Results 1 to 7 of 7

Thread: Looking for the right vacuum line

  1. #1
    Join Date
    Jul 2007
    Location
    Auckland, NZ
    Posts
    2,278
    Total Downloaded
    0

    Looking for the right vacuum line

    I have installed a vacuum gauge into my Stage 1 V8. I have SU carbs, so what vacuum pipe is the best one to cut into for the gauge?

    I tapped into one that comes off the inlet manifold on the rear end of the engine. It looks like goes down by the gearbox so I think that is the CDL pipe. When I start the engine, instead of the vacuum coming sharply, it creeps up then stops at about 12inHg. Revving the engine does not change the vacuum reading, so I am assuming this was not the line to tap into.

    The question is then, what line should I use? I would rather not drill and tap into the manifold.

    (Interestingly, when I was looking through the forum I saw I asked general advice about this five years ago. Finally getting around to it ).
    Alan
    2005 Disco 2 HSE
    1983 Series III Stage 1 V8

  2. #2
    Join Date
    Jan 1970
    Location
    Moruya Heads/Sth. Coast, NSW
    Posts
    6,532
    Total Downloaded
    0
    It needs to go into a port below the throttle plates in the carbys as close as you can to the throttle plates, sounds like you have tapped into a ported vacuum source, you need to get a non-ported source, regards Frank.

  3. #3
    Join Date
    Jul 2007
    Location
    Auckland, NZ
    Posts
    2,278
    Total Downloaded
    0
    Would the dizzy vacuum advance be appropriate?
    Alan
    2005 Disco 2 HSE
    1983 Series III Stage 1 V8

  4. #4
    Join Date
    Jan 1970
    Location
    Moruya Heads/Sth. Coast, NSW
    Posts
    6,532
    Total Downloaded
    0
    You should have around 18' of hg (mercury) at idle, if you have no vacuum at Idle through whichever spot you choose to connect then you are likely connected to ported vacuum, to confirm raise the revs and if a Vacuum reading starts at higher revs, then you have ported, look elsewhere, regards Frank.

  5. #5
    Join Date
    Jul 2007
    Location
    Auckland, NZ
    Posts
    2,278
    Total Downloaded
    0
    OK. Will try and report back. I have seen a number of other posts where people have asked the same question.
    Alan
    2005 Disco 2 HSE
    1983 Series III Stage 1 V8

  6. #6
    Join Date
    Jan 1970
    Location
    Canberra
    Posts
    18,616
    Total Downloaded
    0
    My 3.5 has the main vacuum sucker for the brakes at the back of the manifold and two smaller suckers on each manifold inlet just under the carbys.

    The passenger side sucker has a T junction on it and is the dissy vacuum and the inlet port for the LPG primer and on the drivers side I have a T junction with a tube to fire in "Start you Bastard" when the engine has trouble starting on - degree mornings and on the other side of the T junction I have a vacuum line attached to a dash vacuum gauge - it uses the clear plastic tube that came with the gauge and works quite well.

    Garry
    REMLR 243

    2007 Range Rover Sport TDV6
    1977 FC 101
    1976 Jaguar XJ12C
    1973 Haflinger AP700
    1971 Jaguar V12 E-Type Series 3 Roadster
    1957 Series 1 88"
    1957 Series 1 88" Station Wagon

  7. #7
    Join Date
    Jul 2007
    Location
    Auckland, NZ
    Posts
    2,278
    Total Downloaded
    0
    Got it working now

    Turns out I had a kink in the pipe, behind the dash

    Now, while putting it all back together, one of the wires on the multi-alarm fell off and I don't which terminal it was. Tried one I thought a likely suspect but now the alarm only switches off when the lights are on.

    Trying to find a wiring diagram for it.
    Alan
    2005 Disco 2 HSE
    1983 Series III Stage 1 V8

Bookmarks

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Search AULRO.com ONLY!
Search All the Web!