1993 Mercury Grand Marquis Spark Plug Torque Spec

[friskyfrankie]

Need the spec, in "ft/lbs" for the standard plugs (Motorcraft AWSF-32C) without anti-seize. I have seen numbers, all over the place, but I am thinking somewhere around 10-11 ft/lb. Just need verification. Never used a torque, for plugs in the past, but maybe I am getting more picky in my old age. If I don't use one, I guess I could simply snug slightly past hand tight but that is not a very accurate way to do it. Non torque wrench tips would be appreciated just in case I decide to go that route. I know the later GMs and CVs had issues with plugs getting loose due to short thread lengths but I never heard that happening for this year. Just to satisfy my curiosity - do these engines have aluminum heads?

[FordMan77]

If you go with an upgraded plug that has nickel threads on it (platinum or iridium) then you shouldn't have to worry about it and they will last you longer. The black oxide ones seem to get stuck more often and could gall the threads. Just personal experience on the 4.6's I've worked on over the years. I've had the oxide ones get a bit hard to remove and was worried about damaging threads while the others simply needed a few turns back and forth to break them loose and spin out just fine with minimal effort.

I have always used 11ft/lbs. I don't like to guess on these heads since they have so few threads in them so I always use a torque wrench.

And yes, they have aluminum heads.

[friskyfrankie]

If you go with an upgraded plug that has nickel threads on it (platinum or iridium) then you shouldn't have to worry about it and they will last you longer. The black oxide ones seem to get stuck more often and could gall the threads. Just personal experience on the 4.6's I've worked on over the years. I've had the oxide ones get a bit hard to remove and was worried about damaging threads while the others simply needed a few turns back and forth to break them loose and spin out just fine with minimal effort.

I have always used 11ft/lbs. I don't like to guess on these heads since they have so few threads in them so I always use a torque wrench.

And yes, they have aluminum heads.

Excellent info and thanks! The main reason for using the OEM stock plugs is that I already have them here. I had them, in my Dad's '93 and they were fine but then the car only had about 30-40 miles on it, after I changed them, before some meathead t-boned it so no way to tell what really long term use would have revealed.

[sly]

12-17 ft-lbs IIRC, I'll pull my service manual when I get home and check. I always use a light dab of anti-seize on my plugs just for good measure.

I typically use whatever is the dead center of the range given.

[friskyfrankie]

12-17 ft-lbs IIRC, I'll pull my service manual when I get home and check. I always use a light dab of anti-seize on my plugs just for good measure.

I typically use whatever is the dead center of the range given.

I'd be curious as those specs are decidedly higher than I have seen. I await your findings.

[GM_Guy]

Need the spec, in "ft/lbs" for the standard plugs (Motorcraft AWSF-32C) without anti-seize. I have seen numbers, all over the place, but I am thinking somewhere around 10-11 ft/lb. Just need verification. Never used a torque, for plugs in the past, but maybe I am getting more picky in my old age. If I don't use one, I guess I could simply snug slightly past hand tight but that is not a very accurate way to do it. Non torque wrench tips would be appreciated just in case I decide to go that route. I know the later GMs and CVs had issues with plugs getting loose due to short thread lengths but I never heard that happening for this year. Just to satisfy my curiosity - do these engines have aluminum heads?

If you have never used a torque wrench for plugs before I would not start now. After the horror stories about plugs in the 4.6 I got a torque wrench just for that, to be safe. Guess what, the old rule of thumb for tapered seat spark plugs (hand snug + 1/8th turn) just happens to be just right. And is a lot easier than trying to listen for a torque wrench click. Never used the torque wrench again. Lesson learned; if you got the feel for it, don't worry about it. People who've never done it before (myself included with the 4.6) get worried for nothing and get hung up on "perfection".

[friskyfrankie]

If you have never used a torque wrench for plugs before I would not start now. After the horror stories about plugs in the 4.6 I got a torque wrench just for that, to be safe. Guess what, the old rule of thumb for tapered seat spark plugs (hand snug + 1/8th turn) just happens to be just right. And is a lot easier than trying to listen for a torque wrench click. Never used the torque wrench again. Lesson learned; if you got the feel for it, don't worry about it. People who've never done it before (myself included with the 4.6) get worried for nothing and get hung up on "perfection".

Good point! I have torque wrenches and have used them before, on several projects, just not for plugs and especially on a 4.6. When I did my Dad's car, I didn't use a torque wrench and no disasters followed so I am thinking of doing the same here. Especially since it appears the torque specs are all over the place. I found my factory manual so just for "grins" I'll see what the recommendations are in this matter.

[sly]

NPI engine is 20Nm 15lb-ft (2000)
PI engine is 15Nm 11lb-ft (2001-2003)

Edit:
Looks like 93/94 shows even less. 9-12 Nm 6.6-8.8 lb-ft

[friskyfrankie]

NPI engine is 20Nm 15lb-ft (2000)
PI engine is 15Nm 11lb-ft (2001-2003)

Edit:
Looks like 93/94 shows even less. 9-12 Nm 2.2-8.8 lb-ft

Thanks for the specs. I do have the official Ford manual so I'll see what they have to say. Never got a chance to check it but will soon.

[sly]

I have the official Ford CD/DVD manuals for 93/94 cars and 2000-2003 all passenger vehicles. So those are the official numbers from Ford for the years specified.

[friskyfrankie]

I have the official Ford CD/DVD manuals for 93/94 cars and 2000-2003 all passenger vehicles. So those are the official numbers from Ford for the years specified.

Great! Saves me the time to research it all as they are official. Sounds pretty low for the 93 but it is what it is. Thanks for taking the time to look it up for me!!

[sly]

should be 6.6 to 8.8 lb-ft. Just saw my typo. dunno how the hell I put 2.2. Bah.

[friskyfrankie]

So we're figuring about 7 ft/lb. Wondering if it even pays or just a slight tightening past snug (which I have done before)? Guess it all depends upon the accuracy of the torque wrench.

[sly]

Yeah... kinda need an inch pound wrench for that.

I think I still used 12-15 lb-ft on my 93 with the original engine. *shrugs*

[friskyfrankie]

Still need to consult my manual to see if they say something different. Who knows?