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Crank case ventalation options 140-160 1971

posted by  someone claiming to be 145volvowayne on  Tue Jan 12 03:08 CST 2010 [RELATED]



Even with the 'new' cylinder head I am still getting a LOT of smoke out of the tail pipe on heavy deceleration (2500 rpm's or greater). Blow-by?? I'm thinking, from some pictures of other engine bays I've seen, my PCV system may not be routed in the best way.

For a carbureted engine what is the best way to connect or isolate the three locations: 1-metal box low on drivers side of engine. 2- PCV valve on oil fill cap. 3- fitting into carb air filter box.

AND how do I test the oil fill cap to determine if the PCV valve is working?

Thanks,
Wayne







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    Crank case ventalation options 140-160 1971

    uid 37336's pic
    posted by  B20Paul. on  Tue Jan 12 16:10 CST 2010
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    last visit: Mon Oct 20 10:54 CST 2014
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    a LOT of smoke out of the tail pipe on heavy deceleration (2500 rpm's or greater).

    Inlet valve guides and/or seals. When you are decelerating is when the vacuum is highest & that's when the cylinders try to pull oil through the inlet guides.

    PCV: I'd be inclined not to use it. The distribution is not good on you DCD manifold.

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








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    Crank case ventalation options 140-160 1971

    uid 5322's pic
    posted by  alschnertz on  Tue Jan 12 06:00 CST 2010
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    last visit: Fri Oct 24 10:32 CST 2014
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    I'm with Dave on the routing.
    Simply blow through the oil cap fitting. There shouldn't be any resistance.

    Are you sure you don't have worn rings causing the blow-by?







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    Crank case ventalation options 140-160 1971

    posted by  Volvo From Heck on  Tue Jan 12 03:49 CST 2010
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    last visit: Mon Oct 13 20:56 CST 2014
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    The way it would be set up originally on the '71 -- From the oil separator (box on L/S of motor) a hose goes to a restricted orifice fitting on the intake manifold. Air is supplied to the motor with a hose from the backside of the filter housing to the oil cap. There is no PCV valve on the B20. An earlier model 140 with the B18 would have one. -- Dave








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      Crank case ventalation options 140-160 1971

      posted by  someone claiming to be 145volvowayne on  Tue Jan 12 08:22 CST 2010 [RELATED]

      In some of the pictures I have seen there is a smalll air filter on the oil seperator box and the oil fill cap is routed to the air filter box. Do you know that the reasoning is behind this setup?

      Thanks for the info.

      Wayne








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        Crank case ventalation options 140-160 1971

        uid 5322's pic
        posted by  alschnertz on  Tue Jan 12 12:14 CST 2010
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        last visit: Fri Oct 24 10:32 CST 2014
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        You may be referring to a late B18.

        At least in the case of my '68 B18...
        1. There is a brass flame trap inserted into the separator canister nipple;
        2. A vertical hose leaves there and goes into a PCV valve;
        3. Leaves the PCV valve and goes into a tee;
        4. One branch of the tee goes to the brake booster;
        5. The other branch of the tee goes to a nipple in the intake manifold which unlike the B20, does not have a restriction;
        6. A second hose goes from the back side of the front air filter to the top of the oil fill cap.

        Basically the routing is opposite on a B18 vs. a B20.







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          Crank case ventalation options 140-160 1971

          posted by  Volvo From Heck on  Tue Jan 12 13:33 CST 2010
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          "Basically the routing is opposite on a B18 vs. a B20." It seems they are very similiar. The B18 is protecting the the crankcase from backfires via the PCV valve. The B20 does the same by the orifice restriction. The B20 provides vacuum to the brake booster via a separate hose going to an unrestricted fitting on the manifold--while, as you say, the B18 has a "T" going to a single open fitting. The oil cap picks up fresh filtered air from the air box on the B20 and accomplishes the same through the front filter of the B18. -- Dave








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            Crank case ventalation options 140-160 1971

            uid 5322's pic
            posted by  alschnertz on  Tue Jan 12 15:03 CST 2010
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            last visit: Fri Oct 24 10:32 CST 2014
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            Here's what I meant by routing is opposite.

            I'm pretty sure the filtered air on my '72 B20 entered the crankcase at the canister and exited through the oil fill cap and then into the intake through the restricted nipple.
            Vs. the B18 where filtered air entered the oil fill cap.

            Gonna have to go check the green book. An interesting but useless exercise I suppose, but I'm bored.







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              Crank case ventalation options 140-160 1971

              posted by  Volvo From Heck on  Thu Jan 14 08:01 CST 2010
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              last visit: Mon Oct 13 20:56 CST 2014
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              "I'm pretty sure the filtered air on my '72 B20 entered the crankcase at the canister and exited through the oil fill cap and then into the intake through the restricted nipple.
              Vs. the B18 where filtered air entered the oil fill cap."
              I took a look in the Green Book I have for the '73 140--probably the same for the '71. I stand corrected--you are absolutely right--air enters through the side canister from the filter housing---exits from the oil cap to the intake manifold. -- Dave







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