The crank bolt is critical!

On my Fabia 1.2, I arranged a lock for the crank bolt. It is critical if it is loosen, and it should be tightened with a gargantuan torque - 90 Mn plus 90 degrees.

I went there as I could, but did not quite reach the last 90 ranks. Would not have motor crash, so therefore this. Used also use Locktite to be sure. 

 

 

Chopped off a 3 mm piece of a 18 mm pipe/tube and welded at a glance none, 1 mm thick.

 

 

Bent tabs on each end and glued matter stuck to the nut and washer with epoxy.

 

 

My cat wondered bad about what I was doing?

 

He thought well I'm crazy !?

Edited 6 March, 201610 yr by Torbo

From what I have read the crankbolt should be replaced when removed.

What length of bar were you using to attempt the 90 degree turn?  I find that a long bar makes these types of jobs much easier and more in control.

 

Something like this : http://www.amazon.co.uk/Sealey-750mm-2-inch-Breaker-Drive/dp/B002PMJ2LE/ref=sr_1_1?ie=UTF8&qid=1457282107&sr=8-1&keywords=breaker+bar+750mm

 

Possibly with a long extension out through the wheel arch so you can get the necessary arc of turn without hitting things.

 

I've seen a figure of 150Nm plus 180 degree turn for the AZQ/BME 12-valve variant and wonder how it could be soooo much more, Possibly finer thread pitch or bigger diameter bolt?

Crank bolt torque is critical. If it slips the engine timing will be effected.

Im an old an nervous man that have experienced a lot! So I don't take chances!

The bolt should have opposite threads, so the chance to loosen was near zero.

I can tackle much, miscellaneous parts, but not not a broken engine in my tours. Im driving much.

 

I know that is not normal to do things like this, but i it can be called a experiment. 

 

Im working with old Volvo-engines, B16, B18 and so on, and in the good old days they use locking plates in all the critical parts inside the engines.

Old School....

What length of bar were you using to attempt the 90 degree turn?  I find that a long bar makes these types of jobs much easier and more in control.

 

Something like this : http://www.amazon.co.uk/Sealey-750mm-2-inch-Breaker-Drive/dp/B002PMJ2LE/ref=sr_1_1?ie=UTF8&qid=1457282107&sr=8-1&keywords=breaker+bar+750mm

 

Possibly with a long extension out through the wheel arch so you can get the necessary arc of turn without hitting things.

 

I've seen a figure of 150Nm plus 180 degree turn for the AZQ/BME 12-valve variant and wonder how it could be soooo much more, Possibly finer thread pitch or bigger diameter bolt?

Thanks! I was thinking of to by one like this for some days ago, but I didn't of some reason?

From what I have read the crankbolt should be replaced when removed.

I have read that to. But I have newer done that. I have repeated some engines, since the 60-s, and never have some problems. 

It's probably best and change, but I limit usually costs in motor jobs. Correct or incorrect? Sure correct but everything cost money....

Edited 6 March, 201610 yr by Torbo

You're welcome.

I like the idea of your 'retaining device' but I don't really think it's strong enough to do what you hope.

Think about how much force/effort you put into doing up that bolt. Now imagine a force nearly that big acting to try and rotate your nicely welded/bent device. Do you think those bent tabs wouldn't bend back and allow the rotation? I think they would.

I do like your ability to improvise and fabricate stuff.

If it's not clamped tight enough the whole lot will spin behind anyhow and the pistons are going to get very friendly with the valves.

The power of the tail is the result of the momentum that is there now minus any force created by loosening.

It will never be up to the locking torque. 

 

So will not locking more Enne a fraction of torque as it is screwed with.

Part of the purpose is also keeping an eye on whether the bolt has a tendency to loosen.

And when the bolt has been in a while so it will settle more firmly. Typiskt of steel against steel.

 

An old Volvo example: The lock on camshaft can not hold more than about 20 - 30 Nm, while torque on the nut is 120 Nm.

