tbirdscwd

How would torque have anything to do with them cracking? Your not torqing down the porcelain portion of the plugs. The clogged catalytic converter sounds possible. The cat doesn't need to be completely clogged for there to be excess backpressure. It may run just fine under normal driving conditions and just not allow enough flow at high rpms. There has to be something causing extreme cylinder pressures to get a spark plug to do that. Unless you happen to be the unlucky person who got shafted with a bunk set of plugs. But 3 in a row sounds like something is killing them for you. Were they all on the same side?

ottos

YEah over torque won't cause the ceramic part to break. It looks like the ceramic part is almost popped out.

Looks like Champion FTL. I've only trusted NGK, Denso, Motorcraft, or Bosch.

FDNYBullitt

First off stay away from Chumpion plugs, as stated they are great for lawnmowers and such--Motorcraft or NGK-- and nothing else was said about the bottom part you said fell into the motor, or did it just burn off the electrode. Looks to me as if you got a bad batch of plugs is all, it happens or do you still have that silly rubber insert inside your plug socket, with that still in there it makes it easier to crack the top of the plug just like yours when installing/tightening them. Just the slightest tilt of the socket and they will crack.

bjh061487

and this is for all of those people that think SOME back pressure is good... IT ISN'T

jwog666

defective plugs, champions suck