I got my M54b30 cams this week. I'll get one setup on my bench and measure it. the intake definitely looks like it's easily got the 240º duration with the way the lobe looks; The lobe is fat and the peak is rounded/fat too. The lift is 9.7mm (as measured with a mic).
The exhaust looks way different. The peak is pretty sharp but with close inspection of the profile it looks like the ramp is way more gradual. That could account for the long advertised duration (244º). With my old school engine builder eye, at face value it looks shorter due to the width of the peak but it could be that this profile is optimized for exhaust and manipulation by the vanos.
I'm planning on adapting both of these cams to the M52b28 I've got. The intake is an easy swap; Most cut the splined cog for this so it's flush with the top of the fastener, around 4-5mm. Since that surface (the outer face of the splined vanos/cam register) is not used, pretty much anybody with a cut-off wheel can cut this as long as they can get close.
One thought I had was to use the M54 vanos hub to build a sort of manually adjustable exhaust advance off the front of the exhaust side. Then I may be able to dial in the exhaust cam advance/retard for optimal power and usability. The challenge there would be to build something that would last. On the other hand, I may just weld it in at roughly neutral and call it good.
Once I get the exhaust cam benched out I'll post the results. |