VIS motor repaired - Page 2

supernehru · 26th October 2007, 22:06

Hi

I followed your advice and removed the rear VIS motor and dismantled it:

Almost the same faults as the first one - one micro switch was broken (always open) and the soldering didn't look too good. There was even one dodgy looking pad on the relay. There was also a lot of oil in it which I cleaned up.
The electric motor tested OK.
I reassembled the motor and put it back in the car . When I reset it, it ran slightly over centre, i.e. it went a few degrees past the marking on the plastic. (counterclockwise if looking from the manifold side)
This meant that the square plastic valve in the manifold was slightly under tension (open) when I remounted the motor. Is this normal? Should the valve be in the open position at rest?
I can't see how the motor could stop anywhere else when looking at how the switches are aligned inside.

A road test afterwards gave a positive indication, even if I didn't notice any major difference from before.

Tomas

BigJacko · 15th December 2007, 01:47

SuperNehru - firstly, thanks for such excellent detective work.

Looking at the service histories of the 75 I've just inherited, I can see mention on there of 'noisy VIS valves' and suggestion for a new manifold and a quote of £850 to fit! That was on a service in Sept 2006 (and it's had one since then, in August 2007), but I'm still looking for the paperwork on that one, alas - so I don't know if this was ever addressed (and whether my late father got fleeced for a whole new manifold, poor devil.. although he was 'insured' under some kind of 3-year £400 extended warranty he purchased in 2005, but reading the small print, practically nothing seems covered, and I sure they'd have blamed any new manifold on 'wear and tear' and made him pay!)

Anyway - assuming it IS still an open issue, I'm thinking that rather than make a certain garage nearly a grand richer for ripping off my dad, I'd investigate it myself first. Your notes have been very helpful in that regard. I'm a dab-hand with a soldering iron (electronic engineer in a past life), and I've almost worked out a circuit diagram of the whole VIS motor now, from your excellent photograph.

However, I'm still having a tiny bit of trouble working out the exact arrangement of the SIEMENS relay vs the inputs - any chance you can see the Siemens part/model number on your original photos? It's a bit hard to see on the digital ones.

I'm hoping that if I can figure out the circuit diagram exactly, then I should also be able to knock up my own testing widget, to check that the microswitches are actually working properly at the appropriate revs.

By the way - your replacement microswitch... I'm pretty sure I could locate something similar at Maplins... but it'd be really handy to know what exact part you used, and where you sourced it, if at all possible. I'll probably find I need at least one, going by your findings!

Thanks again for the inspiration! I hope my alleged noise (which I can't tell for sure even exists, cos I never heard the engine when it was new!) turns out to be just dodgy VIS motors, and not a whole new valve-actuator arm and manifold... but we'll see, eh? It's got to be worth a check, given the prices that I'm being shown, hasn't it?

Keith · 15th December 2007, 09:20

The relay is there as it provides the method to reverse the supply to the motor depending on if the ECU is driving the actuator closed or open the switches are in series to stop the motor once fully closed or open.

All fairly simple

The switches develop dry joints due to the appalling way they are mounted, glueing or screwing them down resolves that.

However the poor design extends to lack of adequate sealing of the motor around the actuators output shaft where it connects to the valve. This allow oil vapour from the emmision control systems to enter the vis assembly this contaminates the motor and begins to form a conductive grinding paste with the swarf from the brushes

Eventually assuming the switches have not packed up the motors fail due to loss of brush contact or short out, this inturn can cause the tracks on the pcb to fuse as you will notice the tracks are very thin around the relays so can't take much current.

On and off I have fixed lots of these but it is not always 100% successfull what you must do is thoroughly degrease the motor, test it carefully check all tracks and deal with the microswitches, even then I have had a couple that have gone up in smoke afterwards which is damn annoying after wasting 45 minutes or so working on it!

If building a test box to be safe you need two connectors as the vis motors do not share indentical pin outs.

Lates and I did think of offering an exchange repair but imho the time to do one properly makes it financially not cost effective to bother other than as a personal DIY exercise as a new motor is just over £50 plus vat. An an hour of my time P&P plus contingency for returns from 'awkward' customers make buying a new one in reality not so expensive after all!

I have seen several badly assembled brand new motors and the lowest mileage car I have had in for tests on my testbook had a dead vis at 17,000 miles as a rule 8 out of 10 cars I work on have one but typically two completely dead motors as they are really that bad!

