[IDBMW]

Originally Posted by Bizall

Couldn't you just drill out the inside of the CDV to make it larger like the aftermarket ones? Cheaper and it couldn't be detected by the dealer unless they took it off and looked in it. Sounds like another alternative.

This is what Zeckhausen Racing says about the CDV on why you should not drill them out. However, our is different but for $30 I would buy one from someone that machined it out instead of me with a vise and drill.

"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."