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Car Forum / Honda Cars / July 2006crank bolt right or left hand thread?
Just bought a used zHonda and am installing timing belt righ or left hand thread? Thanks SW 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 > Just bought a used zHonda and am installing timing belt > righ or left hand thread? > 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. Mike > "Elle" <honda.lioness@nospam.earthlink.net> wrote >> Right hand thread. [quoted text clipped - 4 lines] > 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. >> "Elle" <honda.lioness@nospam.earthlink.net> wrote >>> Right hand thread. [quoted text clipped - 33 lines] > 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 > 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. :-) > "Michael Pardee" <michaeltnull@cybertrails.com> wrote > [quoted text clipped - 15 lines] > > I'll think about that. Seems reasonable enough. :-) 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. >>>I just recalled that you suggested a spot of nail polish >>>to match-mark the bolt head and pulley, and I'm fresh out [quoted text clipped - 18 lines] > the bolt hasn't moved. I'm more inclined to believe that the > tightening is from a cold weld or by other mechanical means. 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. > The markings I made are from a razor sharp carbon punch. > I believe the car was driven some 7-8 thousand miles. is the pulley wheel splined? you don't state the vehicle's age. > 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. 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. > is the pulley wheel splined? you don't state the vehicle's age. 88 Accord...no spline. > "Elle" <honda.lioness@nospam.earthlink.net> wrote >> [quoted text clipped - 23 lines] > bolt > (83-lbft on a 2.0L.) 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. > Lo and Behold! Today I went to check and > the bolt hasn't moved. I'm more inclined to believe that [quoted text clipped - 4 lines] > The markings I made are from a razor sharp carbon punch. > I believe the car was driven some 7-8 thousand miles. Did you also try to break the bolt free? If so, any estimate of how much torque was needed? Thank you for doing this. > What model is this? 88 Accord, around 286k miles. > I know the 84-87 Civics have an 83 ft-lb pulley bolt spec, > but some have a 2.9L engine? [quoted text clipped - 4 lines] > Did you also try to break the bolt free? If so, any estimate > of how much torque was needed? 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? > Thank you for doing this. Your welcome. >> What model is this? > [quoted text clipped - 16 lines] > 150-lbft > and pretty exhausted. :-) 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. > 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. 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. > :-) > [quoted text clipped - 3 lines] > I will say that my coolant block bolt was only tough the > very first time I freed it. 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 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. 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. > If your Accord's pulley bolt is not very tight, then this > just suggests (to me) little time has transpired since it [quoted text clipped - 6 lines] > threaded bolt subjected to terrific dynamic loads and > temperature variations. >> Right hand thread. >> [quoted text clipped - 4 lines] > 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.  SignatureTeGGeR® The Unofficial Honda/Acura FAQ www.tegger.com/hondafaq/ "TeGGeR����������������������" wrote: >>>Right hand thread. >>> [quoted text clipped - 11 lines] > 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. > 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 > > 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 [quoted text clipped - 5 lines] > 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. >>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 [quoted text clipped - 3 lines] > 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. >>>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 [quoted text clipped - 8 lines] > misunderstanding!] - the rotation direction is incorrect. check it out > yourself. Well, I'll be! You're right! Mike > "jim beam" <nospam@example.net> wrote >> you can do this experiment at home: loosen the pedals on [quoted text clipped - 8 lines] > left hand thread on left side pedals. There is no > equivalent force on the crank bolt. 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#d40aeb3b8 76c7ffa . 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.) >>>you can do this experiment at home: loosen the pedals on >>>a bike so they're only finger tight. now, pedal around [quoted text clipped - 33 lines] > 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. > 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.) "jim beam" <nospam@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 [quoted text clipped - 16 lines] > 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? > "jim beam" <nospam@example.net> wrote > E wrote [quoted text clipped - 28 lines] > 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 [quoted text clipped - 6 lines] > 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. > Elle wrote: >> "jim beam" <nospam@example.net> wrote [quoted text clipped - 38 lines] > first release requires a little "bounce" of that weight, > so what's that? 330? not 400 though. I think it's hard to estimate the effect of bounces. A person jumps say six inches, s/he accelerates to a certain velocity. Whatever s/he hits decelerates the person from that velocity, producing the force that is higher than mere body weight, as I trust you and others here are aware. Surely your bouncing is less than around 550 ft-lbs., but I base this number