Resonance and vibrations after timing chain change

[320iSwede]

Had my 320i with N43 at the BMW dealer for timing chain replacement. Very annoying vibrartions occured after the change and the garage couldn't find the reason and said it was probably OK.

I have searched a lot and I wonder if the center bolt in the front of the enginge should wobble like it does on my engine.
This bolt and the balance wheel was removed since it also holds the timing chain wheel.

The center bolt is, as I understand it, screwed into the crank shaft and if it is wobbling, it must be bent or wrong mounted to the crank shaft.

Pease see this slowmotion youtube when the car is on idle: https://www.youtube.com/watch?v=vqICuPSojgk

[michael320]

Did you visually inspect the crank pulley? In a lot of cases you will be able to detect an imbalance by eye. Especially if the pulley is incorrectly installed.

[320iSwede]

Thanks for the reply.
The pulley (balancing wheel) looks OK, but is slightly rotating "offcenter" as you can see on the youtube above.
If the center bolt would have been rotating without any uncircular movement, I would suspect the pulley or the hub that the pulley is mounted to with the six bolts.

But now all of it moves unconcentric when the enginge is running. I can not figure out anything else than that the center bolt is deformed.

It's like if you put a drill in a drilling machine, a straight drill will rotate like a line however you move the drilling machine. If you put a bent drill in the machine, it will wobble.

The car is back at the dealer today. I've paid approx EUR1500 for this and I would really like it to be as good as it was before the chain change...

[michael320]

This bolt should be changed any time its taken off, I'm surprised that a BMW dealer would refit the same bolt. If it were me I'd have them check over their work and replace the bolt as a start. Its not that expensive to buy and not difficult to change.

[320iSwede]

My opinion as well. They made a change that caused a noise. The problem is probably in that area and now there is a bolt and a heavy pulley wobbling around.

They say that the engine needs to be reset in cams and crank shaft when that bolt is replaced....

[michael320]

Time to take your problem up with the service manager. Its not acceptable for a main dealer to leave a car back with issues like this.

[320iSwede]

Update from yesterday. Was at the dealer and also talked to the mechanics. They said that the pulley can be worn out in the rubber and cause vibrations, and the enginge support on right side slowly looses the vacuum will cause this noise. I almost belived it but when they said that the replacement cost for this two parts was approx EUR700 I wanted to convince myselves a bit more.

Took the car to a garage and had the belt and balance wheel removed. My thought was that if the hub looks perfect, a new balance wheel might help.
Here is the centerbolt and hub when the car is on idle: https://www.youtube.com/watch?v=y3-yR2CP8kk
The hub is also wobbling, probably approx 1.0 mm. I can not in any way belive that BMW engines has tolerances on the outgoing axis of the motor like this. There will be heavy vibrations when the balance wheel is rotated off center like this at 700 - 7000 RPM.
I've spent 15 years of my life as and engineer at Saab Automobile until the bankrupcy and I can say by experience that the rubber in the balance wheel will loose it's mechanical properties shortly.

The seal around the hub was not changed which also suprices me when you do a repair like this at a main dealer. It looks like some kids has done the job. They are also MINI-cerified with fancy glass walls so I would expect more, but an independent garage is problably better.

[Don B]

@[Valdelisbmw] changed the timing chain on our 320i last year...thread below, might be of some help...shows what was changed etc

http://www.bmwhaus.ie/forum/showthread.php?tid=3253

[320iSwede]

Thanks, I've read that post and it looks great. Wish I had an independent garage that knew BMW well close to me. Will keep you updated about the progress.

[HealyC]

Your oil pump balance shafts are out of timing, nothing to do with the crank pulley/bolt. The oil pump drive sprocket obviously moved when the timing chain was being replaced.

It's the same as N42/6 engine http://workshop-manuals.com/bmw/3_series_e46/318i_n42_tour/2_repair_instructions/11__engine_(n42)/41__oil_pump_with_filter_and_drive/1_ra__removing_and_installing_replacing_oil_pump_( n40_n42_n45_n46)/page_729/