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Discussion Starter #1
hey guys...yesterday a friend of mines was driving his 91 turbo supra and suddenly his Spark plug broke on #3..he told me this isnt the first time his sparkplug broke on him...he was running champions ..i was like wtf...put some denso's or ngk..but is it normal for cheap plugs to break like this?any other reasons it will break?
 

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Is he using a Spark Plug socket that has the rubber piece inside that helps prevent cracking when tightening them? If not one little bit of tilt and it's cracked and you'll never know. Also always use some Nickle Anti_ seize on the threads so they tighten to the proper spec and they come out easy without removing the aluminum in the head.
 

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Breaking a spark plug is almost always a sign of detonation - tell him to turn the boost down and get his car on a wideband and tuned ASAP!!!

PS, I've never had a problem with cheap plugs in the 7M - I've run all the 'baller' NGK's and the like, and the Autolite 3923's that you could get at any Wal-Mart worked just as well or better.
 

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Will my Supra ever run?!!
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I've had problems with cheap plugs in a 300ZX TT running at 20psi. Pretty much the same problem, the electrode broke off.

I told him to switch to a better brand of plug, and he's never had any problem... BUT, the electrode did kill his engine, and we had to rebuild and thus retune.

It COULD also be detonation since that loves to kill plugs as well.

I agree that you should throw a wideband at your car and make sure that it's not running lean and detonating. If that doesn't work, switch to some NGKs or something.
 

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I had this exact thing happen to me with champions - #1 cylinder spark plug failed, but under deceleration. Put ngk R's in and had no more issues. This occurred when the car was running approx 10psi. I've heard of several champion plugs failing in this manner as well.
 

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3 of my platinum NGK's had the ceramic brake on them, so I changed to NGK coppers and haven't had a problem since. NGK copper part number is BCPR6ES
 

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Discussion Starter #9
while taken out the plugs...we notice a lot of antifreeze mixed with oil on the plugs as well !
 
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