crank bolt right or left hand thread?

"Michael Pardee" <michaeltnull RemoveThis @cybertrails.com> wrote
> "Elle" <honda.lioness RemoveThis @nospam.earthlink.net> wrote
>> Right hand thread.
>>
>> The crankshaft pulley bolt is typically extremely tight.
>>
> We never did do a test to determine whether the bolt is
> actually tightening over time or whether the bond is just
> strengthening, did we?

You wouldn't want this group to be boring, would you?

I am not sure a test exists that would persuade everyone or
persuade effectively.

I wasn't willing to perform tests on my 91 Civic's.

I am convinced that the fact that it's not merely a fine
thread but a super fine thread means the bond becomes
stronger over time, especially when subject to heat cycling.
Bolt metal melds into the metal of the crankshaft. I
certainly think it's possible that this is all that's
causing it to become so difficult to break loose. I won't
hold my breath, but we might all agree on this point.

Having conquered (well, with a lot of group support) eight
frozen, fine thread, suspension bolts, and noticing that at
least one appeared to be welded to the inner sleeve (and had
to be completely cut out with an air die grinder), I can
believe that the pulley bolt sees similar forces and so
similarly becomes "more tightly bonded" as time goes on.

The contravening evidence is J. Beam's claim that the pulley
bolt becomes extremely tight again after just a very short
time driving (like less than a day, IIRC).

>All everybody agrees on is that it is a devil to get loose,
>at least for the first timing belt change.

After two timing belt changes, mine still required over
about 300 ft-lbs, by my calculations.
 >> Stay informed about: crank bolt right or left hand thread? 

"Elle" <honda.lioness.DeleteThis@nospam.earthlink.net> wrote in message
news:3dYrg.2021$vO.1051@newsread4.news.pas.earthlink.net...
> "Michael Pardee" <michaeltnull.DeleteThis@cybertrails.com> wrote
>> "Elle" <honda.lioness.DeleteThis@nospam.earthlink.net> wrote
>>> Right hand thread.
>>>
>>> The crankshaft pulley bolt is typically extremely tight.
>>>
>> We never did do a test to determine whether the bolt is actually
>> tightening over time or whether the bond is just strengthening, did we?
>
> You wouldn't want this group to be boring, would you?
>
> I am not sure a test exists that would persuade everyone or persuade
> effectively.
>
> I wasn't willing to perform tests on my 91 Civic's.
>
> I am convinced that the fact that it's not merely a fine thread but a
> super fine thread means the bond becomes stronger over time, especially
> when subject to heat cycling. Bolt metal melds into the metal of the
> crankshaft. I certainly think it's possible that this is all that's
> causing it to become so difficult to break loose. I won't hold my breath,
> but we might all agree on this point.
>
> Having conquered (well, with a lot of group support) eight frozen, fine
> thread, suspension bolts, and noticing that at least one appeared to be
> welded to the inner sleeve (and had to be completely cut out with an air
> die grinder), I can believe that the pulley bolt sees similar forces and
> so similarly becomes "more tightly bonded" as time goes on.
>
> The contravening evidence is J. Beam's claim that the pulley bolt becomes
> extremely tight again after just a very short time driving (like less than
> a day, IIRC).
>
>>All everybody agrees on is that it is a devil to get loose, at least for
>>the first timing belt change.
>
> After two timing belt changes, mine still required over about 300 ft-lbs,
> by my calculations.
>
I absolve you of the burden

I just recalled that you suggested a spot of nail polish to match-mark the
bolt head and pulley, and I'm fresh out of nail polish.

All that aside, I agree that it is probably a cold-weld process that makes
the break-away torque so high. People have also reported that working both
in the loosen and tighten directions with an impact gun helps, which
supports that theory.

Mike
 >> Stay informed about: crank bolt right or left hand thread? 

"Michael Pardee" <michaeltnull DeleteThis @cybertrails.com> wrote

> I just recalled that you suggested a spot of nail polish
> to match-mark the bolt head and pulley, and I'm fresh out
> of nail polish.

Oh right you are. I do a timing belt change next summer and
might try this then.

I figure that bolt is good for only so many cycles of
tightening and loosening by hand.

> All that aside, I agree that it is probably a cold-weld
> process that makes the break-away torque so high. People
> have also reported that working both in the loosen and
> tighten directions with an impact gun helps, which
> supports that theory.

I'll think about that. Seems reasonable enough.
 >> Stay informed about: crank bolt right or left hand thread? 

