Honda Spark Plug Torque Dilemma

[INDYMAC]

The only Honda I'm familiar with is the S2000. Back around 2001 Honda issued a TSB raising the torque setting for NGK Plugs (no anti-sieze) from 13 to 18 ftlbs. There were some problems with plugs loosening causing damage. Some owners and techs take it up to 21, but I just use the 18.

 

[hattaresguy]

Just tighten the plug just past when the gasket crushes. You don't need a torque wrench, it takes a lot to strip out a plug you have to be pretty ham fisted to do it.

 

[Tegger]

Originally Posted By: INDYMAC
The only Honda I'm familiar with is the S2000. Back around 2001 Honda issued a TSB raising the torque setting for NGK Plugs (no anti-sieze) from 13 to 18 ftlbs. There were some problems with plugs loosening causing damage. Some owners and techs take it up to 21, but I just use the 18.

You're referring to TSB 02-042. This TSB simply says that spark plugs with faulty gaskets may cause the plugs to loosen and set a misfire DTC. It does not mention possible damage, and does not specify manufacturer or anti-seize.

The way the TSB reads, it seems to be saying that the problem has to do specifically with the plugs that were shipped with the vehicle when new. The overtorque from 13 to 18 may be a measure to prevent such an occurrence should the owner encounter defective plugs again. Maybe this particular engine is sensitive to plug quality.

 

[SkaT]

If you pull the plugs and reinstall them (in a Honda of course to keep with the topic) once or twice or several times, should you put on new gaskets? Can you even buy new gaskets for, say, NGK plugs? Wouldn't an old gasket change the 2/3 turn past finger tight rule?

 

[The_Eric]

Originally Posted By: mechtech2
My reasoning is that the 2/3 turn is more accurate and easier.
This is for NEW gasket type plugs.
1/8 turn [never more, sometimes a bit less]for tapered seat 5/8" plugs is also more accurate and easier, but on these sometimes I use a TW for appearance sake.


Agreed. NGK even prints (or used to) the specs right on their boxes. It used to say 2/3 turn for gasketed plugs and 1/16 turn for tapered seat plugs.

 

[Tegger]

Originally Posted By: SkaT
If you pull the plugs and reinstall them (in a Honda of course to keep with the topic) once or twice or several times, should you put on new gaskets? Can you even buy new gaskets for, say, NGK plugs?

NGK/Denso plugs for sure -- and I believe ALL plugs with gaskets -- have captive gaskets: you can't get them off.

I've removed and reinstalled plugs many times, with no apparent ill-effects. But then I always use a torque wrench for new and old plugs, which I believe to be best practice; certainly, much better than the angle rule.

Originally Posted By: SkaT
Wouldn't an old gasket change the 2/3 turn past finger tight rule?

Absolutely. The turning-angle spec takes into account a new, uncrushed gasket. When reusing an old plug, you MUST use a torque wrench, and MUST tighten to the proper spec for your engine.

I believe that the angle rule is meant to accommodate people who don't own a torque wrench. Honda and Toyota factory specs always give a torque number, not an angle.

 

[KrisZ]

Originally Posted By: SkaT
Wouldn't an old gasket change the 2/3 turn past finger tight rule?


Yes, and if that's the case, treat the plug as if it were a tapared type, so 1/8 of a turn will do just fine.

 

[mechtech2]

How in the world can we know the correct torque spec of a used gasketed plug??
It varies by how much the old plug was tightened, for one thing.

This is a feel thing - experience shows when a gasket is too compressed or has some give left.

 

[INDYMAC]

Originally Posted By: mechtech2
How in the world can we know the correct torque spec of a used gasketed plug??
It varies by how much the old plug was tightened, for one thing.

This is a feel thing - experience shows when a gasket is too compressed or has some give left.


So you're saying a DIY'er should go by feel, rather than use a torque wrench? That's interesting.

 

[yonyon]

Originally Posted By: Tegger

NGK/Denso plugs for sure -- and I believe ALL plugs with gaskets -- have captive gaskets: you can't get them off.


I'm going to go ahead and say this doesn't hold true for Autolite, Bosch, or Champion.

 

[antiqueshell]

Originally Posted By: yonyon
Originally Posted By: Tegger

NGK/Denso plugs for sure -- and I believe ALL plugs with gaskets -- have captive gaskets: you can't get them off.


I'm going to go ahead and say this doesn't hold true for Autolite, Bosch, or Champion.


Most Bosch plugs also have non removable crush washers on them.

