Camshaft dual pattern, higher lift or extended duration?

[ReverendZ]

After all of my troubles that have since been ironed out I still get follower noise or something on cold starts. I have been looking g at the variable profile camshaft and am curious to whether it is truly higher lift or an extended duration in design. Looking at the pictures the base profile of the low lift side is a quick ramp short duration type which is expected for smooth idle, the other ramp seems to extend the profile longer but is it more lift on the valves? I am just positing this question as a point of discussion and to better understand the engineering behind the design as it relates to valve timing and performance. I do have a basic understanding of VVT systems in relation to opening closing events and their effects on power output. Idle thoughts in the sunshine...

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[TheRealStreetcommander]

With the original factory fill at ~1200 miles, I too get some minor clatter on cold start-up. Maybe .75-1.25 seconds. To me, it sounds like chain/guide or maybe phaser noise, perhaps from tensioners or phasers having at least partially drained over night. After that initial cold start, it won’t do it again. I’ll be transitioning to Rotella T6 for my first OC. We’ll see what if any effect the T6 has on this.

As for the big lobe, yes, as near as I can see, the big lobe increases duration and effective lift. I haven’t personally measured the lift, but it would seem the big lobes smaller base circle and perhaps the follower geometry and fulcrum point is what creates the added lift. I also agree, to my eyes it looks like the big lobe’s lift is dimensionally shorter than the small lobes.

Maybe it’s the era I grew up in, but darn I wish the lobe transition made the same noticeable sound and power difference the first generation Honda B-series VTEC did.