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BMW E30 M20 Flywheel Dual Mass or One Piece & Resurfacing

June 16, 2010

Q
Do you know if I have a single or dual mass flywheel in my 1988 325ic? Can either one be resurfaced?

A
The M20 engine in your 88 325ic, uses a standard one-piece flywheel. All 325i models thru 91 (and the 92 325ic) use the one-piece flywheel. The dual-mass flywheel is used on 325e models from 5/86 on. The one-piece flywheel can be resurfaced, the dual mass units can not be resurfaced. However, the shop must be aware of the stepped surface and must cut the face in two steps, to keep the proper step height. BMW does not list a specification for the height of the step, but we have measured an average of 0.010″ for the height of the step on a new flywheel.

BMW non-dual mass flywheel - Note stepped friction surface

BMW non-dual mass flywheel stepped friction surface = 0.010"

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Categories → 3 Series 84-91 - E30

3 Comments
  1. Martin Charles permalink

    Yes, the dual mass flywheel cannot be resurfaced. I have a 88 325 (super-eta). As my dual-mass flywheel was shot, it had to be replaced. I actually swapped it with a 325i flywheel (single mass). I also had to replace my clutch with a e30 325i clutch though.

    The single mass flywheel I had resurfaced. Almost like turning brake rotors.

  2. Mike Holland permalink

    Does anyone know the OEM Part # for the single mass Flywheel?

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