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16th May 2007, 20:57 | #11 |
This is my second home
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16th May 2007, 21:21 | #12 |
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That manifold on the BBA site looks totally different to the usual KV6 manifold
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16th May 2007, 21:38 | #13 |
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16th May 2007, 21:39 | #14 |
This is my second home
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16th May 2007, 21:55 | #15 |
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Bernard they are just plain hideous inside.
first they get full of oil residue from the recirc system this coats the plastic butterfly valves and the ball joints they have which connects them to the single operating rod Then over time you have a combination of the oil and carbon deposits plus heat effectively making a grinding paste this wears down the ball joints and rod cups allowing slight movement of each butterfly hence they probably don't all then close properly meanwhile the butterfly spindles are also wearing, again causing the butterfly valves to move about and probably not seal. Eventually the ball and cups wear to the point the rod starts to fall off the butterfly and that is when you begin to hear the infamous rattle. Finally if really unlucky the valve due to worn spindles etc can jam causing the ball and cup to break The working parts in these things are formed from solid plastic seamingly moulded in situ you can't for example remove the six butterfly's without destroying them. Horrid piece of engineering I would like to know the BBA process but having read all the posts on XPF on this I am not convinced they are doing what needs to be done i.e replacing the butterflys spindles and operating rod in their entirity as that is the only way to to do it imho You can pull a heat melted access panel off the unit and inspect it but to repair one needs better access or CNC tooling to be able to accurately drill the spindles through the body then repair and plug the holes If I was still working at GEC I could do it but sourcing the right material and making the valves would be tricky any heat expansion problems would cause seizures etc |
16th May 2007, 22:22 | #16 | |
I really should get out more.......
75 V6 Saloon 2003 LPG MGZT V8 260 LPG Join Date: Dec 2006
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Quote:
Surely the action of these valves does not need to be leakproof so they could be designed with sufficient clearance. Or would the air whistle when passing through a very small gap? Although thinking about it, the coefficient of expansion of the plastics material is probably greater than any metal parts. Definitely got my attention now, thought that I had outgrown rising to a challenge. But I'm keeping my car for many years and it's bound to happen. A pal has one showing faulty VIS, perhaps we'll rip his apart 'cos there's a buyer for the one on the forecourt and there won't be time to play. Last edited by Bernard LPG; 16th May 2007 at 22:24.. Reason: typo |
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16th May 2007, 22:35 | #17 |
This is my second home
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Don't get muddled a faulty vis on T4 is vis motor generated now these you can fix easily I did one for Mike last night hour and a half tops
and yes I think either the butteflys or the balance valve must be fully closed in operation otherwise the different tuned lengths of the inlet will be comprimised Lates posted lots of pics of the one he pulled apart and then sent it to me so he probably will stick em here shortly Unfortunately Swmbo binned it thinking it was junk before I had a chance to get really stuck in but I had stored in my garage bin as it was very oily |
16th May 2007, 22:57 | #18 |
I really should get out more.......
75 V6 Saloon 2003 LPG MGZT V8 260 LPG Join Date: Dec 2006
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No, it's OK, I'm not confused about the faults. It's just that it gives me an excuse to get him to rip it all apart!
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17th May 2007, 09:01 | #19 |
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Bernard - there have been photos of the wear elsewhere on this site and there are some in MG Enthusiast a couple of issues ago when I wrote about changing my VIS over.
Keith - has anyone found out yet what Nanjing are fitting to their new ZTs? I asked Rog this a while ago after his trip to China for the launch, but at that stage he had no information. After splitting my old VIS apart to see what went wrong, it definitely needs new butterfly assemblies and more effective ball joints before it could be used again. Even just getting these parts would be helpful. |
17th May 2007, 10:04 | #20 |
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I know the Chinese KV6 is Euro 4 compliant but whether that means they have reworked the manifold is unknown.
Chances are it is on the to do list unless they have been able to buy them in at radically reduced prices as over there they can probably build a whole car for £600! but I guess the current parts bin cars we have seen use standard parts. Maybe just Maybe theirs will be better than the original but will it be available or even interchangeable who knows, sods law says it won't be. Or by the time X-Part get them here for distribution they price will be just as silly It is a lot of money to pay for a badly designed self destructing bit of plastic isn't it! |
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