M20 flywheel with 24v questions

[dice2012]

I'm planning on using my M20 flywheel as I already have a new clutch for it, and a new 24v flywheel and clutch looks expensive. I have read that my options are to either get the M20 flywheel lightened down to <1mm above the ring gear, or shave the e34 oil pan. I'm looking to daily drive this E30, so I have a few questions regarding everything.
Is the lightweight M20 flywheel bad for daily driving?
IF I want to go down the route of shaving the oil pan, what part do I shave, and how much do I shave off? I can't find any pictures, and I feel it would help a lot to actually see it done. Also, is shaving the oil pan risky?

[TobyB]

Huh. Now I have to go look at an E34 oil pan again...

t
has parts he hasn't used... yet

[Northern]

Here's the step in the back (engine side) of the stock M20 single mass flywheel.




Here's an example of how it should look after shaving until the lip is 1~2mm from the ring gear face:



Some people go further and remove more material (bottom, stock on top) but I don't think it's necessary.:



Shaving the pan, It should be easy to see where once the pan is installed and you can stick the flywheel on. I haven't done this, but it's probably something like:


Blue is probably where this edge sits, and red is where you might make contact.

[Northern]

I also don't think shaving the lip down is going to make much difference to drivability. It's easy to look at this and say "that's a lot of material" but I think it works out to ~1kg on an ~8.4kg flywheel, plus the mass of the pressure plate.

[mtech325]

On a few 24v swaps, I've had the back side of the m20 single mass flywheel shaved down by a machine shop. It still weighed about 16 lbs, so it's wasn't crazy light. For street driving it was perfectly fine and made the 24v feel a little peppier. I've had bad luck however with the m20 aftermarket clutches making too much noise upon engagement or being overly grabby (had to go this route before due to s52 swap with m20 flywheel) but your results may differ.

For an M50 car though the stock e30 m20 clutch is perfectly fine, but if you're planning on a higher powered engine like S50 or S52 etc., the matching stock clutch & flywheel is what I would recommend for daily driving as it holds the power and drives like normal -- not sure if the e36 m3 clutch will fit in a g260 though, so may need to convert to ZF 5 speed if you haven't already.

[dice2012]

Alright, thanks for the input. Definitely gonna shave down the m20 flywheel and use the fresh clutch and pressure plate I already have. Unfortunately the original dual mass attached to the engine was fried and had wayyy more than 20mm of play in it, so that went straight to the scrap pile.

I’m also stubborn and want a 6spd, but I’m already over budget by $$$$$. So looks like the original driveline is here to stay behind the engine. Worst case scenario the clutch slips a ton and I hate how it feels and I just do it “the right way”