clutch unlock valve?
04-05-2009 | 04:45 PM
#3
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My Ride: 2006 550i sport package, manual, black on black w/ anthracite trim, pdc, logic 7, cold weather pkg.
Originally Posted by ADD' post='837226' date='Apr 5 2009, 05:57 PM
Do you mean what BMW calls the "Lock Valve"?
Or commonly referred to as a CDV (Clutch Delay Valve)?
Or commonly referred to as a CDV (Clutch Delay Valve)?
04-05-2009 | 05:50 PM
#4
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From: Originally from Koeln, Deutschland. Enjoying it in Bonita Springs, Florida Now :)
I talked to a BMW tech who had a similar valve and he told me that his clutch basically exploded.
The lock valve prevents you from absolutely killing your clutch...I would leave it in.
The lock valve prevents you from absolutely killing your clutch...I would leave it in.
04-05-2009 | 06:08 PM
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From: Originally from Koeln, Deutschland. Enjoying it in Bonita Springs, Florida Now :)
Originally Posted by dusandimic' post='837323' date='Apr 5 2009, 09:04 PM
i was about to order one until you just scared the sh-t out of me.
Exploded huh?
Exploded huh?
04-05-2009 | 06:11 PM
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Originally Posted by dusandimic' post='837323' date='Apr 5 2009, 08:04 PM
i was about to order one until you just scared the sh-t out of me.
Exploded huh?
Exploded huh?
Te following was taken from http://zeckhausenracing.com/
Problems shifting your BMW E60 5-Series?
Many models of BMWs with 5-speed or 6-speed manual transmissions have a Clutch Delay Valve (CDV) installed by the factory. This valve is the culprit behind the jerky shifting that makes your BMW hard to drive, even if you have been driving a standard transmission all your life. When replaced with the Zeckhausen Racing modified CDV, your clutch is suddenly transformed into the smooth, easy to modulate clutch that should have been delivered from the factory as standard. Extend the life of your clutch and increase the enjoyment of your BMW driving experience today!
Theory of Operation - What is a CDV?
The Clutch Delay Valve (CDV) is a one-way restrictor installed by the factory between the clutch slave cylinder and clutch master cylinder, as shown in Figure 1. It "delays" the engagement of the clutch, much like old record players used a damped tone-arm to gently lower the needle onto the surface of a record.
Because of this valve, no matter how quickly you lift your foot off the clutch pedal, the clutch engages the flywheel at a constant (slow) rate. In theory, it can save the driveline from shock, were an inexperienced (or immature) driver to dump the clutch at high RPM. But in practice, all it does is prematurely wear out the clutch and turn experienced drivers into people who, despite 20 years of practice, cannot shift gears smoothly. During parallel parking maneuvers, the delay can be infuriating, causing constant clutch slippage. And during hard acceleration, the large amount of clutch slippage can greatly shorten the life of your clutch. During normal, sedate driving, the shift from first into second gear is often jerky, leading passengers to question your skill. As the driver, you can see your passengers' heads bobbing back and forth during every shift! Yes, in their minds, they are laughing at you.
Interestingly, BMW did not install a CDV on the E39 M5. The terrible shifting behavior would be unacceptable to these high performance customers. For some reason, BMW does not seem to think the rest of their 3-Series & M3, 5-Series, 6-Series, X3, X5, Z3, Z4 and Z8 customers who shift their own gears will notice. They were very wrong!
Since BMW models have different clutches, they have different CDVs with different valve openings and springs. In order to reduce the odds of a factory worker installing the wrong part on the assembly line, each CDV has a different number of ribs and may even have a different barrel shape. (See Figures 3 & 4 below) The effect on all of these cars is the same. The driving experience is degraded.
The solution is to replace* the CDV with a modified valve which has had the interior parts carefully removed. We do not drill these valves. Drilling will damage the taper at both ends of the valve. The male tapered end seals against the female taper of the clutch slave cylinder. And the male hydraulic fitting seals against the CDV's tapered seat at the female end. It does not seal via the threads. Drilling a CDV may cause it to leak under pressure and leave bits of valve material behind, potentially migrating into and damaging the clutch hydraulics.
We have developed a technique for removing the interior valve and spring without damaging the delicate tapered seat at the female end and without touching the taper on the male end. Zeckhausen Racing provides a free service to modify CDVs which are mailed to us. Click here for details.
Benefits of replacing your CDV with a modified unit
After the stock CDV is replaced with one of our modified units, you will be able to shift gears in your BMW just like a "normal" car. No more vague, inconsistent clutch engagement. No more jerky 1-2 shifts. You can actually chirp the tires when shifting from 1st to 2nd gear! Parallel parking becomes a breeze and your clutch will love you for it and last much longer. Best of all, your passengers will stop making fun of your driving skills.
04-06-2009 | 05:03 AM
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From: Originally from Koeln, Deutschland. Enjoying it in Bonita Springs, Florida Now :)
Originally Posted by dbpack' post='837490' date='Apr 6 2009, 12:07 AM
Remove the CDV. It makes a noticeable difference. Your clutch won't explode...that's ridiculous.