Originally Posted By: y_p_w
Originally Posted By: Le_bow_ski
Originally Posted By: y_p_w
I recently installed some NGK platinum plugs in my wife's Civic, but then realized that the beam torque wrench I used had units in N*m and in-lbs. I was thinking the ft-lbs spec in the owner's manual, but was looking at the N*m gauge. So I took them out and realized they were somewhat loose. I got curious and looked at the plugs, and the washers looked like they did new. When I pulled out the factory-installed plugs, their washers were totally compressed and couldn't get any flatter.
The factory installed plugs may have been torqued to a higher level, and/or their washers may have been of a different material or design.
Originally Posted By: y_p_w
So I did it again this morning to about the spec'ed 18 N*m or 13 ft-lbs. I pulled them out again and the washers still looked uncompressed. Does the washer really need to be squished or is can there be enough tension if it's properly torqued?
The goal isn't to compress the washer, it's to provide the proper seal and heat transfer. The manufacturers torque spec is designed to achieve both goals without damaging the plugs or head.
My big worry is that if only a portion of the washer is in contact with the seating surface, it's not going to transfer heat from the plug to the head.
Also - I noted the plugs. They were NGK PZFR6F-11 bought as a 4-pack at Pep Boys. They were marked as made in Japan. The factory-installed plugs were the identical model number, but marked as assembled in the US of Japanese parts. If anything, I was thinking perhaps manufacturing variations. I've installed plugs before, and in my experience the washers flatten pretty easily with only moderate effort.
You're over thinking things on both counts, and you're very likely wrong on both counts (I'm being generous here). Given the way things are going the most likely outcome of your efforts to flatten the washer will be damaged or destroyed spark plug threads.
Stop what you're doing, follow the manufacturers recommendations for torque explicitly, and move on to something that really needs fixing.