I would recommend buying new but immeadiately take them apart and properly secure the switches with screws or an oil and heat proof glue like araldite

I also strongly recommend the motors are regularly tested as they are a major design weak point and comprimise the performance of an otherwise good engine

Lastly rarely does a failed Vis motor contribute to a rattle to do so would mean it had to have failed with the valve part open or closed and for a rattle to occur that valve would probably have to be unhealthily loose on its ball joint coupling already. Normally the motors simply fail to move from their last open or closed postion

BigJacko · 15th December 2007, 11:23

Thanks Keith - an extremely helpful post. I get the impression you're 'in the trade' with these Rover beasties - I've seen a few of your posts now and they all seem very knowledgeable! Good to have you around!

I'm still not entirely certain that the engine actually has 'Vis Rattle' - other than the words I've seen on a bit of paper from last year. I've just listened to the clip on the post here: http://www.the75andztclub.co.uk/foru...8&postcount=27 - and must confess that my engine doesn't sound ANYTHING like that, which is a truly horrible and noticeable noise. Mine purrs, by comparison, and I'm wondering whether either Dad had it fixed before he died, or whether the garage was just 'trying it on'. Shame I can't find out either way now. I will ask Mum if she remembers Dad grumbling about an £850+ expense recently, or if she's found any paperwork for it. You never know - I might get lucky. I really don't to find out I've inherited a 'poisoned chalice' that's simply going to bleed me white! The darn thing is due for its 6-year service next summer, and that's the one with the expensive cambelt change in it, so I've got enough lined on my plate already, without having a duff inlet manifold to deal with! Sods Law, eh?

Thanks again for the advice, anyway... I will keep beady eyes (and ears) very much open.

26th October 2007, 22:06	#11
supernehru Newbie Rover 75 Saloon X3 Join Date: May 2007 Location: Göteborg Posts: 14 Thanks: 0 Thanked 0 Times in 0 Posts	second VIS motor fixed Hi I followed your advice and removed the rear VIS motor and dismantled it: Almost the same faults as the first one - one micro switch was broken (always open) and the soldering didn't look too good. There was even one dodgy looking pad on the relay. There was also a lot of oil in it which I cleaned up. The electric motor tested OK. I reassembled the motor and put it back in the car . When I reset it, it ran slightly over centre, i.e. it went a few degrees past the marking on the plastic. (counterclockwise if looking from the manifold side) This meant that the square plastic valve in the manifold was slightly under tension (open) when I remounted the motor. Is this normal? Should the valve be in the open position at rest? I can't see how the motor could stop anywhere else when looking at how the switches are aligned inside. A road test afterwards gave a positive indication, even if I didn't notice any major difference from before. Tomas

15th December 2007, 01:47	#12
BigJacko Avid contributor Rover 75 Tourer 2.0 V6 Club (2002) Join Date: Dec 2007 Location: Bath Posts: 236 Thanks: 47 Thanked 16 Times in 12 Posts	SuperNehru - firstly, thanks for such excellent detective work. Looking at the service histories of the 75 I've just inherited, I can see mention on there of 'noisy VIS valves' and suggestion for a new manifold and a quote of £850 to fit! That was on a service in Sept 2006 (and it's had one since then, in August 2007), but I'm still looking for the paperwork on that one, alas - so I don't know if this was ever addressed (and whether my late father got fleeced for a whole new manifold, poor devil.. although he was 'insured' under some kind of 3-year £400 extended warranty he purchased in 2005, but reading the small print, practically nothing seems covered, and I sure they'd have blamed any new manifold on 'wear and tear' and made him pay!) Anyway - assuming it IS still an open issue, I'm thinking that rather than make a certain garage nearly a grand richer for ripping off my dad, I'd investigate it myself first. Your notes have been very helpful in that regard. I'm a dab-hand with a soldering iron (electronic engineer in a past life), and I've almost worked out a circuit diagram of the whole VIS motor now, from your excellent photograph. However, I'm still having a tiny bit of trouble working out the exact arrangement of the SIEMENS relay vs the inputs - any chance you can see the Siemens part/model number on your original photos? It's a bit hard to see on the digital ones. I'm hoping that if I can figure out the circuit diagram exactly, then I should also be able to knock up my own testing widget, to check that the microswitches are actually working properly at the appropriate revs. By the way - your replacement microswitch... I'm pretty sure I could locate something similar at Maplins... but it'd be really handy to know what exact part you used, and where you sourced it, if at all possible. I'll probably find I need at least one, going by your findings! Thanks again for the inspiration! I hope my alleged noise (which I can't tell for sure even exists, cos I never heard the engine when it was new!) turns out to be just dodgy VIS motors, and not a whole new valve-actuator arm and manifold... but we'll see, eh? It's got to be worth a check, given the prices that I'm being shown, hasn't it? Last edited by BigJacko; 15th December 2007 at 01:50..