Michael Pardee wrote:
> "jim beam" <nospam RemoveThis @example.net> wrote in message
> news:f-adnZ-O0NVJKSzZnZ2dnUVZ_uudnZ2d@speakeasy.net...
> >
> > you can do this experiment at home: loosen the pedals on a bike so
> > they're only finger tight. now, pedal around the block. you'll find you
> > need a wrench to get them undone again. that's precession that tightens.
> > and it's why left hand pedals have a left hand thread.
>
> That's a very different physical arrangement, though. The friction of the
> bearings, small as it may be, works to screw the pedals in - as you point
> out, that's why the left hand thread on left side pedals. There is no
> equivalent force on the crank bolt.

Only the pully does I believe.
 >> Stay informed about: crank bolt right or left hand thread? 

"Michael Pardee" <michaeltnull RemoveThis @cybertrails.com> wrote in
news:oa2dneT-Eoy11C3ZnZ2dnUVZ_uqdnZ2d@sedona.net:

> "Elle" <honda.lioness RemoveThis @nospam.earthlink.net> wrote in message
> news:iLXrg.4938$PE1.4853@newsread2.news.pas.earthlink.net...
>> Right hand thread.
>>
>> The crankshaft pulley bolt is typically extremely tight.
>>
> We never did do a test to determine whether the bolt is actually
> tightening over time or whether the bond is just strengthening, did
> we? All everybody agrees on is that it is a devil to get loose, at
> least for the first timing belt change.
>



I had an email conversation I had with an engineer at
www.boltscience.com .

He said the bolt is not rotating. Period. There are several other well-
established mechanical reasons for the apparent increase in torque over
time. Rotation after the final installation setting is **NOT** one of them.

--
TeGGeR®

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/
 >> Stay informed about: crank bolt right or left hand thread? 

"TeGGeR����������������������" wrote:
> "Michael Pardee" <michaeltnull.TakeThisOut@cybertrails.com> wrote in
> news:oa2dneT-Eoy11C3ZnZ2dnUVZ_uqdnZ2d@sedona.net:
>
>
>>"Elle" <honda.lioness.TakeThisOut@nospam.earthlink.net> wrote in message
>>news:iLXrg.4938$PE1.4853@newsread2.news.pas.earthlink.net...
>>
>>>Right hand thread.
>>>
>>>The crankshaft pulley bolt is typically extremely tight.
>>>
>>
>>We never did do a test to determine whether the bolt is actually
>>tightening over time or whether the bond is just strengthening, did
>>we? All everybody agrees on is that it is a devil to get loose, at
>>least for the first timing belt change.
>>
>
>
>
>
> I had an email conversation I had with an engineer at
> www.boltscience.com .
>
> He said the bolt is not rotating. Period. There are several other well-
> established mechanical reasons for the apparent increase in torque over
> time. Rotation after the final installation setting is **NOT** one of them.
>
with respect, the pics i showed definitely /do/ evidence rotation.
there's angular galling on the washer/bolt interface. that simply
cannot happen if it's static. besides, bolt precession is well known.
much more attention is given to loosening since that tends to be
catastrophic, but tightening happens as well.

you can do this experiment at home: loosen the pedals on a bike so
they're only finger tight. now, pedal around the block. you'll find
you need a wrench to get them undone again. that's precession that
tightens. and it's why left hand pedals have a left hand thread.
 >> Stay informed about: crank bolt right or left hand thread? 

"jim beam" <nospam.TakeThisOut@example.net> wrote in message
news:f-adnZ-O0NVJKSzZnZ2dnUVZ_uudnZ2d@speakeasy.net...
>
> you can do this experiment at home: loosen the pedals on a bike so
> they're only finger tight. now, pedal around the block. you'll find you
> need a wrench to get them undone again. that's precession that tightens.
> and it's why left hand pedals have a left hand thread.

That's a very different physical arrangement, though. The friction of the
bearings, small as it may be, works to screw the pedals in - as you point
out, that's why the left hand thread on left side pedals. There is no
equivalent force on the crank bolt.

Mike
 >> Stay informed about: crank bolt right or left hand thread? 

"TeGGeR®" <tegger.DeleteThis@tegger.c0m> wrote
> "Michael Pardee" <michaeltnull.DeleteThis@cybertrails.com> wrote
>> "Elle" <honda.lioness.DeleteThis@nospam.earthlink.net> wrote
>>> Right hand thread.
>>>
>>> The crankshaft pulley bolt is typically extremely tight.
>>>
>> We never did do a test to determine whether the bolt is
>> actually
>> tightening over time or whether the bond is just
>> strengthening, did
>> we? All everybody agrees on is that it is a devil to get
>> loose, at
>> least for the first timing belt change.
>>
>
>
>
> I had an email conversation I had with an engineer at
> www.boltscience.com .
>
> He said the bolt is not rotating. Period.

Be fair. You shared the message with me. He said it was
unlikely, or words to that effect. That's his opinion.

