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Old 05-10-2016, 22:10   #1
kindofblue
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MG 2016 VIS Report & Update

KV6 VIS Actuators Power and Balance - check, clean, repair.

Part One

I've been threatening to do this for a while but with family, work, the Summer it got away from me. I'm not going to go over old ground because Nigel / Sheddist did the original work and posted thorough instructions. I will focus on the job from a none mechanic, none electrician layman's point of view to provide an experience review that may encourage you to make these mods / repairs yourself, with various checks noted along the way. Note: if you are flush and just cannot be bothered, there is a guy selling recon units on eBay for about 40 each - note recon, not new, so no guarantee or warranty comes with them.



Pics are of my Zed during the job unless stated. I will link to previous posts and this video (here) posted on Youtube to provide an easy start point. A note on the video, the guy is pretty rough taking things apart (like breaking off one of the blade connectors) and I had less trouble with mine taking a little more care over the dismantle. Not to say I don't appreciate his effort in recording and posting the source.

Not too much tonight as its late and I am still working .

Power VIS first.

...as its the easier of the two. 4 cross head screws, pretty easy to get to above the engine towards the rear here. Disconnect the power cable first (small bendy arm on the clip body). You dont need to disconnect the car battery but DONT turn the ignition over whilst the VIS is off.



I found my screws were dry and stiff for 4 or 5 turns - I cleaned them with Duck oil, dried and greased them up for refit later. Note: the re-fit requires a vacuum so take care not to damage the rubber strip gasket on the VIS body - stayed in place on mine and I wiped it and the case on the manifold clean. The screws need to be 'tight' so the grease helps.


Pic courtesy of the75andztclub.co.uk

With the Power VIS unit out you should see this brown plastic bar in the cavity. This is the arm that is operated by the VIS rotor to controls the valves. It is the source of the chronic inlet manifold 'rattle' reported on the KV6 - it can fracture and in some cases, break into pieces. To check operation first push it down gently as shown below. It should feel springy vertically with a little resistance - don't press down hard obviously or it may snap. Having noted its rest position (for later refit), now push it left and right horizontally. Again there will be some resistance but it should move relatively smoothly and easily. Mine was OK thankfully and with a light smidgeon of oil, nothing messy. I've had an oil catch tank on the breather pipe since nearly new.

Note: if you suspect a breather pipe blockage then its worth taking the pipe off and cleaning / replacing it as this is a known issue and not just this engine - happened on a Rover 800 2.0 ltr for me back in the day pouring black smoke out the exhaust - thought the car was on fire.

I stuffed a wrag in the body and hit the hobby desk for the unit strip down.

Part 2 coming.


P
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Last edited by kindofblue; 05-10-2016 at 22:17.
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Old 09-10-2016, 23:14   #2
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MG Re: 2016 VIS Report & Update

Part 2

So Power actuator on the hobby desk. The lid is secured with these plastic clips around all four sides, which need to be eased over a peg on the body. Go steady or you may snap them off. The lid wont pop off as its stuck down with gasket - the whole unit works in a vacuum as its open inside to the manifold. I used a flat metal spade (I have for iPad glass removal) but a thin screwdriver should do. Ease the top away a little at a time putting lollipop sticks or similar under the open section so that it cannot close again. Work one side at a time and at a point you will hear the lid give as the seal finally loses its grip.



Your not there yet though. Even with the lid a couple of mm high of the body all around four sides, it wont come off yet as the 4 spade connectors (for unit's plug you disconnected earlier) are sealed in. Don't try and yank it off with brute force - your likely to snap the circuit board the spades are soldered to internally.

Sheddist used a small piece of wood at this point pushed down the plug cavity to press down on the 4 spade ends. I found that a quick spray of duck oil on the spade connectors and I could wiggle and pull the top gently upwards without any damage. Lid off below with all clips intact.



Before you start on the repair clean up the lid removing any traces of oil and clear out all the old gasket material (the yellow stringy stuff) with the flat of a small chisel. The white putty is OK left as is - just a little gunk to help secure the motor.







This is what you will be working on next. See what I mean about those spade connectors being attached to the board? It's worth taking a picture on your camera phone to remind you how all the bits were set before dismantle.



You will need everything out of the case to do the repair. First remove the yellow cog - you can press it upwards from underneath and it will come away easily as it's well greased. The circuit board isn't 'fixed' - it sits on black plastic pegs which site it. However, it wont lift up at this stage as the motor holds it down firmly, being clipped into the case at its rear and two points on the spindle arrowed below.



I found that the best way to get this out was to put the flat of a small screwdriver under the rear of the motor first and lever it just past its clip. Then use the same technique under the spindle just next to the two clips. Once these two pop upwards the motor and spindle will then come away. The spindle splits apart at the position of the rectangle above.



