Flywheels

[digger]

What are the different flywheels used on e30 325i? What mass were they and what alternatives are there? I have seen Al flys but those seem quite light for a street car.

[RobertK]

Your best bang for the $$ is to take a OEM "i" single mass flywheel and have it lightened a few pounds at a local machine shop.

[digger]

how much does the single mass flywheel weigh stock? What about the dual mass one? WHich year model has the single?

Cheers

[DanielHStout]

Anything before 87' has a single mass, anything after 12/86 has a twin mass. I don't know if you can just replace a twin mass with a single mass but if you can, DO IT!!! It is not advised to resurface a twin mass FW. This means you can only use a TMFW for two clutch jobs before you have to buy a $300 plus new one. If you figure out a conversion for a dual to single mass let it be known. The downsides to this conversion would be more noise and a stiffer more "jerky" clutch. Upsides are that it saves weight, its less expensive and you are able to resurface.

[erik325i]

Anything before 87' has a single mass, anything after 12/86 has a twin mass.

Wrong.

-Erik

[nando]

yeah, M20B25 cars came with single mass flywheels.

it weighs about 22lbs. I had mine shaved down to 15lbs, cost me a whole $35.

[Low Level E30]

Where is the BMW Part # on the flywheel? I was given a flywheel for free, but I don't know what E30 it comes from... :D

[EtaSport]

Post a picture, if you've never seen a dual mass flywheel, you'll definitely know its different. Its nearly 1 1/2 thick, and weighs a ton.

You can easily put a single mass flywheel from an early eta into an eta with a dual mass flywheel, as long as you make sure its from an eta, and you use the clutch/pressure plate/throw out bearing from the early single mass. IMO it will be smoother than a dual mass as I have driven my car (dual mass) and a 325i (single mass) and the clutch operation and grab exceeds mine greatly. Mine is jerky, inconsistent, and harsh, I hate it.

[DanielHStout]

Quote:
Originally Posted by DanielHStout
Anything before 87' has a single mass, anything after 12/86 has a twin mass.

Wrong.

-Erik

Do you care to explain yourself? I just went through a whole e30 flywheel extravaganza so I think I know this topic fairly well. We are talking about 325 e and i cars aren't we? Check the part numbers and cross reference them with the years. You will obviously see that in 1987 they stopped using single mass flywheels and started using only twin mass ones. The twin mass flywheel part number for pre 87 cars does not match the TMFW PN for the i cars. Also the whole point of using a TMFW is to isolate torque peaks and reduce vibrations hence making clutch operation smoother. On the same note your flywheel isn't the only mechanism that contributes to the "smoothness" of a shift, if you will. You can't compare a low end torque lsd es to an i. There is no way that they will feel even remotely the same regardless of what flywheel they have.

[digger]

From looking at realOEM.com

TM = twin mass.

325i Manual

Upto 11/1986 11221706575 US
From 11/1986 11221706573 US
Upto 08/1987 11221706575 Euro
From 08/1987 11221706573 Euro

325i Auto

Upto 12/1986 11221716275 US
From 12/1986 11221716276 and 11221706573 US
Upto 12/1986 11221716275 and 11221716276 Euro
From 12/1986 Upto 09/1987 11221716275 Euro
From 12/1986 11221716276 Euro

So it seems that the 325i uses a single mass flywheel. This is based upon that the for the late eta engines the description mentions that it is a twin mass flywheel and the price is twice as much.

There are two types for a manual (575 and 573) but i don't know whether the cat has anything to do with it.

There are three types for a manual (275 and 276 and 573 used on later US autos).

325e Manual

Upto 03/1986 11221705046 Euro
From 03/1986 21211225979 TM and 11221716276 and 11221287079 Euro
Upto 05/1986 11221705046 US
From 05/1986 21211225979 TM US

325e Auto
Upto 12/198611221713883 and 11221287079 Euro
From 12/198611221287079 and 11221716276 Euro
Upto 12/198611221287079 US
From 12/1986 11221716276 US

So it seems the eta with manual transmission is the only one that uses a twin mass flywheel.

Korman http://www.kormanfastbmw.com/e30drive.htm mention that the ETA has TM flywheel has a weight of 27.6lbs.

Metric Mechanic http://www.metricmechanic.com/pgs100.htm mention that the i has a flywheel weight of 22lbs as Nando said.

[DanielHStout]

So it seems the eta with manual transmission is the only one that uses a twin mass flywheel.

I don't think that this is correct, the manual 325 i, is, and ix all used twin mass flywheels starting in 1987 (11/86). Try to buy the correct OEM flywheel for an manual 1989 325i and you will learn this along with way more than anybody ever needs to know about e30 flywheels. I know, I have been there. Auto cars really have nothing to do with this anyway though. Their only function is to provide a ring for the starter. The rotational mass comes from the torque converter.

[erik325i]

I don't think that this is correct, the manual 325 i, is, and ix all used twin mass flywheels starting in 1987 (11/86). Try to buy the correct OEM flywheel for an manual 1989 325i and you will learn this along with way more than anybody ever needs to know about e30 flywheels. I know, I have been there.

I hate to tell you this, but whatever parts guy you were using at your local dealership must suck.
There is no year cutoff for all e30s to switch to dual mass flywheels.

m20b25's (325i, 325is, 325ix...) used a single mass flywheel, whereas the m20b27 (325, 325e, 325es) used a dual mass flywheel.


I personally pulled the flywheel from my '89 325i when I replaced the clutch. I can assure you that it is a single mass flywheel. My brother's '89 325i also has a single mass flywheel.

-Erik

[DanielHStout]

m20b25's (325i, 325is, 325ix...) used a single mass flywheel, whereas the m20b27 (325, 325e, 325es) used a dual mass flywheel.

I can pretty much assure you that your full of it, or maybe just mistaken.:up: I can assure you of this because I just replaced the clutch and flywheel on my '89 iX last weekend. I also have had experience with my '86 325es, my old '84 325e, and my sisters '89 325i. I got my flywheel shit pretty much down by now. Anyway I don't really give a shit, I am just trying to give accurate information. I have contributed all that I have to this thread and I am not here to argue. I will post no more.:bow:

This pelicanparts.com screenshot pretty much says it all.

[James Crivellone]

All ETA's I messed with had dual mass flywheels (both were 86/87)

1 87i/4 I did the clutch on had a single mass flywheel, my 89I parts car had a dual mass, and the 91 I did it on had a single mass.

The single mass flywheel I have now came from a 89 525i M20.

[digger]

for those whoi have said their 325i had a single mass, how did you know? What is involved in swapping a single mass flywheel into a car originally equipped with a dual mass one? Is it only the clutch that changes, or are spacers and so forth required?