He also did not offer any particularly compelling
alternative explanation.
 >> Stay informed about: crank bolt right or left hand thread? 

Michael Pardee wrote:
> "jim beam" <nospam DeleteThis @example.net> wrote in message
> news:f-adnZ-O0NVJKSzZnZ2dnUVZ_uudnZ2d@speakeasy.net...
>
>>you can do this experiment at home: loosen the pedals on a bike so
>>they're only finger tight. now, pedal around the block. you'll find you
>>need a wrench to get them undone again. that's precession that tightens.
>>and it's why left hand pedals have a left hand thread.
>
>
> That's a very different physical arrangement, though. The friction of the
> bearings, small as it may be, works to screw the pedals in

yes and no. yes, it's a different physical arrangement, but it's not
the bearing friction that works the thread in [a remarkably widespread
misunderstanding!] - the rotation direction is incorrect. check it out
yourself. it's precession - just like the rotation of gears in a
planetary gearbox.

> - as you point
> out, that's why the left hand thread on left side pedals. There is no
> equivalent force on the crank bolt.

correct, it's not directly equivalent, but there /is/ a tightening
impulse from the momentum difference between an ignition stroke and the
inertia of the pulley. saying that bolts don't tighten is incorrect and
i used the above example as an easily tested home illustration. once we
can agree on examples of where tightening /can/ occur, hopefully we can
move on to examine the facts of exactly how it happens. just saying "it
doesn't happen" when there's clear evidence to the contrary, makes no sense.

interestingly, the later versions of the honda pulley/crank have both
splines [in addition to the woodruff] /and/ loctite as oem, unlike the
older series motors that end up being discussed here. they still take
torque to remove because of the loctite, but they do /not/ evidence the
galling and the amount of torque to move is substantially less. i
posted pics of all this back in the day. i can repost if required. it
appears that the splines help reduce the amount of lash, and if there's
no lash [in conjunction with the loctite], the bolt can't move hence
it's now easier to unscrew.
 >> Stay informed about: crank bolt right or left hand thread? 

"jim beam" <nospam.RemoveThis@example.net> wrote in message
news:y82dneXHT8wZzy_ZnZ2dnUVZ_sWdnZ2d@speakeasy.net...
> Michael Pardee wrote:
>> "jim beam" <nospam.RemoveThis@example.net> wrote in message
>> news:f-adnZ-O0NVJKSzZnZ2dnUVZ_uudnZ2d@speakeasy.net...
>>
>>>you can do this experiment at home: loosen the pedals on a bike so
>>>they're only finger tight. now, pedal around the block. you'll find you
>>>need a wrench to get them undone again. that's precession that tightens.
>>>and it's why left hand pedals have a left hand thread.
>>
>>
>> That's a very different physical arrangement, though. The friction of the
>> bearings, small as it may be, works to screw the pedals in
>
> yes and no. yes, it's a different physical arrangement, but it's not the
> bearing friction that works the thread in [a remarkably widespread
> misunderstanding!] - the rotation direction is incorrect. check it out
> yourself.

Well, I'll be! You're right!

Mike
 >> Stay informed about: crank bolt right or left hand thread? 

"jim beam" <nospam DeleteThis @example.net> wrote
E wrote
>> I still wouldn't bet money on all the causes I propose at
>> my web site being behind the pulley bolt becoming so
>> tight. I would bet money that the very fine thread and
>> heat and high dynamic load cycling does have something to
>> do with it.
>
> good point about "all causes". i don't know all causes
> either, but i am however trained to observe carefully, and
> from that the following facts emerge:
>
> 1. there is angular galling under the bolt head. that's
> hard evidence of some rotation.
> 2. the rotation direction on the crank is such that the
> bolt would tighten against a "stationary" pulley wheel.
> 3. the apparent pulley bolt torque increases from ~120
> ft.lbs to ~300ft.lbs in ~30 miles.
>
> i also know from other research that bolts can tighten.
> now, the dots on this may not all be joined, but an
> outline appears to be there.

That's properly qualified and so reasonable, AFAIC. It's an
outline, but nothing certain as yet.

I am interested in point 3 above. I remember your mentioning
some months ago that you had generally evaluated the
tightness after torquing to spec and then driving briefly.
Did you redo this experiment a few times, estimating as best
you could the torque necessary to free the bolt each time?

I am still not willing to remove my Civic's pulley bolt more
than is necessary--too lazy and I don't like putting wear
and tear on such an expensive bolt with super fine threads,
and so more susceptible to stripping in my estimation, at
that. Admittedly that might be overworry on my part.

