Lightweight Flywheel conversion

[lambertius]

I've been thinking of converting my DMF to a SMF with a  lightweight kit. I've seen a few posts of people who say its worth it for the feel, but I was wondering what the drive line noise was like? I drive the car pretty much every day, and though it would be nice if it felt more responsive I am worried about driveline chatter. Is it much? Is there any at all? Is it like a swarm of metallic bees?

Cheers

[Slowered318]

I only have experience with the Valeo kit (it's not actually lighter, it's just single mass).

The additional noise is definitely noticeable. Especially 1st and 2nd gear or with the clutch in at a drive through. I wouldn't suggest doing this if you admire refinement in your BMW.

[lambertius]

I only have experience with the Valeo kit (it's not actually lighter, it's just single mass).

The additional noise is definitely noticeable. Especially 1st and 2nd gear or with the clutch in at a drive through. I wouldn't suggest doing this if you admire refinement in your BMW.

It is really difficult to find any useful feedback anywhere on this, most of the posts I see when googling are, "aw yeah its awesome it revs so much better" but no one talks about if its noisy or difficult to drive. It won't bother me so much at idle, but if its happening while driving then that would be a problem. My only real concern would be noise on the freeway when you're in top gear and the car is more or less cruising. If its just a matter of being in the right gear while driving then that won't bother me as much, but when you're on the freeway you don't want to be screaming along in 4th!

Also, I don't suppose you would be able to record the noise and put it up on youtube? I'd found a few people talking about the Valeo kit but you're the first one to mention any driveline chatter.

[Slowered318]

Not sure if my camera could pick up the sound over the exhaust and various other engine noise. It's "character" is just there as soon as you start the car and sometimes when your cruising around.

Been chasing drivetrain noise for over a decade with this car. When I remedy one problem another pops up a few months later, I have more or less given up trying to refine the car. I'm pretty sure this is typical of old 4 banger BMW's so the lightened single mass is an acceptable comfort/performance compromise for most people.

The Valeo flywheel/clutch doesn't bother me much, it's like having a budgie. You can machined it down to reduce weight, it's fairly inexpensive, grips good for normal driving. However I now realize why the dual mass is used in the first place... it does reduce vibration. Beyond that I really can't give an accurate review, I would have to rule out all other problem areas (transmission, crank bearings, differential, heat shield) and keep on the merry go 'round.

[colin86325]

You will really only hear it at idle.  If this is concern, then stick with your dual mass flywheel.

[Slowered318]

You will really only hear it at idle.  If this is concern, then stick with your dual mass flywheel.

So you don't notice any vibration/noise when you let out the clutch 1st, 2nd, and 3rd gear? Strange... maybe one of my bearings is the culprit?

[colin86325]

No noise or vibration in those gears.  If I have the A/C on and am creeping along in a parking lot in first gear and then let off the gas I have to sometimes feather in the clutch to prevent a jerkiness that was not present with the heavier dual-mass flywheel.

[wazzu70]

If you have issues with vibrations in gear, its not due to the flywheel/clutch. This does not matter if its the single mass flywheel/clutch from an M42 or an M20.

The noise I think Slowered318 is referring to is the notorious "Getrag rattle" which pretty much all getrag transmissions have at this point in time (and even a decade ago). The issue is the input shaft bearing...and it can only be replaced with a full transmission rebuild. Most shops don't have the tools to do this so a rebuild is major $$$$ and most people just ignore the noise since its just annoying and not any kind of harmful issue.

You will hear the noise when the clutch is released. Its amplified and most noticible when you are in a tunnel, near a center divider, or by a wall like in a drive through. The sound reflects back to you in this case and many times in these areas the window is down making the noise even more noticable.

When you replace a drivetrain component, you are usually listening more closely than you did before for issues and you pick up on the noise that was alwas there! Seriously, and I know from experience as thats when I first noticed it myself and researched the issue.


To help supress the noise, use Lucas gear oil in a 50/50 blend with conventional gear oil. Synthetic oils like Redline MTL will make the noise more audible.

[Slowered318]

If you have issues with vibrations in gear, its not due to the flywheel/clutch. This does not matter if its the single mass flywheel/clutch from an M42 or an M20.

The noise I think Slowered318 is referring to is the notorious "Getrag rattle" which pretty much all getrag transmissions have at this point in time (and even a decade ago). The issue is the input shaft bearing...and it can only be replaced with a full transmission rebuild. Most shops don't have the tools to do this so a rebuild is major $$$$ and most people just ignore the noise since its just annoying and not any kind of harmful issue.

You will hear the noise when the clutch is released. Its amplified and most noticible when you are in a tunnel, near a center divider, or by a wall like in a drive through. The sound reflects back to you in this case and many times in these areas the window is down making the noise even more noticable.

