OM617 Crank Pulley Wobble - Page 2 - PeachParts Mercedes-Benz Forum

Diesel911 · #16 11-09-2010, 12:31 AM

Even with the Torque on the 27MM Bolt some Members have had the whole unit come lose from the end of the Crankshaft and had the cylindrical Key Holes/Pins get chewed up.

ashedd · #17 11-09-2010, 12:43 AM

what is that torque? over 200 I think.

ashedd · #18 11-09-2010, 01:20 AM

Here is the HIGH resolution video.

http://www.youtube.com/watch?v=VeDJNERJaCg

Stretch · #19 11-09-2010, 02:58 AM

To hold the pulley in place there are 8 or 10 allen head screws that bolt through the pulley and onto the balancer bit. These are positioned around the "circumference" of the 27mm "main bolt".

If you are tightening these bolts it is best to lock the flywheel. To do this you'll find a little plate in front of the bell housing that allows access to the fly wheel teeth. There is a special tool that grips across to hold it in place. I guess a simulation of this effect with a clamp and a bit of wood may suffice. Otherwise I have heard that jamming a screw driver into the hole where the starter goes also works - remove starter first! Be careful of your flywheel!

Renntag · #20 11-09-2010, 09:41 AM

Sounds like locking the flywheel and torquing the crank bolt is in order. Might be best to get it on a lift in order to use a big torque wrench. (Unless you can find somewhere to park it with a great overhang such that there is enough clearance to the ground to swing a 30" TQwrench.

If I may suggest, in the future (in order to help others FIND your video), try giving it a name other than MVI 1046.

ashedd · #21 11-09-2010, 10:04 AM

I have had success in locking MB flywheels with vicegrips. The top of the claw fits right in between the teeth.

The videos are private

. You have to use the links above to navigate to them. But I was sure I renamed them

ashedd · #22 11-13-2010, 05:07 PM

Ok so I got maybe two of the six pulley bolts to snug down a bit AND the big boy in the middle also snugged down a little with my 18" breaker bar.

So is there any change in seriously over torquing that big bolt? I still do not know the torque value nor do I have a TQ wrench that big at home. I could go a little bit more with my 18" breaker. Just go until it stops?

I would really hate to snap that bolt. I can't really fire it up and test it with the radiator out of the car... darn transmission cooling lines!

tangofox007 · #23 11-13-2010, 05:11 PM

Unless you are a direct descendant of King Kong, you won't overtorque the balancer bolt with an 18" breaker bar.

Quote:

Originally Posted by ashedd

I still do not know the torque value

Let's fix that problem. 270-330 Nm.

kerry · #24 11-13-2010, 05:13 PM

If you could move it at all with an 18" breaker bar, I'm pretty sure this means it was undertorqued.

ashedd · #25 11-13-2010, 05:20 PM

ok cool. I hope the vicegrips I have on the timing plate

don't slip. Do ya think I should pull that bolt out and locktite it? I would prefer not to take the belts off and stuff. I am getting ready to ditch this car btw.

ashedd · #26 11-13-2010, 05:20 PM

Quote:

Originally Posted by kerry

If you could move it at all with an 18" breaker bar, I'm pretty sure this means it was undertorqued.

I could get the 24" out lol

Diesel911 · #27 11-13-2010, 08:44 PM

The torque for the Crank Bolt is 270-330 Nm
About 200-243 foot pounds

It might be you could get a free rental Torque Wrench from Autozone that would go up to 250 foot plunds.

ashedd · #28 11-13-2010, 10:24 PM

I hit it with my 150 lb TQ wrench and it moved another 1/2 inch. Harbor freight want like $70 for one that big.. So I dunno.

Stretch · #29 11-14-2010, 04:02 AM

An inconvenient way of replicating the effect of a torque wrench is to use a T bar and a suitable spring balance.

Torque is defined as force X distance.

If you had for example a metre long T bar then you could apply a force of 300N at the end to get your 300Nm torque requirement. A 50cm (0.5 metre) T bar would require a force of 600N etc etc

As spring balances are usually calibrated in units of weight (mass) you need to convert Newtons to kilograms say => Force = mass X g (gravity). g = 9.81m/s^2 => so an approximate conversion is to divide the value in Newtons by 10 to get the appropriate weight. So for the examples above:-

Apply about 30kg to the end of a 1 metre T bar

or

Apply about 60kg to the end of a 0.5 metre T bar

(Strictly speaking the weight should be acting in the vertical plane - but in practice that is going to be difficult as you've got a car in the way)

So in real terms the weight of a 5 foot slim woman hanging on the end of a 50cm T bar should be about right...

I don't know about where you live but it might be easier to buy a torque wrench!

tangofox007 · #30 11-14-2010, 08:32 AM

Quote:

Originally Posted by ashedd

I hit it with my 150 lb TQ wrench and it moved another 1/2 inch. Harbor freight want like $70 for one that big.. So I dunno.

I am no light weight and it's not easy for me to generate the required force on that bolt using a 250 ft/lb torque wrench. So I would suspect that if you gave it your best effort with a 25" breaker bar, you would likely get the torque in the zone.