VVC Bearing removal

[Old gh bug]

Has anyone separated the bearing from the drive of the cam , I was wondering which way to it comes off?

[Rob Bell]

I reckon it needs pulling out...

[Tipper]

Is there a bearing?
I ask because most if not all camshaft related bearing surfaces are the alloy of the head and camshaft carrier.
I've not looked at any exploded diagrams, just going from experience of dismantling and reassembling the camshafts and VVC bits.

[Rob Bell]

Absolutely, yes: not for the cams themselves, which like the standard K16, are within the cam ladder in the cylinder head, but within the VVC mechanisms (a gearbox of sorts) at each end of the cylinder head, controlling both pairs of inlet cams. Here's the picture of the SKF manufactured bearing mentioned earlier in the thread:

[Tipper]

Ah yes, I see it now!

My understanding of the 'tappety' VVC gear is that it is wearing of the little square block cam sliders that are the noisy bits due to the increased clearances created.
I believe that on original assembly the block sizes are selected for the best fit. Once a few thousand miles has been run the blocks wear and hence the noise.

[Old gh bug]

Interesting about the block wear, does anyone know what tolerance there is on them i:e how many thou gap they have when new ?

[Rob Bell]

I went with "no palpable play"

[Old gh bug]

Hmm ,,,,
Well I have two spare sets let’s see if I can get a good set built

[Rob Bell]

Does anyone know what "A", "D" and "G" signify? See block carriers below:





I wonder whether they relate to the dimensions of the block channels? (I don't recall this being mentioned in the K16 workshop manual, but I may have missed it)

[Old gh bug]

I have an A and a B on mine ??

[Tipper]

I have seen some posts on rebuilding the mechanisms and block selection/sizes in the past. I'll see if I can find the links.
Edit: sorry my bookmarks no longer work so I suppose the webpages are no longer maintained.

[Countax]

This may help.
https://wiki.seloc.org/a/VVC_Informatio ... Strip_down

However, i fear you may have already gone too far if you have not marked the position of each part as it was removed, including the orientation of the blocks. I had tappet noises that made mine sound like a diesel and tried everything to cure it including buying new VVC mechanisms from Mike Satur. I spent a lot of money trying to solve it, but never did and i never found anyone on the forums who had also managed to stop the tapping sounds. I even replaced the entire head and that still did not fix it so in the end i concluded i was not getting sufficient oil pressure or flow up to the head even though it seemed ok when measured at the filter sensors. Finally i scrapped the block and fitted a replacement engine. Problem solved !
The blocks have incredibly tight tolerances and must go back in the same orientation.
Nigel

[Rob Bell]

The workshop manual is very clear that the VVC mechanism should never be disturbed, and the reason for that is exactly as you say Nigel - these components are very tightly toleranced. There is a tool to facilitate the removal of these mechanisms from the without risk of the gearset falling out (yup, that happened to mine). In my case, the mechanisms were excessively noisy anyway, so I don't think I've lost anything here, so long as the system runs smoothly. I'll guess I'll find out how badly this has gone when the engine is rebuilt and fired up for the first time!

Was your original problem piston slap Nigel?

I have seen some posts on rebuilding the mechanisms and block selection/sizes in the past. I'll see if I can find the links.

That'd be really helpful, thanks!

[Old gh bug]

I’m with Rob on this one as well, I’ve nothing too loose , and I’m not sure what all the hidden secrets are about taking them apart.

It would be nice to know the tolerance for them .

I will rebuild the ones I have and try them.

[mgtfnut]

I looked for a TF 135 over a VVC, as although technically brilliant, it looked a nightmare to attend to if needed.

You have to admire the design and precision when conceived. The extra power is mostly gained at revs not really suited to general road use for me Mapping for a bit more mid range torque is what I went for in the end.

Good luck with the build - pity a PTP person can't pop up and advise.

[Rob Bell]

Having a PTP person would be great, I agree Jerry!

The genius of the VVC (and it is genius) is how the torque and power is optimised throughout the rev range. At its most simple, the VVC head is simply a big valve, big port design. Usually this gives you top end power, but at the expense of low-end/ mid-range torque.

There is no doubt that the VVC gives you the top end: 145 - 160PS depending on tune, but there is literally no sacrifice in terms of torque to the "standard" K16 engine. That's the real trick. It's so good, you don't notice it; there's simply no crude power or torque step in the delivery.

Hats off to the engineering team: a quarter of a century on and the system has proven bullet proof

[Tipper]

I have seen some posts on rebuilding the mechanisms and block selection/sizes in the past. I'll see if I can find the links.

That'd be really helpful, thanks!

Sorry my bookmarks no longer work so I suppose the webpages are no longer maintained.

[Rob Bell]

Which forum was it on? Post the link if you can, and I may be able to work it out