When you replace a drivetrain component, you are usually listening more closely than you did before for issues and you pick up on the noise that was alwas there! Seriously, and I know from experience as thats when I first noticed it myself and researched the issue.


To help supress the noise, use Lucas gear oil in a 50/50 blend with conventional gear oil. Synthetic oils like Redline MTL will make the noise more audible.

I agree with you about paying more attention after changing something. I shouldn't be so quick to blame Valeo, but I don't think it helped with the "Getrag rattle"

Can you explain in more detail why the roller bearing 23121224375 on the transmission input shaft cannot be easily replaced by a good mechanic? I was going to include this part with my next big order.

Your right, using Redline, but it's the D4 ATF suggested for the G240. Should I try Redline MTL or something a little thicker? I'm getting a fair bit of noise and gear changes aren't exactly "effortless".

[Slowered318]

No noise or vibration in those gears.  If I have the A/C on and am creeping along in a parking lot in first gear and then let off the gas I have to sometimes feather in the clutch to prevent a jerkiness that was not present with the heavier dual-mass flywheel.

That's not bad at all, it sounds like the single mass flywheel conversion is going well for you. It's possible mine was damaged or thrown off balance during shipping (the box was badly mangled and the key inside was broken in pieces) It could also be installed poorly. Really hard to dig into this without a lot of down time and money.

[wazzu70]

I agree with you about paying more attention after changing something. I shouldn't be so quick to blame Valeo, but I don't think it helped with the "Getrag rattle"

Can you explain in more detail why the roller bearing 23121224375 on the transmission input shaft cannot be easily replaced by a good mechanic? I was going to include this part with my next big order.

Your right, using Redline, but it's the D4 ATF suggested for the G240. Should I try Redline MTL or something a little thicker? I'm getting a fair bit of noise and gear changes aren't exactly "effortless".

I have read you need special tools to remove the transmission components, which is why not just anyone can do it. I have never tried to rebuild a getrag so I cant comment from personal experience. If you are curious though give Metric Mechanic a call and have them explain it. They rebuild the getrag transmissions, have all the tools, and are nice guys.

Any synthetic will be way too thin to supress the noise. You need the good ol cheap stuff Doesn't shift as nice but stops the rattle. Theres no free lunch here unfortunately.

Try replacing the trans fluid first and see if that helps. Its a cheap and easy test.

[Slowered318]

I have read you need special tools to remove the transmission components, which is why not just anyone can do it. I have never tried to rebuild a getrag so I cant comment from personal experience. If you are curious though give Metric Mechanic a call and have them explain it. They rebuild the getrag transmissions, have all the tools, and are nice guys.

Any synthetic will be way too thin to supress the noise. You need the good ol cheap stuff Doesn't shift as nice but stops the rattle. Theres no free lunch here unfortunately.

Try replacing the trans fluid first and see if that helps. Its a cheap and easy test.

Sorry to hijack this thread BTW.

I will ask MM about this, I need to call them anyways about a rebuilt diff.

Should I replace with Redline MTL or D4 ATF, any significant difference? I don't see why BMW calls for ATF, but I've always used it knowing the hydraulic properties are useless in a manual.

[wazzu70]

MTL is too thin, its not going to be an improvement over what you have now.

Just use non-synthetic ATF and see if that helps.

[lambertius]

So I disappear for a few days and I come back to a whole lot of useful information!

Really appreciated!

If I'm honest it hasn't put me off doing a lightweight clutch conversion, since I can hold my clutch in when stopped if the rattle really bothers me, my real concern was if it rattled in motion. I would like to try and see the different response. If anyone has any experience with a lightweight flywheel specifically please share their experience with it. I managed to find a few different threads on the Valeo kit (after much searching) after I posted this thread, but still nothing on a lightweight flywheel specifically.

Since it is kind of related, I was wondering if anyone has tried any different short-shift kits and what their experiences with it are?

[wazzu70]

Glad the info has been helpful. I have had both a lightened M20 flywheel 323i spec, 13lb) and a E36M3 single mass lightweight flywheel/clutch from F1 on ebay. No real difference in feel between them. Reason for switching to the F1 is because I wanted the M42/M50 ring gear to use a factory starter.

If I did it again I would just use the M20 flywheel/clutch with the late model M20 starter, or have the M50 ring gear pressed on the M20 flywheel. The M50 based flywheel/clutch kits cannot fit in the E30 transmission bellhousing.

A secret to the lightweight flywheels is there is a TOO LIGHT. The super lightweight aluminum ones are too light IMO. They rev up and down so fast it burns the clutch in day to day driving. The single mass steel units are the way to go. Its whats mandated in many racing series like Grand Am and most racecars I have worked on prefer the steel units for the reasons I mentioned.


Also, most racecars I have worked on just use the Z4 OEM "short shifter". Its a good throw length, cheap, and OEM quality. Hard to beat that!