only on general reports of how much torque is needed to free the bolt, not any rough physics calculations involving body deceleration, and so force applied, by the breaker bar. I am not troubled by the second release being a bit easier. Goes towards arguing that years of heat and load cycling do contribute to the tightness. >> I am still not willing to remove my Civic's pulley bolt >> more than is necessary--too lazy and I don't like putting [quoted text clipped - 4 lines] > > it's not delicate. pitch is 1.25mm, so not that fine. It's delicate to me, though maybe not because of the fine pitch. Maybe it's the fatigue it sees. I have a vague recollection that the bolt is supposed to be replaced every so often. >> I will say that in 2004 when I first got some experience >> with my 91 Civic's pulley bolt that the first time I [quoted text clipped - 9 lines] > sure, but it sure is tighter than the torque-wrenched > tightening that precedes it! That might be something to expect. IIRC, one important point (of many) Tegger has brought up on this subject is that the torque to free can vary quite a lot from the torque to tighten, even if it was just a few moments before that the bolt was tightened. I believe plenty of sources back this up. It's a very inexact science, though, like many sciences, with high reliability. Torque does not directly, formulaically correlate to clamping strength. Or, rather, formulae used to determine clamping strength from torque are crude estimates. There is just so much at play: Dry surface age and so condition, lubricants, torque wrench inaccuracies, material differences from one bolt to the next, temperature... >> Why is it again that you feel the abrasion beneath the >> bolt head could not occur while torquing the bolt to spec [quoted text clipped - 10 lines] > large angle rotation - it definitely appears to be lashing > within a limited range. Your opinion is noted. > 1. there is angular galling under the bolt head. that's hard evidence of > some rotation. [quoted text clipped - 5 lines] > 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 > 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. Your Volvo has a rock stiff engine mount. We have an 82 Volvo and it still runs but drives like a tank. >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. >>1. there is angular galling under the bolt head. that's hard evidence of >>some rotation. [quoted text clipped - 8 lines] > I have experienced the tightness with age in other cars with clockwise > rotating engines, also. interesting. do you have any thoughts on the fact that it has an "harmonic balancer" also? they do a lot to reduce rotational inertia which might tighten a bolt in one direction, but loosen in another. for a balanced crank and flywheel, there's really isn't a lot something low mass like this can achieve vibrationally. besides, hondas run successfully without them, so i wonder about its actual purpose. > 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 [quoted text clipped - 4 lines] > > Mike >> I have experienced the tightness with age in other cars with clockwise >> rotating engines, also. [quoted text clipped - 5 lines] > like this can achieve vibrationally. besides, hondas run successfully > without them, so i wonder about its actual purpose. The purpose is to transfer US $100+ from my pocket to Volvo's coffers occasionally (the first lasted about 150K miles). For those trying to picture this device, imagine your crank pulley with a strip of rubber running the circumference and bonding the pulley part to the core. The rubber eventually shears.... For whatever reason, the B230 engine has a harmonic balancer - also called a harmonic damper... not sure which term is official - while the very similar B23 engine has a conventional pulley. Hmm. Mike >>>I have experienced the tightness with age in other cars with clockwise >>>rotating engines, also. [quoted text clipped - 11 lines] > running the circumference and bonding the pulley part to the core. The > rubber eventually shears.... it does indeed! > For whatever reason, the B230 engine has a harmonic balancer - also called a > harmonic damper... which is even more interesting. it definitely will damp the rotational inertia spikes that will transient between the crank and those rotating masses the pulley drives. > not sure which term is official - while the very similar > B23 engine has a conventional pulley. Hmm. > > Mike > interesting. do you have any thoughts on the fact that it has an > "harmonic balancer" also? they do a lot to reduce rotational inertia > which might tighten a bolt in one direction, but loosen in another. for > a balanced crank and flywheel, there's really isn't a lot something low > mass like this can achieve vibrationally. besides, hondas run > successfully without them, so i wonder about its actual purpose. Successful? What about the galling on the crank bolt head you've talked about. That could've been caused by the torque pulsation of the vibrating engine. Take for instance, when ever I do a brake lathe without the vibration damper on the brake disc there is a wave effect on the surface. On the crankshaft, these wave (oscillating) effects can transfer eat up the transmission gears or various parts. > "Michael Pardee" <michaeltnull@cybertrails.com> wrote >>> Right hand thread. [quoted text clipped - 13 lines] > > 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. >All everybody agrees on is that it is a devil to get loose, at least for >the first timing belt change. After 375k I've done a bunch. It was a bitch the first time and it was a bitch the most recent time. In all cases the usual 250ish foot-pound impact wrench on a quarter-inch hose wouldn't budge it, though I wasn't willing to spend all day on it before breaking out the big guns. |
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