CSK 911 C4S

For those that have DIY'ed your 40K service, what torque do the spark plugs require?

Doing a search a few threads pop up on the 997 forum saying 30Nm-22ft/lbs ...... which is pretty normal/standard for plugs at least on my past Audi's and VW's.

Any other info available?

Edit:
Information from 991.1 repair manual 2011-2015
Spark plug → Tightening torque: 32 Nm (24 ftlb.)+/-2 Nm (+/-1.5 ftlb.) → Tightening torque: 25 Nm (19 ftlb.)+3 Nm (+2 ftlb.)

SDaddy

Sorry, my '15 has a couple of years before I will be changing the plugs. Thanks for asking the question and I'm anxious to hear the answer so I'm ready when the time comes...

PS, Does anyone have a tip for getting a credible 991 service manual for us DYIers?

worf928

Assuming that it is the same for the 991 as the 981 (and why shouldn't it be?) the torque spec is 32 N-m (24 ft-lbs) for a new plug and 25 N-m (19 ft-lbs) for re-installed plugs.

If you are interested in 991 manuals, head over to planet-9 and do a search. You'll find a guy...

LexVan

Why are reinstalled plugs lower torque? Why would someone remove a plug, only to reinstall it? Thank you.

mtony

Because the crush washer has already been crushed. Can't answer the second question.

CSK 911 C4S

The only reason I've removed a plug and reinstalled it on other cars has been to trouble shoot a misfire condition. Move the plug and coil pack around to see if the misfire follows before throwing new parts at a car.

Arcoril

If you're doing a PPI and you want to do a compression test or use a boroscope to check the cylinder linings you've gotta remove the plugs, for example.

worf928

Or because PCNA won't reimburse your tech's dealer for the $3 each plugs despite their direction to pull them...

I'm just reading from the WSM. I figure the different specs have something to do with the crush washer. But, that doesn't make much sense. The threads in the hole don't know if the crush ring's crushed. 32N-m is 32N-m whether or not you crushed something to get there.

CSK 911 C4S

delete

Z00mie

Completed a plug change today on my 2013 C4S (40K), Pretty easy stuff, if you are somewhat hesitant, don't be! I suggest starting on passenger side. I wasn't able to use a torque wrench on either rear plug (L/R bank). Took about 2.5 hours including cleaning the inside of both rear wheels while removed. Plug part number is 999 170 151 90, 32NM for torque.
There is a great deal of satisfaction in working on your own car. The Porsche techs have to develop experience somewhere and it was likely on your car! Heck, if someone is gonna learn (on your car) it ought to be you!

991carreradriver

Funny, my 991 manual specifies 24ft lbs for the first tightening and 19 ft lbs for the second tightening. Ask him to show you the source of his opinion, I would be willing to bet that he is wrong.

CSK 911 C4S

You are correct.

Found this in the 991.1 manual.

Spark plug → Tightening torque: 32 Nm (24 ftlb.)+/-2 Nm (+/-1.5 ftlb.) → Tightening torque: 25 Nm (19 ftlb.)+3 Nm (+2 ftlb.)

So 30 Nm (22ft/lb) recommendation was erring on the side of "don't screw this up"

I must not have had the manual at the time of doing my 40K.

drcollie

Not really! A 2015 would be due for a plug change soon - every 4 years is the Porsche Spec.

mtgadbois

Remember those torque specs assume NO lubricant (or anti-seize) on the plug threads! I like anti-seize and used a torque wrench only once. Cracked 2 plugs and then I went back to the method I've used for over 40 years. Namely, tight and then about a 1/4 turn more. Do it a few times and you'll get the feel. Never had a plug loosen up and, of course, never had one stick.

Macster

The torque specs are for new plugs that come with a thread "coating" or treatment from the plug factory that acts as some kind of thread lubricant. Using anti-seize is not recommended because this can foul the O2 sensors. Anti-seize can remain between the head and plug threads and affect the heat transfer from the plug to the head causing the plug can run hotter that it would otherwise. Also, the anti-seize provides room for combustion gases to work their way up the threads. Even plugs that have not had any anti-seize can show combustion gas discoloration/corrosion all the way up the plug threads.

Ditch the anti-seize.