Thats the little extra if I can set it that way.

My saving is also to avoid vibrations that can make loosening. tiltrekningsmoment 

 

If I had arrived at this before, I would threaded two holes in the pulley and used screws to secure.

It could have been better, but they are only to take the difference between the loosening torque and tightening torque to be hedged.

 

If the nut was loose before I mont it, I understand the moment is to weak. 

 

It is like a bracing the bolt on the back of some to be screwed together. It should be small force to hold, although torque is very large there screwing. Was this understandable? Uposit ....

Edited 6 March, 201610 yr by Torbo

It is also a fact that the engine does not break with loose bolt, as it is a wedge that holds the interposer to the cam gear in place without it rotates. But it is only when the bolt falls out completely that there is danger ahead. Meanwhile, there can be an noyse, and if I keep my  eye on the lock then you are safe

The lock will also prevent the bolt from falling off.

They recalled the 1.2 as the bolts were not torqued up tight enough. Resulted in a fair few slipped timing chains and new engines.

Just saying.

I think the correct torque and a bit of Loctite would have been enough. Seems total overkill to me.

Edited 7 March, 201610 yr by TMB

They recalled the 1.2 as the bolts were not torqued up tight enough. Resulted in a fair few slipped timing chains and new engines.

Just saying.

Interesting! I understand ther was some missing there, since the torque is so high!

I have the same problem wit my VW Camper 91-modell. The crank bolt was hard to get off and on. I will change belt soon, after 5 year and 40 000 km, and I will safe the bolt there to. - like it or not... 

Better solution with to extra bolts on the metal.

I have the same problem wit my VW Camper 91-modell. The crank bolt was hard to get off and on. I will change belt soon, after 5 year and 40 000 km, and I will safe the bolt there to. - like it or not... 

Better solution with to extra bolts on the metal.

The bolt came loose on my friend's car, VW Caravelle, and it resulted in engine failure. He had to change engine.

I'm not so sure this is sufficient. You're attempting to lock against the actual part which could spin (despite small key) which needs the clamping force from the crank bolt. If the bolt were to ever come loose, then the locking against the pulley wouldn't save it.

 

Even with a 600mm breaker bar, you should be able to set the torque angle. Most of the bolts are of a recessed head type and need to be tightened to 150nm plus 180 degree turn.

Kinda pointless really it would have made more sense to make a keyway to locate the drive pully if your that worried about it.

The chain drive has a tiny key to locate it but is only 3mm wide so as soon as the pressure is taken away by the bolt loosening it jumps

Thats why I was thinking of av locking bolt/-nut.....

No need if you Loctited it, it won't come undone by accident, Loctite is simply fantastic, it's routinely used by good engine builders to guarantee that conrod bolts won't come undone and it also means it doesn't matter if the bolt is tight enough or not, this allows you to very accurately control bearing pinch on conrods, mains and cam bearings without compromising reliability.

I was taught to use lock tight on flywheel bolts when I was at college.

A race engineer guy came in and showed us how they apply the same amount on a cotton bud and put it on the threads on the crank rather than on the bolts so it's all even and balanced when building high spec engines.

Just saying :P

No need if you Loctited it, it won't come undone by accident, Loctite is simply fantastic, it's routinely used by good engine builders to guarantee that conrod bolts won't come undone and it also means it doesn't matter if the bolt is tight enough or not, this allows you to very accurately control bearing pinch on conrods, mains and cam bearings without compromising reliability.

Good one.

Good one.

 

I see what you mean, what I meant was that torque setting becomes less critical as long as you have exceeded a reasonable minimum value. Thanks for pointing that out.

The lockout will soon again go on again.

My be i will drill holes in the small wings and use lock wire instead of epoxy?

 

Im not sure before I´m very sure. 

This even motor to be repaired once and for all!

 

And I always have some money with me if something happend:

 

To bee sure and more....

Edited 11 March, 201610 yr by Torbo

Dude, just use some Loctite. You're massively overthinking it.