crank bolt tightening debate
jim beam
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...
TeGGeR®
s...@speakeasy.net:
> 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:
<snip>
Jim: Properly tightened, that bolt does NOT allow any sort of movement. It
/cannot/, and it /does not/. Period. Full stop. End of story.
You may be an electronics whiz, but you are clearly no mechanical engineer.
The pulley and the pulley bolt do NOT move in use, and the bolt absolutely
does NOT rotate so as to "tighten" after initial torque.
If you choose to believe that the bolt tightens more through rotation after
initial tightening torque, then you are misleading yourself and everyone
who reads your posts.
There are many reasons why some crank bolts are difficult to remove.
Rotation after initial tightening torque is *NOT* one of them.
--
TeGGeR®
The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/
Burt S.
> Jim: Properly tightened, that bolt does NOT allow any sort of movement. It
> /cannot/, and it /does not/. Period. Full stop. End of story.
> The pulley and the pulley bolt do NOT move in use, and the bolt absolutely
> does NOT rotate so as to "tighten" after initial torque.
If the bolt doesn't move then locktite would have been recommended, but
instead they recommend oil.
http://square.cjb.cc/images/oilgood.gif
> If you choose to believe that the bolt tightens more through rotation after
> initial tightening torque, then you are misleading yourself and everyone
> who reads your posts.
Not observing the different variety of bolts manufactured is misleading.
Patents are create for almost everything, possibly including the tap and
die used on self-tightening bolts.
> There are many reasons why some crank bolts are difficult to remove.
> Rotation after initial tightening torque is *NOT* one of them.
Most of these crank bolts show no signs of wear, crystalization,
bonding or rust. However there is a slight wear on the face of the bolt
which probably suggest that it's moving.
Burt S.
As I suspected. I've created a page just to explain my reasoning
check it out here.
http://square.cjb.cc/bolts.htm
jim beam
> jim beam <nos...@example.net> wrote in news:jY2dnf6UQMdVmPHeRVn-
> s...@speakeasy.net:
>
>
>>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:
>
>
>
> <snip>
>
>
>
> Jim: Properly tightened, that bolt does NOT allow any sort of movement. It
> /cannot/, and it /does not/. Period. Full stop. End of story.
i've just emailed you the photo evidence. if you host it, we can all
discuss it.
>
> You may be an electronics whiz, but you are clearly no mechanical engineer.
i'm no electronics guy and no engineer. i'm an [ex] metallurgist. and
metallurgists spend a big proportion of their time sorting out the
screw-ups the engineers make because half of them don't know what
they're doing and were asleep in materials 101 or are too egotistical to
bother to ask.
>
> The pulley and the pulley bolt do NOT move in use, and the bolt absolutely
> does NOT rotate so as to "tighten" after initial torque.
check your email. i've just sent you the galling evidence. it's a
perfect textbook example.
>
> If you choose to believe that the bolt tightens more through rotation after
> initial tightening torque, then you are misleading yourself and everyone
> who reads your posts.
the loctited bolt/splined pulley does not move. the torque-only
bolt/woodruff-only pulley does. the galling proves it.
>
> There are many reasons why some crank bolts are difficult to remove.
> Rotation after initial tightening torque is *NOT* one of them.
except that we have the photo evidence to prove to the contrary!
jim beam
that's bunk. you're citing rolled vs. cut threads as evidence of some
kind of ratchet mechanism? no. threads are rolled for fatigue
resistance - rolling has nothing to do with ratcheting. oh, and yes, i
/have/ looked at plenty of bolts under microscopes, thanks.
Elle
I agree with Jim that, upon vibration, the cut of the threads does not tend
to tighten the bolt. Your Figure 3, Burt, doesn't show anything different
from a coarse thread cut. The threads are helically cut on both coarse and
fine thread designs, of course, so back-and-forth vibrating forces will tend
to have the same effect on both, absent other forces being at work.
So far I think the rest of the site has much to offer.
I would suggest
1.
Making sure you use the right units for torque. The units for torque in
automobile manuals are conventionally given as ft-lbs or newton-meters in
manuals. I realize English is not your first language, so maybe something
got lost in translation here.
2.
From my reading, "momentum force" is not a commonly accepted way of
characterizing the forces acting on the pulley under normal car operating
conditions. Inertial force is okay, being one way of saying centrifugal
forces are what mostly tend to push it off the crankshaft. (Recognizing, for
the physics-inclined among us, that whether it's accurate to call the
effects of centripetal forces "centrifugal forces" depends on what frame of
reference is used. What "centrifugal force" means in practical, hands-on
applications is well-understood, so I'm using it.)
3.
