Go Back   The 75 and ZT Owners Club Forums > The 75 and ZT Owners Club Forums > Technical Help Forum
Register FAQ Image Gallery Members List Calendar Mark Forums Read
Notices

Reply
 
Thread Tools Display Modes
Old 16th May 2007, 20:57   #11
Lates
This is my second home
 
Jaguar XE

Join Date: Nov 2006
Location: Coventry
Posts: 4,321
Thanks: 56
Thanked 59 Times in 55 Posts
Default

Quote:
Originally Posted by Bernard LPG View Post
However, we have a 75 for sale at the moment that needs HG fix so I may get a look at the manifold when it comes off.
Details please, pre repair of course
Lates is offline   Reply With Quote
Old 16th May 2007, 21:21   #12
Tatts
This is my second home
 
MG6 TL

Join Date: Nov 2006
Location: Tarn
Posts: 5,269
Thanks: 2
Thanked 46 Times in 37 Posts
Default

That manifold on the BBA site looks totally different to the usual KV6 manifold
Tatts is offline   Reply With Quote
Old 16th May 2007, 21:38   #13
Simon
Banned
 
-

Join Date: Nov 2006
Location: -
Posts: 10,318
Thanks: 0
Thanked 4 Times in 3 Posts
Default

Quote:
Originally Posted by Tatts View Post
That manifold on the BBA site looks totally different to the usual KV6 manifold
It's upside down and back to front...
Simon is offline   Reply With Quote
Old 16th May 2007, 21:39   #14
Tatts
This is my second home
 
MG6 TL

Join Date: Nov 2006
Location: Tarn
Posts: 5,269
Thanks: 2
Thanked 46 Times in 37 Posts
Default

Quote:
Originally Posted by Simon D View Post
It's upside down and back to front...

Ahhhhhh............. that'll be why then!
Tatts is offline   Reply With Quote
Old 16th May 2007, 21:55   #15
Keith
This is my second home
 
ZT400

Join Date: Oct 2006
Location: Ellesmere
Posts: 5,948
Thanks: 0
Thanked 43 Times in 29 Posts
Default

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
Keith is offline   Reply With Quote
Old 16th May 2007, 22:22   #16
Bernard LPG
I really should get out more.......
 
75 V6 Saloon 2003 LPG MGZT V8 260 LPG

Join Date: Dec 2006
Location: Evesham
Posts: 2,134
Thanks: 0
Thanked 1 Time in 1 Post
Default

Quote:
Originally Posted by Keith View Post

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
Keith, machining etc. not a problem, remember I'm a CNC and Robotics Engineer really and still keep my hand in, but not in the sense of being a gynaecologist.

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
Bernard LPG is offline   Reply With Quote
Old 16th May 2007, 22:35   #17
Keith
This is my second home
 
ZT400

Join Date: Oct 2006
Location: Ellesmere
Posts: 5,948
Thanks: 0
Thanked 43 Times in 29 Posts
Default

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
Keith is offline   Reply With Quote
Old 16th May 2007, 22:57   #18
Bernard LPG
I really should get out more.......
 
75 V6 Saloon 2003 LPG MGZT V8 260 LPG

Join Date: Dec 2006
Location: Evesham
Posts: 2,134
Thanks: 0
Thanked 1 Time in 1 Post
Default

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!
Bernard LPG is offline   Reply With Quote
Old 17th May 2007, 09:01   #19
Malcolmr
Regular poster
 
MG ZT-T

Join Date: Dec 2006
Location: Canberra
Posts: 44
Thanks: 3
Thanked 0 Times in 0 Posts
Default

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.
Malcolmr is offline   Reply With Quote
Old 17th May 2007, 10:04   #20
Keith
This is my second home
 
ZT400

Join Date: Oct 2006
Location: Ellesmere
Posts: 5,948
Thanks: 0
Thanked 43 Times in 29 Posts
Default

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!
Keith is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 12:21.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright © 2006-2023, The Rover 75 & MG ZT Owners Club Ltd