VIS motor fault question

john116 · 7th December 2020, 21:07

Recently I noticed what sounds like loud tappet noise on my Rover 75 (2001) with KV6 engine.

TOAF reports a faulty balance VIS motor - could this also be the cause of the noise (which sounds like it's coming from the manifold)?

I have a new VIS motor, but currently not close by, so can't swap it out for a few days yet.

Thanks,
John

stocktake · 7th December 2020, 21:15

Hi John,
A faulty Balance Vis will not cause a tapping/rattling noise in the manifold I'm afraid.
A power vis that has failed in a mid position can cause a slight wear in the butterflies to be amplified,

There is also the operation of the purge valve to consider as this sounds like a slack tappet but is very intermittent and more prominent/active when cold, all quite normal.
D...

stocktake · 7th December 2020, 21:22

Purge valve is opposite side of manifold to balance Vis, on the top at an angle, two wire connection and when disconnected the noise stops straight away.

Edit:
When you do change your balance Vis make sure you check the balance flap behind it. It needs to be absolutely free in its entire operation of 90 degrees. If it is sticking at any point it needs cleaning in something like carb cleaner and even emery paper on the edge pf the flap.

john116 · 8th December 2020, 01:04

Hi - so tried the purge valve test - not that. I also don't think it's tappet noise, has a very 'rattley' type sound to it. Car has done 70,000km - so does that leave me with a not so healthy intake manifold chamber? I have no experience with these - is it a gradual thing, or does something break. The 'noise' from memory just happened suddenly one day a few weeks ago.

stocktake · 8th December 2020, 06:21

Hi John,
To check the arm for wear you will need to remove the power Vis. Unplug the electrical connection and there are four cross head screws that hold the Power vis in place. Some people disconnect the servo pipe for better access but it isn't needed.

Once you remove the Vis motor look into the hole below. The brown arm should be fully over to the right hand side, if it isn't then the Vis motor has failed and that could be the cause of the amplified noise. Look at the underside of the Vis with the cut out to the top left, the peg should be at between three and 4 o'clock. any other position and its failed.

The brown arm with an elongated hole in it is connected to the 6 butterflies via the cup and cone joints that wear.

Hold the bar and move it side to side (left to right) and this is the action the bar goes through when in operation, it should be free but firm in its operation. Then check the bar for up and down and forward and backward movement, a perfect one will flex only, any loose feeling is wear.

When you refit the Vis motor make sure the peg is located in the hole in the bar and when inserting the screws they are a self tapping affair so turn them anticlockwise initially until you feel them "drop" this will mean they have found the original thread and wont try to make a new one which makes them really difficult to get back in.

Just for clarity left and right
[IMG]

[/IMG]

vitesse · 8th December 2020, 07:57

Thanks for using left or right rather than the most confusing off / near side - by the time I've considered whether the poster is UK based or not (RHD / LHD) I usually don't bother reading anymore. Hint to others

Keep well

SD1too · 8th December 2020, 08:24

Quote:

Originally Posted by john116

... does that leave me with a not so healthy intake manifold chamber?

And thanks to John for using the correct term: the manifold chamber!

Anyway, do you hear this rattle all the time John or just for a few minutes after the engine is started from cold? Is it equally audible with the bonnet closed or open?

Simon

john116 · 8th December 2020, 08:45

Simon,

Rattle is all the time. With bonnet closed, can hardly hear it. With bonnet open very noticeable.

SD1too · 8th December 2020, 09:25

Quote:

Originally Posted by john116

Simon,

Rattle is all the time. With bonnet closed, can hardly hear it. With bonnet open very noticeable.

Thanks John. That exactly matches what I heard recently on a friend's KV6 and we were in little doubt that it was the VIS power linkage. His is a high mileage engine though, having covered over five times the distance of yours which makes me wonder what the underlying cause is.

Simon

john116 · 9th December 2020, 04:33

Simon, have removed the power VIS motor, and as per your advice above the motor peg is in about the 9 o'clock position. Also, TOAF confirms this motor has died (not the balance motor as I incorrectly stated before). However, the other thing is that the linkage is VERY loose and rattly. No wonder it's making so much noise. Guess I need a new manifold (but why it is faulty after only 70,000kms, I don't know?) Age? Anyone have a spare one?