Your wording is not perfect, but then rarely is mine. I can understand your
other points and tend to agree with them. I think it is particularly
noteworthy that oil is supposed to be used, /not/ something like Loc-Tite,
on the threads. For now, I agree the purpose is to ensure that the bolt and
shaft threads can move relative to each other upon commencing operations.
4.
I want to look further into your hypothesis about what causes that loud
crack when the bolt frees. I think you're right that it may be due to
release of a large axial load in the bolt and so is a sonic boom(?). If it
is a sonic boom, then that does tend to suggest that the pulley bolt is in
fact under very high axial load. It's not, like Tegger has been contending,
merely the galling of female and male threads against each other,
essentially adhering one to the other.
5.
OTOH, I think galling does play a role. One need only consider some of the
exhaust bolts that become so hard to remove. Many of them are fine threaded
(not sure if they're super-fine, non-standard fine threads or not). Fine
threads are used to minimize the likelihood of the bolts vibrating free
during operation. The greater surface area contact between male and female
threads is what holds fine threaded applications more tightly together than
coarse threads. But unlike the pulley bolt, the exhaust bolts don't have a
rotating mass attached to them. The exhaust bolts also get very hot, though,
and they also vibrate while they're hot. Heat cycling--temperatures being
alternately raised and lowered, causing the metal to expand and contract and
fill in whatever microscopic gaps there are between male and female thread
surfaces--may play a huge role, as I believe SoCalMike, for one, proposed.
So the exhaust bolts seize up principally due to galling. (Not sure they're
all so terribly exposed to, say, gases of combustion causing corrosion,
though. Temperature may cause foreign materials on the bolt to crud up the
thread surfaces, OTOH.) The exhaust bolts are all I believe notably smaller
in diameter than the pulley bolt. Is the torque required to loosen these
exhaust system bolts in some proportion to the pulley bolt torque? I
couldn't say with certainty. In sum, right now I personally can't rule out
either a highly axially loaded bolt or galling due to massive heat cycling
causing that loud "crack" when one frees the pulley bolt.
6.
At the bottom of your site, I do not think your explanation of why the
loosening torque is often higher than the tightening torque is accurate. I
agree with boltscience.com , Tegger, and Scott that the main reason the
loosening torque is higher is the difference between the dynamic coefficient
of friction and the static coefficient of friction. The static coefficient
is higher.
> threads are rolled for fatigue
> resistance - rolling has nothing to do with ratcheting. oh, and yes, i
> /have/ looked at plenty of bolts under microscopes, thanks.
Jim, re your current investigation: All you noted is interesting. For me,
the fretting on the one car's bolt-washer mating surfaces is particularly
so.
I would hypothesize that the 92 vehicle hadn't been in operation long with
the loc-tited bolt. Also, if it had continued to run for some time, it was
at higher risk of the pulley bolt coming undone, since no oil was used to
facilitate relative (tightening) motion between female and male threads,
leaving the vibrations/pulsing of the pulley against the bolt head to
potentially overwhelm the system, vibrate free the bolt, and so knock the
pulley free of the crankshaft.
I hope you bring "pillows" to the yard when you're jumping up and down on
that 1.5 foot breaker bar. ;-)
I may take pictures in a few weeks if I free up my Civic's pulley bolt
during a tire rotation, and the safety engineers among us can have at it.
:-)
This remains an interesting academic debate, for bona fide engine
enthusiasts (pity the poor soul who comes here lately just wanting to know
whether he should change the washer for his oil drain plug at every oil
change!). I trust others here are wise enough to keep the boxing gloves off
and attend to them. I for one put my web site back up, and it does have some
changes reflecting some of the discussion here, FWIW.
Elle
Still an amateur learning much from those with specialized experience!
Matt Ion
I don't know how much relevance this has to crankshaft pulley bolts, but
on every table saw or radial-arm saw I've ever used, reverse-threaded
nuts are used to hold the blade on the threaded shaft, because the
clockwise (looking at the shaft) rotation of the blade would cause a nut
with a normal thread to come loose and spin off. And yes, they do
tighten up, with very little use.
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jim beam
http://www.snapfish.com/thumbnailshare/AlbumID=31395672/t_=36454773
Elle
photo(s), I would be happy to post it as a query topic on the "Queries" page
of my site.
Email: honda....@earthlink.net
"jim beam" <nos...@example.net> wrote
Burt S.
> Hmmm, not to add to the confusion, but...
> I don't know how much relevance this has to crankshaft pulley bolts, but
> on every table saw or radial-arm saw I've ever used, reverse-threaded
> nuts are used to hold the blade on the threaded shaft, because the
> clockwise (looking at the shaft) rotation of the blade would cause a nut
> with a normal thread to come loose and spin off. And yes, they do
> tighten up, with very little use.
Same thing on my angle grinder, my right hand and left hand radial arm
saw. The bolt/nut are screwed in the opposite direction of the spinning
blade. Even finger tight the bolt/nut will tighten (spin inward) over time.
