snip

I suspect this is the consensus, and I think it's a good point to throw in
the mix: Galled bolts are hard to free for a number of turns after the
initial breakloose. This hasn't happened in the maybe three times I've
loosened my 91 Civic's pulley bolt.

Okay.

And no surprise about the impact wrench you're using. It's a popular method,
by all reports here.

Okay.

Aside: If the thread's bolts are seized, I remain baffled at why the bolt
head doesn't shear off the way they commonly do on certain suspension bolts.

No, I'm uncertain if the galling is the result of other movement (either in
torquing or in service) and that the galled surfaces are producing the
excessive break-loose torque. I've dealt with galled threads before, and
crank bolts just don't feel that way - once they back off a bit they always
have been smooth for me. Disclaimer - I've only done a handful of crank
bolts, not dozens or hundreds like pros encounter.

I have never used extensions - really! The impact socket rotates an
estimated 1/4 turn before it takes off. I always watch it, trying to will it
to turn ;-)  I've never really kept track of how far it rotates to reach
torque specs when tightening.

That's where I'm heading, but I don't really know if that's right. My
opinion is still in freefall on this.

You mean they are a result of?

Galled refers to a surface that has been rubbed by something else.

Are you sure you're not referring to the roughly quarter turn of typically
1/2-inch drive extension tool windup that occurs?

'Cause that will rotate about 45 degrees at 300 ft-lbs of torque. If more
torque is required to breakloose the bolt, then even more angular deflection
occurs. But it's not the bolt turning.

Are you saying you think the head and washer are adhering, and that's why
the breakloose torque is so high?

Quite right.

I still dunno. I've seen galled steel flat washers and bolt heads various
places before (but I don't recall where they have been), so I wouldn't have
thought it was unusual. I would speculate that the torque we need to apply
to break crank bolts loose isn't being directed to the threads but to the
head, where the galled surfaces are responsible for the excessive
break-loose torque. Pure speculation, though.

Usually crank bolts (Honda or otherwise) need to loosen a quarter turn or so
before they come free, and then there is no evidence of the threads
galling - leading me to the speculation of the galled head and washer
surfaces being the key. That would also be consistent with the observation
that the break-loose torque goes up over the years, if engine heat and/or
vibration is important in the development of the galling.

I don't think we have enough to work with to come up with a definitive
answer.

Mike

ok, let's try this instead:

http://www.flickr.com/photos/38636024@N00/

lower res pics are here:

http://www.snapfish.com/thumbnailshare/AlbumID=31395672/t_=36454773

this afternoon, i went to my favorite junkyard and bought two crank
bolts.  one from an 91 civic, one from a 92 civic.  i'm going to post
the pics later this evening, but the observations are these:

_91_
* eyeball=poppingly hard to shift - had to get a fulcrum and bounce full
bodyweight at the end of a 18"x3/4" breaker bar.
* no evidence of loctite.
* clear fretting damage on the mating surface between the washer & the
bolt head.
* no evidence of corrosion.  [i'm in california]
* pulley wheel locked with single woodruff key.

_92_
* it was definitely snug, but i could remove with one hand.
* bolt thread clearly loctited.
* no evidence of fretting.
* no evidence of corrosion.
* pulley wheel splined /and/ woodruffed.

now, we all know what loctite does - it binds threads so they don't
move.  no movement means no possible further tightening.  loctite also
means a bolt is hard to remove compared to its fastening torque.

conclusions:

1. there is /definitely/ lash in the 91 pulley wheel - something that
honda evidently felt needed to be addressed with the addition of a
splined interface for the 92.  [splines don't eliminate lash, but help
mitigate it.]  fretting [or lack thereof in the case of the 92] is as
clear an evidence of lash as you can get.

2. loctite /prevents/ further tightening of the bolt!  hence the 92 was
much easier to remove, despite the loctite's binding function.  the
reduced lash would help in this regard also.

time to get out the camera...