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Thread: VVL: how it works

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Posts: 1-10 of 12
2013-05-15 01:05:35
VVL: how it works
At the heart of the vvl system is the rocker arm assembly. The shaft mounted finger follower rocker arm has three rocker arms and the middle RA(rocker arm) is independent from the two outer RAs. It's able to freely move relative to the outer RAs. Middle RA movement is control by the big high cam.

During low rpm operation, when the vvl solenoids are off, no oil pressure to the piston in the RA, the middle RA is free to move up and down without affecting the two outer RAs. The middle RA is only pushing down on the lost motion spring underneath it.

During high rpm, when the vvl solenoids are triggered, oil pressure will push the rocker arm piston out against what I like to call the RALP (rocker arm latch pad). The RALP will slide underneath the middle RA when the big cam is on its base circle (0 lift). Now, the middle RA will take over the outer RAs. An analogy would be a person standing 5 feet away from the door and trying to open it. They can't open the door because their arms are too short. But if that person was given a 3 foot long pole (don't worry about the pole length, lol) they can now open the door. Think of the RALP as the pole.

Obviously, pictures are better than words. Enjoy.

Exploded view

The electrical triggers/solenoids and solenoid housing oil circuit.

Last edited by KillerKrossover on 2013-06-19 at 18-35-25. Reason: supplement
2013-05-15 04:55:59
is there any video of how it works?

2013-05-15 09:56:06
Pretty solid explanation and great pics, nice one!
2013-05-15 11:44:54
now that we have an understanding.... how do we modify to attain 14+mm lift sir
2013-05-15 12:06:31
Originally Posted by datsun_sky
is there any video of how it works?


2013-05-15 19:02:37
Originally Posted by sss4me

LOL, come on, not even close to what I showed, wrong VVL. Did you even look at the video?

Originally Posted by blo0d
now that we have an understanding.... how do we modify to attain 14+mm lift sir

For 14 plus mm lift, lose the middle rocker arm, basically a VVL killer setup. The middle RA pivot point gets in the way of the big lift lobe. Apparently the middle RA is also the weak link in whole rocker arm assembly. There are pics over-revved engines, and they showed the middle RA snapped in half.

Under 14mm lift, like say 13.5mm, get a smaller base circle cam. That way you can still run VVL.
2013-05-16 01:40:42
like this

2013-05-16 03:25:21
i seen one great video

2013-05-17 03:29:08
5speed, good job. Love this kind of stuff. Vadim or Benfenner, gotta make this one a sticky. Manifesto worthy no doubt.
2013-12-09 09:40:33
I have a question on this, maybe somebody can help me.
During a regular check up I found out that from 1 intake rocker arm the lost motion spring was stuck. The middle rocker arm wasn't pushed against the rocker. I fixed it and there was no further damage. The engine was running fine, hadn't noticed it.
Does this mean that the VVL for this intake lobe wasn't engaged? Thanks!
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