This is caused by (my theory) the force of acelleration of the motor is
stronger than the inertial mass of the blade. Another words, the blade
wants to sit still. Now, if you look at the face or washer of the bolt you
realize that it has a greater surface area contact than on the other side
of the blade. The greater surface area (should not be oil or otherwise
the bolt won't tighten) is actually moving. However, the threads should
be oiled to prevent galling. I believe the same principle is used on the
crank pulley.
Burt S.
> "jim beam" <nos...@example.net> wrote
> > that's bunk. you're citing rolled vs. cut threads as evidence of some
> > kind of ratchet mechanism? no.
Jim, I don't cite rolled vs. cut threads as evidence of some kind of
ratchet mechanism, the images were simply not well drawn. I was
citing the mechanisms that cause the bolt to wind inwards caused by
they way the bore is tapped and the effects of the pulley.
Galling is possible on the exhaust bolt since they don't require lubricants.
Once locked together you will notice the extreme "snap" upon release. O2
sensor are one the parts that can benefit from the anti-seize compound to
prevent galling. On some areas on the exhaust system, self locking nuts
are used instead.
> 6.
> At the bottom of your site, I do not think your explanation of why the
> loosening torque is often higher than the tightening torque is accurate. I
> agree with boltscience.com , Tegger, and Scott that the main reason the
> loosening torque is higher is the difference between the dynamic coefficient
> of friction and the static coefficient of friction. The static coefficient
> is higher.
Good work for showing what I should fix. I probably have to add better
sketches to visualize a theory and avoid further confusions. Several
sections are fixed based on your input and others not pertaining to the
crank bolt is eliminated.
< snip>
--
http://square.cjb.cc/bolts.htm
TeGGeR®
news:nQ_af.9785$7h7....@newssvr21.news.prodigy.com:
> "TeGGeR®" <teg...@tegger.c0m> wrote in message
> news:Xns9704E508...@207.14.113.17...
>
>> Jim: Properly tightened, that bolt does NOT allow any sort of
>> movement. It /cannot/, and it /does not/. Period. Full stop. End of
>> story. The pulley and the pulley bolt do NOT move in use, and the
>> bolt absolutely does NOT rotate so as to "tighten" after initial
>> torque.
>
> If the bolt doesn't move then locktite would have been recommended,
> but instead they recommend oil.
As I said before, the il is a crude friction stabilizer. It is common for
high-stress bolt situations to specify friction stabilizers, either as a
coating, or as user-applied materials.
>
> http://square.cjb.cc/images/oilgood.gif
>
>> If you choose to believe that the bolt tightens more through rotation
>> after initial tightening torque, then you are misleading yourself and
>> everyone who reads your posts.
>
> Not observing the different variety of bolts manufactured is
> misleading. Patents are create for almost everything, possibly
> including the tap and die used on self-tightening bolts.
The bolt on your crank pulley is NOT "self tighetening".
>
>> There are many reasons why some crank bolts are difficult to remove.
>> Rotation after initial tightening torque is *NOT* one of them.
>
> Most of these crank bolts show no signs of wear, crystalization,
> bonding or rust. However there is a slight wear on the face of the
> bolt which probably suggest that it's moving.
>
>
Whatever the cause of the face wear (the face isn't oiled, remember), it
isn't moving.
TeGGeR®
> Hmmm, not to add to the confusion, but...
>
> I don't know how much relevance this has to crankshaft pulley bolts, but
> on every table saw or radial-arm saw I've ever used, reverse-threaded
> nuts are used to hold the blade on the threaded shaft, because the
> clockwise (looking at the shaft) rotation of the blade would cause a nut
> with a normal thread to come loose and spin off. And yes, they do
> tighten up, with very little use.
Totally different application.
Honda is just about the only manufacturer whose bolts run in a tightening
direction. Everybody else has bolts that run in a LOOSENING direction, and
these DO NOT COME LOOSE IN USE.
Everybody elses' bolts are the same as Honda's, and are torqued to similar
tensions.
Michael Pardee
been through at least one timing belt change, so we don't know how diligent
the mechanics were about retightening to the spec'd torque. It could be that
the one who loctited the bolt also wimped out on the torque, relying on the
loctite to hold the bolt. (Not good practice, but it happens.)
I'm completely undecided on this debate.
Mike
Elle
> What muddies the comparison is that the cars were both old enough to have
> been through at least one timing belt change,
I was figuring they were junked cars, so their age and mileage might have
been quite low. One Honda Civic vintage early 1990s I saw in a junkyard last
year had only 5500 miles or so on it. Pretty well stripped, so I figure it
had been there awhile.
Maybe Jim will give the odometer readings next time.
