What is the part inside the air breather housing with vac lines going to it?

Discussion in 'Small Block Tech' started by 72skylarkconvt, Sep 30, 2019.

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  1. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    The round part on the top end of the snorkel is called a vacuum motor. It operates the door inside the snorkel. If you apply vacuum directly to that, the door will close and stay closed as long as the vacuum is applied. I'm suggesting that you use the vacuum available directly from your running engine to test the vacuum motor/door. The vacuum motor has a rubber diaphragm that can dry rot and leak. That may be your problem. To see, jump out the system. Pull the
    hose off the vacuum motor. Then with the engine running, pull the intake manifold hose off and put it directly onto the vacuum motor and see if the door closes. That will tell you whether the vacuum motor is good or not. That is your FIRST step. Test and diagnose.:)
     
    LARRY70GS, Oct 2, 2019
    #21
    MrSony likes this.
  2. 72skylarkconvt

    72skylarkconvt Well-Known Member

    I will do this test this evening.
     
    72skylarkconvt, Oct 2, 2019
    #22
  3. MrSony

    MrSony Well-Known Member

    You can occasionally find vacuum motors on eBay that are nos. Idk of any place that sells them new.
     
    MrSony, Oct 2, 2019
    #23
  4. 72skylarkconvt

    72skylarkconvt Well-Known Member

    The vac motor is toast. I did it like you told me, did not move at all. Tried sucking on the line also, ha ha, did not move. Have to say the flapper in the snorkel seems rather STIFF movement wise, the vac I felt on my finger from the line off the manifold was not going to move that motor.
     
    72skylarkconvt, Oct 2, 2019
    #24
  5. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    You'd be surprised what vacuum can do. The flapper is stiff, but engine vacuum will close it.
     
    LARRY70GS, Oct 2, 2019
    #25
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