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weirdbeardmt

Active Member
Hi

The engine / exhaust is very rattly on tick over. Have been reading through some of the threads here and it seems most likely it's the inlet manifold [chamber] issue. If I understand correctly, over time some little movable gubbins within it start to move more than it should and hence starts to rattle.

A few questions:

1) What happens if you don't fix it? Will it cause any damage?
2) Would this fault cause the feeling of loss of power?
3) How do you go about buying one... since most are from breaking vehicles, how do you ensure you don't just get a replacement with exactly the same problem? I've tried to find refurbished ones but not having much joy and had a look on Famous Four but they only seem to have new / ultra punchy ones.

Have been looking at ebay... you can get some ridiculously cheap ones - about £20 : Genuine OEM,Rover 200 25 400 45 75 MG MGF TF ZR ZS New Inlet Manifold. LKB106330 | eBay

You can get some more expensive ones with new VIS gubbins as well: ROVER 75 & MG ZT 2.0/2.5 KV6 INLET MANIFOLD COMPLETE WITH VIS MOTORS ,FREELANDER | eBay

Or you can get some insanely expensive (new?) ones: Rover 75 2.5 Upper Inlet Air Intake Manifold Genuine OE Engine Replacement | eBay

So what's the best approach to getting it?

Thanks!
 
Question 1. Yes I've seen a broken flap valve break up and get into the engine, this bent an inlet valve and damaged the piston. So yes after a while it can or at least might cause engine damage.
Question 2 Yes the loss of the power valves will cause a reduction in torque, something like 30 ftlb at 2500 rpm and varering losses above that engine speed. You fuel consumption will increase too.
Question 3 Second hand they are a gamble. I've seen them for about £450 new, this is the only way to guarantee a working replacement.
Good luck.
 
Nodge68 said:
Question 1. Yes I've seen a broken flap valve break up and get into the engine, this bent an inlet valve and damaged the piston. So yes after a while it can or at least might cause engine damage.
Question 2 Yes the loss of the power valves will cause a reduction in torque, something like 30 ftlb at 2500 rpm and varering losses above that engine speed. You fuel consumption will increase too.
Question 3 Second hand they are a gamble. I've seen them for about £450 new, this is the only way to guarantee a working replacement.
Good luck.
Click to expand...

Hi Nodge... sorry, missed your reply. Thanks for the comments.

I'm not sure what to do now and I'm getting confused as to where the fault lies - most of the talk seems to be surrounding some black plastic butterfly valves, whereas all a lot of the inlet manifold replacements I'm seeing are metal. According to wiki the KV6 engine was changed from metal to plastic, around 99 so I would assume by 2003 V6 has plastic manifolds? Doing more reading seems there are upper and lower manifolds.

Have read through this http://www.landyzone.co.uk/lz/f9/v6-inlet-manifold-rattle-24606.html which seems to be the master thread on the topic... can you shed a bit more light on what Phil004's advice was? i.e., exactly which bits do i need to get?

I know I'm being a nuisance, but I'd like to get the parts here in advance of the long weekend (couple of days' delivery here at least) but can't go and look in the car due to being at work :S so any advice gratefully received... !
 
I seem to recall when I put the diagnostic tool on it that there was an error relating to VIS motor stuck open.. I will probably run through the details in the VIS_Motors pdf and check for some of those signs.
 
weirdbeardmt said:
I seem to recall when I put the diagnostic tool on it that there was an error relating to VIS motor stuck open.. I will probably run through the details in the VIS_Motors pdf and check for some of those signs.
Click to expand...

If you read the posts I highlighted from the Rover 75 boards, there is lots there to make your own decision. Both use the same plastic manifold.
 
zefrench said:
If you read the posts I highlighted from the Rover 75 boards, there is lots there to make your own decision. Both use the same plastic manifold.
Click to expand...

hi, thanks... have been doing so all morning. (don't tell my boss.) have found a number of threads that sort of all point to my problem. and it sounds like either

a) one or both of the VIS Motors are faulty and rattling, and/or
b) the butterfly valve in the manifold is faulty and rattling.

the bit i was losing the plot with is... where do these bits actually sit. Although I did get a bit confused when it seemed to suggest that having the VIS motors working properly was good for an extra 20hp... but then there were threads talking about taking them out!!
 
There are 2 VIS motors. One is for the balance valve and the other controls the power valves.
Both motors are susceptible to oil ingress. This causes the motors to be overloaded, this then burns out the circuit board. The limit switchs also break loose which confuses the ECU.
The balance valve it's self seldom gives trouble.
The power valves are the ones that make all the noise. They are operated by a plastic linkage with ball joints at the flap valve flap ends. These ball joints wear and eventually drop apart causing the value flap to flop about uncontrolled. This is what you hear.
The whole assembly is a throw away unit but the motors are available separately. The motors are also home repairable, I've fixed many over the years.
Once fixed, I drill a 0.5 mm hole in the motor casing. This hole keeps the motor at a higher pressure than the manifold, this keeps the oil out.
The earlier metal plenum chamber was changed when the KV6 got a redesign. It can be made to fit the late engines but the manifolds need modification as does the wiring.

Power wise, the balance and power wise work together to boost torque at key points in the rev range. From what I've seen on the rollers, you can loose 30+ ftlb of torque at 3400 rpm and around the same at 5500 rpm. This would equate something like 30 bhp at hi revs. There is also an increase in fuel consumption as a result of the loss of torque.
 
