Volvo RWD 140-160 Forum

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SU needles 140-160

Does someone use the combination B20F, twin SU HIF6 carbs (not HS6) and K&N air filters? If so, then I'd very much like to know which needles you have in your SU's.
BAL needles are allright if an original air filter is used, but not so with K&N filters.
I hope to get the answer here instead of making an expensive visit to a rolling road... Thanks in advance.








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    I'm about to 140-160

    Have some installed on an F. Too bad my engine just bit a bullet, and is now having problems. I'm not sure if i'm just going to get some nice headwork done, or if i'm going to swap in a 75 motor... But I'll let you know what happens with the needles Rhys provided me with. Peace and good luck!








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    SU needles 140-160

    The K&N filter will not change the mixture to any degree. The BAL needles are fine, and if you want a bit richer go to BBB. But the air filter doesn't dictate that, the engine does in terms of its compression, cam, exhaust, and head work.








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      SU needles 140-160

      Hi Rhys,

      This is a rare occasion that I will disagree with you. :) The stock flat air filter is restrictive to stock B20B's & would therefore cause the mixture to gradual go richer the higher the RPM's. I would agree with BBB however, they are the standard needles for B20B's with HIF6's here.

      Cheers,
      Paul.








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        SU needles 140-160

        Hi Paul - I'll agree with you too if we are talking the Crossland brand panel air filter. They are terribly restrictive when new, let alone with a few miles on them. The volvo filter, especially the later ones, seems to be OK for the B20. The biggest restriction I have found is the silly hot air valve in the snorkel. I just discard the entire thing and allow the air filter box to take air from the engine compartment.
        American B20B's got the BAL while Canadian market cars had a mixture of BAL and BBB. I can't explain the reasoning behind the choices except that we are a bit chillier up here....
        Rhys








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    SU needles 140-160

    I found that BAL needles were OK on my B20 (with milled and ported B20F head
    and IPD 7001 cam) either with or without filters. K&N are
    somewhere in between. Needles are about the last thing you change unless
    you have some that are REALLY unsuitable (like for a MUCH bigger or smaller
    engine than yours). BTW I am also using HIF6 carbs on a B30 with the same BAL
    needles and the big flat air cleaner and they work great there too. Seems to
    do about the same with the aircleaner removed.

    I'd suggest that you make sure you don't have air leaks and that your mixture
    is adjusted right. If the seals on your throttle shafts are old you should
    replace them to eliminate a pair of potential air leaks at the worst possible
    place on each carb.

    Also make sure your float level setting is right and that your float valves
    are indeed opening and closing like they are supposed to do.
    --
    George Downs, Bartlesville, Oklahoma, Central US








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      SU needles 140-160

      George, you are right. My twin SU's came from a 145 and the rear one has a takeoff for the vacuum line to the distributor, which I did not recognise as such (until today that is...) because it is mounted upside down and under instead of on top of the carburettor body. Never saw that before. Also on occasions fuel was leaking through it, so I thought it was kind of an additional overflow pipe. Anyway, problem solved!







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