crank bolt tightening debate

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

 

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.

 

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.

 

thanks dude - appreciate it.

on the one hand, it's healthy to be skeptical. on the other, i've done
enough failure analysis on enough machinery to know what i'm looking at.
i can also deduce something of the service history based in what i see.

sorry, but i'm the guy that took it off. and if you can't accept that
the pictured galling happened with the key installed, then we have a
debate beyond the tech arena. the woodruff key, the pulley wheel and
the crank keyway were all in perfectly acceptable condition, although
there was evidence of lash - much like the lash evident on the splines
of a driveshaft. there was no evidence of the pulley wheel ever having
been spun out.

without the woodruff, the pulley would absolutely rotate. the more the
bolt was torqued, the more difficult it would be to turn, but saying it
won't & can't move is like denial of elasticity.

regarding the 91 vehicle's history, i know that it had been relatively
well serviced. it had 220k miles. and that pulley bolt had been
removed 3 times. you can't see it from the pic, but the skid mark at 2
o/c on the l/h bolt's washer in this pic:

http://www.tegger.com/hondafaq/misc/jim-beam_pulley_pics/both_washer_u-side.jpg

it has 3 of those skidmarks, coinciding with the keyway, one for each
removal. the galling evident on the other side of the washer is not
what you would see from 3 removals. not by any stretch.

the 92 bolt otoh, you can see the evidence of one removal [evident from
the keyway mark] on the bolt, by me. the bolt side of that washer shows
some minor skid evidence, but as you can see, it's not impacted the
plating and there's no evidence of galling whatsoever.

 

thanks dude - appreciate it.

on the one hand, it's healthy to be skeptical. on the other, i've done
enough failure analysis on enough machinery to know what i'm looking at.
i can also deduce something of the service history based in what i see.

sorry, but i'm the guy that took it off. and if you can't accept that
the pictured galling happened with the key installed, then we have a
debate beyond the tech arena. the woodruff key, the pulley wheel and
the crank keyway were all in perfectly acceptable condition, although
there was evidence of lash - much like the lash evident on the splines
of a driveshaft. there was no evidence of the pulley wheel ever having
been spun out.

without the woodruff, the pulley would absolutely rotate. the more the
bolt was torqued, the more difficult it would be to turn, but saying it
won't & can't move is like denial of elasticity.

regarding the 91 vehicle's history, i know that it had been relatively
well serviced. it had 220k miles. and that pulley bolt had been
removed 3 times. you can't see it from the pic, but the skid mark at 2
o/c on the l/h bolt's washer in this pic:

http://www.tegger.com/hondafaq/misc/jim-beam_pulley_pics/both_washer_u-side.jpg

it has 3 of those skidmarks, coinciding with the keyway, one for each
removal. the galling evident on the other side of the washer is not
what you would see from 3 removals. not by any stretch.

the 92 bolt otoh, you can see the evidence of one removal [evident from
the keyway mark] on the bolt, by me. the bolt side of that washer shows
some minor skid evidence, but as you can see, it's not impacted the
plating and there's no evidence of galling whatsoever.

 

it's not - because bolts move! that's why there's a whole industry
dedicated to the production of locking mechanisms for threaded fastners.
usually, we only care about the ones that loosen because they are more
likely to cause the failures.

which is consistent with lash of the pulley wheel!

that's part of it, but ultimately, as we can see from the skid marks on
the underside of the washer, the bolt is still free to turn. the
question is, at what torque. once it is turning, that sob is still in
there /way/ tight, and way tighter than when torquing to fastening spec.

depends if we've spent time doing this kind of work before!

 

it's not - because bolts move! that's why there's a whole industry
dedicated to the production of locking mechanisms for threaded fastners.
usually, we only care about the ones that loosen because they are more
likely to cause the failures.

which is consistent with lash of the pulley wheel!

that's part of it, but ultimately, as we can see from the skid marks on
the underside of the washer, the bolt is still free to turn. the
question is, at what torque. once it is turning, that sob is still in
there /way/ tight, and way tighter than when torquing to fastening spec.

depends if we've spent time doing this kind of work before!

 

Spines can reduce or eliminate movement if the spines channels are
tapered. This is noticeable when you will require a gear puller to remove
the pulley. But woodruff key aren't and they can produce play, or
movements. I once removed a crank bolt (1988 at 180k miles) with a key.
The face of the bolt is pretty worn from movements. Unlike a radial-arm saw
the inertia from the weight load on the pulley develops in both directions but
the bolt has to move in one direction so the woodruff key is used.

What do you mean?... Honda have made motors than spin clockwise and
counterclockwise. And the crank bolts are always Lefty Lucey and Righty Tighty.

 

Spines can reduce or eliminate movement if the spines channels are
tapered. This is noticeable when you will require a gear puller to remove
the pulley. But woodruff key aren't and they can produce play, or
movements. I once removed a crank bolt (1988 at 180k miles) with a key.
The face of the bolt is pretty worn from movements. Unlike a radial-arm saw
the inertia from the weight load on the pulley develops in both directions but
the bolt has to move in one direction so the woodruff key is used.

What do you mean?... Honda have made motors than spin clockwise and
counterclockwise. And the crank bolts are always Lefty Lucey and Righty Tighty.

 

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.

 

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.

 

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.

 

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.

 

The units are irrelevant as long as the quantities
are correct.

Normal operating conditions or not, a moment of force
is commonly called torque.

Whatever that is, it is beyond me to see any relevancy
to the bolt tightening debate.

What would this be good for - the bolt should remain
lose "upon commencing operations"?

It's not the greater surface area that "holds fine
threaded applications more tightly together," it is
the smaller lead (the pitch in a simple bolt).
<http://www.efunda.com/designstandards/screws/faste
ners_intro.cfm?search_string=thread>

Galling is abrasion and fusion caused by friction,
not heat cycling.

 

The units are irrelevant as long as the quantities
are correct.

Normal operating conditions or not, a moment of force
is commonly called torque.

Whatever that is, it is beyond me to see any relevancy
to the bolt tightening debate.

What would this be good for - the bolt should remain
lose "upon commencing operations"?

It's not the greater surface area that "holds fine
threaded applications more tightly together," it is
the smaller lead (the pitch in a simple bolt).
<http://www.efunda.com/designstandards/screws/faste
ners_intro.cfm?search_string=thread>

Galling is abrasion and fusion caused by friction,
not heat cycling.

 

If someone else would like to address this gentleman's comment above and his
other assertions, then please be my guest.

snip for brevity

 

If someone else would like to address this gentleman's comment above and his
other assertions, then please be my guest.

snip for brevity

 

That's a good point.

Mike

 

That's a good point.

Mike

 

you can see from the pics that there are no binding problems with the
threads. even the 91 which has been removed 3 times shows no signs of
distress.