Engine Question

[IronClad]

1971 Newport 360

What is this line running from the valve cover? and where does it go?

 

[rkrochen]

Maybe I am wrong but that doesn’t look right. The breather should be hooked to the air filter and is part of the positive crankcase ventilation system. Is the pcv valve hooked up on the other side. Could explain why oil is leaking.

 

[IronClad]

you cant see it in this pic but it does have a thicker hose going up to the air cleaner, and a smaller one running to the carb. I was thinking a vent for the fuel tank but i thought I should at least ask first

 

[Wildaugust]

On the big block there is a line like that, similar, that runs back to the little vapor separator by the fuel tank. That one will be basically the same thing. It's just a fuel vapor return line. The PCV valve should be on the other valve cover IINM.

 

[IronClad]

Theoretically, if I ran a fuel return line from a vapor separator fuel filter to vent back into the fuel tank. would this line offer enough pressure relief?

 

[Wildaugust]

Unless you have to disconnect that line from the engine to make modifications, etc. I think I would leave it hooked up. You may have to use a vented gas cap if you change the way the line hooks into the evap system.

 

[IronClad]

good to know.

 

[Davea Lux]

That setup started with California emissions for the '70 model year and went to everything else for '71. The system used the engine crankcase as a repository for fuel vapor coming off the fuel tank. Theory was that the fuel vapor could be stored in the crankcase to be burned as the engine was running rather than allowing it to vent into the atmosphere. It did not work very well in practice, often caused a lot of black smoke on start up in warm weather as the PCV system sucked up the fuel vapor, also sometimes caused oil contamination issues.. This system was replaced with the charcoal canisters from '72 on which was a much better system.

Dave