I decided to take a look at my plugs at 27,500 miles- found that #3 and #4 were WAY undertorqued at the factory, and there was no sign of any anti-sieze compound having been used. I brass wire brushed the threads, applied a VERY thin coat of anti-sieze campound(per the Honda service manual) and torqued the plug to 13 ft-lbs. I found that if you hold the torque with the wrench (bend-bar type-NOT the clicker type which are all JUNK (IMHO)) for a time the plugs continue turning at the specified torque for a considerable amount of time. I think 13# is a good number especially with the anti-sieze compound acting as a lubricant going in. Primary function of spark-plug torquing is heat-transfer from the hot plug to the head(instead of to the coil) but over-torqueing could compromise the threads. Don't be tempted!

One reason for checking the plugs was to see if the 1qt/1500 miles I've seen since switching to Mobile 1 (10W-30) might be due to bad rings on one cylinder. happily, I found no raw oil or oil fouling, but I'm sure glad I found the loose plugs before they led to serious damage.

WRT oil consumption, this post by SEEKERone in response to another thread I started is interesting-

"honda's official word to us dealership technicians
1 quart per 1000 miles is normal and acceptable
synthetic burns a little bit more
but most important
use 10W30 oil...use of 5W30 or 5W20 will cause more rapid consumption of oil"

 

There's a new TSB out for the plugs specifying 18 ft-lbs instead of 13. Also, when the search function comes back up, look for anti-sieze and sparkplug...it's been decided that anti-sieze stuff is bad since it allows you to effectively torque to nearly TWICE what you have your wrench set at. In a nutshell, when giving a torque rating, friction between the bolt and hole is included in the calculation.

 

[QUOTE]Originally posted by MacGyver
[B]There's a new TSB out for the plugs specifying 18 ft-lbs instead of 13.

 

[QUOTE]Originally posted by MacGyver
[B]...it's been decided that anti-sieze stuff is bad since it allows you to effectively torque to nearly TWICE what you have your wrench set at.

 

The new TSB indicates that the plugs should be torqued to 18 ft-lbs. Torque is relative. There is run down torque, break out torque, service torque, and final torque just to name a few. Most Automotive service manuals (as well as AMM's - Airframe Maintenance Manuals and TSO's -Technical Service Orders) reference final torque. The actual service torque should be the run down torque + the final torque. This would say that I would add less with anti-seize then a dry metal for the additive run down torque. Improper torquing of fasteners is the number one cause of accidents in the aviation industry today. I have studied this subject for many years and currently work with the FAA to try to improve knowledge of torque requirements amongst the Airframe and Powerplant (A&P) mechanic community.

Utah

P.S. The final goal of torque is a attaining a prescribed degree of stretch in the fastener.

 

I agree on all counts here, except that the objectives when torqueing spark plugs are to provide for adequate heat transfer and to prevent the plugs from loosening, as opposed to structural fasteners where stretch (fastener loading) is what matters. However, a properly torqued spark plug would result in thread-loading being within a desired range. If you plotted the actual thread-loading of a large population of spark plugs installed by a large number of individuals using various torque wrenches at 13 ft-lbs dry, you would end up with a bell-curve. Clearly, too much of the bell curve falls to the left of the desired range of thread loading at 13# dry, so something had to be done. Honda elected to issue a TSB raising the number to 18# dry. The effect is to shift the entire bell curve to the right by a substantial amount. My earlier post is suggesting that some part of the new bell curve MAY be so far off to the right that, in some cases, structural damage to threads in the head could occur. As individual mechanics, we have the ability to install our spark plugs far more precisely than the population Honda has to deal with. Given all I've seen and read on the subject, my own choice will probably be something like 15# with a touch of anti-sieze, though I believe 13# to be quite adequate when done properly.

 

Why did you install the old plugs? Seat washers only crush once.

 

Well, pal, I crushed them a little bit more! Actually quite a bit more since they were so poorly installed at the factory. And please- do send me any nearly-new platinum plugs in perfect condition you happen to be throwing away because the gaskets have been crushed.

Seriously- its done every day by mechanics everywhere. (See sec. 4- p. 19 of the official Honda service manual for the S2K)

 

Uhhhh, OK.....I'm wrong about it being decided as an absolute. Frankly, that post scared me making me think I was actually torqueing everything to twice what's recommended, but also figured that's what happens everyday in most service centers (so it couldn't be ALL bad). I'll just smile and nod on this one, regardless of the outcome...don't know enough to fight for either side this time.

 

[QUOTE]Originally posted by S2K2GO!!!
[B]

Well, pal, I crushed them a little bit more!