KV6 2.5 VIS balance. - MG-Rover.org Forums

Terry Jay · 01-01-2009, 15:29

Hi forum boffins,
Can anyone explain specially the function of the VIS balance valve and what controls it, a diagram would be helpful. Does it work in unison with the power valve or does it have separate operating parameters? I ask this question because, before I take it apart and glue, screw, clean and resolder as advised on the forum, I would like to know what will be achieved. From the pictures I have found in the forum I more or less understand the power valve function.
Terry

storming · 01-01-2009, 18:04

Dont quote me but does "the balance valve spilts the chambers from 3 to 6 and then back to 3 for the final torque boost".

A diagram would be nice!!!

shroonie29 · 01-01-2009, 18:18

http://www.mgcars.org.uk/cgi-bin/gen...6variable.html

The inlet manifold chamber incorporates a Variable Intake System (VIS). The air flow from the throttle body feeds into a “Y” piece which separates into two secondary pipes. The secondary pipes feed into two main plenums, one for each bank of three cylinders. At the closed end of the plenums is a VIS balance valve, operated by an electrical motor. This valve enables the two plenums to be connected together. From the two plenums, the primary tract length to each cylinder is approximately 500mm. Each of these tracts has a side function, fitted with a VIS power valve and feeding into the short tract plenum, approximately 350mm from the cylinder head face. All of the VIS power valves are connected to a link rod which is operated by an electric motor.

alexward · 01-01-2009, 18:27

I've got a VIS problem shroonie. No surge of power at the 3000rpm ish mark. Do you know which one needs replacing, or is it both??
Cheers.

Andy K · 01-01-2009, 20:11

how do you know when you have a VIS motor fault ?
does the ecu light come on ?

storming · 01-01-2009, 23:10

No faults will flash up in the car only a code reading tool will show up that the power or the blance motors are not working.
If the car fells guttless then power valve has gone, but they can be repaired as long as the little motor has not burn out, being that it has to swim in oil from the breather system!!.

storming · 01-01-2009, 23:14

I so wish i had two grand to spend on the super charger for the kv6!!

01-01-2009, 15:29	#1
Terry Jay Registered User Join Date: Dec 2008 Location: Dresden Germany Car: Rover 75 2.5 Tourer, AC cobra replica 5.2L Posts: 10	KV6 2.5 VIS balance. Hi forum boffins, Can anyone explain specially the function of the VIS balance valve and what controls it, a diagram would be helpful. Does it work in unison with the power valve or does it have separate operating parameters? I ask this question because, before I take it apart and glue, screw, clean and resolder as advised on the forum, I would like to know what will be achieved. From the pictures I have found in the forum I more or less understand the power valve function. Terry

01-01-2009, 18:04	#2
storming Registered User Join Date: Jun 2008 Car: MG ZTT Posts: 48	balance valve Dont quote me but does "the balance valve spilts the chambers from 3 to 6 and then back to 3 for the final torque boost". A diagram would be nice!!!

01-01-2009, 18:27	#4
alexward hijackers inc Join Date: Feb 2008 Location: Sandy, Bedfordshire Car: Volvo C70 T5 GT-255bhp and 340 NM of torque! Posts: 1,650 Blog Entries: 1	I've got a VIS problem shroonie. No surge of power at the 3000rpm ish mark. Do you know which one needs replacing, or is it both?? Cheers. __________________ Alex. (Transport Manager - hi jackers inc)

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01-01-2009, 18:18	#3
shroonie29 Registered User Join Date: Feb 2006 Location: KV6 Heaven :) Car: ZS 180 saloon Posts: 2,069	http://www.mgcars.org.uk/cgi-bin/gen...6variable.html The inlet manifold chamber incorporates a Variable Intake System (VIS). The air flow from the throttle body feeds into a “Y” piece which separates into two secondary pipes. The secondary pipes feed into two main plenums, one for each bank of three cylinders. At the closed end of the plenums is a VIS balance valve, operated by an electrical motor. This valve enables the two plenums to be connected together. From the two plenums, the primary tract length to each cylinder is approximately 500mm. Each of these tracts has a side function, fitted with a VIS power valve and feeding into the short tract plenum, approximately 350mm from the cylinder head face. All of the VIS power valves are connected to a link rod which is operated by an electric motor.

01-01-2009, 20:11	#5
Andy K Registered User Join Date: Jul 2003 Location: UK Car: Rover 75 2.5 ConSE Saloon Xreg Posts: 164	how do you know when you have a VIS motor fault ? does the ecu light come on ?

01-01-2009, 23:10	#6
storming Registered User Join Date: Jun 2008 Car: MG ZTT Posts: 48	No faults will flash up in the car only a code reading tool will show up that the power or the blance motors are not working. If the car fells guttless then power valve has gone, but they can be repaired as long as the little motor has not burn out, being that it has to swim in oil from the breather system!!.

01-01-2009, 23:14	#7
storming Registered User Join Date: Jun 2008 Car: MG ZTT Posts: 48	I so wish i had two grand to spend on the super charger for the kv6!!

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