Spark plus torquing, crush washer, feel

[harveyjdavis]

Does anybody really torque their spark plugs to 18 to 22 ft-lbs? I've got an 84 911 Carrera. I've done this on a 356 and a VW bug (year ago), but I only torqued till I felt the crush washer flatten. So I torqued by feel. I've always had my mechanic do valve adjustment and spark plugs on my daily driver 911, but this time I really wanted to do it. When I removed the plugs (cold engine of course) the plugs came out as if they were almost loose - hardly any back out effort. Now when installing new plugs and torquing, I feel like I'm way beyond flattening the crush washer when I get up to 150 in lbs (12.5 ft lbs). (I'll bet the crush washer flattens at 120 in lbs, 10 ft-lbs.) I have stopped at 150 in lbs - I find that #4 plug seems not be be torque-able beyond 150, seems to be just turning without more resistance.
Please offer your comments and suggestions.

[HFR_Racer]

I absolutely torque my spark plugs. Yes!!!!

[KNS]

Using the factory spark plug tool, I find that the Allen wrench is just the right length to put the correct amount torque onto the plug. I'm not sure if that helps you...

[chicago_82sc]

Originally Posted by HFR_Racer

I absolutely torque my spark plugs. Yes!!!!

Me 2

[Flat Six]

Originally Posted by harveyjdavis

Does anybody really torque their spark plugs to 18 to 22 ft-lbs?

Yes, 18-22 lbs./ft. -- both NGK and Bosch recommendations for (our) 14mm plugs in aluminum heads.

Originally Posted by harveyjdavis

I have stopped at 150 in lbs - I find that #4 plug seems not be be torque-able beyond 150, seems to be just turning without more resistance.

Uh oh . . . . .

[JAR0023]

Originally Posted by harveyjdavis

Snip - I find that #4 plug seems not be be torque-able beyond 150, seems to be just turning without more resistance.
Please offer your comments and suggestions.

This doesn't sound good.

J

[harveyjdavis]

To KNS using allen wrench:

Then I'll bet you are torquing by feel, and not much more than flattening the crush washer. You can't confidently get 18 to 22 FT-lbs without a torque wrench, unless you practice doing precisely that and are thinking about that, without a torque wrench you have to go by your body force and the moment arm of the wrench or allen tool.

[Neel]

A torque wrench is your (and your car's) best friend.. I've won many a bet over the years with guys who 'knew' their torque by feel..

[Ronnie's.930]

Originally Posted by harveyjdavis

Does anybody really torque their spark plugs to 18 to 22 ft-lbs? I've got an 84 911 Carrera. I've done this on a 356 and a VW bug (year ago), but I only torqued till I felt the crush washer flatten. So I torqued by feel. I've always had my mechanic do valve adjustment and spark plugs on my daily driver 911, but this time I really wanted to do it. When I removed the plugs (cold engine of course) the plugs came out as if they were almost loose - hardly any back out effort. Now when installing new plugs and torquing, I feel like I'm way beyond flattening the crush washer when I get up to 150 in lbs (12.5 ft lbs). (I'll bet the crush washer flattens at 120 in lbs, 10 ft-lbs.) I have stopped at 150 in lbs - I find that #4 plug seems not be be torque-able beyond 150, seems to be just turning without more resistance. Please offer your comments and suggestions.

This would indicate that the threads in the head are stripped/damaged . . .

[Neel]

^^^+1...

[Flat Six]

Hey Harvey -- did you get a chance to check that #4 plug?