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Thermo Time Switch access?

Discussion in 'Technical Q&A' started by M.James, Oct 2, 2004.

  1. M.James

    M.James F1 Rookie

    Jun 6, 2003
    2,721
    Worcester, MA
    Full Name:
    Michael.C.James
    I'm looking at getting access to my Thermo Time Switch and the ElectroValve-sensitive switches nestled in what appears to be at the center of the engine 'V', under the Plenum cover of my 84 308 QV. I can barely see the units, but if I remove the oil filter I have a better view of them. Is it necessary to remove the Plenum Cover to remove/replace these items? What precautions do I need to follow to do this, taking into consideration the engine Throttle linkage and various hoses in the vicinity?
     
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  3. ferrarifixer

    ferrarifixer F1 Veteran
    BANNED

    Jul 22, 2003
    8,520
    Melbourne
    Full Name:
    Phil Hughes
    Removing the plenum is fiddly but no real trouble.

    Just unscrew all the nuts with an open spanner, and then the cold start connection etc.
    When lifting the plenum be very careful not to drop the steel spacers that are in the rubber gaskets around each stud...they'll go straight down an inlet track, and usually the one with the open valve......!
     
  4. tbakowsky

    tbakowsky F1 World Champ
    Professional Ferrari Technician Consultant

    Sep 18, 2002
    15,400
    The Cold North
    Full Name:
    Tom
    Just a question....why do you need to replace these sensors? Is your car acting funny..bad cold start performance or bad running when hot?
     
  5. 308GTS

    308GTS Formula 3

    Dec 27, 2001
    2,220
    TN
    You don't need to remove the plenum to remove the TTS.
     
  6. carlrose

    carlrose Formula Junior

    Nov 25, 2003
    300
    Hi Mr. James,

    As others have noted, not necessary to remove intake plenum to access TTS. Sure makes it easier, though. Taking the plenum off is tedious (lots of semi-accessible nuts & injector lines) but isn't complicated. Excellent opportunity to replace the small vacuum lines underneath. That said, if I had to remove the plenum for any other reason I'd replace this switch (approx $70) as prophylaxis due to difficulty of access.

    One can access after removal of oil filter with a large combination wrench (cannot recall size). You'll need to drain the coolant down a bit to prevent flooding on removal.

    :) Carl
     
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  8. M.James

    M.James F1 Rookie

    Jun 6, 2003
    2,721
    Worcester, MA
    Full Name:
    Michael.C.James
    Alright, if I remove the oil filter I can gain access to the side with a large spanner wrench, looks as though I'll need to empty the coolant overflow tank first and the contents empty all over the engine from where the TTS is located (according to the shop manual).

    Poking in there, I see two devices that are wired together - one device looks like a large bolt screwed into the center of the block from the top, and the other device is mounted longituinally, parallel to the axis of the block mounted further in - which is which?
     
  9. carlrose

    carlrose Formula Junior

    Nov 25, 2003
    300
    TTS is the large sensor mounted directly "into" V of block. The smaller sensor parallel to camshafts that looks as if it inserts into small "crossover" plenum is the dash gauge temperature sender

    :) Carl

    PS on my 328 two wires into TTS only one into temp sender.
     

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