> so we don't know how diligent
> the mechanics were about retightening to the spec'd torque. It could be
that
> the one who loctited the bolt also wimped out on the torque, relying on
the
> loctite to hold the bolt. (Not good practice, but it happens.)
Sure.
> I'm completely undecided on this debate.
This is a healthy position in which to be, AFAIC.
Matt Ion
The difference is, sawblades are not splined or keyed, so they can turn
(and tighten) indefinitely. Splining or keying the pulley WOULD mitigate
this effect.
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jim beam
> lower res pics are here:
>
> http://www.snapfish.com/thumbnailshare/AlbumID=31395672/t_=36454773
>
ok, let's try this instead:
TeGGeR®
> TeGGeR® wrote:
>>
>> The pulley and the pulley bolt do NOT move in use, and the bolt
>> absolutely does NOT rotate so as to "tighten" after initial torque.
>
> check your email. i've just sent you the galling evidence. it's a
> perfect textbook example.
The pics are here:
http://www.tegger.com/hondafaq/misc/jim-beam_pulley_pics/
>
>>
>> If you choose to believe that the bolt tightens more through rotation
>> after initial tightening torque, then you are misleading yourself and
>> everyone who reads your posts.
>
> the loctited bolt/splined pulley does not move. the torque-only
> bolt/woodruff-only pulley does. the galling proves it.
Unfortunately, the pics aren't really evidence of much other than this:
You've taken photos of a pulley from an unknown car with an unknown history
given unknown servcicing by persons of unknown competence.
These pics are strongly suggestive of a pulley having been installed at
some point with no Woodruff key, or otherwise installed incorrectly. I can
assure you a pulley properly installed will not gall that way.
>
>>
>> There are many reasons why some crank bolts are difficult to remove.
>> Rotation after initial tightening torque is *NOT* one of them.
>
> except that we have the photo evidence to prove to the contrary!
>
>
A properly tightened joint dowes not rotate. Your pictures do not prove
anythng one way or the other because we do not know the car's history.
TeGGeR®
> TeGGeR® wrote:
>> Matt Ion <sou...@moltenimage.com> wrote in
>> news:ZY6bf.419264$tl2.287104@pd7tw3no:
>>
>>
>>>Hmmm, not to add to the confusion, but...
>>>
>>>I don't know how much relevance this has to crankshaft pulley bolts,
>>>but
>>> on every table saw or radial-arm saw I've ever used,
>>> reverse-threaded
>>>nuts are used to hold the blade on the threaded shaft, because the
>>>clockwise (looking at the shaft) rotation of the blade would cause a
>>>nut with a normal thread to come loose and spin off. And yes, they
>>>do tighten up, with very little use.
>>
>>
>>
>>
>> Totally different application.
>>
>> Honda is just about the only manufacturer whose bolts run in a
>> tightening direction. Everybody else has bolts that run in a
>> LOOSENING direction, and these DO NOT COME LOOSE IN USE.
>>
>> Everybody elses' bolts are the same as Honda's, and are torqued to
>> similar tensions.
>
> The difference is, sawblades are not splined or keyed, so they can
> turn (and tighten) indefinitely. Splining or keying the pulley WOULD
> mitigate this effect.
That's one difference. Also the automotive pulley bolts are to be torqued
to such a figuure as to prevent movement. Your saw blade nuts/bolts are
just snugged by hand to an unknown torque, and are meant to be repeatedly
removed and replaced.
I restate:
"Honda is just about the only manufacturer whose bolts run in a tightening
direction. Everybody else has bolts that run in a LOOSENING direction, and
these DO NOT COME LOOSE IN USE." Nobody can explain why this is, if it's
assumed that the pulley and bolt can move relative to the crank.
And even on a Honda, a pulley bolt insufficiently tightened (as little as
20 lbs short of the proper figure), will eventually result in a bolt that
*FALLS OUT*. Talk to any mechanic familiar with this subject.
The damned assembly is SOLID in use when properly assembled. Nothing
anybody says here will change that fundamental fact.
Michael Pardee
news:M-idnbzPL_x73fPe...@speakeasy.net...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
Elle
> "jim beam" <nos...@example.net> wrote in message
> news:M-idnbzPL_x73fPe...@speakeasy.net...
> > ok, let's try this instead:
> >
> > http://www.flickr.com/photos/38636024@N00/
> >
> 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
You mean they are a result of?
Galled refers to a surface that has been rubbed by something else.
> 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,
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.
> 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.
Are you saying you think the head and washer are adhering, and that's why
the breakloose torque is so high?
> 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.
Quite right.
jim beam
> jim beam <nos...@example.net> wrote in
> news:u9CdnaR9Ubh...@speakeasy.net:
>
>
>>TeGGeRŽ wrote:
>
>
>>>The pulley and the pulley bolt do NOT move in use, and the bolt
>>>absolutely does NOT rotate so as to "tighten" after initial torque.
