crankshaft pulley bolt

[nissandoms47]

when i was doing my transmission swap i left a ratchet on the crank bolt and started it. it ended up loosening the crank bolt. how do i tighten this back up with out having hte crankshaft move while i torque the bolt?

 

thanks

 

-Alex

[jj big shoe]

Couldn't you just put the trans in a drive gear?

[Guest psyopper]

It depends on which way the engine roatates (clockwise or counterclockwise) and which way the bolt rotates (CW or CCW). A drive grar or reverse would be ost appropriate.

 

Also, set your paring brake to provide some more resistance and block the rear and front wheels.

[nissandoms47]

humm alright but mines an automatic wouldnt the torque converter just spin or something? and it spins clockwise

Edited January 8, 2006 by nissandoms47

[94extreme]

what's wrong with tightening the thing by hand (using the said ratchet?)

[sw]

your supposed to remove the starter motor and jam the flywheel by means of a BIG screwdriver instered into one of the flywheel teeth. when you turn the nut the screwdriver will hit the trans housing and bingo. you can torqe up the nut.

 

your right, without pressure in the trans if you turn the nut on the crank shaft it will just spin the shaft and the torque converter will do nothing.

 

- mz crank shaft pulleys normally like a lot of torque on the nut holding them, usually up around and above 70 foot pounds - thats a LOT of force, normally a breaker bar comes in handy to acheive that level of torque.

Edited January 8, 2006 by sw

[Vsicks Pathy]

Well. I have certainly learnt alot today? Anti clock wise? Fair dinkum. Do motors turn in the opposite direction in the southen hemispher? Just joking!

 

All cranks should turn clockwise unless of course you hav a 'Go Go Mobile'; they can turn over each way. Pretty good if you think about it. You get to go the same speed backwards as you do forward but that's another story.

 

As for torquing up your bolt? No need to do that. Pull it as tight as you can so as to make sure your pully lines up true, and drive happily away. The rotation of the crank will tighten it fully by itself. It over tightens the bolt if you ask me.

 

They way to pull it up is to have the belt on and put tension on it to stop it moving too much.

[nissandoms47]

humm alright ill try that out once i figure out why my engine wont start

[unccpathfinder]

BFH (big friggin hammer)...i always just put it in gear tighten it down and then take a breaker bar and a hammer and hit it a good couple times b/c i know mine spins the way that if it vibrated it would tighten it instead of loosen...but theres no easy way to torque it to exact spec...

[RedPath88]

As for torquing up your bolt? No need to do that. Pull it as tight as you can so as to make sure your pully lines up true, and drive happily away. The rotation of the crank will tighten it fully by itself. It over tightens the bolt if you ask me.

Yep, I have always just tightened it up by hand as much as I can and called it good... so for I have not had a problem doing it that way.

[94extreme]

They way to pull it up is to have the belt on and put tension on it to stop it moving too much.

that's the way i do it too. sure beats the screwdriver in the fly wheel thing.. lol

[mws]

Another place impact wrenches are very nice. After some experimentation, I found mine at torque setting 3 is about 100 lb-ft, and 4 is about 150.

 

And you can get flywheel wrenches at most parts stores for under $20. Works similar to the screwdriver jammed in the flywheel teeth, but less prone to dramatic slips.

It does require 2 persons - one to hold the flyweel, one for the torque wrench.

 

Note I said torque wrench. As an engineer, I have to point out that some fasteners are too critical to be subjected to the "good enough" or "gootentite" approach. Too loose leads to them coming loose, too tight means fastener failure. Neither one will leave you happy.

[Vsicks Pathy]

Note I said torque wrench. As an engineer, I have to point out that some fasteners are too critical to be subjected to the "good enough" or "gootentite" approach. Too loose leads to them coming loose, too tight means fastener failure. Neither one will leave you happy.

Lucky the fly wheel isn't one of those things. Though by all accounts you can, I would not use RP88's method.

 

Besides the internals of an engine, can anyone think of anything else on a car that needs to be torqued?

 

You'd think that wheel nuts, given their importance, should be torqued along with brake callipers, wouldn't you? Don't get me wrong, there are torque settings for these things. There are aslo torque settings for body panel bolts and the bolt that holds your horn in place......................

