Getting sick of gas/blowby fumes...

[MopaR&D]

I've been putting a lot of street miles on my fresh 360 Magnum in my '70 Duster including a 7-hour (each way) road trip through the mountains. It runs fantastic but the gas and blowby fumes have started to get on my nerves; my clothes often stink of gas after I've been driving for a while.

First I noticed my gas cap was on pretty loose and leaking a bit when making sharp turns or stops; I fudged it to make it seal better. My car came with the Evaporation Control System since it's from Cali which includes the expansion tank and vapor "bottle" in the trunk which has a line going to the crankcase breather on the engine. I no longer have that special breather with the nipple for the vapor line. Where can I find one of these? My current breather is "open" and just vents to the air, you can definitely smell it after hitting the throttle for a couple seconds (I do have a working PCV valve though). I also want to connect the bowl vent to the breather if possible instead of just leaving it open to the air.

Also I've considered getting a charcoal/vapor canister to route all these lines to but there are so many different ones out there for different cars; would there be any advantage to this over venting to the crankcase like the factory did for this model year?

 

[dusterglenn]

Do you have tailpipes? If your exhaust exits under the car, it's amazing how stinky it can get.

 

[67Dart273]

Tailpipes and HOW IS your trunk seal?

Get the vapor system hooked up. If you cannot do anything else, run it into the air filter bonnet

And speaking of which that is where your "open breather" BELONGS. The entire purpose of the breather is to INTAKE air for the crankcase until pressure is too much for the PCV valve (and check it, by the way.............) and when the crankcase pressure becomes positive, the original breather system is supposed to route OUTgoing crancase vapors INTO the air filter and down the engine.

You have a shop manual? I have my old paper '70 manual, and if you need, I can post a photo of the evap system routing for ya.

 

[TrailBeast]

Could be that it's coming in through the trunk seal also.

Do you have tailpipes? If your exhaust exits under the car, it's amazing how stinky it can get.

 

[72Plymouth]

Do you have a hood to cowl seal? If you want to use your original gas cap, you can buy a new cap and use the seal from the new one.

 

[Tracy S]

I bought a car and had the same problem until I realized the breather was open and not connected to the air cleaner. A dollar piece of hose fixed the problem.

 

[Abodybomber]

Same here.My Scamp had the same problem.Traced it to trunk seal.Also got cleaner with full length tailpipes.Might try a smoke test,if able.

 

[slantsixdan]

See this post and this one. Also, you need to have the correct gas cap in good condition, and of course the carb float and bowl vent must be adjusted correctly. You may also want to make or buy a heat shield to put under the carburetor.

 

[MopaR&D]

Awesome thanks slantsixdan that's exactly the info I was looking for. I'll go get a '72 charcoal canister and look for a donor car with the bracket. I bought a breather with a fitting today, just have to switch around my valve covers so it's closer to the air cleaner.

BTW I saw you were mentioned in Mopar Action recently, you did that article a little while ago on lighting right? That was great info, if I ever have lighting questions I'll know who to ask!

 

[slantsixdan]

Glad to help when and where I can!

Yep, lighting article some years ago in Mopar Action was mine, too.