Flywheel replacement

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There is an alignment pin that has to be aligned for it to go on. Here are the specific directions for your vehicle. The attached pictures correlate with these directions.

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11 22 500 REMOVING AND INSTALLING/REPLACING FLYWHEEL
11 22 500 - Removing and installing or replacing flywheel (N51)


picture 1


Special tools required:


picture 2



Important!
Aluminium-magnesium materials.

No steel screws/bolts may be used due to the threat of electrochemical corrosion.

A magnesium crankcase requires aluminium screws/bolts exclusively.

Aluminium screws/bolts must be replaced each time they are released.

Aluminium screws/bolts are permitted with and without

color coding (blue).

For reliable identification:

Aluminium screws/bolts are not magnetic.

Jointing torque and angle of rotation must be observed without fail (risk of damage).


picture 3


Necessary preliminary tasks:
- Remove transmission See: Manual Transmission/Transaxle > Removal and Replacement > 23 00 019 Removing and Installing Transmission (GS6-37BZ).
- Remove clutch.


picture 4


Block flywheel (1) with special tool 11 9 260, use an old transmission screw for this purpose.

Installation Note:
Replace aluminium screws.

Unfasten flywheel screws.

Tightening torque: 11 22 1AZ. See: Flywheel > Mechanical > 11 22 Flywheel

Installation Note:
Flywheel (1) is secured with an alignment pin.

Fit new flywheel screws.

Clean crankshaft thread for flywheel screws.


picture 5


Secure flywheel with an old transmission screw (1) and special tools 11 9 260 and 11 9 265.

Installation Note:
Replace aluminium screws.

Release flywheel screws with special tool 11 4 180.

Installation Note:
Flywheel is secured with a dowel pin.

Fit new flywheel screws.

Tightening torque: 11 22 2AZ. See: Flywheel > Mechanical > 11 22 Flywheel


picture 6


Assemble engine.

Let me know if this helps or if you have other questions.

Take care,
Joe

Everything is lined up and dowel pin is in correct hole but it almost seems like the crankshaft flange expanded and is bigger than it should be.
Can I have the flywheel flange area machined to be a little bigger so it fits over the crankshaft flange?

Welcome back:

That is not recommended. Is it the same size as the one you removed? Maybe you got the wrong part.

Joe

It is the same part as the one that was on it, I even used a micrometer and it is the same.

Check it for any tiny burrs or dings. If the part is the correct one it should fit with no modification. It has to fit very close so the parts stay centered which is why Joe said it's a bad idea to try grinding on it. Is this a factory part or an aftermarket unit?

It is a OEM part.

Okay, it should fit if it's the same part number. As I said look it over very close, they only clear by a few thousands of an inch so a small burr or even having it at a slight angle can be enough to stop it from sliding on.
Which engine do you have, there were two 3.0 engines used, an N51 and an N52K., It looks like they used the same dual mass flywheel but with BMW I hardly ever trust what the books say.

N52

One other thought, check for corrosion. Like he said, there is a very close tolerance. It has to be straight and the mating surface must be clean and undamaged.