spark plug torque

[JFP in PA]

The only one that matters is Porsche: Spec is 22 ft. lbs. +/- 2 ft. lb.

[Jamesp]

From the Boxster service manual as of MY 2005 - which usually means MY 2003 for engines:

Spark plugs Using new spark plugs Tightening torque 30 (22 ftlb.) Nm
Spark plugs Re-using old spark plugs Tightening torque 25 (19 ftlb.) Nm

The recommendation is to back off on used plugs.

[lkchris]

Originally Posted by Jamesp

The recommendation is to back off on used plugs.

... because the crush washer is already crushed.

[lkchris]

Originally Posted by JFP in PA

The only one that matters is Porsche: Spec is 22 ft. lbs. +/- 2 ft. lb.

Porsche doesn't have much say in the specification of the crush washer the plug manufacturer includes with the plug.

I'll use the plug manufacturer recommended torque.

[JFP in PA]

Originally Posted by lkchris

Porsche doesn't have much say in the specification of the crush washer the plug manufacturer includes with the plug.

I'll use the plug manufacturer recommended torque.

Perhaps, but they do have a very good idea on what it should take to get a correct seal on any brand of plug without damaging the threads in the cylinder heads.....

[lkchris]

Originally Posted by JFP in PA

Perhaps, but they do have a very good idea on what it should take to get a correct seal on any brand of plug without damaging the threads in the cylinder heads.....

They do indeed, but the plug folks recommend less than they do, which will not damage threads and be farther from doing so.

Yes, wrench calibration and operator technique certainly mean being "spot on" is unlikely.

VERY important is dry threads and reducing torque when reinstalling previously installed plugs. If someone just can't listen to those that make plugs, at least reduce the torque if you have to lube the threads, antiseize being lube of course.