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Thread: Plugging vacuum ports

  1. #1
    Join Date
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    Plugging vacuum ports

    Does anyone have any suggestions for a cleaner/more-permanent way to cap vacuum ports than a rubber cap with a hose clamp (or the classic piece-of-hose-with-a-golf-tee)? Specifically, there are a lot of unused connections on the 'log' portion of my pre-facelift intake manifold that I would like to improve and forever remove from the list of possible vacuum leaks. Most importantly, the large port that is on the bottom of the log and is inaccessible when the intake is in-place.

    I was thinking that if I could find appropriately-sized metal caps that I could solder or epoxy them in place, so they could theoretically be re-opened in the future. Or maybe I should just weld them up, the odds of me ever using those ports again is very small.

  2. #2
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    You pull out the sleeve and then drill and tap the hole for a plug. There is an excellent thread on it, which I don't have the patience to find on my phone.

  3. #3
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    So those ports are threaded in? That is great news, I will see if I can remove those port connections without damaging the threads. Thanks!

    Update: Oh wait, I see that by "excellent thread" you mean a forum thread, not threads in the aluminum. But still, it should be easy enough to do.
    Last edited by dreiermann; 02-10-2017 at 01:44 PM.

  4. #4
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    Plugging the big EGR hose nipple on the bottom of the log was a thread started by Bimmerknut.

    For the small hose nipples on the log, just use vacuum caps that are color coordinated to your car
    Tbd

  5. #5
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    Vacuum caps color-coordinated to my Sierrabeige car? A good idea. I will use a pre-chewed wad of Wrigley's Gum, perfect color-match. Then I can blow bubbles out of the tailpipe!

  6. #6
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    There you go!
    Tbd

  7. #7
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    I accidently discovered an open nipple on the bottom of my post face lift intake manifold. Plugging it up resulted in a huge improvement in the car's driveability. Have no idea of the original purpose of the nipple, if any.

  8. #8
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    '78 320is 83 320i R.I.P.

    Oh SNAP!!! German Engineering is IN DA HAUS YAH!!!

  9. #9
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    Thanks for posting the link! I had tried searching for the thread earlier, but didn't find it. This will be one of my weekend projects.

  10. #10
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    I am still waiting for the 5/8" tap to arrive, but I did do the smaller ports with a 1/4" tap. Just to be sure that it is sealed, I put RTV on the upper bolt threads. Looks much better than the caps-with-clamps that I had on there before!
    Attached Images Attached Images

  11. #11
    Join Date
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    Quote Originally Posted by John Adkins View Post
    I accidently discovered an open nipple on the bottom of my post face lift intake manifold. Plugging it up resulted in a huge improvement in the car's driveability. Have no idea of the original purpose of the nipple, if any.
    Which nipple are you referring to?

  12. #12
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    Perhaps referring to #9 on the attached real oEM image?
    When I purchased my e21 a couple of years ago it would barely stay running when they rolled it off the delivery truck. It started and ran very smooth other than trying to stall if you didn’t keep your foot tapping on the accelerator.
    I opened the hood and started looking for vacuum leaks, and just stumbled across a cracked plug under the intake manifold. I couldn’t see under the manifold, so I plugged it with my finger and it ran perfect.
    I got a new/similar plug at the hardware store and haven’t had an issue since. Think mine is red, or it was when I pulled it off.

    IMG_0886.jpeg

  13. #13
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    1986 BMW E30 325
    Just a side question, if you remove a vacuum cap from the intake manifold, and the cap is filled with oil, what can that be a sign of? Excessive blowby?
    80 320i / 82 320i / 85 735i / 86 325

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