 

No, I can't think of a single place, other than the guts of a donk, that using a torque wrench is necessary.

[mws]

I will choose to disagree with you and say there are a LOT of fasteners that should be torqued - wheel nuts being one of them.

 

Yes, I know they rarely are, and are rarely perceived as being a problem. But it is all playing the odds. Overtorquing a fastener will not "guarantee" it will fail, it just increases the odds. And having one fail is more an inconvenience than a disaster.

 

Kinda like driving at high speeds on underinflated tires. The tire may not blow out immediately, but the more you do it and more it is underinflated, the greater the risks of it eventually biting you. And when it does, the tire is usually blamed rather than how the tire was used. Torquing is the same thing. If the stud eventually snaps, it is assumed it was defective. Every broken stud I have analyzed (only a handful, but that's all I've had to examine) showed signs of having been overtightened at least once.

 

I will be honest and admit I was very callous about torquing stuff like lug nuts. Until I took ME-138 in college. That was the course in the Mechanical Engineering curriculum that dealt with fasteners, their applications, and their failure modes. Now I torque or somehow lock pretty much ANYTHING that could lead to injury or death if it came loose or failed. That's my experience and resulting behavior. You are welcome to your own.

[94extreme]

yeah, i torque my lug nuts too.. most imortant, imho.

[Vsicks Pathy]

I will choose to disagree with you and say there are a LOT of fasteners that should be torqued - wheel nuts being one of them.

 

Yes, I know they rarely are, and are rarely perceived as being a problem. But it is all playing the odds. Overtorquing a fastener will not "guarantee" it will fail, it just increases the odds. And having one fail is more an inconvenience than a disaster.

 

Kinda like driving at high speeds on underinflated tires. The tire may not blow out immediately, but the more you do it and more it is underinflated, the greater the risks of it eventually biting you. And when it does, the tire is usually blamed rather than how the tire was used. Torquing is the same thing. If the stud eventually snaps, it is assumed it was defective. Every broken stud I have analyzed (only a handful, but that's all I've had to examine) showed signs of having been overtightened at least once.

 

I will be honest and admit I was very callous about torquing stuff like lug nuts. Until I took ME-138 in college. That was the course in the Mechanical Engineering curriculum that dealt with fasteners, their applications, and their failure modes. Now I torque or somehow lock pretty much ANYTHING that could lead to injury or death if it came loose or failed. That's my experience and resulting behavior. You are welcome to your own.

I will choose to disagree with you and say there are a LOT of fasteners that should be torqued - wheel nuts being one of them. 

 

And the others that you do use a torque wrench on are?

 

 

If the stud eventually snaps, it is assumed it was defective.  Every broken stud I have analyzed (only a handful, but that's all I've had to examine) showed signs of having been overtightened at least once.

 

Stud overtightening is a big problem. Overtightening comes 99.99% of the time from tyre repair and replacement shops. They use air powered rattle guns. The trouble with those is that if air pressure is low at the time of use the nuts will be loose. This has happened to me (once ever) and it was not pleasent nearly losing a wheel at 60MPH. It is very hard to regulate an air tool, as you would know, especially when other tools are running from the same compressor etc. So over compensation is the normal practice. Ever needed to change a wheel and couldn't budge the nut even while standing on, and jumping up and down on the lever? I wish I had a $ for evertime that has happend to me. It happens like that so when pressure in the comp is low the wheel will still be tight. And no two air guns will torque the same at the same settings either, there are just to many varibles built into them.

 

I think I will stick to using my tyre lever/wheel brace. It has yet to let me down.

[Simon]

I snapped a wheel stud not too long ago, just with a cross-type lug wrench. Leaned on it too hard, and *snap* there was my stud in the lug.

 

I'm sure it had been previously overtightened, but I also know that since that, I've tightened my lugs with a torque wrench.

[mws]

You're right about rattle guns - most are pretty consistent if properly taken care of and properly used. But most AREN'T. And tire repair shops are notorious for grossly overtightening. I always bring my own torque wrench when if I have to let them put the wheels on, and insist on doing the final torque myself. I even offer to sign paperwork saying so.