7th December 2020, 21:07	#1
john116 Avid contributor Rover 75 Saloon Join Date: Nov 2018 Location: Sydney Posts: 176 Thanks: 82 Thanked 41 Times in 21 Posts	VIS motor fault question Recently I noticed what sounds like loud tappet noise on my Rover 75 (2001) with KV6 engine. TOAF reports a faulty balance VIS motor - could this also be the cause of the noise (which sounds like it's coming from the manifold)? I have a new VIS motor, but currently not close by, so can't swap it out for a few days yet. Thanks, John

7th December 2020, 21:15	#2
stocktake Vis Whiz Rover 75 2.5 auto Saloon Join Date: Jun 2007 Location: LEEDS Posts: 20,586 Thanks: 2,057 Thanked 3,056 Times in 1,621 Posts	Hi John, A faulty Balance Vis will not cause a tapping/rattling noise in the manifold I'm afraid. A power vis that has failed in a mid position can cause a slight wear in the butterflies to be amplified, There is also the operation of the purge valve to consider as this sounds like a slack tappet but is very intermittent and more prominent/active when cold, all quite normal. D... __________________ Dave... Lost a few stones and a Gall Bladder and part of a bile duct and all of my dignity in the suppository incident Last edited by stocktake; 7th December 2020 at 21:17..

7th December 2020, 21:22	#3
stocktake Vis Whiz Rover 75 2.5 auto Saloon Join Date: Jun 2007 Location: LEEDS Posts: 20,586 Thanks: 2,057 Thanked 3,056 Times in 1,621 Posts	Purge valve is opposite side of manifold to balance Vis, on the top at an angle, two wire connection and when disconnected the noise stops straight away. Edit: When you do change your balance Vis make sure you check the balance flap behind it. It needs to be absolutely free in its entire operation of 90 degrees. If it is sticking at any point it needs cleaning in something like carb cleaner and even emery paper on the edge pf the flap. __________________ Dave... Lost a few stones and a Gall Bladder and part of a bile duct and all of my dignity in the suppository incident

8th December 2020, 06:21	#5
stocktake Vis Whiz Rover 75 2.5 auto Saloon Join Date: Jun 2007 Location: LEEDS Posts: 20,586 Thanks: 2,057 Thanked 3,056 Times in 1,621 Posts	Hi John, To check the arm for wear you will need to remove the power Vis. Unplug the electrical connection and there are four cross head screws that hold the Power vis in place. Some people disconnect the servo pipe for better access but it isn't needed. Once you remove the Vis motor look into the hole below. The brown arm should be fully over to the right hand side, if it isn't then the Vis motor has failed and that could be the cause of the amplified noise. Look at the underside of the Vis with the cut out to the top left, the peg should be at between three and 4 o'clock. any other position and its failed. The brown arm with an elongated hole in it is connected to the 6 butterflies via the cup and cone joints that wear. Hold the bar and move it side to side (left to right) and this is the action the bar goes through when in operation, it should be free but firm in its operation. Then check the bar for up and down and forward and backward movement, a perfect one will flex only, any loose feeling is wear. When you refit the Vis motor make sure the peg is located in the hole in the bar and when inserting the screws they are a self tapping affair so turn them anticlockwise initially until you feel them "drop" this will mean they have found the original thread and wont try to make a new one which makes them really difficult to get back in. Just for clarity left and right [IMG][/IMG] __________________ Dave... Lost a few stones and a Gall Bladder and part of a bile duct and all of my dignity in the suppository incident

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8th December 2020, 01:04	#4
john116 Avid contributor Rover 75 Saloon Join Date: Nov 2018 Location: Sydney Posts: 176 Thanks: 82 Thanked 41 Times in 21 Posts	Hi - so tried the purge valve test - not that. I also don't think it's tappet noise, has a very 'rattley' type sound to it. Car has done 70,000km - so does that leave me with a not so healthy intake manifold chamber? I have no experience with these - is it a gradual thing, or does something break. The 'noise' from memory just happened suddenly one day a few weeks ago.

8th December 2020, 07:57	#6
vitesse I really should get out more....... Rover 75 Saloon Join Date: Jul 2011 Location: Gävle Posts: 2,528 Thanks: 395 Thanked 823 Times in 652 Posts	Thanks for using left or right rather than the most confusing off / near side - by the time I've considered whether the poster is UK based or not (RHD / LHD) I usually don't bother reading anymore. Hint to others Keep well

8th December 2020, 08:45	#8
john116 Avid contributor Rover 75 Saloon Join Date: Nov 2018 Location: Sydney Posts: 176 Thanks: 82 Thanked 41 Times in 21 Posts	Simon, Rattle is all the time. With bonnet closed, can hardly hear it. With bonnet open very noticeable.

9th December 2020, 04:33	#10
john116 Avid contributor Rover 75 Saloon Join Date: Nov 2018 Location: Sydney Posts: 176 Thanks: 82 Thanked 41 Times in 21 Posts	Simon, have removed the power VIS motor, and as per your advice above the motor peg is in about the 9 o'clock position. Also, TOAF confirms this motor has died (not the balance motor as I incorrectly stated before). However, the other thing is that the linkage is VERY loose and rattly. No wonder it's making so much noise. Guess I need a new manifold (but why it is faulty after only 70,000kms, I don't know?) Age? Anyone have a spare one?