Clutch delay valve

Perhaps that's the difference.. There is no restriction in any direction on the one I removed yesterday ?

Meaning..... if the valve had failed totally,then the shifts would be noticably worse than a car that had an operating valve ???


Perhaps thats why some people feel a huge difference and some feel next to none?
 
That's an interesting theory - if the valve has failed, but not been removed, you could experience variable clutch feel / operaton / response, right ? Is the valve itself made of a material that can deteriorate ?
 
It is not a valve, it is a piece of metal causing an obstruction. No way that can fall out either.

If it is not there, it has just been removed already.
 
PVR..

Are you suggesting its just a hole bored through the metal?

Looking at a post Schutch posted, he has sketched how there is an insert fitted that acts as a valve within the CDV body ?
 
No, it is a piece of metal inserted in there. As per Steve's post it takes some effort to hammer it out and no way that can happen by itself.

I just bought pre removed units from zeckhausen.
 
A piece of metal in the shape of a valve or just a reducer?

If it is a valve in any way it has a capacity to fail.. It doesn't have to fall out totally
 
Yea...

It just got the better of my curiosity and I have taken the one off my Z apart this mornin..

I fail to see how it restricts only one way, it a hole...
 
Is there a decent how to on here for removing the CDV? Assuming you can clamp the hose like you would with brakes to avoid having to fully bleed?
 
It really is simple..

Clamp hose.. Undo 11mm union on slave cylinder pipe, then undo CDV out of flexi (2x17mm) spanners.

Reassemble pipe directly into flexi through holding bracket. Unclamp hose...If you then open the nipple on sale cylinder you can gravity bleed the system..
 
Z4M-2006 said:
Yea...

It just got the better of my curiosity and I have taken the one off my Z apart this mornin..

I fail to see how it restricts only one way, it a hole...
Click to expand...

You only had to look at my old thread :poke:

http://www.z4-forum.com/forum/viewtopic.php?f=25&t=1227

cdv1.jpg
 
Actually, I can see how that would restrict flow in one direction more than the other, but it will restrict flow in both directions. Might have mine removed - just to wind up PVR :D
 
Just remember that the M has a protective plate over the CDV unlike the lesser powered models.
 
Neither of my M cars have had any plate over the CDV's..

Srhutch..... So there is a hydraulic operated piston in there ?

So there is moving parts ??? So is PVR wrong then ?
 
Well, it sounds like someone has there before then :)

It has a plate you have to remove to be able to get to the CDV on the M.

That bit from SRHutch's picture is showing the fixed obstruction that he hammered out, it is not a piston, it is a fixed bit of metal.
 
This write up i did back when i had my E46 330 may be useful to some, though by the sound of it the M has a slightly different version of CDV.

http://www.e46zone.com/forum/topic/2064-cdv-diy/

As you can see from some of the pics the one on the E46 330 was just a hole, nothing else in there that i can remember. The zachusen replacement just had a larger hole.
 
Thats what i thought PVR........So would you say that it restricts fluid on downstroke and upstroke???

But in Srhutch's description he says its a piston that moves under hydraulic pressure...

"When you depress the clutch the piston (C) moves towards the insert (B) due to hydraulic pressure which allow hydraulic fluid around the piston due to its design, when you remove your foot from the clutch the hydraulic pressure forces the piston back which forces the hydraulic fluid through the 1.5mm diameter hole. There is no spring in the valve; the force of the hydraulic fluid alone moves the piston to its required position.

The insert does two jobs, to retain the piston, and locate and seal the rigid hydraulic pipe. As it located on a step when the insert is refitted it will be in its original location. The insert is retained only by the slight interference fit with the body so is easily removed and reinserted. The slight interference is confirmed by the fact the piston has retained most of its shape after removal, if this had required a lot of force the piston would be have deformed more before the insert was removed and would probably be flat."




Oh.... I doubt that both of my M cars would have the protection plate removed?? Both have never had clutches and both the CDV's where intact.. I cant think what other job you would be in that area for.....Suggestions?
 
pvr said:
Well, it sounds like someone has there before then :)

It has a plate you have to remove to be able to get to the CDV on the M.

That bit from SRHutch's picture is showing the fixed obstruction that he hammered out, it is not a piston, it is a fixed bit of metal.
Click to expand...

PVR, it's not fixed, it moves a little.

The flow is restricted one way because when you put your foot on the clutch the bit moves allowing flow around the edge as well as through the hole. However when you release the clutch the bit is pushed back restricting flow through the hole only.
 
I've had my M for 5yrs now and I've never felt the need to remove this. The first couple of weeks of driving was a bit hit and miss with the clutch biting point but it's been fine ever since :driving:
 
Just do it. Worked a treat on my M.
Don't recall one single comment that removing makes things worse, by far the majority of forum comments appear to be positive tho a few report no change.
If your current gear change is crappy then why not do this cheap mod? You have nothing to lose.
Let us know how you get on.



Silver grey Z4MC
Mods: Strongstrut 3 piece / CDV delete / Stormworks ST1 gearknob / clutch stop / stubby / ipod integration / LED interior / Magnaflow custom exhaust
 
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