crank bolt tightening debate

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

Reply to
Michael Pardee
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"Michael Pardee" wrote

You mean they are a result of?

Galled refers to a surface that has been rubbed by something else.

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.

Are you saying you think the head and washer are adhering, and that's why the breakloose torque is so high?

Quite right.

Reply to
Elle

thanks dude - appreciate it.

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.

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.

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:

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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.

Reply to
jim beam

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.

which is consistent with lash of the pulley wheel!

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.

depends if we've spent time doing this kind of work before!

Reply to
jim beam

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.

What do you mean?... Honda have made motors than spin clockwise and counterclockwise. And the crank bolts are always Lefty Lucey and Righty Tighty.

Reply to
Burt S.

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. Disclaimer - I've only done a handful of crank bolts, not dozens or hundreds like pros encounter.

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.

That's where I'm heading, but I don't really know if that's right. My opinion is still in freefall on this.

Reply to
Michael Pardee

"Michael Pardee" wrote

snip

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.

Okay.

And no surprise about the impact wrench you're using. It's a popular method, by all reports here.

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.

Reply to
Elle

snip

The units are irrelevant as long as the quantities are correct.

Normal operating conditions or not, a moment of force is commonly called torque.

Whatever that is, it is beyond me to see any relevancy to the bolt tightening debate.

What would this be good for - the bolt should remain lose "upon commencing operations"?

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).

Galling is abrasion and fusion caused by friction, not heat cycling.

Reply to
karl

"karl" wrote

If someone else would like to address this gentleman's comment above and his other assertions, then please be my guest.

snip for brevity

Reply to
Elle

That's a good point.

Mike

Reply to
Michael Pardee

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.

Reply to
jim beam

"Michael Pardee" wrote in news: snipped-for-privacy@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).

Reply to
TeGGeR®

"jim beam" wrote snip

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).

Reply to
Elle

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

Reply to
Michael Pardee

probably more of a Y-65P or R-510 nail polish guy

Reply to
robm

"robm" wrote in news:Ny0df.7810$ snipped-for-privacy@newsread3.news.atl.earthlink.net:

Do they make nail polish in NH-526M?

Reply to
TeGGeR®

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

Reply to
robm

bet an auto paint store would have something close! House Of Kolor makes some interesting showcar paint.

Reply to
SoCalMike

That is right; anything else is rubbish.

Reply to
karl

snip

snip

Mitigate? Splining precludes rotation!

I agree, everything else is rubbish.

Reply to
karl

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