Sorry if this is answered elsewhere. I’ve been searching but can’t seem to find what I’m looking for. I’m ready to replaced the plugs on my 87 TR with NGK Iridium DR8EIX. The manual says use champion plugs and apply graphite grease. The consensus on NGK seems to be “don’t use grease cos it makes the torque readings inaccurate.” So my questions are: 1) Do I apply graphite grease to NGK plugs? 2) If not, should I still tighten to the torque given in the manual? Many thanks in advance.
As a general rule I use copaslip (copper grease) to prevent damage and allow easier removal. The tightening method differs between new and used plugs as the washer on the bottom gets crushed with new plugs. From memory, I install finger tight, then turn it a certain number of degrees more as specified by NGK.
Many thanks. I decided to ask NGK tech support, who said under no circumstances use any lubricant on their plugs. They said the plugs have a microscopic coating that does the same job. Their advice was to tighten to the same torque that Ferrari recommends - which in this case is 12 lb ft or 16.27 Nm. They said their plugs work from 15 - 20 Nm.
