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  1. #11
    Join Date
    May 2004
    Location
    STOKE ON TRENT, U.K.
    Age
    54
    Posts
    10,163
    Aaron:
    Yes, you understood correctly.

    Drammyboy:
    The Diff in Aaron's car is not attached to the suspension arms. So will not be a problem.
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  2. #12
    Join Date
    Mar 2009
    Location
    liverpool
    Age
    46
    Posts
    389
    Aaron,

    Remember the app has limits -

    IF ONE OR MORE ANGLES EXCEED SPECS:Sorry! It appears that one or more of your angles is incorrect or exceeds the recommended limits. Press the “?”for more information about these results.Your angles appear to be outside of the recommended range. Please consider the following information:

     This app targets a maximum universal joint angle of 3-degrees and an overall driveline operating angle (thedifference between Angle 1 and Angle 2) no greater than 2-degrees. If either universal joint angle exceedsthe recommended limit, the driveline operating angle will always result in a failing grade.

     If the results are within the accepted range, but were flagged as incorrect, it is because the app has detectedthe engine/trans and rear axle to be at opposing angles rather than complimentary as desired. Due to thenarrow limits of this app, the condition may not cause significant vibration. However, angles that are ‘equaland opposite’ are most desirable. See diagram at beginning of app for example of appropriate configuration,noting the dashed lines.

     Results of “0.0” throughout the driveline are also considered ‘out-of-spec’ because a slight amount of preloadis recommended for proper function of the needle bearings in the universal joint bearing caps.

     Correcting out-of-spec angles may require raising or lowering the engine/transmission or rear axle assembly,or rotation of the rear axle assembly.

     Remember, this app does not account for compound angles resulting from the horizontal offset of majorcomponents in the vehicle, or those that may not be properly squared in the vehicle chassis. Either of theseconditions may result in universal joint angles being greater than indicated, and vibrations may occur.

    Perfect alignment is Desired, to minimize the chance of vibration. you set it as best you can.

    It doesn't mean your finished settings will cause any vibration. At this stage you can only deal with what you have now.

    Trying to iron out every kink at the earliest stage only make for a long build (I know!)

    All the best and the only way is forward!

  3. #13
    Join Date
    Jan 2004
    Location
    Southwest, Somerset, U.K.
    Age
    35
    Posts
    3,221
    Throw the phone and app away. Then pick the phone back up and call bailey Morris

    Speak to their tech guys or Andrew Evans. They will talk you through it all and the options available

    I’ve had instances where we have had mis alignment issues and with their help and custom Shafts brought things back to an acceptable standard.

    From memory I think the maximum mismatch of joint/flange angles can be 2 degrees

    Either way Andrew can explain and discuss the path of least resistance in getting it all work.

  4. #14
    Join Date
    Feb 2011
    Location
    Northampton
    Age
    41
    Posts
    4,044
    I think most places (well, the places I've tried to call) are closed until next week - but I'll give them a call.. that said, I believe you're right about the degree limits, and I can't see a way to get mine 'under' those limits; close, maybe, but not under.

    With the gearbox sitting roughly where the slimmer rear mount puts it (and where the gear shift stuff will clear the underside of the tunnel), I have the following kind of layout:



    I'm using the ground as my plane of reference, which is maybe 0.5º off the chassis according to my inclinometer, but it's also the only flat, straight thing around So the diff is at roughly 90º to the chassis - maybe a hair pointing 'up', so we could call it 90.5º maximum.
    The gearbox tail is pointing 'down' at 87º from horizontal.
    The distance between flanges is 282mm, and that leaves the prop running 4.4º 'uphill' between the two.

    According to online calculators that puts the driveline angles at 1.4º on the gearbox and 3.9º on the diff UJ, and to make matters worse since the gearbox and diff are at different angles, "the internet" tells me it might shake itself to bits.

    If I was capable of adjusting the diff so that it matched the gearbox then the front operating angle would be worse (as the prop would be at a steeper angle) but the rear might get better.
    If I raise the tail of the gearbox enough that it, too, is almost dead on 90º then I need an almost 100mm tall gearbox mount, and the carb is now pointing downhill (forward) about 6º because the engine is so far off level.. and I'm not sure the engine can come 'up' without hitting the underside of the bonnet.

    All in all it just seems engineered 'wrong', so I feel like I'm missing something.. maybe the chassis is just too short to get it 'perfect' with a very-long T56 and a huge FE, and a big compromise is needed.

    On the bright side, I have a lot more time in the evenings now I'm not in the garage!
    My DeDion build diary..
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  5. #15
    Join Date
    Mar 2009
    Location
    liverpool
    Age
    46
    Posts
    389
    Hi Aaron,

    If I understand it correctly. You are 87 Deg down at the end face of the gearbox making the driveline though the engine/gearbox 3 Deg down. 4.4 Deg upwards on the prop and the diff flange at 0 Deg. Using the spice calculator raising the gearbox to 0 Deg would give operating angles for joints 1 & 2 of 4.4 Deg. Is this not acceptable? The joints would be under load due to the angle of the prop?

  6. #16
    Join Date
    Mar 2009
    Location
    liverpool
    Age
    46
    Posts
    389
    Forgot to say, once the gearbox is raised 2 Deg the prop angle and both working angles would be slightly less than 4.4 deg

  7. #17
    Join Date
    Feb 2011
    Location
    Northampton
    Age
    41
    Posts
    4,044
    Ah, if I raise the tail of the gearbox to be at almost 90deg, then it sits all the way up here - so high it's no longer in the tunnel:


    And the prop is now 6deg downhill from box to diff..
    My DeDion build diary..
    Hon Sec of the Digidash branch of the Unpopular Kit Car Design club

  8. #18
    Join Date
    Feb 2011
    Location
    Northampton
    Age
    41
    Posts
    4,044
    Back to Dave's idea, my maths says that the top diff mount would have to come down a little over 16mm to achieve a 3deg angle on the input flange if I was trying to make diff match the natural position of the gearbox - which sounds like an awful lot, and would certainly mean having a new mount manufactured somewhere..
    My DeDion build diary..
    Hon Sec of the Digidash branch of the Unpopular Kit Car Design club

  9. #19
    Join Date
    Nov 2012
    Location
    Lanarks
    Age
    63
    Posts
    223
    My my my – a long road for a shortcut

    Now that you have found out raising the gearbox is a no no
    then……….
    secure your gearbox rubber mount to the chassis mount
    Remove your rubber engine mounts
    Support the front of the engine on a trolley jack and lower to suit.
    Test this and if the angle of dangle at the rear works out then get a cut-off disc
    and lower the actual Chassis mount to suit.

    I take it your diff prop is offset
    You’ll need some out -of -line to help the U/J grease move around in the cups
    Does your chassis have a small shaped bracket between the chassis rails for
    – the propshaft to just clear ?

    Have a go and don’t say….Oh the sump is too low.
    It can be sectioned and widened if need be.
    Carbs can have an angled leveling plate
    Similar situation to steering and exhaust manifolds
    Leave the important bits (steering shaft) and alter the header tubes

  10. #20
    Join Date
    Mar 2009
    Location
    liverpool
    Age
    46
    Posts
    389
    Sorry Aaron, just realized you had already looked at that. My RV8/LT77 is 18mm per degree at the box. Your must be nearly double that.

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