Also very important is not to forget that once you remove a nickle plated thread spark plug from the engine you have "used up" the anti-seize feature. So it would be a good idea to use a little new paste to coat the threads.

 

[ltslimjim]

Originally Posted By: INDYMAC
Originally Posted By: mechtech2
How in the world can we know the correct torque spec of a used gasketed plug??
It varies by how much the old plug was tightened, for one thing.

This is a feel thing - experience shows when a gasket is too compressed or has some give left.


So you're saying a DIY'er should go by feel, rather than use a torque wrench? That's interesting.


I've never used a torque wrench, but I'm also not more than a novice learner. However, with anti-seize and more easily to turn, I still get them just starting to crush the washer in my 92 and turn it a 1/2 turn-2/3s(max). Never a problem.

In fact, I was so hesitant without anti-seize during my first spark plug change on this car that my mechanic(old one) said the plugs weren't tight enough therefore not 'grounded', wasting spark I suppose?

 

[SOHCman]

I am starting to think people are incorrectly assuming that the torque is "thread torque" and makes antisieze wildly throw off the torque reading. Isn't the gasket/taper seat pressure what we are really "torquing" and antisieze on the threads doesn't really make as much difference as we make out?

Just speculation, especially with all this talk about 3/4 of a turn for seat pressure being what really matters.

 

[doitmyself]

Originally Posted By: SOHCman
I am starting to think people are incorrectly assuming that the torque is "thread torque" and makes antisieze wildly throw off the torque reading. Isn't the gasket/taper seat pressure what we are really "torquing" and antisieze on the threads doesn't really make as much difference as we make out?

Just speculation, especially with all this talk about 3/4 of a turn for seat pressure being what really matters.


This is taking the subject matter beyond what's practical, but here goes. I actually think that you are incorrectly assuming what torque actually is a measure of....turning force, not "seat pressure". Turning force is a poor measurement for "tightness" because it depends on too many variables: friction, stretch, etc.. If the mfg. posts a torque value based on clean, dry threads and you alter that by applying a lubricant, then there is a chance that the torque reading will not reflect the actual clamping force (stretch) that occurs between the threads and the "seat pressure", the seat being a nut, bolt head, or spark plug contact point.

Using degrees (1/8 or 2/3 turn past finger tight) does away with many of the variables involved with torque measurement. Study any engineering site about torque measurement and you will discover that +/- 30% error is the standard for torque measurements.

On the other hand, people here are describing the starting point (finger tight/until contact) with different definitions. After these starting differences, I imagine that the difference in 1/16 - 1/8 turn (tapered seat) or 1/2 and 2/3 turn (crush gasket) amounts to a large difference in clamping force. Thus the recommendations here to use "common sense" feel.

An academic discussion, at this point and just a reflection of my boredom and wish to share info.

 

[randomhero439]

Just use a torque wrench to turn it 2/3. See how it feels, and let common sense do the rest.

 

[garlicbreadman]

always use torque wrenches for spark plugs...the key thing is consistency and that is only achieved through a torque wrench

and of course..hand start the spark plugs in the threads!

i torqued the spark plugs on my integra to 15ft pd...never a problem.

 

[mechtech2]

Originally Posted By: INDYMAC
Originally Posted By: mechtech2
How in the world can we know the correct torque spec of a used gasketed plug??
It varies by how much the old plug was tightened, for one thing.

This is a feel thing - experience shows when a gasket is too compressed or has some give left.


So you're saying a DIY'er should go by feel, rather than use a torque wrench? That's interesting.


Since there is no torque value for an undetermined amount of variable squish, my answer is absolutely yes. Feel is better.
Why do you assume there is a torque value for a part that is very changeable in form?

 

[Tegger]

Originally Posted By: mechtech2
Since there is no torque value for an undetermined amount of variable squish, my answer is absolutely yes. Feel is better.
Why do you assume there is a torque value for a part that is very changeable in form?

No factory shop manual that I have ever read gives a turn-angle figure for tightening plugs, but always a torque number. Sometimes there are two figures, one for used plugs, and one for new ones. Sometimes there are different figures depending on the particular plugs being used.

Torque cannot be exerted until the "squish" is squeezed out from between the contact surfaces. Your torque wrench will not register much above a pound or two until the spark plug's crush-washer is fully compressed. Once the crush is complete, torque will be quite consistent.

I believe that the angle-numbers are meant for people who do not own torque wrenches, which likely describes most home grease-monkeys. Plus, angle-numbers are meant for NEW plugs only, as they take into account the rotation necessary to crush the washer.