[QUOTE]Originally posted by xviper
This may be hijacking this thread but it is important enough that something needs to be said.

On the subject of SPARK PLUG torques:
Originally, Honda sent our cars out with 13ft/lbs of torque on the plugs.

 

Adding my 2 cents. You should use a torque wrench that has sufficient range to cover your torque. For instance, if you need to torque a bolt to 45 ft-lbs, try to use a wrench that goes to 100 ft-lbs instead of 50. Get 2 wrenches, one for small stuff and one for bigger stuff. Like munkee I bought my beam-types at Sears for $25.

 

Yeah I have two as well. Most torques I can do by feel, and that is from experience. Esp drain and fill plugs. Spark plug torques are too ikmportant to do by feel, so I am anal abou those, and vcheck several times.

Here are tips for clicker types:

1) Loosen the adjusting screw when not in use - leaving it tightened will quickly reduce accuracy.
2) The firest few clicks are not as accurate as later ones. I like to set the torque, then "tighten" and loosen and re-tighten a non-critical bolt to get the clicker warmed up. This will give much more accurate readings.

3) Accuracy and longeveitry are best if used in the middle spec range - so for my 1/4" drive clicker, somewhere in the 75-150 inch pounds.


BTW, you can interchange drive adaptors (3/8 to 1/4) with no problems. Convert inch/lbs to ft/lbs by dividing by 12 (or the reverse by mutiplying).

 

Good quality "clicker" torque wrenches can be certified to be within FAA specifications when they are re-calibrated. If the accuracy is good enough for the FAA (I forget the exact specifications required: I believe it's +/- some % at low, mid, and high range, with specifications for both left and right), then it is probably good enough for the S2000. However, this implies that the wrench is calibrated regularly. Finding a place to do this may require a bit of work. I think most places that calibrate will provide FAA certification for little or no extra cost when they calibrate the wrench. I think many auto shops follow the FAA standards just to CYA...

 

What happens to the torque when you put on an extension, swivel, or use a crows foot?

 

so what do you suggest that the spark plugs be torqued at? 30#?

 

[QUOTE]Originally posted by jyeung528
so what do you suggest that the spark plugs be torqued at?

 

I'd like to hear from an expert on this, too, but my feeling on this is that you would introduce a bit of added flex with these attachments BUT once you reach the end of that flex, the torque should still be conveyed to the nut or bolt. It's not like a torque stick on an impact wrench that limits the amount of torque that can be relayed because of the "hammering" effect of the tool.
(I may stand corrected on this.)

 

Theoretically, the extension will not affect the reading. You are still measuring torrque at the bolt or nut. The extension may "twist" a little before you reach the desired torque.

On a swivel, the torque wrench is still accurately measuring the torque, but the question is, what is it measuring? Some of the torque may be the resistance of the swivel.

 

Since we are driving this thread all over the torque spectrum, let me share a few other pointers.

1. Dissimalar metals. When removing a threaded unit from a dissimilar material, you cannot expect the torque required to remove the threaded element to be equal to the torque that was used to install it. Activity between the two metals will often require greater torque to remove the unit than the amount that was applied when installing it.

2. Heat cycled metals. When removing fasteners that have gone through heat extremes, expect the torque required to remove the fastener to exceed the force used to install the unit.

3. Fasteners exposed to the products of combustiom. Same as above.

Note that spark plugs in aluminum heads fall into all three of the above catagories. If the plug was tightened enough to prevent the plug from backing out from vibration, you will often find that the torque required to remove steel threaded plugs from aluminum heads to be greater than the torque used to install them. This was a notorious problem with Jaguars and Alfas back in the 60s.

4. When you tighten a fastener you are stretching it. Fasteners resist the stretch and that is the force that is holding your fastened materials together. Fasteners can only be stetched so many times before they fatigue and fail to hold their specified torque. This is why head studs should be replaced after one rebuild. Some say to only use them once.

5. Lubricants on fastener threads and fastener mating surfaces like the face of the bolt and the face of the washer, result in greater bolt stretch (tightness) with the same amount of torque applied. The lubricant reduces the friction on these surfaces. The friction generated while tightening a fastener requires torque and reduces the amount of fastener stretch required to reach a given torque setting. Unless instructed otherwise, I torque fasteners dry to avoid over stretching. Some head bolts and nuts must be lubricated to reach the proper stretch to hold the head tight to the block. If in doubt, ask or research the application.