crank bolt right or left hand thread?

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Just bought a used zHonda and am installing timing belt righ or left hand thread?
Thanks
SW

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Right hand thread.
The crankshaft pulley bolt is typically extremely tight.
See discussion at http://home.earthlink.net/~honda.lioness/id6.html and http://www.tegger.com/hondafaq/cranktool/index.html

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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.
Mike
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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).

After two timing belt changes, mine still required over about 300 ft-lbs, by my calculations.
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wrote

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
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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.

I'll think about that. Seems reasonable enough. :-)
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I made a post back in Nov 2005 and said that I'd mark the bolt (83-lbft on a 2.0L.) Lo and Behold! Today I went to check and the bolt hasn't moved. I'm more inclined to believe that the tightening is from a cold weld or by other mechanical means.
The markings I made are from a razor sharp carbon punch. I believe the car was driven some 7-8 thousand miles.
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Burt wrote:

possible, but that doesn't explain the discrepancy between the galling being present on the pre-92 vehicles and there being none on the later ones.

is the pulley wheel splined? you don't state the vehicle's age.
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The galling was probably caused by the lack of a vibration damper. At best guess, the 92 Accord's balancer shaft may have helped. This and the high bolt torque, 160-lbft, may explain why the galling isn't present on the post-92 Accords, which I've also witnessed myself.

88 Accord...no spline.
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What model is this?
I know the 84-87 Civics have an 83 ft-lb pulley bolt spec, but some have a 2.9L engine?
Little discrepancy that we should clear up to make sure we're on the same page.

Did you also try to break the bolt free? If so, any estimate of how much torque was needed?
Thank you for doing this.
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88 Accord, around 286k miles.

Yes, I could break it loose but I'd just broke loose the 92 Accord engine block coolant drain bolt today which took about 150-lbft and pretty exhausted.
Tell you what, tommorow I will:
1. Hook up a beam torque wrench to a chain hoist horizontally and slowly chart the effects during unbolting. 2. Do the same to my other 92 Accord. 3. Both cars will be torque and loosen and chart the difference. 4. Both cars will be marked before loosening.
There is a problem with #1. My beam torque wrench only goes to 150 ft-lb, which is design for head work only. I have a clicker type rated at 200-lbft, but this is inconvenient. Other than this, what would be another practical way to measure the loosening torque?

Your welcome.
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wrote

:-)
That's the other one that's a bear for the home mechanic, as you may have heard.
I will say that my coolant block bolt was only tough the very first time I freed it.

I appreciate your enthusiasm, but I don't think doing a careful check of the "break free" torque will reveal anything new. We all already know that after several years and many miles of driving, the bolt becomes very tight.
If your Accord's pulley bolt is not very tight, then this just suggests (to me) little time has transpired since it was last freed.
There are some other suppositions that one can make, but I don't care to venture into what may be fantasy land.
It certainly could be simply "cold welding" of this fine threaded bolt subjected to terrific dynamic loads and temperature variations.
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As you've probably known, the bolt has a very shallow head. This was the main problem. I had to build a jig to steady the tool. After some thought the jig was nothing but two blocks of wood (a 2x4 and a 2x1) and it was freed easily. :~)

I see. But looks like I do this at a later time. I'd set up the chain come-along but I can't locate a buddy of mine who has a 5-ton crane scale.
The 88 Accord pulley bolt which I believe had driven some 80k miles before the belt was changed was loosen easily. The 92 Accord was driven about the same miles but the bolt needed help from a machine.

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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
  Click to see the full signature.
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"TeGGeR����������������������" wrote:

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.
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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
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Michael Pardee wrote:

Only the pully does I believe.
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Michael Pardee wrote:

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.

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.
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Well, I'll be! You're right!
Mike
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ISTM a number of bicycling enthusiasts throw the term "precession" around (IMO, so loosely as to be reckless) to explain the ordinary, expected motion between female and male (bolt, stud, nut etc.) threads against each other when it comes to bike pedal rotation. It seems that some of the more sophisticated ones point out that it is not the tap-on-a-gyroscopic-and-watch-it-spin-around-now-a-second-axis notion of precession meant here. Some guy named Andy tries to make the distinction as follows: http://groups.google.com/group/uk.rec.cycling/browse_frm/thread/3f2111409ccd2635/d40aeb3b876c7ffa?lnk=st&q=precession+pencil+%22effect-based%22&rnum=2#d40aeb3b876c7ffa . I am not sure he's being entirely accurate with his wording, either, but at least he recognizes it's not gyroscopic precession that's meant here.
As one pedals to move a bike forward, the left pedal rotates so as to loosen a right-hand thread (put bearings in between, if anyone wants). It's still simply torque being applied directly to the pedal stud so as to loosen (if it's a right hand thread) and tighten (if it's a left-hand thread, which it is on the left pedal).
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.
Getting material specifications would help, but using Google I can't even nail down exactly what steel is used in Snap-On socket extensions, never mind the "special bolt" used for the crankshaft pulley. (Any fool can guess of course, and plenty do.)
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