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Torque Education Needed

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abscate
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Post by abscate »

I try to encourage people to learn what correct torque feels Like. When you are stuck on the road, Ou probably won’t have a torque wrench to deal with that bad spark plug.

After you get it off, hand tighten the plug. , then a nip with a 12 inch breaker.

The m6 on the course is a light 15 Nm torque so a wrist tight touch there.

Finally those m27 Torx on the plastic cover...finger tight
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Post by RickHaleParker »

BlackBart wrote: 20 Oct 2021, 13:02 is about 12-15 ft-lbs for spark plugs.
A new spark plug is not "torqued" you tighten it until you feel the Crush Washer crush.
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Post by kallekula »

How much do you torque the spark plug to if you're reusing a plug where the crush washer is flat?

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Post by RickHaleParker »

kallekula wrote: 20 Oct 2021, 23:01 How much do you torque the spark plug to if you're reusing a plug where the crush washer is flat?
Snug them in: Finger tighten until the crushed Crush Washer touches the bottom of the Spark Plug Well. Then ½ – ⅔ turn more with a spark plug socket and ratchet. In other words just enough to get a good seal.

You are not try to bolt two pieces together. Just hold the plug in the hole and get a good seal is the objective. The threads on the plug is what holds the plug in and the Crush washer seals it. There are no rotational forces ( Torque ) there to loosen the spark plug. Snug, for a good seal, is all force you need on a spark plug. Go past that and you have problems getting them out later.
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Post by abscate »

Rick has pointed out a classic case where a torque number is a bad guide for correct fitment. If you just blindly torque to a number and some carbon or crud on the spark plugs bungs up the threads, you will reach torque before the washer seats. That will get ugly fast
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Post by RickHaleParker »

On new plugs.
1. Finger tighten with a socket and extension until the Crush Washer touches the bottom of the Spark Plug Well.
2. Attach a Ratchet.
3. Hold the extension with one hand.
4. Place two finger on the end of the Ratchet ... three if you are a sissy or getting old.
5. Pull steady with your finger muscles ( do not move your arm ). You will feel pain in your fingers.
6. When the Ratchet slips a notch and the pain lessens. That is the Crush Washer crushing.
7. STOP! You are done with that plug.
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Post by BlackBart »

RickHaleParker wrote: 20 Oct 2021, 18:57
BlackBart wrote: 20 Oct 2021, 13:02 is about 12-15 ft-lbs for spark plugs.
A new spark plug is not "torqued" you tighten it until you feel the Crush Washer crush.
Yes. That advice was for old V8s and iron heads. I'm much more careful now.
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Post by RickHaleParker »

BlackBart wrote: 21 Oct 2021, 10:24 Yes. That advice was for old V8s and iron heads. I'm much more careful now.
It never was carelessness and it is still not carelessness. Matter of fact it is being careful. A Torque wrench is not going to clue you when to stop. That makes the Torque wrench the careless way for Spark plugs.
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2004 S60R, B8444S TF80 AWD. Yamaha V8 conversion ( I moved, the project did not )
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Post by BlackBart »

Misunderstanding each other - I never used a torque wrench. The one-wrist method with some care gives you a feel for what's happening, and you can't apply much force. That's all.
ex-1984 245T wagon
1994 850T5 wagon
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