crank bolt right or left hand thread?

Page 2 of 2  
Elle wrote:


http://groups.google.com/group/uk.rec.cycling/browse_frm/thread/3f2111409ccd2635/d40aeb3b876c7ffa?lnk=st&q=precession+pencil+%22effect-based%22&rnum=2#d40aeb3b876c7ffa .

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.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
E wrote

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?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Elle wrote:

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.

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

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

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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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.

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.

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...

Your opinion is noted.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Your Volvo has a rock stiff engine mount. We have an 82 Volvo and it still runs but drives like a tank.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Michael Pardee wrote:

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.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Michael Pardee wrote:

it does indeed!

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.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.