Two port breather - Alternatives?

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trebor75

trebor75

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1970 Plymouth Duster. Originally /6 but now have a 273. This breather came of my slant 6. The small hose, is that for gas tank ventilation?
I was thinking of blasting and painting my valve covers with black wrinkle paint and I thought it would look nice with a chrome breather (i have the pcv hooked up on the other side). I can't seem to find an aftermarket breather with 2 ports like the one I have. I dont want to compromise the system. How did all the other guys with nice and chrome 1 port breathers work around this?

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Take that one to your local chrome plating guy. I did mine like that, and I love the stock look with a twist.

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Really nice engine! I love the look of a nice /6. And surely, that is one way to go. But I'm still curios how other people have solved this or if the simply rout the vent to the atmosphere!?
 
Or get the standard one port and use one of these on the other line.....

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Thanks mguner. I think that is the way I will go. How come they vent the tank into the valve cover?
 
Get a charcoal canister to catch the fumes, that breather was a one-year-only setup and it's not a great design; letting gas vapors collect in the crankcase will just dilute your oil over time (also might be hazardous??).
 
since were on the subject, would it make sense to put that filter/breather right at the tank and just remove all that extra breather line?
that should also keep the fumes away from the cab
 
diymirage said:
since were on the subject, would it make sense to put that filter/breather right at the tank and just remove all that extra breather line?
that should also keep the fumes away from the cab
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That might be possible but 1970 cars had a unique clean-air package with that breather and also an odd foot-long metal tube in the trunk next to the gas filler tube which vents the tank and collects condensed gasoline vapors. My '70 Duster came with this setup; I got an old charcoal canister from the forum here and just connected the vapor hard line under the hood to the inlet on the canister instead and just ditched the breather; it's kind of a pain to remove all the hard lines and such for the 'Clean Air System'. I have no problem with fumes building up when I park it in the garage after a drive, but before I put in the charcoal canister I just had the lines disconnected and open and I DID have noticeable vapor buildup (smell) then.
 
That "breather" is the tank vent on later cars. Whatever you do, you must have it "end" higher than the fuel will ever be, to prevent siphon/ spillage.
 
MOPEkidD-3 - Yes that is the same setup my 70' Duster have.
 
trebor75 said:
Thanks mguner. I think that is the way I will go. How come they vent the tank into the valve cover?
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The idea was that the PCV system would suck the fumes into the intake manifold and they would be burned in the engine.
 
69_340_GTS said:
The idea was that the PCV system would suck the fumes into the intake manifold and they would be burned in the engine.
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I thought it was something like that. But, would that not interfere with the a/f ratio?
 
trebor75 said:
I thought it was something like that. But, would that not interfere with the a/f ratio?
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Possibly a bit but no more than a purge line from a charcoal canister would; you don't have a constant flow of vapor anyways it all pretty much gets 'consumed' within the first few seconds of startup and really just builds up once the car is shut off. It was kind of a stop-gap measure to keep gas vapors from venting to the open air after shutoff, before they started using charcoal canisters.

I finally found this article written by our local 'wizard' Dan Stern (slantsixdan), explains everything you need to know about the "ECS" system on our '70-71 cars:

Fixing 1970s Evaporation Control Systems
 
MOPEkidD-3 said:
Possibly a bit but no more than a purge line from a charcoal canister would; you don't have a constant flow of vapor anyways it all pretty much gets 'consumed' within the first few seconds of startup and really just builds up once the car is shut off. It was kind of a stop-gap measure to keep gas vapors from venting to the open air after shutoff, before they started using charcoal canisters.

I finally found this article written by our local 'wizard' Dan Stern (slantsixdan), explains everything you need to know about the "ECS" system on our '70-71 cars:

Fixing 1970s Evaporation Control Systems
Click to expand...

That was an interesting read. Thanks a lot for the link.
 
I agree, Dan's level of detail and knowledge of how this stuff works is a real treat as well. Everyone tends to think of all emissions control devices as needless junk, but if working properly things like a charcoal canister and even EGR will have no affect on performance and if tuned right (esp. EGR) you can actually gain a bit of MPG.

IMO unless you like your garage reeking of raw gas fumes when you shut down after a drive there's no good reason not to add a charcoal canister, except for being able to see it in the engine bay which if you have a fully detailed show-quality engine compartment might be another reason not to use it.
 
1970 2 port breathers were for /6 cars with N95 - Required for California sale. Does the fender tag show N95?
 
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