Rb Idler Bearing Bolt

[dontfeelcold]

I got my genuine Nissan idler bearing bolt and this is the first thing I see.

The runout of the last thread looks pretty nasty, lots of grooves (stress risers).

Has anyone else got a new idler bearing bolt to see if it is like mine?

Maybe post up a picture?

[Ben C34]

I'm 99.99% sure the bolts or studs break because guys over tighten them .Not because of what you have noticed

[dontfeelcold]

Point taken.

It's not good though, its like putting a groove in a shaft or what I call the "break here please" mark.

[Shoota_77]

It's not a bolt that needs to be super tight so will not be a problem at all.

If it was a torque to yield bolt you might be concerned but not for an idler bolt that is only tight not stetched.

[89CAL]

Can't believe there was a thread made for this.......

You dont use the last thread

There is only about 20ish Nm of torque on the nut

I've seen worse, People re-use these without problems

Honestly. If it is worrying you that much, Just buy another one, They arent expensive

[GeeDog]

Can't believe there was a thread made for this.......

No pun intended?

[Ben C34]

Boom tish.

[89CAL]

Haha, accidental pun is great

[dontfeelcold]

Can't believe there was a thread made for this.......

You dont use the last thread

There is only about 20ish Nm of torque on the nut

I've seen worse, People re-use these without problems

Honestly. If it is worrying you that much, Just buy another one, They arent expensive

I know what is wrong with the bolt, I was curious if other people had noticed the same thing.

Just because you don't use that section of the thread doesn't mean its not doing anything. Its actually doing alot more than the threads that are engaged.

Torque for that bolt is 43 - 58Nm and it is in single shear.

I am buying another one.

Some suggested reading material.

http://www.engr.sjsu.edu/youssefi/me154/notes/Bolt%20failure.pdf

http://arp-bolts.mobi/p/tech.php?page=2

[dontfeelcold]

This is another good one.

http://news.sherrylabs.com/laboratory-news-article.php?news_id=44

[89CAL]

Remember that the stud/nut are clamping the stationary part of the bearing

My comment about the nut not using that part of the thread was more about - your not going to make the thread any worse, then say if you ran a nut over it and damaged either the thread on the nut or stud. I'm fully aware of how forces are applied on bolts/studs

I was only saying, I can't see a major fault with the thread from the photo, maybe its the way the flash has gone off but it doesnt look that bad at all to me. And there is always chances of minor defects in a manufacturing process. And for the sake of a $2 part.......

As for your reading material, don't assume people are clueless when you dont know what they do for a living.

[jiffo]

Quite a long time back there was a spate of engine failures due to breaking of the idler bolt.

I spoke with Gary Cook regarding better quality bolts as the stocker isn't anything out of the box.

Gary had bought a selection of Nissan studs and the quality control was appalling.

Plenty of Unbrako quality to choose from but they don't fit under the cover, head is a bit too long.

Then almost overnight, no more breakages of the stock stud.

So were owners over tightening the stud or perhaps the belt, or did Nissan improve their quality control??????

[dontfeelcold]

I have drawn an arrow pointing right at what I am seeing. This is in the runout of the thread.

Can you see the grooves?

Please keep the comments concise and objective.

[Ben C34]

It's your bolt. If you don't like it and don't want to use it get another one.

Your mind won't be changed by anyone's comments and you won't sleep well untill you get a new bolt.

[MrStabby]

The cross section there looks to be a fair bit bigger than in the next valley where the thread is fully formed, and those scratch marks dont appear to deep. So it doesn't look too scary to me, but i've never looked that closely before.

[iruvyouskyrine]

My method of installing bolts.

Does this bolt fit? > Yes > put it in and tighten it to FT spec

> No > don't use it

Do I have another one that fits? > Yes > Use that one then

> No > ......where did I put my tap and die kit....

Edited August 7, 2014 by iruvyouskyrine

[dontfeelcold]

I am buying another one.

It's your bolt. If you don't like it and don't want to use it get another one.

Think you may have skipped a post there.

I am just curious to see what other peoples thoughts are.

It turns out it's to hard to show fine detail in a picture and very few people actually understand how surface finish can affect the life of something is under stress, so hopefully this thread can educate some people.

Here is another excellent article, scroll down to Surface Roughness

http://www.efunda.com/formulae/solid_mechanics/fatigue/fatigue_factor.cfm

[White GTS-T]

http://www.skylinesaustralia.com/forums/topic/290065-bolt/

[89CAL]

I believe you are over thinking the whole thing. I would use it unless the picture doesn't show some horrible defect.

It looks pretty standard like marks from the machines used to roll or cut the thread

Edited August 7, 2014 by 89CAL

[dontfeelcold]

The threads are rolled, very poorly I might add. The finish indicates worn forming tools. I can say this due to experience in manufacturing head studs.

So, back to my original question.

Has anyone else got a new idler bearing bolt to see if it is like mine?
Could you please post up a close up picture?

I'm not interested in anyone's opinion, that's not what I am asking for. I am asking for a picture of the threads.