1993 Mercury Grand Marquis Spark Plug Torque Spec

[friskyfrankie]

Just dug out the Official Ford Manual for this car and the spark plug torque is stated as 6.6.7.3 Lb-Ft (9-20 N.m). Not sure if they recommend anti-seize compound or not as I have yet to find it.

[sly]

9-20Nm doesn't match up to 6.6-7.3 lb-ft... that would be 6.6-15 lb-ft.

[friskyfrankie]

9-20Nm doesn't match up to 6.6-7.3 lb-ft... that would be 6.6-15 lb-ft.

Not certain of the conversion but I am only stated what it said. Misprint?

[friskyfrankie]

Your conversion is basically correct (14.75) but that is posted in more than one place in the manual (inside and on the back cover) so not really sure what the real deal is?

[GM_Guy]

And just for added fun, the low spec end of the spec got superceeded by a higher spec at some point.

[friskyfrankie]

And just for added fun, the low spec end of the spec got superceeded by a higher spec at some point.

Makes you just want to ditch the entire "torque wrench thing" and let experience guide me!

[sly]

Go with the 2000. That's the last NPI engine spec.

[friskyfrankie]

Dug out the official manual and specs are as follows:

9-12 N m or 6.6 -8.8 LB FT

Seems a tad low but I guess they don't want the plugs "crucified" into the heads!

[sly]

Since there was no change in the heads themselves 92-00, I'd go with the later specs myself and consider the original specs the absolute minimum. That's just me though.

[friskyfrankie]

Seems the more recent spec (approximately 13 LB FT) is a little more appropriate than the original one of about 7.

[GM_Guy]

It is. reports of plugs loosening becuase they where not tight enough.

[friskyfrankie]

Guess they were being overly careful - maybe to prevent lawsuits?