Variable intake runner fix
01-12-2009, 12:18 PM
#11
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How can I tell if mine are broken? I want the magical free horsepower JKay talks about...
<ul><li><a href="https://forums.audiworld.com/a8/msgs/145214.phtml">Free horespower magic here.</a></li></ul>
01-12-2009, 02:32 PM
#14
So the "freezing point" is btn the shaft and the front cap that you removed with the puller?
Could that be "serviced" without dismantling the intake manifold? I mean pull the cap clean lube and close everything working only from the front of the engine?
01-12-2009, 04:33 PM
#15
AudiWorld Super User
try to move the arms by hand. They should move but with a pretty strong resistance.
if the arms are broken, that's probably why.
The diaphram produces and amazing amount of pull and if the runners are frozen, snaps the arms.
Bob
The diaphram produces and amazing amount of pull and if the runners are frozen, snaps the arms.
Bob
01-12-2009, 04:43 PM
#16
AudiWorld Member
Thread Starter
Re: So the "freezing point" is btn the shaft and the front cap that you removed with the puller?
Yes, the ID of the end cap/guide corrodes and closes up the bore size. If it is still free at all, it should be possible to get the end cap off and service it without taking apart the manifold.
03-10-2016, 07:10 PM
#20
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Need a repair end
I would like to know if I can get some repair ends that you made. Mine broke while carefully trying to remove the seized bushing end.
Having the engine/transmission out I took the opportunity to look in through the throttle body and see if the variable intake flaps were actually operating. The pivot arms were free, but the flaps were not moving so I knew they were broke. There is practically nothing in the Bentley about it, so I decided to just begin disassembling it. I started by pulling of the arms off. Here is the where they were broken:
<img src="http://i48.photobucket.com/albums/f202/G1968Y/2000_A8_intake_fix/DSC_0957.jpg">
This is the part that broke off, it keys the flapper pivot rod into the control arm.
<img src="http://i48.photobucket.com/albums/f202/G1968Y/2000_A8_intake_fix/DSC00317-1.jpg">
I had to apply some serious force to press the rod out of the end guides. These things were really frozen in!
<img src="http://i48.photobucket.com/albums/f202/G1968Y/2000_A8_intake_fix/DSC_0962.jpg">
Now what to do with this?!
<img src="http://i48.photobucket.com/albums/f202/G1968Y/2000_A8_intake_fix/DSC00302.jpg">
After searching every online resource I could for a replacement part to no avail and then mulling it over for a day or two, this is what I came up with. First I set up the arms and used an external boring tool to turn down the end to .375 diameter. You cant see the boring tool because it blurred out from motion:
<img src="http://i48.photobucket.com/albums/f202/G1968Y/2000_A8_intake_fix/DSC00303.jpg">
Here are the parts after machining, I went about 0.800 down from the end with the turn-down. The base rod is aluminum. Then from the measurements of control arms, I fabricated these pieces to fit on the turned-down ends. They are made of 12L14 CRS (screw machine stock), the back side is bored 0.375 diameter to fit over the turned down rod ends.
<img src="http://i48.photobucket.com/albums/f202/G1968Y/2000_A8_intake_fix/DSC00306.jpg">
Originally I planned to cross-drill these and add a roll pin to keep the radial orientation of the new part from slipping. But they pressed on so nicely that I decided to forgo that step.
<img src="http://i48.photobucket.com/albums/f202/G1968Y/2000_A8_intake_fix/DSC00308.jpg">
Here is the re-assembly. I used an emery cloth strip attached to a ¼" mandrel on a die grinder to clean out the ID of the end guides. Because I am concerned about corrosion from dissimilar metals, I made sure the metal part is about 0.005" smaller in diameter than the plastic part that is left, so the plastic part should touch. I also lubed it heavily with anti-seize paste on the rod end.
<img src="http://i48.photobucket.com/albums/f202/G1968Y/2000_A8_intake_fix/DSC00313.jpg">
That's it!. After cleaning the deposits out of both halves of the manifold, I lovingly reassembled and torqued the top part back in. The arms operate freely...for now at least.
<img src="http://i48.photobucket.com/albums/f202/G1968Y/2000_A8_intake_fix/DSC00318.jpg">
Hope this helps somebody!
Greg
<img src="http://i48.photobucket.com/albums/f202/G1968Y/2000_A8_intake_fix/DSC_0957.jpg">
This is the part that broke off, it keys the flapper pivot rod into the control arm.
<img src="http://i48.photobucket.com/albums/f202/G1968Y/2000_A8_intake_fix/DSC00317-1.jpg">
I had to apply some serious force to press the rod out of the end guides. These things were really frozen in!
<img src="http://i48.photobucket.com/albums/f202/G1968Y/2000_A8_intake_fix/DSC_0962.jpg">
Now what to do with this?!
<img src="http://i48.photobucket.com/albums/f202/G1968Y/2000_A8_intake_fix/DSC00302.jpg">
After searching every online resource I could for a replacement part to no avail and then mulling it over for a day or two, this is what I came up with. First I set up the arms and used an external boring tool to turn down the end to .375 diameter. You cant see the boring tool because it blurred out from motion:
<img src="http://i48.photobucket.com/albums/f202/G1968Y/2000_A8_intake_fix/DSC00303.jpg">
Here are the parts after machining, I went about 0.800 down from the end with the turn-down. The base rod is aluminum. Then from the measurements of control arms, I fabricated these pieces to fit on the turned-down ends. They are made of 12L14 CRS (screw machine stock), the back side is bored 0.375 diameter to fit over the turned down rod ends.
<img src="http://i48.photobucket.com/albums/f202/G1968Y/2000_A8_intake_fix/DSC00306.jpg">
Originally I planned to cross-drill these and add a roll pin to keep the radial orientation of the new part from slipping. But they pressed on so nicely that I decided to forgo that step.
<img src="http://i48.photobucket.com/albums/f202/G1968Y/2000_A8_intake_fix/DSC00308.jpg">
Here is the re-assembly. I used an emery cloth strip attached to a ¼" mandrel on a die grinder to clean out the ID of the end guides. Because I am concerned about corrosion from dissimilar metals, I made sure the metal part is about 0.005" smaller in diameter than the plastic part that is left, so the plastic part should touch. I also lubed it heavily with anti-seize paste on the rod end.
<img src="http://i48.photobucket.com/albums/f202/G1968Y/2000_A8_intake_fix/DSC00313.jpg">
That's it!. After cleaning the deposits out of both halves of the manifold, I lovingly reassembled and torqued the top part back in. The arms operate freely...for now at least.
<img src="http://i48.photobucket.com/albums/f202/G1968Y/2000_A8_intake_fix/DSC00318.jpg">
Hope this helps somebody!
Greg