Soo, I just got my car back from the shop and for the second tine in 6 months, A spark plug (#6 this time, #7 last time) shot out of the head, stripping the threads and shattering the COP. Is there any reason they would be doing this? I dont think its due to me not tightening them down enough bc the were stripped (or so the shop said).

I just wanna make sure this doesnt happen AGAIN!

 

What year is your car??? Some of the years had heads that the spark plugs only thread down in about 3 full threads or so and they blow out frequently when not torqued to spec.

 

Its a 2000 gt. yea i know mine are the flawed ones. If it makes a diff, i did not use a TQ wrench when i put my plugs in around a year ago, but i did make them pretty snug i though

 

You need to torque them down man...i dont remember what the spec is to torque them to but you really should.

 

you have to be aware that over torquing is bad, and very easy to do. check it next time, although from the sounds of it, you may just want to save and have them sent to MHS to have all the plugs fixed...lol probebly cheeper than replacing a cop every month along with the cost of an in the car engine repair

 

There's your problem right there.

The torque spec is 11-13 lb/ft, which is NOT "pretty snug"; and in fact if you use a 1/4" torque wrench, as you should, you'll find that it doesn't seem anywhere near tight enough--but it is...

 

CLIFF!!! i like when you prove me right!

 

The maintenance schedule for the plugs calls for them to be replaced every 100k miles, that's maybe 2 changes over the service life of the vehicle. Because of this, and to minimise the probability of seizing if the full 3/4" thread were used, Ford's engineers used a counter-bored plug hole with only 6 or 7 threads at the inner end.

What they discounted was the "we don't need no stinkin' torque wrench" approach many would bring to the table. I've been in dealerships and watched "factory trained technicians" use a 1/2" drive ratchet to "torque" the plugs...

For those who use conventional "copper" (actually copper-cored nickel/chrome alloy) plugs and change them every 20k miles it is even more crucial that they be torqued properly.

I am sure that those who have actually used a torque wrench on the plugs will agree that the 11-13lb/ft really doesn't seem tight enough--and I freely admit to giving just a bit more twist after the wrench clicks...

 

http://www.modularheadshop.com/Articles/timesert.htm

 

What they discounted was the "we don't need no stinkin' torque wrench" approach many would bring to the table. I've been in dealerships and watched "factory trained technicians" use a 1/2" drive ratchet to "torque" the plugs...


i think i used a torque wrench maybe 1 or 2 times when i worked at the dealer