I will say that in 2004 when I first got some experience
with my 91 Civic's pulley bolt that the first time I broke
it free (some three years after it was last removed)
demanded, from memory, notably more force than the next few
times I freed it. (I spent a few weeks researching and
preparing to replace the front crankshaft seal blah blah,
and so ended up freeing the bolt I think maybe four times
algother during this period.) I did not try to estimate the
torque to free it after the first removal, since I was kinda
hurried.

Why is it again that you feel the abrasion beneath the bolt
head could not occur while torquing the bolt to spec with
the pulley fixed?
 >> Stay informed about: crank bolt right or left hand thread? 

Elle wrote:
> "jim beam" <nospam DeleteThis @example.net> wrote
> E wrote
>
>>>I still wouldn't bet money on all the causes I propose at
>>>my web site being behind the pulley bolt becoming so
>>>tight. I would bet money that the very fine thread and
>>>heat and high dynamic load cycling does have something to
>>>do with it.
>>
>>good point about "all causes". i don't know all causes
>>either, but i am however trained to observe carefully, and
>>from that the following facts emerge:
>>
>>1. there is angular galling under the bolt head. that's
>>hard evidence of some rotation.
>>2. the rotation direction on the crank is such that the
>>bolt would tighten against a "stationary" pulley wheel.
>>3. the apparent pulley bolt torque increases from ~120
>>ft.lbs to ~300ft.lbs in ~30 miles.
>>
>>i also know from other research that bolts can tighten.
>>now, the dots on this may not all be joined, but an
>>outline appears to be there.
>
>
> That's properly qualified and so reasonable, AFAIC. It's an
> outline, but nothing certain as yet.
>
> I am interested in point 3 above. I remember your mentioning
> some months ago that you had generally evaluated the
> tightness after torquing to spec and then driving briefly.
> Did you redo this experiment a few times, estimating as best
> you could the torque necessary to free the bolt each time?

yes, best estimate #'s. i've done it twice on the 91 crx and twice on
the 89 civic. pretty much the same tightening experience on both. i
will say though, second release was not /quite/ as high as first. full
body weight at 18" = 300ft.lbs for second release, near enough. first
release requires a little "bounce" of that weight, so what's that? 330?
not 400 though.

>
> I am still not willing to remove my Civic's pulley bolt more
> than is necessary--too lazy and I don't like putting wear
> and tear on such an expensive bolt with super fine threads,
> and so more susceptible to stripping in my estimation, at
> that. Admittedly that might be overworry on my part.

it's not delicate. pitch is 1.25mm, so not that fine.

>
> I will say that in 2004 when I first got some experience
> with my 91 Civic's pulley bolt that the first time I broke
> it free (some three years after it was last removed)
> demanded, from memory, notably more force than the next few
> times I freed it. (I spent a few weeks researching and
> preparing to replace the front crankshaft seal blah blah,
> and so ended up freeing the bolt I think maybe four times
> algother during this period.) I did not try to estimate the
> torque to free it after the first removal, since I was kinda
> hurried.

sure, but it sure is tighter than the torque-wrenched tightening that
precedes it!

>
> Why is it again that you feel the abrasion beneath the bolt
> head could not occur while torquing the bolt to spec with
> the pulley fixed?

there will be some abrasion on simple tightening, but that's usually
really superficial. comparison between two identical bolts, one from a
splined/loctited pulley wheel and one from a single woodruff/no loctite
show that the latter is abrading substantially and therefore lashing,
the former is not. this is consistent between junkyard hondas i've
inspected of the splined/unsplined eras. the type of galling is also
inconsistent with that seen from large angle rotation - it definitely
appears to be lashing within a limited range.
 >> Stay informed about: crank bolt right or left hand thread? 

"jim beam" <nospam RemoveThis @example.net> wrote in message
news:kIudnbjwvu7NjC7ZnZ2dnUVZ_u2dnZ2d@speakeasy.net...
> 1. there is angular galling under the bolt head. that's hard evidence of
> some rotation.
> 2. the rotation direction on the crank is such that the bolt would tighten
> against a "stationary" pulley wheel.
> 3. the apparent pulley bolt torque increases from ~120 ft.lbs to
> ~300ft.lbs in ~30 miles.
>
> i also know from other research that bolts can tighten. now, the dots on
> this may not all be joined, but an outline appears to be there.
>
I have experienced the tightness with age in other cars with clockwise
rotating engines, also. Our Volvo took much more than the spec'd 190 ft-lbs
the first time I changed the timing belt. I had a floor jack under the 9
inch socket handle and the tires had started to come up off the ground
before the bolt moved. When the harmonic balancer failed a few months later
it took much less. With the second timing belt change it was back to its
wicked ways.

Mike
 >> Stay informed about: crank bolt right or left hand thread?