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Thread: A question for V8 Stromberg CDSE specialists

  1. #1
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    A question for V8 Stromberg CDSE specialists

    After rashly stating a month ago on this forum that my 1984 V8 110 had been a paragon of reliability for 20 years I suddenly had a problem with one of the stromberg 175CDSE carburettors that was resolved by putting a new kit through it.

    While doing that I obviously had the carb off, and saw the white 'teeth' on the inlet manifold side of the carbs as shown in the photo I hope appears below.

    The workshop manual refers to these, but I do wonder whether they are a milder version of the throttling that was applied (I understand) to de-tune the V8 in the Stage 1 Series III V8s. Is there any advantage in removing these, and, in any case what are the 'teeth' for?

    20200621_132410.jpg

    Any advice gratefully received!


    Michael


    110 300tdi (1999)
    110 V8 County (1984)
    SIII 'Game' (1977)

  2. #2
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    Maybe to modify the airflow out of the carb to get better atomisation, I doubt that they would provide much restriction. Maybe a factory Hiclone

    Regards,
    Tote
    Go home, your igloo is on fire....
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    MY2016 Aintree Green Defender 130 Cab Chassis
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  3. #3
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    Quote Originally Posted by Tote View Post
    Maybe to modify the airflow out of the carb to get better atomisation, I doubt that they would provide much restriction. Maybe a factory Hiclone

    Regards,
    Tote
    Thanks Tote

    The same thoughts crossed my mind - especially the Hiclone thought!!

    Michael


    110 300tdi (1999)
    110 V8 County (1984)
    SIII 'Game' (1977)

  4. #4
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    its a restriction plate,

    the teeth create turbulance which does a couple of things

    1. it damps the incoming airs velocity by forcing it into a turbulent flow pattern

    2. it helps with distributing that fuel air so you get a more thorough mix.


    try this...

    run the back edge of a comb through a bath of water with it just at the surface (holding it by the teeth)

    now do it with the teeth in the water.

    similar concept.
    Dave

    "In a Landrover the other vehicle is your crumple zone."

    For spelling call Rogets, for mechanicing call me.

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    Archaeoptersix 1990 6x6 dual cab(This things staying)


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  5. #5
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    So Dave,
    If it was removed would the increased flow offset the better mixture and atomisation from the teeth or at the end of the day would you not notice any difference?

    Regards,
    Tote
    Go home, your igloo is on fire....
    2014 Chile Red L494 RRS Autobiography Supercharged
    MY2016 Aintree Green Defender 130 Cab Chassis
    1957 Series 1 107 ute - In pieces

    Assorted Falcons and Jeeps.....

  6. #6
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    yes and no...

    the main desired effect IIRC is to damp the air flow on sudden throttle openings which is supposed to help with the mixing of the fuel and the air preventing flat spots during sudden losses of manifold vacuum.

    (damping meaning to reduce the rate of change)
    While the engine is pulling air quickly vorticies are setup behind the teeth, when you open up the throttle as the vorticies collapse they produce a short low pressure which draws a little more air through helping the carby do the carby thing. When you close the throttle off (or engine RPMS rise) the vorticies start up again and promote turbulant air flow mixing the fuel a little better and preventing the fuel from falling out of the mix and lining the intake.

    If you're not driving in a style that warrants them then they probably make no difference, however, I quietly believe that they work because they help maintain smooth flow through the carby and not because of any "hiclone" effect they have.
    Dave

    "In a Landrover the other vehicle is your crumple zone."

    For spelling call Rogets, for mechanicing call me.

    Fozzy, 2.25D SIII Ex DCA Ute
    Tdi autoManual d1 (gave it to the Mupion)
    Archaeoptersix 1990 6x6 dual cab(This things staying)


    If you've benefited from one or more of my posts please remember, your taxes paid for my skill sets, I'm just trying to make sure you get your monies worth.
    If you think you're in front on the deal, pay it forwards.

  7. #7
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    Thanks to both Tote and Dave

    I think you have clarified things for me.

    One final consideration has just crossed my mind and which supports the suggestion that removing them would have little or no effect is the fact that the diameter of the aperture defined by the inside of the 'teeth' is still significantly larger than the mouth of the Stromberg carburettor at the throttle butterfly, so it would be unlikely that the 'teeth' would act as a limit on the flow of the air/fuel mixture.

    The subtext of my original question was that I was trying to work out why the rated power output of the V8 in the 110 is significantly lower than is claimed for a similarly aged Range Rover (approx 110 bhp for the 110 vs 125 -135 bhp for the RR depending on source) with the same engine/carb combo. But I now see in the RR parts catalog that the same restrictor plate is shown for the RR, so the restrictor plate cannot be the source of the difference. Perhaps there is a camshaft difference causing this (and when I rebuilt this engine I seem to recall installing a RR camshaft) and/or the quoted bhp figures just represent higher rpm and hence peak power for the RR (although the figures I see show peak power at around 4000 rpm).

    Thanks once again


    Michael


    110 300tdi (1999)
    110 V8 County (1984)
    SIII 'Game' (1977)

  8. #8
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    The FC101 3.5 does not have any restrictor or sharks teeth and is rated at 120hp in 12v form. The only difference to the same RR engine is the exhaust - the 101 exhaust manifold is designed for more torque at lower revs and tapers off at higher revs.

    As far as I know - all LR carb 3.5s have the same cam shaft

    So differences in power comes down to restrictors/shark teeth, 24v or 12v (in the case of a 101) and exhaust design. Nor real differences in basic engine.

    Garry
    REMLR 243

    2007 Range Rover Sport TDV6
    1977 FC 101
    1976 Jaguar XJ12C
    1973 Haflinger AP700
    1971 Jaguar V12 E-Type Series 3 Roadster
    1957 Series 1 88"
    1957 Series 1 88" Station Wagon

  9. #9
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    My impression always was that the sharks teeth main function was to help idle stability as the turbulence caused reduced fuel pooling in the manifold.
    Regards PhilipA

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