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Discussion Starter · #1 ·
I finally narrowed down the "problem" I'm having with my MT to OEM dual mass flywheel. This being my first DMF car I thought there was something wrong with the car but apparently it's just the way they build MTs these days.

I found this thread on a mazda forum and it describes the issue pretty well:
I Hate This Dual Mass Flywheel - Mazda 6 Forums : Mazda 6 Forum / Mazda Atenza Forum

Then I found this article on ebay:
DMF flywheels and converting to Solid mass flywheels | eBay

So now I want me some single mass flywheel! And I'm wondering if anyone here has done the conversion to SMF and what aftermarket flywheel and clutch kit to install if I decide to do get it done.
 

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Will you be ok with greater NVH? Does the accord transmission rattle with a single mass flywheel? I don't know but it's a problem with other cars when they switch to single mass. You can also hurt performance by lighting the flywheel to much.
 

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Honda Buff
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I finally narrowed down the "problem" I'm having with my MT to OEM dual mass flywheel. This being my first DMF car I thought there was something wrong with the car but apparently it's just the way they build MTs these days.
Exactly what problem are you having with your dual mass flywheel? I ask because while I admit that I haven't read the entire Mazda 6 thread you linked, the very first thing he complains about is clutch engagement feel/repeatability. Have you removed the clutch slave cylinder check valve yet? This change alone makes a world of difference in the clutch feel and takeup.
 
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Discussion Starter · #5 ·
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Will you be ok with greater NVH? Does the accord transmission rattle with a single mass flywheel? I don't know but it's a problem with other cars when they switch to single mass. You can also hurt performance by lighting the flywheel to much.
Well, I don't know, that's why I'm asking. It'd be nice to get a lighter flywheel but my main objective is replacing DMF with a SMF.


Exactly what problem are you having with your dual mass flywheel? I ask because while I admit that I haven't read the entire Mazda 6 thread you linked, the very first thing he complains about is clutch engagement feel/repeatability. Have you removed the clutch slave cylinder check valve yet? This change alone makes a world of difference in the clutch feel and takeup.
Is check valve and clutch delay valve the same thing? Mine is an I4, I know I4s don't have a clutch delay valve so unless a check valve is something different I don't think my car has it. The problem I'm having is exactly as described in the first post in that mazda thread: slow shifts, slow uptake, vague engagement etc..
 

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7th Gear
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Is check valve and clutch delay valve the same thing? Mine is an I4, I know I4s don't have a clutch delay valve so unless a check valve is something different I don't think my car has it. The problem I'm having is exactly as described in the first post in that mazda thread: slow shifts, slow uptake, vague engagement etc..
Uh... I'm pretty sure it does. Looking forward to removing mine sometime this summer.
 

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It's not a "check" valve, it's a "restrictor" valve, so "delay" is the function it serves.

"Slow shifts, slow uptake, vague engagement" are symptoms the restrictor valve causes.

FWIW, there isn't these problems when the valve is new, there is a small wire mesh filter screen inside the valve, part of the problem is when gunk gets caught up on this screen which then causes even more delay and inconsistency.

How do I know this? When I attempted to remove the restrictor valve on the original clutch slave cylinder, the corroded end cap and retaining ring fused into the end cap prevented me from getting it done, however I back flushed the valve and saw some gunk come out before I put the old slave valve back in while ordering a new slave cylinder.

For the next week and half while I waited for the new slave cylinder to come in, the clutch acted completely normal! No noticeable delay, no inconsistency, it was surreal to suddenly have "normal" clutch feel without removing the restrictor valve.

So the only conclusion is the gunk caught on the filter screen was causing the erratic behavior.

At the end I removed the restrictor valve from the new slave cylinder to install on the car, as I knew the vagueness and inconsistency would return if I left the restrictor valve in there.

I would suggest you take out the slave cylinder and flush the line and the cylinder, put it back, bleed the system and try it out for a while to see if you notice any difference.
 

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Yeah, did the 7th gen I4 MT's have the slave delay valve? I thought they started that later.
 

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It's not a "check" valve, it's a "restrictor" valve, so "delay" is the function it serves.
Yes, you're right. It is a restrictor. But it only restricts in one direction, so it is also a type of "check" valve. It allows the clutch to disengage quickly, but slows the engagement of the clutch.

I'm pretty sure this valve's true purpose is for warranty mitigation. It slows the engagement of the clutch, which causes more clutch slippage and less shock to the drivetrain. Thus, it causes more wear on the clutch (a normal "wear" that isn't covered by the warranty) to protect the drivetrain (which IS covered by the warranty).
 

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Yeah, did the 7th gen I4 MT's have the slave delay valve? I thought they started that later.
I looked at the workshop manual for my 03 Coupe I4M5, and it seems (????) to be an ordinary slave without a restrictor.

Do we know when this started being used?
 

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Discussion Starter · #11 ·
I looked at the workshop manual for my 03 Coupe I4M5, and it seems (????) to be an ordinary slave without a restrictor.

Do we know when this started being used?
My guess is 7th gen V6s and 8th gen I4s, based purely on different threads I read about it.
Do you have any issues with clutch engagement on your I4?
 

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My guess is 7th gen V6s and 8th gen I4s, based purely on different threads I read about it.
Do you have any issues with clutch engagement on your I4?
Thanks.

My clutch engagement is sweet.

I did my first brake fluid flush for the clutch hydraulics about a year ago, so 12 years on the factory fill. It was small but the clutch pedal was a bit smoother, but engagement and disengagement were unaffected.

I'm pretty easy on clutches having owned a few of those ultra fragile British sports cars in my youth.
 
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