Getting 78 20R ready for Smog

Discussion in '1976-1983 Build-Up/Project Threads' started by Chris Garrecht-Williams, Nov 22, 2020.

  1. Chris Garrecht-Williams

    Chris Garrecht-Williams Newbie

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    BVSV.png


    Hey y'all,

    First post here. I am trying to get a 1978 20r engine ready for smog out here in California and I've hit a stumbling block. Valve circled above is not attached to anything, and no matter how many times I look at the schematic spaghetti diagrams, I can't seem to suss out where the vacuum lines should go.

    I'm pretty sure it is COOLANT BYPASS BIMETAL VALVE, and when I find the valve itself for sale on ebay it seems to have something to do with the coolant and the heater, but I haven't gotten further than that. Any tips?

    Thanks,
    Chris
     
  2. Perkolator

    Perkolator Addict

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    Sorry nobody replied- I believe it’s a vacuum switch that hooked up to the intake somewhere under the stock air cleaner. TVSV/thermal vacuum switch valve I think
     
  3. nottoshabi

    nottoshabi Enthusiast

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    @Chris Garrecht-Williams Under the carb intake manifold there is a valve with 2 nipples on it I think it hooks up to that.
     

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