911 Sparkplug Replacement

[jedoyle]

Hi All,

Planning to replace the spark plugs for the first time in my 911SC. I have the spark plug tool and Allen wrench from the tool kit like people describe on the forum. But that isn’t 3/8” like my torque wrench. If I want to torque the new spark plugs to spec, do I just use a standard 21mm socket or is there something better?

[John W.]

Definitely use the special tool, makes it easy. As I recall I used my torque wrench with an adapter to fit into the tool. Good luck.

[wazzz]

Here's what I do. I use a small 1/4" torque wrench to drive a 10mm socket. I cut a length of 10mm Allen wrench to make a stub of roughly 1 inch long. I use this stub as an adapter between the spark plug special tool and the 10mm socket.
May be you could do this with your 3/8" torque wrench and a 3/8" 10mm socket.

[fintstone]

Personally, I just use the allen tool wrench to tighten the plugs by feel. They don't need to be very tight and you will find it almost impossible to over tighten with a short allen wrench (with the engine installed) unless you are superhuman (or use an extension).

[proporsche]

same here as flintstone.....I never use torque wrench..just the hand feel..the spark plug has a crush washer at the end,once you feel you went by the washer it is tight.Also use some lubricant just not graphite....easy job with your original tools...
Ivan

[47silver]

I use a metric allen socket, in the porsche tool and use a 3/8 torque wrench. I dont trust my hands

[booyah911]

Most spark plugs tell you how to tighten them on the box. Depending on whether there is a taper or crush washer, usually it says what percentage of a turn to apply after initially bottoming out (usually 1/2 to 2/3 of a turn). I use a stubby wrench when doing this too.

[gdp_samson]

Originally Posted by proporsche

same here as flintstone.....I never use torque wrench..just the hand feel..the spark plug has a crush washer at the end,once you feel you went by the washer it is tight.Also use some lubricant just not graphite....easy job with your original tools...
Ivan

Hi Proporsche,

some swear by 'no lubricant whatsoever on the threads of a spark plug' where others tend to disagree...
I use copper grease for its conductive characteristics but sometimes I get headwind...
never got a spark plug issue, but no idea if lubricant is necessary either, I just do it...

any idea why opinions do vary a lot on this subject ?

[ant7]

I guess the main reason some are against using copper slip, or any form of conductive grease is encase it might get on the insulator, and track the spark to ground, but to be honest, you'd have to be quite messy, and use an extreme amount to tempt this.
Ant

Originally Posted by gdp_samson

Hi Proporsche,

some swear by 'no lubricant whatsoever on the threads of a spark plug' where others tend to disagree...
I use copper grease for its conductive characteristics but sometimes I get headwind...
never got a spark plug issue, but no idea if lubricant is necessary either, I just do it...

any idea why opinions do vary a lot on this subject ?

[safe]

Porsche says to use anti seize on the spark plug threads, but don't use any on the washer and you get a good contact patch there.
I use the 1/2-2/3 turn "torquing" as on the spark plug box.

[Schulisco]

An experienced mechanic will have a feeling for how much torque is required. A novice is better off using a torque wrench. For 911 engines, 25-30Nm is the torque to be used. This gives you the certainty of not damaging the ceramic insulator and avoiding new problems during installation...
I got my torque wrench tool out of the bicycle toolbox...costed me less than 50€ ten years ago...worth every penny for this purpose ...

[safe]

Bonus tip, get spark plugs with a 16mm hex, then it's not so freaking tight so you have to use the original tool, but any spark plug socket works. I prefer a socket with a magnet to hold the plug. Sockets with a rubber thing can be a nightmare if it sticks to the plug.....
Example NGK BCPR7ES, it's the BC instead of B that indicates the smaller hex.

[proporsche]

Originally Posted by ant7

I guess the main reason some are against using copper slip, or any form of conductive grease is encase it might get on the insulator, and track the spark to ground, but to be honest, you'd have to be quite messy, and use an extreme amount to tempt this.
Ant

On spark plugs i use HHS 2000 by Wurth..
Ivan

[KNS]

As others have mentioned, I just do it by feel and apply a *tiny* bit of copper paste.

I have a socket with a magnet and the socket with extension is the same overall length and size as the Porsche tool. In the past I've had the silly rubber holder slip out of the socket and get stuck on the plug - ugh.

[Funracer]

My experience using the Porsche plug tool:
#6 Spark Plug. Then This Happened

Any idea when was the last time the plugs were changed? In my case I know it was over ten years as the PO had owned it for that long and told me he had never done anything to the car except had the oil changed.

[proporsche]

for the job i use spark plug socket-Craftsman(all tools bought it in 1986) and Snap-on extensions and ratchet
Ivan

[Schulisco]

Regarding copper paste or other grease in the spark plug thread: I don't use it and don't recommend it. There are other opinions here.

My concern: "contact corrosion" between the copper and aluminum cylinder head and the steel thread of the spark plug in between. The greased thread can also lead to the torque being exceeded. Finally, the grease can insulate so that the heat cannot be dissipated from the spark plug as intended. Too much concerns for me. Clean the threads by brush and gently screwing the spark plug and applying the torque with the torque wrench.

Thomas

[mike sampsel]

As long as you change the plugs often, i believe there is no need for anti-seize or other things on the threads. If one goes too many miles (between plug changes) then the risk of two different metals seizing is an issue. I've never used anti-seize or any other lubricant on my plugs.

I believe, I'm in the "John Walker's workshop" camp here.

Ivan likes HHS 2000 (assume this is the same as HHS plus with our host). It's another camp ...

I use a piece of hose (gas line or rad hose) that grips the plug to start them all. It's very difficult to cross threat with the gas hose on the plug
Then move to the plug socket-extension-stubby ratchet after the hose is spinning.

[gamin]

Gearwrench 80547 3/8 drive 13/16 magnetic swiveling 6 inch spark plug tool. Perfect for air cooled 911's. All you need is this tool and a 3/8 ratchet.

[ccallana]

Do you all put anything like dielectric grease on the top side of the plug into the wire? or is that just making a mess for nothing?