If they were to refuse to let me do the final torque, I would immediately remove the lugs and retorque in the parking lot. If the nut took more than the OE specified torque +25% to loosen, I would insist they replace studs or give me a piece of paper stating they accept all liability for any damages incurred if the stud ever fails for the life of the vehicle. I explain this right up front in a very non-accusational way before they begin work - I just state I am a mechanical engineer and am a bit anal about safety... and I have never had a shop object in 15 years. Most understand and appreciate the fact I understand and care.

 

I use quality and known accurate torgue wrenches on:

 

- All internal engine bolts (actually use "stretch measuring" devices wherever possible)

- Exhaust manifold bolts (very critical to prevent leaks or broken studs)

- Intake manifolds

- Anything attached to the crankshaft that sees cyclic loads: flywheel, TC or clutch, harmonic balancer, driveshaft

- most other accessory drive pulleys

- drive axle components (differential bolts, axle retainers, etc)

- Wheel lugs

- Almost all suspension and steering bolts

- Seat belts, seats

- Engine mounts

 

That's all I can think of for now...

 

The idea behind "torquing" is to tighten the bolt until the head is being pulled down hard enough to "stretch" the shank of the bolt an ideal amount.

You want to stretch it as that tension leads to a constant and considerable friction force in the threads and between the head and part to keep it from loosening. The more it is elastically deformed, the more it clamps. But only within the "elastic" range of the bolt.

 

If you stretch it beyond the elastic zone, then the clamping force no longer increases and instead the bolt just stretches in what we call plastic deformation - which means it is permanent deformation and does not reverse when the force is removed. And when that happens, two things happen: 1) It changes the granular stucture of the metal, and 2) it necks down and gets smaller in diameter.

 

To throw out one last bit of technical jargon, both of these are what we call "bad things".

[mws]

I snapped a wheel stud not too long ago, just with a cross-type lug wrench. Leaned on it too hard, and *snap* there was my stud in the lug.

 

I'm sure it had been previously overtightened, but I also know that since that, I've tightened my lugs with a torque wrench.

I'll wager all my earthly possessions that you are correct.

 

And IMHO, taking over responsibility for your safety is the right thing to do.

 

Years ago, things tended to be grossly overengineered to compensate for mediocre materials, so most bolts were oversized and could be overtightened with minimal risk.

 

But with modern designs, bolts are becoming more ideally sized to reduce size, weight, and cost, so they are less "idiot" proof.

Now if only we could get the idiots out of the tire shops...

 

I'm surprised I haven't heard about any loudly publicized neglicence lawsuits regarding lug nut abuse? Maybe consumers and lawyers :oops: just aren't aware enough?

[Precise1]

I always bring my own torque wrench when if I have to let them put the wheels on, and insist on doing the final torque myself. I even offer to sign paperwork saying so.

If they were to refuse to let me do the final torque,

I 100% agree, other than the last part. I always tell them just to snug the lugs, and they always argue that they cant. I say "write it on the work order or I walk". PERIOD !! Don't give me this you can't crap ! Do what I ask or get out of my way when I head for the door or your A$$ is going down and getting trampled (with an extra boot to the head or two!!) !! When I say "sorry, I don't trust you idiots" just say ok, take my $ and humor me...

I'll agree with most of mws's list but will add All clutch components (I don't want to take it apart again until the friction disk is shot) and anything that threads into a cast aluminum part with a hex bolt... Thats the easiest way to strip crappy metal. I know to watch for it, and still do it sometimes; 8 lbs means it will back out. 12 lbs is right. 15-18 lbs is ripping out the threads... Seen it too many times !!

 

B

[94extreme]

my tire guys do as i ask and i ask for hand tightening to Nissan specifications.. never had to stand on the ratchet.. lol

[RedPath88]

Though by all accounts you can, I would not use RP88's method.

Perhaps I should have said that a little differently and maybe explained a bit further...

 

I have "typically" always tightened them by hand. When I said "as much as I can" it was kind of a force of habit there. When I was in HS, my auto shop teacher made me repeat the process of torquing a crank bolt (to get the feel for it)... over and over and over again, then he gave me an 18in breaker bar (which is what I also use now) and had me do the same, until I could get it within 3+/- pounds of the correct number. He also ran me through that drill on a wide range of torques settings

 

Since I became really good at hitting that mark, it's kinda stuck with me.