>>
>>check your email. i've just sent you the galling evidence. it's a
>>perfect textbook example.
>
>
>
> The pics are here:
> http://www.tegger.com/hondafaq/misc/jim-beam_pulley_pics/
thanks dude - appreciate it.
>
>
>
>>>If you choose to believe that the bolt tightens more through rotation
>>>after initial tightening torque, then you are misleading yourself and
>>>everyone who reads your posts.
>>
>>the loctited bolt/splined pulley does not move. the torque-only
>>bolt/woodruff-only pulley does. the galling proves it.
>
>
>
>
> Unfortunately, the pics aren't really evidence of much other than this:
> You've taken photos of a pulley from an unknown car with an unknown history
> given unknown servcicing by persons of unknown competence.
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.
>
>
> These pics are strongly suggestive of a pulley having been installed at
> some point with no Woodruff key, or otherwise installed incorrectly. I can
> assure you a pulley properly installed will not gall that way.
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.
>
>
>
>
>>>There are many reasons why some crank bolts are difficult to remove.
>>>Rotation after initial tightening torque is *NOT* one of them.
>>
>>except that we have the photo evidence to prove to the contrary!
>>
>>
>
>
>
>
> A properly tightened joint dowes not rotate. Your pictures do not prove
> anythng one way or the other because we do not know the car's history.
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.
jim beam
> "jim beam" <nos...@example.net> wrote in message
> news:M-idnbzPL_x73fPe...@speakeasy.net...
>
>>ok, let's try this instead:
>>
>>http://www.flickr.com/photos/38636024@N00/
>>
>
> 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.
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.
> 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.
which is consistent with lash of the pulley wheel!
> 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.
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.
>
> I don't think we have enough to work with to come up with a definitive
> answer.
depends if we've spent time doing this kind of work before!
>
> Mike
>
>
Burt S.
> That's one difference. Also the automotive pulley bolts are to be torqued
> to such a figuure as to prevent movement. Your saw blade nuts/bolts are
> just snugged by hand to an unknown torque, and are meant to be repeatedly
> removed and replaced.
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.
> I restate: "Honda is just about the only manufacturer whose bolts run in a tightening
> direction. Everybody else has bolts that run in a LOOSENING direction, and
> these DO NOT COME LOOSE IN USE." Nobody can explain why this is, if it's
> assumed that the pulley and bolt can move relative to the crank.
What do you mean?... Honda have made motors than spin clockwise and
counterclockwise. And the crank bolts are always Lefty Lucey and Righty Tighty.
Michael Pardee
> "Michael Pardee" <michae...@cybertrails.com> wrote
>> 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
>
> You mean they are a result of?
>
> Galled refers to a surface that has been rubbed by something else.
>
>> the excessive
>> break-loose torque. Pure speculation, though.
>>
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.
>> Usually crank bolts (Honda or otherwise) need to loosen a quarter turn or
> so
>> before they come free,
>
> Are you sure you're not referring to the roughly quarter turn of typically
> 1/2-inch drive extension tool windup that occurs?
>
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.
> '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.
>
>> 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.
>
> Are you saying you think the head and washer are adhering, and that's why
> the breakloose torque is so high?
>
That's where I'm heading, but I don't really know if that's right. My
opinion is still in freefall on this.
Elle
> "Elle" <honda....@nospam.earthlink.net> wrote
snip
> 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.
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.
> Disclaimer - I've only done a handful of crank
> bolts, not dozens or hundreds like pros encounter.
> >> Usually crank bolts (Honda or otherwise) need to loosen a quarter turn
or
> > so
> >> before they come free,
> >
> > Are you sure you're not referring to the roughly quarter turn of
typically
> > 1/2-inch drive extension tool windup that occurs?
> >
> I have never used extensions - really! The impact socket rotates an
> estimated 1/4 turn before it takes off.
Okay.
And no surprise about the impact wrench you're using. It's a popular method,
by all reports here.
> > Are you saying you think the head and washer are adhering, and that's
why
> > the breakloose torque is so high?
> >
> That's where I'm heading, but I don't really know if that's right. My
> opinion is still in freefall on this.
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.
karl
> == 3 of 5 ==
> Date: Sat 5 Nov 2005 16:42
> From: "Elle"
>
snip
>
> I agree with Jim that, upon vibration, the cut of the threads does not tend
> to tighten the bolt. Your Figure 3, Burt, doesn't show anything different
> from a coarse thread cut. The threads are helically cut on both coarse and
> fine thread designs, of course, so back-and-forth vibrating forces will tend
> to have the same effect on both, absent other forces being at work.
