KV6 inlet manifold arm not moving smoothly - opinions on a video please!

[Bolin]

Hi all

I've got a replacement KV6 upper inlet manifold chamber but the arm/rod for the power butterflies doesn't move smoothly.

It feels as if there is resistance in the centre of movement, more so when moving the arm inwards, when sometimes it seems to jam and won't move fully inwards without a bit of a wiggle.

Not sure what to make of it, it doesn't seem good to me, as my worn and rattly one moves beautifully smoothly - is this just due to the wear or should the replacement move smoothly too? I would have thought the latter.


Replacement manifold (<15,000 miles) (https://picasaweb.google.com/109044143627863800065/HerMajestySDrawingRoomOnWheels?authkey=Gv1sRgCIm0g o-i_rzLUA#5911292642279089458)


Original manifold (108,000 miles) (https://picasaweb.google.com/109044143627863800065/HerMajestySDrawingRoomOnWheels?authkey=Gv1sRgCIm0g o-i_rzLUA#5911292640787405314) - note that for most of the video I am pausing before each movement, that's not a build up of force required to move the arm!

Any thoughts? Replacement one doesn't feel good to me:shrug:

Thanks, Bolin

[SD1too]

In your shoes Colin I wouldn't be rushing to fit that replacement chamber either!

Simon

[Bolin]

Thanks Simon, so it's not me that thinks it doesn't operate correctly then.:(

[Teflon]

I have a brand new manifold sitting in the shed, put aside for when the inevitable happens.

Just been out and tried it - the arm perhaps feels a little stiff, but there is even resistance the whole length of travel both inwards and out.

Don't know if this helps or not. :shrug:

Cliff

[Bolin]

Thank you very much Cliff, that is extremely helpful - as a new one has even resistance and my worn one has none (therefore even!) then it strongly points to this 15,000 miles replacement being faulty.

Having seen pictures and video of the innards of these, I cannot see why the arm would feel like it does:shrug:

[mantianak]

If it's feeling a bit stiff try blasting it with carb cleaner. That should remove any gunk restricting it's movement. And even if it's not gunked up, do it anyway :) Good to do it every so often.

[Canonite]

Before condemning it, I'd definately give it a thorough clean out as someone already suggested. It would only take a small grain of grit to get into the wrong area to cause it to jam. My good one which is fitted to the car has a firm but smooth arc in its travel.

[Bolin]

Ok I've given it a good squirt of carb cleaner, but I'm not convinced it's improved it. Oddly, the arm feels like it has more 'play' since squirting cleaner in there.

I note that the arm doesn't have as much play as my rattly one, but much more than a couple I found in a scrappy (wouldn't sell without whole engine!) that had solid arms in anything other than the intended direction of movement - when I got this low mileage one I assumed the ones in the scrappy were gummed up.

Feeling the up-and-own movement in the arm, it does tend to 'click' at times - I'm wondering if one of the ball-and-sockets is disengaging at times, causing the occasional jamming?

I'll clean the whole thing thoroughly and test it on the car.

[Bolin]

Well, after a couple of days I used some more carb cleaner and the movement of the arm now feels much better, still a little of resistance in the middle of the movement I think, but far far better than it was in the video. However, the occasional 'click' when moving the arm downwards did at times co-incide with the still resistance in the middle of the movement returning - which makes me believe that one of the ball-and-sockets was dislocating, and jamming the movement of the rod until it popped back in place - that's my theory.

I fitted it to the car with the power butterflies fully open, the balance butterfly half open and both VIS motors disconnected - from cold there did seem to be a bit of a rattle, not as bad as my original manifold, and it did seem to quieten down as the engine warmed up.
Video (https://picasaweb.google.com/109044143627863800065/HerMajestySDrawingRoomOnWheels?authkey=Gv1sRgCIm0g o-i_rzLUA#5912428278725979154)

I then revved the engine very slightly, and a sort of 'scratching' sound started, not always present, but almost always, just briefly disappearing for an occasional moment or so. I have never heard my car make this noise before, so I believe it must be due to the new manifold - it seemed to be coming from the furthest end of where the power rod is inside the manifold. The noise got worse as the engine was revved.
Video (https://picasaweb.google.com/109044143627863800065/HerMajestySDrawingRoomOnWheels?authkey=Gv1sRgCIm0g o-i_rzLUA#5912428276930046274)
Video (https://picasaweb.google.com/109044143627863800065/HerMajestySDrawingRoomOnWheels?authkey=Gv1sRgCIm0g o-i_rzLUA#5912428276724437170)
Note that I turn the cameraphone so to get the microphone nearer the engine.

I think I need to reject the manifold, I'm not convinced it's in good order.