 

I do take a torque wrench to them every now and then... just to make sure I am still accurate.

 

Now for the really odd part, although I do not use one on that bolt every time, I do use a torque wrench on just about every other bolt and nut that has a torque rating... including lug nuts.

 

Is it right? No but if I hit the mark that does not make it wrong either Would I recommended that others do it this way.. no And if anyone read it that way, torque that bolt the right way!

 

Guess some old habits.. right or wrong ...are just hard to break.

 

Oh and for the record, I would and do not ever do that on someone else's rig... everything gets tightened to spec.

Edited January 10, 2006 by RedPath88

[Vsicks Pathy]

my tire guys do as i ask and i ask for hand tightening to Nissan specifications.. never had to stand on the ratchet.. lol

And they have a torque wrench and a manual? Good shop.

[Vsicks Pathy]

You're right about rattle guns - most are pretty consistent if properly taken care of and properly used. But most AREN'T. And tire repair shops are notorious for grossly overtightening. I always bring my own torque wrench when if I have to let them put the wheels on, and insist on doing the final torque myself. I even offer to sign paperwork saying so.

If they were to refuse to let me do the final torque, I would immediately remove the lugs and retorque in the parking lot. If the nut took more than the OE specified torque +25% to loosen, I would insist they replace studs or give me a piece of paper stating they accept all liability for any damages incurred if the stud ever fails for the life of the vehicle. I explain this right up front in a very non-accusational way before they begin work - I just state I am a mechanical engineer and am a bit anal about safety... and I have never had a shop object in 15 years. Most understand and appreciate the fact I understand and care.

 

I use quality and known accurate torgue wrenches on:

 

- All internal engine bolts (actually use "stretch measuring" devices wherever possible)

- Exhaust manifold bolts (very critical to prevent leaks or broken studs)

- Intake manifolds

- Anything attached to the crankshaft that sees cyclic loads: flywheel, TC or clutch, harmonic balancer, driveshaft

- most other accessory drive pulleys

- drive axle components (differential bolts, axle retainers, etc)

- Wheel lugs

- Almost all suspension and steering bolts

- Seat belts, seats

- Engine mounts

 

That's all I can think of for now...

 

The idea behind "torquing" is to tighten the bolt until the head is being pulled down hard enough to "stretch" the shank of the bolt an ideal amount.

You want to stretch it as that tension leads to a constant and considerable friction force in the threads and between the head and part to keep it from loosening. The more it is elastically deformed, the more it clamps. But only within the "elastic" range of the bolt.

 

If you stretch it beyond the elastic zone, then the clamping force no longer increases and instead the bolt just stretches in what we call plastic deformation - which means it is permanent deformation and does not reverse when the force is removed. And when that happens, two things happen: 1) It changes the granular stucture of the metal, and 2) it necks down and gets smaller in diameter.

 

To throw out one last bit of technical jargon, both of these are what we call "bad things".

I should have elaborated a little more on things like the diff internals, gear box or tranny internals and by saying engine internals, well, the fly wheel is covered. It does have massive loads applied to it. The rest is questionable as to needing torque settings. But whatever blows your horn.

 

Ignore my other post. I just saw that you bring your own torque wrench. Bit too late to take the studs off in the car park if they were over tightened at the shop. Do they let you in to oversee the nuts being tightened?

 

Thanks for the run down on mild steal too.

[Vsicks Pathy]

Oh and for the record, I would and do not ever do that on someone else's rig... everything gets tightened to spec.

I was not having a go at you RP88. You'd freak to know how I loosen the bolt then.

 

As for doing everthing to spec, I would love to see the manuals you guys use.

 

Absolutely every nut and bolt on a car, without exception, from new, has a torque spec that must be met before it can be passed. These specs are there to cover the arse of the manufacturer.

I was a quality control inspector for Toyota for eigth years and know the industry inside and out. It was my job to make sure that the cars were OK. Let me tell you. There can be 100's of lbs PSI between lower and upper tolorences on any nut or bolt. As long as it does not drop below a certain spec ie. 7 lbs PSI, it is fine. So to do everything to spec, even without knowing what a torque wrench is, is very easy to do for well over 90% of any car.

 

As a rule, if you have to open to get to it, then it needs to be exact.