Spark plugs - torque wrench, or finger tight plus quarter turn?
I'm going to change the plugs in my 2005 KJ for the first time over the weekend - I've always had it done by a garage before. I have the Mopar plugs, and there's a little diagram on the box that seems to be indicating that you should get them finger tight and then a quarter turn with the ratchet.
Is that the best way, or should I use a torque wrench? (I'm assuming that there's a torque spec in the FSM, just haven't looked yet). I'm used to using a torque wrench for plugs, but then I've only changed them on the iron-head 4.0L before, not an aluminium head.
Hello, Sorry to sound like an authority figure. I'm brand new to Liberties. I've yet to see the plugs; so I'm learning too. Try to find a torque value or other spec for plugs in an aluminum head. The box many spark plugs came in had a pictogram. Plugs with a crush gasket had a quarter turn (90º) picture. You could turn them more but why do that? Bevel edged, non-gasketed plugs had an eighth turn (45º) picture. Anyone would have to be nuts to go more. I'd make darn sure of any instruction to go a half turn (180º) beyond contact; ESPECIALLY in an aluminum head. Like I said, you can crush a washer way-way down if there is one; but why do that? I never had any problem following the 1/4 turn-1/8 turn guideline. Feel free to sign on and call me names. Kira
This is what NGK instructs to do.
"4. Tighten the spark plug finger tight first until the gasket reaches the cylinder head, then screw about ½ - ¾ turn more with a plug wrench. (Conical seat; about 1/16 turn more)."