m20 clutch/FW conversion question

[reyesch3]

Hey guys, been looking around prob didnt look hard enough, but i was wondering what are the possible alternatives for replacing the flywheel.

my 318is clutch burnt out so i got a new one, the flywheel however are expensive so i wanted to see if there is a way around this. whether using an m20 flywheel or is it possible to get the flywheel machined somehow.


thanks!

im a noobie by the way so take it easy;D

[TobyB]

M20 flywheel is supposed to work- I read that on here, so dig deeper.

Valeo sells a single- mass conversion kit, but it is pretty spendy.

t

[Gerta]

Hey guys, been looking around prob didnt look hard enough, but i was wondering what are the possible alternatives for replacing the flywheel.



my 318is clutch burnt out so i got a new one, the flywheel however are expensive so i wanted to see if there is a way around this. whether using an m20 flywheel or is it possible to get the flywheel machined somehow.





thanks!



im a noobie by the way so take it easy;D

M42 club.com has a great write up on what you need. Google it. Also Search is your friend... most won't tolerate people not looking.

Link here: http://www.m42club.com/forum/index.php?topic=16724.0

Welcome!

[reyesch3]

Thanks, and yeah ive been doing alot more reading, i ended up getting a stock flywheel.

[Gerta]

OP - Congrats! It's not too bad of a job to change the flywheel with the engine out! Post up some pictures!

[reyesch3]

i should be getting the flywheel tomorrow, ill post some pics then. thanks

[reyesch3]

decided to go with the m20 FW and clutch conversion instead, im a bit confused on what is needed.

I already purchased 325i Clutch, pressure plate, and FW.

I am planning on ordering :
323i Release Bearing,
flywheel bolts (12x28mm) ---- do they need to be modified?

does anyone know where can i buy m20 starter?

Im i missing anything else?

[varg]

I used the 325i release bearing with my m20 flywheel conversion. The bolts needed were shorter than the stock M42 flywheel bolts, but I don't remember the dimensions. I used a generous amount of loctite on them and have had no leaks. I had to have the flywheel spacer holes enlarged for the locating sleeve on the crank, which I hadn't seen on the web, YMMV. Also, with my spacer disc and flywheel, no modifications had to be made to the rear main seal case to make it fit, as I had seen in some posts about the conversion. Again YMMV.

As an aside, if you're planning on turbocharging at any point, get an aftermarket clutch with a good torque rating, the stock 325i clutch might not handle it.

[reyesch3]

I had to have the flywheel spacer holes enlarged for the locating sleeve on the crank, which I hadn't seen on the web, YMMV.

As an aside, if you're planning on turbocharging at any point, get an aftermarket clutch with a good torque rating, the stock 325i clutch might not handle it.

i didnt know you had to enlarge the flywheel spacer holes, are you using the m42 spacer?

and yes the plan is too turbocharge it but thats not til much much later, right now i just want to get my car up and running. miss driving that thang

[varg]

Yes. The spacer from the M42 flywheel. If turbocharging is in store, do yourself a favor and get an upgraded clutch now, unless you plan on dropping the transmission again later.

[reyesch3]

Yes. The spacer from the M42 flywheel. If turbocharging is in store, do yourself a favor and get an upgraded clutch now, unless you plan on dropping the transmission again later.

What clutch do your recommend? but yeah i plan on doing that later.

so far i have:

m20 clutch, flywheel, starter. m42 spacer and slave.

waiting for delivery on the flywheel bolts and 323i TOB.

[irish44j]

M42 club.com has a great write up on what you need. Google it. Also Search is your friend... most won't tolerate people not looking.

Link here: http://www.m42club.com/forum/index.php?topic=16724.0

Welcome!

It is a great writeup, if I do say so myself

[VacantSky]

from what I understand, take new(used) M20 flywheel to get it resurfaced, while at the machine shop have them mill down the lip on the back of the flywheel. Now you don't need a spacer and you can just use the 325 throw out bearing, use M20 starter. I'm in the middle of this myself while I'm replacing my M42 for a severely cracked coolant jacket thanks to the pos previous owner...

I have resurfaced flywheel with lip removed on the back and clutch. Still need starter and drop new motor in

[bmwman91]

Yeah, if you leave the M20 FW stock then you will either need the spacer ring and 323i TOB, or you will need to do some filing on the back of the oil pan to make the stock FW clear and in that case (with no spacer) you can use the 325i TOB.

Of course, as suggested above, if you are having the FW resurfaced, which is HIGHLY recommended, you might as well see about having the shop take a few lbs off of it. I am running an 11lb M20 FW in my 2.1L M42 and it is good times. The idle is still just fine, and it revs like a monster. You are almost guaranteed to stall the car the first couple of times after putting the lighter FW in though lol.

Also, one thing that you will find with a stock M20 FW is that the transmission will make a rattling noise when you are sitting at idle with the clutch pedal up. The reduced rotating mass means less damping of the vibration as the engine fires, which rattles the input shaft on the tranny. The lighter the flywheel gets, the worse the rattling gets. With the 11lb FW in mine, my car sounds like a coffee can full of rocks being shaken around when I am sitting at lights lol.

One last item: the M20 PP is a lot beefier than the M42's (228mm vs 215mm). The total weight difference between a stock M42 clutch+FW assembly and a stock M20 clutch+FW assembly is 4.5lbs, or an 11% reduction. It is more than enough to make a noticeable difference.

[gearheadE30]

My M20 FW weighs in at 15.5 lbs, and even taking that much off made a nice difference. I also don't really get any rattles from mine, so maybe that much extra weight helps.

As for the boost bit, the M20 clutch can handle quite a bit more than the stock M42. I'm boosted and have had no issues with the stock M20 clutch on mine.