>
> So far I think the rest of the site has much to offer.
>
> I would suggest
>
> 1.
> Making sure you use the right units for torque.
The units are irrelevant as long as the quantities
are correct.
> The units for torque in
> automobile manuals are conventionally given as ft-lbs or newton-meters in
> manuals. I realize English is not your first language, so maybe something
> got lost in translation here.
>
> 2.
> Frommy reading, "momentum force" is not a commonly accepted way of
> characterizing the forces acting on the pulley under normal car operating
> conditions.
Normal operating conditions or not, a moment of force
is commonly called torque.
> Inertial force is okay, being one way of saying centrifugal
> forces are what mostly tend to push it off the crankshaft. (Recognizing, for
> the physics-inclined among us, that whether it's accurate to call the
> effects of centripetal forces "centrifugal forces" depends on what frame of
> reference is used. What "centrifugal force" means in practical, hands-on
> applications is well-understood, so I'm using it.)
Whatever that is, it is beyond me to see any relevancy
to the bolt tightening debate.
> 3.
> Your wording is not perfect, but then rarely is mine. I can understand your
> other points and tend to agree with them. I think it is particularly
> noteworthy that oil is supposed to be used, /not/ something like Loc-Tite,
> on the threads. For now, I agree the purpose is to ensure that the bolt and
> shaft threads can move relative to each other upon commencing operations.
What would this be good for - the bolt should remain
lose "upon commencing operations"?
> 4.
> I want to look further into your hypothesis about what causes that loud
> crack when the bolt frees. I think you're right that it may be due to
> release of a large axial load in the bolt and so is a sonic boom(?). If it
> is a sonic boom, then that does tend to suggest that the pulley bolt is in
> fact under very high axial load. It's not, like Tegger has been contending,
> merely the galling of female and male threads against each other,
> essentially adhering one to the other.
>
> 5.
> OTOH, I think galling does play a role. One need only consider some of the
> exhaust bolts that become so hard to remove. Many of them are fine threaded
> (not sure if they're super-fine, non-standard fine threads or not). Fine
> threads are used to minimize the likelihood of the bolts vibrating free
> during operation. The greater surface area contact between male and female
> threads is what holds fine threaded applications more tightly together than
> coarse threads.
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>
> But unlike the pulley bolt, the exhaust bolts don't have a
> rotating mass attached to them. The exhaust bolts also get very hot, though,
> and they also vibrate while they're hot. Heat cycling--temperatures being
> alternately raised and lowered, causing the metal to expand and contract and
> fill in whatever microscopic gaps there are between male and female thread
> surfaces--may play a huge role, as I believe SoCalMike, for one, proposed.
> So the exhaust bolts seize up principally due to galling. (Not sure they're
> all so terribly exposed to, say, gases of combustion causing corrosion,
> though. Temperature may cause foreign materials on the bolt to crud up the
> thread surfaces, OTOH.) The exhaust bolts are all I believe notably smaller
> in diameter than the pulley bolt. Is the torque required to loosen these
> exhaust system bolts in some proportion to the pulley bolt torque? I
> couldn't say with certainty. In sum, right now I personally can't rule out
> either a highly axially loaded bolt or galling due to massive heat cycling
Galling is abrasion and fusion caused by friction,
not heat cycling.
Elle
> > Date: Sat 5 Nov 2005 16:42
> > From: "Elle"
> >
> snip
> >
> > I agree with Jim that, upon vibration, the cut of the threads does not
tend
> > to tighten the bolt. Your Figure 3, Burt, doesn't show anything
different
> > from a coarse thread cut. The threads are helically cut on both coarse
and
> > fine thread designs, of course, so back-and-forth vibrating forces will
tend
> > to have the same effect on both, absent other forces being at work.
> >
> > So far I think the rest of the site has much to offer.
> >
> > I would suggest
> >
> > 1.
> > Making sure you use the right units for torque.
>
>
> The units are irrelevant as long as the quantities
> are correct.
If someone else would like to address this gentleman's comment above and his
other assertions, then please be my guest.
snip for brevity
Michael Pardee
> 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.
>
>
Mike
jim beam
threads. even the 91 which has been removed 3 times shows no signs of
distress.
TeGGeR®
news:JtednSfLjYj...@sedona.net:
A representative of Bolt Science Ltd, a bona fide expert company in these
matters, has told me specifically that it is "somewhat improbable" that the
bolt turns in more once torqued.
A quote from an email: "Much more likely is that a change in the friction
conditions in the thread and under the bolt head as occurred." (to explain
why it apparently gets tighter in use).
Elle
snip
> 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.
Any chance you can determine or narrow down what material the pulley bolts
are made of?
For reckless academic fun.
