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Old 19th March 2019, 07:45   #1
ricebridge
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Exclamation The VIS Squad!

Having my fingers full of splinters from scratching my head over the mysterious VIS system and the inlet manifold in general, I thought we could gather all basic-level knowledge about it in a dedicated thread (this one). Remember, I'm one of those old-timers who are used to there being a single simple tube from the air filter to the carburettor (yes, I'm that old).

So let's please take it from the beginning.

1) What is VIS and what does it do?

2) How does it work?

3) How is it affected by how I drive?

4) Why is there coolant in there, where does it get in, and where does it (normally...) get out?

5) How does oil get in there and mess it all up?

6) What can you do to service it or prevent it from failing?

7) What weak points are there and how do you fix them?

8) What is the name and address (with possible sniper positions) of the person who designed it with a plastic mechanism that's prone to breaking (just kidding)

9) Any more info welcome!

i do realise that a lot of these questions have been answered in previous posts . But since there are so many of them, I thought it could be a good idea to gather it all up in one single resource, and then perhaps the moderator could pin it.
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Old 19th March 2019, 08:35   #2
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I'm not even going to attempt to comment on an area which is the preserve of the recognised Gods Of The VIS. However to stop oil getting into the upper inlet chamber I fitted a catch tank. The only difficult thing is finding somewhere to put it!
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Old 19th March 2019, 08:56   #3
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To get you started …

Description - Technical Brochure P138.

There shouldn’t be any coolant in the VIS system, any contaminants are from venting the crankcase. Ensure the gauze separators within the camshaft covers are clean and the pinhole restrictions unblocked (98% chance yours are blocked if not done previously).
Fit “Stocktake” reconditioned motor units, the balance motor suffers the most from crankcase sludge and the units supplied by Stocktake contain a oil seal unlike the originals.

As previous poster, fit catch tank or clean regularly (mine once a year).

If not already a member join RCoS (Rover Club of Sweden) I and others have written about this subject in Roverbladet (magazine).

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Old 19th March 2019, 16:37   #4
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Quote:
Originally Posted by vitesse View Post
To get you started …

Description - Technical Brochure P138.

There shouldn’t be any coolant in the VIS system, any contaminants are from venting the crankcase. Ensure the gauze separators within the camshaft covers are clean and the pinhole restrictions unblocked (98% chance yours are blocked if not done previously).
Fit “Stocktake” reconditioned motor units, the balance motor suffers the most from crankcase sludge and the units supplied by Stocktake contain a oil seal unlike the originals.

As previous poster, fit catch tank or clean regularly (mine once a year).

If not already a member join RCoS (Rover Club of Sweden) I and others have written about this subject in Roverbladet (magazine).

Regards
How do you do all this?

(except for the club thing; already a member of the MG Club ;-) )
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Old 19th March 2019, 17:18   #5
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Get yourself either a written or digital workshop manual, e.g. https://rimmerbros.com/Item--i-ZAA000400

If a member of the Rover club of Sweden you can access the magazine on-line library: Roverbladet 96 & 99 contain a description of the VIS system, Roverbladet 101 Breather system / cam filters.

Regards
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Old 20th March 2019, 11:18   #6
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Quote:
Originally Posted by vitesse View Post
Get yourself either a written or digital workshop manual, e.g. https://rimmerbros.com/Item--i-ZAA000400

If a member of the Rover club of Sweden you can access the magazine on-line library: Roverbladet 96 & 99 contain a description of the VIS system, Roverbladet 101 Breather system / cam filters.

Regards
I have one, but it only says how to fix it, not what it does or how it works.
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Old 20th March 2019, 12:00   #7
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Guessing then you aren't a member of RCoS otherwise you'd have been able to access the magazine archive. If you mail me your email address I'll send you a copy of the magazine article about cleaning the gauze filters (separators), can't see that the club can have any objections as I wrote the article.

If you look at post 8 in this thread https://the75andztclub.co.uk/forum/s...d.php?t=280437 you'll find a gold mine of information including a link to the Technical Brochure which describes in detail the operation of the VIS system.

Regards
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Old 26th March 2019, 20:21   #8
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Now Look E. Hear wot I found me...

https://www.youtube.com/user/kv6coupe

The VIS is explained in detail in the second video, but all three are definitely worth watching.
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Old 26th March 2019, 21:20   #9
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Unless you've actually got a Rover 825 I don't think studying that video is going to help much. While both have the designation KV6, the later KV6 fitting to the 75 had so many changes it could almost be a different engine.

If you mail me your email address I will send you a copy of the correct VIS description for you 75, alternatively you can download it yourself from that link I gave you. And should you ever need "Stocktake" VIS motors I always keep a few in stock up here in Gävle.

Regards
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