Note: don't lose the small washer from the end of the spindle - this sits between the spindle thread and the plastic clip which holds the shaft. There are two washers - one at each end of the spindle.



The circuit board should now lift away easily. Clean the unit itself out of any oil now which may have come in through the filter in the base, marked below. Mine was pretty clean.



Repair
There are a couple of things that can go wrong. The motor can fail and / or become heavily contaminated with oil. Most common is one or both micro switches becoming lose on the board as they are only held by the solder. As you can see in the picture below, I had this fault on one switch - its lifted so high its above the rotor cam (that is supposed to depress it) so not being activated at all.




Here is another shot below showing the extent of the rise - the unit felt lose to touch easily rocking back and forth. The second micro switch was secure.



Motor
My case and motor were clean of oil so for this test I just rigged up a 9 volt supply and attached two wires to the motor terminals. It span freely - not very scientific but effective enough. Note: if you go to the video linked in my first post, the guy actually strips his motor and the micro switches testing them more thoroughly with a meter. Feel free to do this (or simply replace the parts with new).



Micro Switches
You can test these (in a basic fashion) by pressing the switch in - its the little white pin on the cog facing side - it should click loud enough for you to hear it. Turn the board over and desolder both switches. A solder sucker (5 B&Q) helps to remove all the solder from the pin. Remove both switches and clean up the board.





If you fancy you may be coming back to this repair at some stage, Sheddist recommends tapping two screws per switch to hold the microswitches firmly down. Alternatively you can clean the board of any grease with meths and araldite the switches to it.



Despite the 5 minute claim I let them set overnight.



To solder cleanly I set up a magnifying glass so my hands are free. YOu can also see the polymer sealant I used for gasket i this picture.



Put your iron tip on the switch peg and the solder stick at the opposite side i.e. heat through the metal peg not direct to the solder. As it starts to run count one full second and lift. Don't blow on the solder - let it cool naturally.



Re-assemble
Putting it back together is the reverse of the pull apart. Couple of hints here:

(1) The circuit board and the motor are attached to each other BUT if you put these in first the spindle will not go on to the motors shaft. Instead get the motor and board in position but still above the clips, put the small washer on the spindle end and place this above the two clips that will hold the shaft in place. Now gently push everything down at once, i.e. the motor and the shaft - you will here them click into place. Re-grease the cog on the shaft.

(2) replace the yellow cog ensuring that the teeth sit inset with the motor shaft. If you have wiped all the lubricant off whilst cleaning put a small amount back on the teeth now (near the spindle not the switches). You can test that all is well by rotating the motor shaft with a small screwdriver - the yellow cog will turn - if you want you can go all the way to the cam hitting the switches to check these - you will hear them 'click' when the cam presses them in. Note: the position of the cog before re-assembly is important - in the photo below (my first attempt) it is WRONG. Both micro switches are depressed - which according to Sheddist will render the motor in-operative.




I went back to my original strip down photo and re-positioned the cog to its original place (cam beyond both switches to their left).

(3) Once all is set and firmly in place you should prepare the lid with new gasket. I used a polymer sealant from a tube which should remain flexible enough to open things up again. Be generous with this as the seal needs to be good - its a vacuum inside the box remember. You will know if this has worked when the engine is running again - if you hear a 'hissing' then it hasn't sealed effectively. Make sure all the clips are firmly in place over their respective lugs - wipe off excess sealant that squeezes out of the joint.

(4) Back at the car before you re-attach the VIS unit, connect up the electric plug to the spade connectors and turn on the ignition (DONT start the car). This will reset the motor to its correct position (assuming you don't have the cam on both switches as I did first time). Offer the unit up and check that the cam's external lug is positioned above the receiving hole in the brown valve arm. See the picture below. You can move the valve arm left and right to alter the position. Screw down the four screws tightly.


Pic courtesy of the75andztclub.co.uk

Turn the engine over and listen for any escaping air from the unit. If all is well go for a drive. You should feel a bit of a surge around 3000 and again at 4000. The surge at 3000 was quite noticeable on mine although I don't think it was in bad shape to begin with (one switch loose - otherwise clean).

I'll finish with the Balance VIS next post.



P
__________________
:: XBOX360 Live tag: MG180ZS ::
'Tony Banks Custom SS CatBack Performance Exhaust'
'ITG / BMC Hybrid Forced Induction CAF to front grill'
225 / 40 / 17 - 7.5J AVON ZZ3's
EBC Green Pads
'Sheddist' Clutch
'Masher' Oil Catch Tank
Stebel Twin Air Horn
SCU Relay Upgrade

Last edited by kindofblue; 09-10-2016 at 23:39.
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