where I can find M20 single mass flywheel?

[Kristo]

Now I´m so far, that I got engine and just need flywheel.


I read that everybody uses M20 flywheel and I understand that single mass is good, but I can´t find in bmwfans.info witch model have single mass flywheel...

or I understand wrong and there are not any single mass flywheels on M20 and you guys are using twin mass flywheels?


I tried to search, but it dosen´t help me.

[gudgeon]

All M20 e30's have a single mass flywheel and I suspect this will be the case for all M20's
As far as I know the M20B20 and M20B25 use the same flywheel.
You will also need the starter motor.

[DanThe]

How much are you willing to spend? Im having a lightweight billet steel flywheel made at the moment for my track car, if it turns out as expected it will be having more made

[e30-EVN]

Interesting dan , what wieght are you making it mate?
And roughly what sort of figure do you expect it to cost ?

[DanThe]

6kg or less and will be in the region of £200 I believe

[e30-EVN]

Yeah 6kg would work brill. Let me know if you make more mate, I will buy a new clutch kit and fly at the same time

[Kristo]

Thanks, but I dont need any special flywheel, I just want ride this car at streets.

and gudgeon, some virtual beers to you if its true...

[e30-EVN]

Any m20 flywheel will work fine mate, I'm running 1 on mine and its very responsive! She revs like a bike lol

You need a flywheel, clutch and starter off an m20b20 or m20b25

[Kristo]

I get m20b25 flywheel from e34 tomorrow I hope.

http://www.realoem.com/bmw/showparts.do ... g=11&fg=20

this is what bmwfans.info shows for all M20 flywheels.

we see it tomorrow what is true in here

[e30-EVN]

If its an "m20 engined e34" the flywheel ect will be fine mate

[gudgeon]

Thanks for the virtual beer Kristo, I feel virtually refreshed.

I'm not the most knowledgable person about this stuff but I thought you might appreciate the quick response.

As well as the flywheel, starter, clutch, (possibly spigot bearing depending on gearbox) you will need to modify the sump a little bit if you are not lightening the standard flywheel. I'm doing this job myself in the next week or so.

Take a look at e30-dk's useful thread here:
http://www.e30zone.net/modules.php?name ... c&t=181563
(Apologies to Ant)

[e30-EVN]

No apology necessary mate,

As you said though I'm sure I put up pics in there of me grinding the offending points out

[Phill172]

Get the stock flywheel lightened by a machine shop before you stick it in too, its a must

you can get it down to about 6.5kg/7kg makes a huge difference to the old bird

[gudgeon]

I'm reluctant to lighten mine as it's already so much lighter than the stock M50 dual-mass, plus the car itself is lighter than an E36.

Shaving a few bits off the sump sounds easier and will probably result in a smoother driving experience, I'm not after a track car.

Having said that, I have absolutely no direct experience of what I'm talking about. At least I admit it!

[steve_k]

if you are after a light weight M20 flywheel then send a pm to hongkongfuey on here as he ca sort you out with one for £110 & if you send him your old one back he'll give you £20 back.

[Phill172]

Lightening the flywheel wont make the drive anyworse and certainly not turning it into a track car nor make the drive jerky or (cant think of a better word!) unsmooth, just simply if you are going to fit a M20 flywheel its worthwhile for litterely £30 at your local machine shop to shave some wieght off,

The response and pick up is so much better

[shedrool83]

I have my flywheel getting lighten atm .

My thoughts were its off so why not.I had one on the m20 last year and is was a great mod imho

[Kristo]

hmm...

now I get one flywheel from m20b20 engine from E28, but there is problem, it fits perfectly, it won´t need any modifications...

its not rub anywhere and crankcase is not grinded.

is it macined earlier?
does it need balancing now too?

[DanThe]

How heavy is it? Looks thicker than most

[Kristo]

6,2 kg, in UK it´s ca. 13,6 lbs

in this picture is one lihgtned and one stock.
I looked that stock wheel have more material upper the teeths?

http://www.r3vlimited.com/board/attachm ... 1287470854

[gudgeon]

"As far as I know the M20B20 and M20B25 use the same flywheel."

I really should have been more specific, I was talking about e30's and I suppose to be precise facelift ones (as far as my knowledge extends). Your flywheel is clearly not the same, doesn't necessarily mean your e28 one won't work though. If you have the clutch and starter and it all fits together with the gearbox (which one are you using by the way?) I guess it should be OK?

