Dual-mass flywheel discussion

[Simon S]

Good discussion guys.
Thanks for all the input.

[immajackuup]

temping,race car or pleasant driving.

[bwawuz02]

I ran a euro 323i flywheel. 13.5lbs

This is what's going on my current build. bmwman91 explained it properly.

[goinstrong]

I have the euro 323i flywheel in mine too...though it is a little different since it is in an E21. Coupled with the 3.91 differential, the low end torque is pretty amazing. It will rev up and drop down to idle almost instantaneously, so one learns quickly how to play the throttle. My friend has the 318 iS with the dual mass flywheel. The idle kind of hangs before dropping, so the response isn't as quick. I think my car is faster than our E30 iC with the 2.5 M20...
Tim

[aka-e30]

So I assume you need the m20 FW m20 clutch and pressure plate ofcorse ha, m20 throw out bearing and pilot bearing stays the same or do you need to change that to m20? sorry for my ignorance but ive never been under the m42 with the trans out so correct me if im wrong. I just need to know what i need in order to do this conversion. plus my pilot beraing is taking a shit so i was gonna do all this at once. Thanks!

[bmwman91]

You will need an E21 323i throw out bearing. You will also need to drill out the rivets from the little spacer ring on the M42 flywheel, and enlarge one of the holes in it to fit around the locating sleeve in the crank; you then put that spacer between the M20 flywheel & crank.

[Wanganstyle]

Is there stronger dual mass FW clutch replacement for turbo M42?

Yes, a s52 unit is 22 lbs and 240mm vs 228mm. Also designed for m power stress. Will bolt on to a m50/52, and bolt to a m20 also- so it should bolt to a m42 as well.

Many people run m20 flywheels and clutches on m42. I have a n54 clutch on my m20

S52 dual mass should not need any shaving to fit m42, the m20 fly needs the back shaved to fit m42.

I have a shaved m20 fly if anyone is looking for one-

[vpilarrt]

You don't need to back shave the M20 flywheel to fit the M42 if you install the spacer as bmwman91 describes above.

[bwawuz02]

My 323i euro flywheel fit just fine without the spacer. No issues whatsoever. Why is the spacer needed?

[Wanganstyle]

My 323i euro flywheel fit just fine without the spacer. No issues whatsoever. Why is the spacer needed?

323i euro flywheel is lighter and does not have the extra ridge.

the 323i euro part or shaving of the usdm 325i part is needed for M50 install - the extra ridge of the 325i part hits the oil pan of the DOHC engines.

I am not sure of spacer for m42, spacer sounds scary to me.

[mr ilia]

I think there is a confusion, this is m42 discussion and not m50.

[brainspo0n]

Single mass, non AC M42 FW (euro) doesn't work with the M42 dual mass clutch, which adds more cost to the swap. This doesn't really sit well with the whole easy breezy philosophy behind retaining the stock setup. When clutch replacement time rolls around, it would probably be a good idea to price the euro single mass setup, as it is still a good compromise between comfort and performance.

a lightened M20 FW / clutch / starter setup is the way to go if performance is the name of the game (handles power better, much lighter overall)

[Balleristic31]

I'm going with the non ac fw. I plan on machining it down a few pounds and pairing it with a new oem clutch.

I will report details when my fw gets here from Germany

[Balleristic31]

Okay since I'm doing the m42 single mass swap, and haven't really seen many pics/evidence of this swap, I figured I should post my experiences.

Here's just the flywheel for now, stock, full weight straight from Germany.


Note: m42club has the m42 single mas weighs in at 22lbs , notice the actual weight.. :)

[Balleristic31]

Update: got my clutch in from partsgeek.com. It was 107 shipped to my door and the brand was Luc. Came with tob, clutch alignment tool, and pilot bearings. Along with the clutch and pp of course. this brings my total cost so far to $257

I weighed the assembly as a whole an it came out to 32.5 pounds :) 20% less weight compared to dual mass setup. Tomorrow I get the flywheel lightened and balanced with the clutch :D