Volvo RWD 140-160 Forum

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Emissions stuff 140-160

All,
The previous owner of my 71 142S disconnected all the smog control stuff: the evaporative cannister, etc, and vented blow-by to the atmosphere. All inlets to carbs, etc, are capped off. He also replaced the stock air filter with foam filters on each carb. Is there any benefit to restoring it all to the way it was? The car drives fine...








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    Emissions stuff 140-160

    Foam filters are pretty crappy, I would get a pair of big paper filters, the big ones found 115HP B18B's are very good if you can still find them.

    Tank vent: see if there are any places to put a small hoses from the top of the fuel filler pipe. The non-emmision cars ran a hose from there to a hole behind the bumber bar.



    --
    Three 164's, Two 144's, One 142 & a partridge in a pear tree.








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    Emissions stuff 140-160

    Some of this might be worth doing if it's not too difficult.

    The evap canister's absence means the evaporated fuel gets vented to the atmosphere rather than captured in the canister and sucked back into the engine next time it runs. So, if you hook it back up you'll save a teeny tiny amount of fuel via reduced evaporation losses... if you've already got the canister and the hoses, what the heck, why not. If you've got no line on that stuff, no big.

    The foam filters are fine. The stock pre-heat system was pretty worthless. BUT: the stock cold air intake was nice, particularly at highway speed. But then, chances are you don't have a complete intake lying around, and putting it back to stock is probably going to be way more trouble than it's worth.

    The venting of blowby: NO, you should fix that. Venting to open air leaves your crankcase full of blowby, and exposed to unfiltered air. Minor things, but engines last longer when the air inside them is clean and filtered. If you've got the ports and all you need is a couple hoses, it's a no-brainer: having a positive crankcase ventilation system is a Very Good Thing which reduces your maintenance costs by reducing the fouling of your oil.

    The way it's supposed to work: Air is pulled through the air filter, into the crankcase, and blowby (exhaust --> carbon, unburnt fuel, etc) is sucked out of your crankcase and into a restricted vacuum port in your intake manifold. The upside: reduced fouling of your oil, improving the life of your engine, plus a reduction of oily odors emanating from your engine compartment. The downside: not much. A couple hoses to run?

    All you need is two hoses:
    The one from the flame trap goes to a port inside the air filter. (you might have to install such a port if you've got aftermarket air filters.)
    The other one goes from a special restricted port on the intake manifold, to the port on the stock oil cap. Use the stock molded hose for this purpose; they're not expensive.








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      Emissions stuff 140-160

      I don't have a complete intake lying around, nor do I know where to source an air box, so I'll leave that as is. Looking at the tank filler, there seem to be hoses running from there to under the car. I guess that's vent enough, although I do get pressure build up in the tank.

      The PCV system I probably should restore. Looks like the old owner has the hose from the oil filler cap to the intake, but he dropped the hose from the oil trap to the air filter. I don't know if there's a port on the air filter. I'll check tonight. Also, looks like the oil trap (looking down onto it) has a pipe sticking out the top with corrugated metal inside. Would I just attach the hose to this?

      Thanks!








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        Emissions stuff 140-160

        Yes, the corrugated metal thingy inside the pipe on the oil trap, is a flame trap. Glad to know it's there :)

        Run a hose from that to the air cleaner, to filter the air going into the crankcase. Hopefully the air cleaner housing has either a fitting for this purpose, or a place to put one.







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