'course, if you take out every pulley bolt in your local yard, this will
guilt me into removing and then re-installing my 91 Civic's pulley bolt and
painting the whole assembly with a line of pink frost glitter nail polish to
ascertain movement (or not).
Michael Pardee
"bell the cat." And not many of us would go with pink frost glitter nail
polish!
Mike
robm
"Michael Pardee" <michae...@cybertrails.com> wrote in message
news:DaedncZfVfMeae3e...@sedona.net...
probably more of a Y-65P or R-510 nail polish guy
TeGGeR®
news:Ny0df.7810$AS6....@newsread3.news.atl.earthlink.net:
>
> "Michael Pardee" <michae...@cybertrails.com> wrote in message
> news:DaedncZfVfMeae3e...@sedona.net...
>> > painting the whole assembly with a line of pink frost glitter nail
> polish
>> > to
>> > ascertain movement (or not).
>> >
>> >
>> That would settle the question decisively. It's just that none of us
>> want
> to
>> "bell the cat." And not many of us would go with pink frost glitter
>> nail polish!
>>
>> Mike
>>
>
> probably more of a Y-65P or R-510 nail polish guy
>
>
>
Do they make nail polish in NH-526M?
robm
"TeGGeR®" <teg...@tegger.c0m> wrote in message
news:Xns970B69B1...@207.14.113.17...
I know where you can get a bottle with small brush attached to inside of
cap, probably a year supply and you may need little more than nail polish
remover to remove it :)
wonder if they sell pink frost glitter in gallon cans ?
that would be a great project color for an old honda CVCC
SoCalMike
> wonder if they sell pink frost glitter in gallon cans ?
> that would be a great project color for an old honda CVCC
bet an auto paint store would have something close! House Of Kolor makes
some interesting showcar paint.
karl
TeGGeR® wrote:
> jim beam <nos...@example.net> wrote in news:jY2dnf6UQMdVmPHeRVn-
> s...@speakeasy.net:
>
> > 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:
>
>
> <snip>
>
>
>
> Jim: Properly tightened, that bolt does NOT allow any sort of movement. It
> /cannot/, and it /does not/. Period. Full stop. End of story.
>
> You may be an electronics whiz, but you are clearly no mechanical engineer.
>
> The pulley and the pulley bolt do NOT move in use, and the bolt absolutely
> does NOT rotate so as to "tighten" after initial torque.
>
> initial tightening torque, then you are misleading yourself and everyone
> who reads your posts.
>
> Rotation after initial tightening torque is *NOT* one of them.
That is right; anything else is rubbish.
karl
> From: "TeGGeR®"
>
> Matt Ion <sou...@moltenimage.com> wrote in
> news:x3rbf.424095$1i.286090@pd7tw2no:
>
> > TeGGeR® wrote:
> >> Matt Ion <sou...@moltenimage.com> wrote in
> >> news:ZY6bf.419264$tl2.287104@pd7tw3no:
> >>
> >>
> >>>Hmmm, not to add to the confusion, but...
> >>>
> >>>I don't know how much relevance this has to crankshaft
> >>>pulley bolts, but on every table saw or radial-arm saw
> >>>I've ever used, reverse-threaded nuts are used to
> >>>hold the blade on the threaded shaft,
snip
> >> Totally different application.
> >>
> >> Honda is just about the only manufacturer whose bolts run
> >> in a tightening direction. Everybody else has bolts that run
> >> in a LOOSENING direction, and these DO NOT COME LOOSE IN USE.
snip
> > The difference is, sawblades are not splined or keyed, so
> > they can turn (and tighten) indefinitely. Splining or keying
> > the pulley WOULD mitigate this effect.
Mitigate?
Splining precludes rotation!
> That's one difference. Also the automotive pulley bolts are
> to be torqued to such a figuure as to prevent movement.
> Your saw blade nuts/bolts are just snugged by hand to an
> unknown torque, and are meant to be repeatedly removed and
> replaced.
>
> I restate:
> "Honda is just about the only manufacturer whose bolts run
> in a tightening direction. Everybody else has bolts that
> run in a LOOSENING direction, and these DO NOT COME LOOSE
> IN USE." Nobody can explain why this is, if it's assumed
> that the pulley and bolt can move relative to the crank.
>
> And even on a Honda, a pulley bolt insufficiently tightened
> (as little as 20 lbs short of the proper figure), will
> eventually result in a bolt that *FALLS OUT*. Talk to any
> mechanic familiar with this subject.
>
> The damned assembly is SOLID in use when properly assembled.
> Nothing anybody says here will change that fundamental fact.