15th December 2007, 09:20	#13
Keith This is my second home ZT400 Join Date: Oct 2006 Location: Ellesmere Posts: 5,948 Thanks: 0 Thanked 43 Times in 29 Posts	The relay is there as it provides the method to reverse the supply to the motor depending on if the ECU is driving the actuator closed or open the switches are in series to stop the motor once fully closed or open. All fairly simple The switches develop dry joints due to the appalling way they are mounted, glueing or screwing them down resolves that. However the poor design extends to lack of adequate sealing of the motor around the actuators output shaft where it connects to the valve. This allow oil vapour from the emmision control systems to enter the vis assembly this contaminates the motor and begins to form a conductive grinding paste with the swarf from the brushes Eventually assuming the switches have not packed up the motors fail due to loss of brush contact or short out, this inturn can cause the tracks on the pcb to fuse as you will notice the tracks are very thin around the relays so can't take much current. On and off I have fixed lots of these but it is not always 100% successfull what you must do is thoroughly degrease the motor, test it carefully check all tracks and deal with the microswitches, even then I have had a couple that have gone up in smoke afterwards which is damn annoying after wasting 45 minutes or so working on it! If building a test box to be safe you need two connectors as the vis motors do not share indentical pin outs. Lates and I did think of offering an exchange repair but imho the time to do one properly makes it financially not cost effective to bother other than as a personal DIY exercise as a new motor is just over £50 plus vat. An an hour of my time P&P plus contingency for returns from 'awkward' customers make buying a new one in reality not so expensive after all! I have seen several badly assembled brand new motors and the lowest mileage car I have had in for tests on my testbook had a dead vis at 17,000 miles as a rule 8 out of 10 cars I work on have one but typically two completely dead motors as they are really that bad! I would recommend buying new but immeadiately take them apart and properly secure the switches with screws or an oil and heat proof glue like araldite I also strongly recommend the motors are regularly tested as they are a major design weak point and comprimise the performance of an otherwise good engine Lastly rarely does a failed Vis motor contribute to a rattle to do so would mean it had to have failed with the valve part open or closed and for a rattle to occur that valve would probably have to be unhealthily loose on its ball joint coupling already. Normally the motors simply fail to move from their last open or closed postion

15th December 2007, 11:23	#14
BigJacko Avid contributor Rover 75 Tourer 2.0 V6 Club (2002) Join Date: Dec 2007 Location: Bath Posts: 236 Thanks: 47 Thanked 16 Times in 12 Posts	Thanks Keith - an extremely helpful post. I get the impression you're 'in the trade' with these Rover beasties - I've seen a few of your posts now and they all seem very knowledgeable! Good to have you around! I'm still not entirely certain that the engine actually has 'Vis Rattle' - other than the words I've seen on a bit of paper from last year. I've just listened to the clip on the post here: http://www.the75andztclub.co.uk/foru...8&postcount=27 - and must confess that my engine doesn't sound ANYTHING like that, which is a truly horrible and noticeable noise. Mine purrs, by comparison, and I'm wondering whether either Dad had it fixed before he died, or whether the garage was just 'trying it on'. Shame I can't find out either way now. I will ask Mum if she remembers Dad grumbling about an £850+ expense recently, or if she's found any paperwork for it. You never know - I might get lucky. I really don't to find out I've inherited a 'poisoned chalice' that's simply going to bleed me white! The darn thing is due for its 6-year service next summer, and that's the one with the expensive cambelt change in it, so I've got enough lined on my plate already, without having a duff inlet manifold to deal with! Sods Law, eh? Thanks again for the advice, anyway... I will keep beady eyes (and ears) very much open.