Cross Thread
 

Hey all,

I'm pretty sure I cross threaded my spark plugs today- on #4 and #5. At least I couldn't get them to tighten up enough to "get all the way down" so the spark plug wires seat properly.

So, given that, what do I do? Is it expensive :)

Thanks,

Ged

well...the worse thing that can happen is you have to pull that head,,but b4 that I would buy a thread chaser kit from Nappa and se if that works.I think there is even a insert repair you can do........now if this is a high end eng. you might just want to fix it right and skip the cheap tricks.

BTW, I'm an engineer, so I'm a double idiot!!

To fix it right, you have to pull the head, drill, and put in an insert, not a coil thingy.

gedk,

I am a little confused by you saying:

"couldn't get them to tighten up enough to 'get all the way down' so the spark plug wires seat properly."

If they are cross threaded they would be at an angle, and this could possibly cause interference with the spark plug boots.

Are you saying that they just kept turning and wouldn't tighten up? Like over torqued and stripped, as opposed to cross threaded? I guess that would be possible if you REALLY over tightened them...?

Have you removed the plugs and looked at them to see if there is any evidence of stripped aluminum threads?

It is my experience that you would have to be EXTREMELY unlucky to cross thread a plug on a 911 engine.... There is so little room between the spark plug wrench and the head cooling fins that I don't see how you could get the wrench at enough of an angle to cross thread the plug.

It seems to be at a slight angle. The threads seem to be ok, oddly enough.

The plug is about a 1/4" higher than the others. In other words, it sticks out of the head more.

Make any sense?