Flywheel starting issues (help!)

[cjcjcj]

Hi everyone!

So i just bought my first e30. :D

its an imported 1988 320i, still LHD. m20b20 and originally an automatic has now been converted to a getrag 260.

Conversion was done only 8000km ago, so new clutch went in then and a lightened single mass flywheel-all that jazz.

I've been dailying it and not having any issues, other than on start up occasionally it would not engage the fly wheel.

When that happens, I would shake the wires connecting to the starter and it would start to turn over and start up.

2 days ago, it just would not turn over. I could hear the starter spinning, but no matter what i did it would not engage the fly wheel(or so i thought).

I bump started it and drove home, and pulled the starter. I thought something was wrong with the solenoid or Bendix that it was not pushing the starter wheel out, but i tested it once it was out and it worked fine.

Both the teeth on the starter and flywheel are fine.

The issue is, the outer ring on the fly wheel is spinning independently from the inner one, so it is not starting the car! I've attached a photo so you know what i mean.

https://ibb.co/dme5dd

Is there like some pins that hold this flywheel together? Can it be welded? Or do i need to replace my flywheel. I know the flywheels been lightened if it makes a difference.

Another thing too, this is my first post on a forum ever! So feel free to tell me what i did wrong or that this issues been covered already. Just please point me in the right direction.

[TobyB]

Oog.

Your ring gear has come off your flywheel, then. Or the flywheel's physically come apart.

The fix is not pleasant- pull transmission, then replace flywheel. You can replace the ring
gear separately, but if it's come off once it probably will again.

.... well, I suppose you COULD tack weld it. The
stock flywheel's going to be hard to weld to, as it's different metallurgy to the ring gear. Usually.

And a lightened stock flywheel's always a bit scary- it's certainly possible to do safely,
but you are counting on the person lightening it to know what they're doing. And
Previous Owners are not always the best people to trust.

he says, having sold quite a few cars....

t

[cjcjcj]

heyo! thanks for the response!

I think I'm going to try have someone weld it, given that I have no need to replace the clutch or anything else while I'm in there.

the fly wheel has already been lightened, weighs in at about 12 1/2 pounds.

its also a single mass flywheel which is good.

Id hope the guy I bought it off of isn't a liar, he's part of the local e30 owners club here.

[cjcjcj]

Alright, I wound up having it welded.

6 small tack welds placed every 23 teeth, so there evenly spaced.

Car started right up! Feels fine, doesn’t feel unbalanced or anything. I’ll update if this rattles itself apart or something. I’m pretty stoked though!

[TobyB]

Great!
If the welds worked (as in, stuck, penetrated, etc) there's not much chance
of it coming apart again.

I think you're set.

Oh, I didn't mean liar, I meant more like, 'really knew what they're doing'
or 'used a professional shop, not their buddy's brother's friend's best machinist'
12.5 lbs isn't TOO light.

Glad it worked out.

t