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Nodge68 said:
There are 2 VIS motors. One is for the balance valve and the other controls the power valves.
Both motors are susceptible to oil ingress. This causes the motors to be overloaded, this then burns out the circuit board. The limit switchs also break loose which confuses the ECU.
The balance valve it's self seldom gives trouble.
The power valves are the ones that make all the noise. They are operated by a plastic linkage with ball joints at the flap valve flap ends. These ball joints wear and eventually drop apart causing the value flap to flop about uncontrolled. This is what you hear.
The whole assembly is a throw away unit but the motors are available separately. The motors are also home repairable, I've fixed many over the years.
Once fixed, I drill a 0.5 mm hole in the motor casing. This hole keeps the motor at a higher pressure than the manifold, this keeps the oil out.
Click to expand...

thanks. slowly getting to grips with this. my plan now is to pull it all apart over the weekend and see what's what. was just toying with trying to get some new (secondhand) VIS motors or indeed inlet manifold and gaskets here in advance. would do that if i could get guaranteed working cheap ish 2nd hand parts... but again, there's not much about that I can find. I can't find new ones that are cheap enough to warrant it.
 
There's no need to gor any gaskets to remove the plenum chamber. It's sealed with rubber seals and 3 large O rings.
There isn't much you can do with it once it's off without hacking into the bottom cover. They are a devil to get apart. The bottom cover is plastic welded and screwed shut. It's been designed as a throw away unit. I and many others have got them open though. There was a chap planning on making a repair kit for the power valves but I don't think it was worth doing in the end.

The MG boys are well used in plenum plenum problems. Check out the X Power Forum especially the "How To" section. XPowerForums - For MG, XPower & Motorsport Enthusiasts - Powered by vBulletin
Didn't you have a coolant leak? While the plenum is off, it's a good idea to see if the thermostat is leaking.
 
OK. So I got the power VIS motor off, and, if I'm honest - it looked pretty normal. I gave it a good shake and couldn't hear anything particular rattling about. I didn't get as far as opening it up although I guess I should.

I did notice this mangle of cable ties holding the lower coils in... which at best doesn't look right. Can someone tell me which cylinder #2 is? As the ECU was reporting a misfire on it.
 

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Should the orange disc thing with the extrusion on the base of the VIS motor turn freely or should it be fairly rigid? I assumed it would be rigid if it was working correctly and loose if broken. Mine was rigid...

I cleared the DTC codes and ran it again. The P1471 [VIS related] didn't come back, but the P030[x] did - stating misfire on cylinder 2. So will be inspecting that next...
 
weirdbeardmt said:
Should the orange disc thing with the extrusion on the base of the VIS motor turn freely or should it be fairly rigid? I assumed it would be rigid if it was working correctly and loose if broken. Mine was rigid...

I cleared the DTC codes and ran it again. The P1471 [VIS related] didn't come back, but the P030[x] did - stating misfire on cylinder 2. So will be inspecting that next...
Click to expand...

The drive pin shouldn't move by hand. I expect the motor has jumped out of its mount.
You can open the casing, it's broken anyway so you can't make it worse. This link shows how to strip them down. Repair a failed VIS actuator - XPowerForums - For MG, XPower & Motorsport Enthusiasts
 
The software installed in the freelander drives the VIS valves too far causing the ball joints on the links to wear and break. This allows the valves to flap around and rattle. The rover 75 V6 had different software that didn't try to move the valves past the end stops. The A151 software upgrade limits the valve movement to the correct amount so preventing damage to the valves and links. The upgrade is FREE as landrover should have got it right in the first place. As the rover 75 didn't have this problem, second hand manifolds from them should be O.K., so replace yours with one of them, not an old freelander one as it may already be damaged. Get the upgrade done first so you don't damage your replacement.
Check this link V6 Inlet manifold rattle
After I replaced mine I cut open the manifold, removed the links and pined the valves closed, so if it happened again I would put it on like that. Max. power with no rattle. Not sure how it would affect the torque, but it still went alright when it was rattling.
On the above post I put a diagram of the plastic manifold so you can see what it looks like.
 
ianda12 said:
The software installed in the freelander drives the VIS valves too far causing the ball joints on the links to wear and break. This allows the valves to flap around and rattle. The rover 75 V6 had different software that didn't try to move the valves past the end stops. The A151 software upgrade limits the valve movement to the correct amount so preventing damage to the valves and links. The upgrade is FREE as landrover should have got it right in the first place. As the rover 75 didn't have this problem, second hand manifolds from them should be O.K., so replace yours with one of them, not an old freelander one as it may already be damaged. Get the upgrade done first so you don't damage your replacement.
Check this link V6 Inlet manifold rattle
After I replaced mine I cut open the manifold, removed the links and pined the valves closed, so if it happened again I would put it on like that. Max. power with no rattle. Not sure how it would affect the torque, but it still went alright when it was rattling.
On the above post I put a diagram of the plastic manifold so you can see what it looks like.
Click to expand...

I'm sure this software update is a myth,at least where the VIS system is concerned. There's absolutely no way a software update can alter the distance the VIS valves move. There are two switchs inside the motor housing. One switch tells the ECU the valve is in open position, the other switch tells the ECU is in the closed position. It's a purely mechanical limiting method. What can happen is over time the limit switchs begin to move, this would allow the motors to drive a little further before stopping. This could cause the control links to push a little harder on the valves, possibly shortening there life. The main reason the plenum fails, is because it's a piece of cheaply made c**p. The original alloy Rover plenum was much better, sadly BMW cut costs so the good bits got the boot. Obviously they had no interest in making any Rover product reliable!! I suspect the reverse is more accurate.
By pinning the power valves closed you will limit full power, they are power valves after all. Effectively cutting 20+ bhp!!

From the manual
 
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