changed the plug and kept riding. Never had 6 in a row fail. Maybe a bad crimp from the factory.
 

spork

down with the sickness
I'm going to shoot a letter over to NGK and see if they can give me an explanation. I've searched all over the "world wide web" and haven't found squat.
 
I'm going to shoot a letter over to NGK and see if they can give me an explanation. I've searched all over the "world wide web" and haven't found squat.

I know you said you have 180 lbs of compression but what is the squish set at i've seen many plug issues with high compression and the incorrect squish. this usually happens when someone upgrades the head and just puts is some domes that say high compression. hope it helps... when did this start did you just do some mods
 

spork

down with the sickness
I haven't measured the squish, but last year I was running 200psi/cyl with stock head gasket, and this year I went with a much thicker copper gasket and dropped compression. Last year I had zero plug failures (only changed out plugs twice last year).
 
You mentioned 750 SX with 180 compression. If you have a Westcoast head : the domes are not compressed tightly, they can vibrate, causing plugs to come loose or break the porcelain. NGK is not at fault if that's the case.
 
Over the years with the micro sprint engines we have had only a few plug porcelain failures. And that was running diesel type compression ratios on methanol (near 20:1 for short tracks). Before this summer I have never seen a jet ski engine have that problem. However this summer I seen three that the porcelain totally separated from the steel. And two plugs that had no obvious failure but clean as can be and just wouldn't fire. Think we maybe onto a quality control issue with NGK .......
 

SuperJETT

So long and thanks for all the fish
Location
none
Detonation can cause it from the high frequencies it emits which fractures the ceramic material. High compression, advanced timing, long WOT runs, slightly lean tuning, tight squish, etc etc can cause it.
 
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Broken Spark plugs

Hello Guys,


Spork, I would be interested to see these plugs, and any others that this may have happened to so that we can shed futher light on this topic.

If you would please call my office phone at 1-248-926-7107. Further info is listed at the bottom of the page. Also look forward to looking into this for you guys.

Thanks

NGK Spark Plugs Inc. USA
Jason Norwood
Tech and Training Specialist
Aftermarket Division
jnorwood@ngksparkplugs.com
 

john zigler

Vendor Account
Location
wisconsin
Detonation can cause it from the high frequencies it emits which fractures the ceramic material. High compression, advanced timing, long WOT runs, slightly lean tuning, tight squish, etc etc can cause it.

i think Darrin nailed it.

i too have seen it happen. what are you running for fuel & timing?
 

OCD Solutions

Original, Clean and Dependable Solutions
Location
Rentz, GA
I had 2 fail out of the box this past summer, both from the same case. I installed them the same as any other time. Both cracked when I tightened them down. One shattered completely, the other was found loose when I pushed on the spark plug boot and lifted right off the base.
 

spork

down with the sickness
i think Darrin nailed it.

i too have seen it happen. what are you running for fuel & timing?

93 octane 40/1 oil msd enhancer. Let me reiterate that this has happened throughout this entire season on same motor w/no new mods, and no signs whatsoever on piston or electrode area of preignition.
 
If they crack on installation, look carefully at your install tool. A good spark plug wrench will have a foam insert to keep the plug wrench aligned correctly. With a crappy tool, you can allow the socket to flop over and apply pressure to the porcelin.

If the porcelin is cracking or coming loose while riding; Reduce timing or compression or buy higher octane fuel.
This is caused from detonation or too much timing advance. A colder spark plug or richer jetting will not cure this.

Regards,
Randy
 
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OCD Solutions

Original, Clean and Dependable Solutions
Location
Rentz, GA
If they crack on installation, look carefully at your install tool. A good spark plug wrench will have a foam insert to keep the plug wrench aligned correctly. With a crappy tool, you can allow the socket to flop over and apply pressure to the porcelin.

True, but not the issue in my case.
 
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