I agree, everything else is rubbish.
karl
> Date: Sun, 06 Nov 2005 19:06:41 +0000
>
> ==============================================================================
> TOPIC: crank bolt tightening debate
> http://groups.google.com/group/alt.autos.honda/browse_thread/thread/611ca6332c3f50e
> ==============================================================================
>
> == 3 of 6 ==
> Date: Sun 6 Nov 2005 09:50
> From: "Michael Pardee"
> What muddies the comparison is that the cars were both old
> enough to have been through at least one timing belt change,
> so we don't know how diligent the mechanics were about
> retightening to the spec'd torque. It could be that the one
> who loctited the bolt also wimped out on the torque, relying
> on the loctite to hold the bolt. (Not good practice, but it
> happens.)
This is a crucial point. Not only is unknown whether the
timing belt changes were done correctly but it is also unknown
where the parts came from. Therefore, all the provided
"evidence" is worthless and cannot be used in an objective
evaluation.
karl
> Date: Tue, 08 Nov 2005 02:03:46 +0000
>
> ==============================================================================
> TOPIC: Crank Bolt Tightening Debate
> http://groups.google.com/group/alt.autos.honda/browse_thread/thread/611ca6332c3f50e
> ==============================================================================
>
> == 1 of 1 ==
> Date: Mon 7 Nov 2005 19:16
> From: "Elle"
>
> "karl" <otto...@cognisurf.com> wrote [Date: Mon 7 Nov 2005 08:01]
Because no one came forward to help you I will explain it to
you myself. Could be helpful when "educating college
engineering students."
A quantity consists of a value (also called magnitude) and a
unit (also called dimension), for example "4 quarts," or "1
gallon." Here, "4" and "1" are the values and "quarts" and
"gallon" are the units of the quantities. In these examples
the values and the units are different, but they both specify
the same quantity because 4 quarts equal 1 gallon. So, it is
irrelevant in what units a quantity is expressed, but it is
common to choose units that yield easy to handle values -
avoiding very small or very large numbers.
And if you are specific about the "other assertions" I will
help you with those, too.
Now, would you please help me? I don't understand your first
paragraph. But this could be because I am neither a mechanic
nor am I a metallurgist, and I didn't have the benefits of
"materials 101." When rewriting it, please pay particular
attention to the implications of, "the cut of the threads does
not tend to tighten the bolt," and, "The threads are helically
cut on both coarse and fine thread designs, of course, so
back-and-forth vibrating forces will tend to have the same
effect on both." What would be the effects if the threads were
not helically cut, and what bolts would these be?
karl
> Date: Mon, 07 Nov 2005 02:25:00 +0000
>
> ====================================================================
> TOPIC: crank bolt tightening debate
> http://groups.google.com/group/alt.autos.honda/browse_thread/thread/
> 611ca6332c3f50e
> ====================================================================
>
> Date: Sun 6 Nov 2005 19:49
> From: "TeGGeR®"
> jim beam <nos...@example.net> wrote in
> news:u9CdnaR9Ubh...@speakeasy.net:
>
> > TeGGeR® wrote:
>
> >>
> >> The pulley and the pulley bolt do NOT move in use, and the bolt
> >> absolutely does NOT rotate so as to "tighten" after initial torque.
> >
> > check your email. i've just sent you the galling evidence. it's a
> > perfect textbook example.
>
>
> The pics are here:
> http://www.tegger.com/hondafaq/misc/jim-beam_pulley_pics/
>
>
> >
> >>
> >> If you choose to believe that the bolt tightens more through rotation
> >> after initial tightening torque, then you are misleading yourself and
> >> everyone who reads your posts.
> >
> > the loctited bolt/splined pulley does not move. the torque-only
> > bolt/woodruff-only pulley does. the galling proves it.
>
>
>
> Unfortunately, the pics aren't really evidence of much other than this:
> You've taken photos of a pulley from an unknown car with an unknown history
> given unknown servcicing by persons of unknown competence.
>
>
> These pics are strongly suggestive of a pulley having been installed at
> some point with no Woodruff key, or otherwise installed incorrectly. I can
> assure you a pulley properly installed will not gall that way.
>
>
>
> >
> >>
> >> There are many reasons why some crank bolts are difficult to remove.
> >> Rotation after initial tightening torque is *NOT* one of them.
> >
> > except that we have the photo evidence to prove to the contrary!
> >
> >
>
>
>
> anythng one way or the other because we do not know the car's history.
Very well said.
High
>
> A quantity consists of a value (also called magnitude) and a
> unit (also called dimension), for example "4 quarts," or "1
> gallon." Here, "4" and "1" are the values and "quarts" and
> "gallon" are the units of the quantities. In these examples
> the values and the units are different, but they both specify
> the same quantity because 4 quarts equal 1 gallon. So, it is
> irrelevant in what units a quantity is expressed, but it is
> common to choose units that yield easy to handle values -
> avoiding very small or very large numbers.
>
> And if you are specific about the "other assertions" I will
> help you with those, too.
>