[DanThe]

Looks like the early engines had lighter flywheels, check the weight in this link-

http://bmwfans.info/parts/catalog/E28/S ... _flywheel/

Also used on early E30's E21's etc

http://bmwfans.info/parts/catalog/11221264517/

[E30_Crazy]

I think I remember somewhere someone said that sports (or at least tech 1 sports) come standard with a lightened flywheel, almost to the point of not being able to feasibly lighten anymore and retain durability. Anyone know if this holds true? I've got a tech1, and just wondering if I should be on the look for a lighter fly, or if I'm about as good as it gets.

[DanThe]

If you click the link above you will see the 6.3 kg flywheels were only fitted to 320 and 323 models up to September 1984 which is pre-325i anyway

[Kristo]

"As far as I know the M20B20 and M20B25 use the same flywheel."

I really should have been more specific, I was talking about e30's and I suppose to be precise facelift ones (as far as my knowledge extends). Your flywheel is clearly not the same, doesn't necessarily mean your e28 one won't work though. If you have the clutch and starter and it all fits together with the gearbox (which one are you using by the way?) I guess it should be OK?

I belive that flywheel must work
I think I try to use my 318i gearbox.

fly fits to the cranckshaft and clutch fits too.

when I can use the garage, well see how it fits in real life

[gudgeon]

318i gearbox will require a different spigot bearing in the end of the crank. Apart from that if it fits together you should be good. Take care over the clutch release mechanism, you may need to adjust slightly although the thicker flywheel should make this a lesser problem than with a normal flywheel I guess.

[Kristo]

thanks gudgeon, now is bearing changed.
I didn´t know about that before you told it

I measured fly and clutch today.
m20 set is 5 mm thinner that original m40 set.

is there come problems with clutch releasing or it comes normal disk depreciation?
I think it got to be work and this releasing good?

[gudgeon]

I haven't done this myself yet so I'm not the best person to ask, but often the clutch release bearing is thickened with a spacer or an e21 clutch release bearing is used, or the lever is bent slightly. Presumably this is due to the much thinner flywheel and clutch arrangement on an M20 compared with the 318is (and possibly on an M50/M52).

In any case, your flywheel looks thicker, I'm quite surprised that it ends up being even thinner. It's not a big deal anyway, just be wary of it to avoid having to adjust it all once installed in the car.

EDIT: Didn't read properly, you are comparing to an M40 flywheel and clutch, proves what I'm saying really. I expect the difference would be even greater with the usual e30 M20 flywheel and clutch. Wait for someone else to comment, but 5mm may be not significant.

[DanThe]

You wont need to change anything to use the clutch, all the standard parts work fine

[Duke137]

So pre facelift M20 cars have lighter fly wheels? Dan how are your billet ones going mate?

[DanThe]

Pre September 1984 to be exact, but you may find they trickled into some 85 cars

Test fly is nearly there, just waiting on the fancy ring gear to be machined and some drillings before I can bench test it on the back of an engine and have it checked for balance before giving it to someone to abuse on a track car

[E30_Crazy]

Dan, are you going to be in a position to take orders on more of these if everything works out with the tester? And, do you have an estimate so far on what they might cost? I might be interested in them for an engine rebuild if they aren't one of those "Don't really need it, just that little extra edge on the track" sort of thing.

Thanks!

[DanThe]

Yes if it works out good I already have a few guys that are up for one to put on their track cars, im expecting them to cost around £200 but wont know till I get the final bill

[Kristo]

how tight must torque this hybrid like M50 engine + M20 fly?
I torqued with 120 nm, is it enough? I think its good

autodata shows M20 @ 98 - 112 nm
M50 @ 113 - 130 nm

I use bolts from M40, those are 3 mm shorter than M20 bolts.

and I use locktite 243 blue threadlock there.

clutch is sowed in autodata 34nm with 10.9 bolts, but I used stronger (12) bolts and torqued with 50nm - thats not bad too I think?

[blue30]

On the fly I used blue threadlock and put then in with an impact gun. On the clutch cover bolts I just did them by hand to somewhere a little bit tighter than where I didn't think they would come out again!!

Could be wrong but I think the mods around the thicker release bearing etc. are more to do with which gearbox & slave combo you're using, some of the boxes put the slave much further back. As someone said earlier there's not that much in it thickness wise once you've got the taller M20 clutch cover on. I extended the rod in the M20 slave cylinder on mine by something like 50mm (just going by memory here), 5mm (or 10mm once you take the lever into account) would have been nowhere near. The standard slave wasn't even touching the end of the lever even with the rod hanging out of it. (ZF M50 box)