Crankcase repair (53 Vincent restoration)

Discussion in 'Vincent' started by Buellingvincent, Mar 22, 2016.

  1. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    Me too!
     
  2. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    I found a couple of pics of the set up that Patrick did on my Egli.

    Note the double sided belt to drive the Alton alternator. Also note the one off cush drive he made for it, very clever and neat.

    Second pic is the one off outer cover he made, deeper than standard and slotted for ventilation.

    The double sided belt is tricky in this application. The big Vin motor expands a lot. Precise distance of alternator drive centre to clutch centre doesn't matter much with a chain as the teeth can slide in and out a lot and cope with the expansion and contraction.

    With a belt though, its a lot more sensitive. Too tight and the belt is 'crushed' and the alternator bearings put under undue load. They'll probably fail before the belt (as mine did), so you'll at least catch the belt in time. Too loose and too much tension is put on the teeth of the belt, and it will fail. I also think the belt is put under a lot more heat in this application, so probably not aiding long belt life.

    Race bikes, without and alternator, are a different ball game and are very straightforward of course. Patrick was dead against doing this on a road bike and only did it because I twisted his arm. We both regretted it! That's why this was the first, and last, road going Egli Vincent Godet with a belt drive primary!

    003.jpg 013v.jpg
     
  3. Buellingvincent

    Buellingvincent

    Joined:
    Oct 1, 2014
    Eddie,
    Thanks for your input. I have decided to test with some Belleville Washers/Disc Springs below and above the dynamo clamps to get a slight flexibility for the dynamo against the belt.
    Just ordered a few so probably early next week I have them.
    Patrik
     
  4. Buellingvincent

    Buellingvincent

    Joined:
    Oct 1, 2014
    Was just checking the thermal expansion value for alu. The difference of the shaft center distance of the crank and clutch (approx. 9") for a 200 degree Celsius (centigrade) temperature change (260 degree F) is roughly 1 mm (0.4"). I do not believe the lower section of the crank case will ever get that hot but anyway. I don't have the exact shaft center distance of dynamo and clutch available but it should be roughly half of the crank/clutch.

    Can the temperature changes really have such a big influence on the dynamo pulley to belt alignment?
     
  5. Buellingvincent

    Buellingvincent

    Joined:
    Oct 1, 2014
    Some progress again. Finally it starts to look like an engine and not only as bits and pieces. :)
    Patrik

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  6. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    Well, if it did move 0.4mm, and if it was already tight, that may well be enough to be a problem.

    But that’s only one aspect, the pulleys, both front and back, are going to expand as well, thus increasing the tension.
     
  7. Buellingvincent

    Buellingvincent

    Joined:
    Oct 1, 2014
    Hi Eddie, Yes many aspects. I will try it out at least and check thoroughly while the bike is cold and hot to see the variations.

    Spend most of the weekend (wife not super happy) in the garage/work shop. Now soon (I hope) time to unite the engine with the rest.

    /Patrik

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  8. Fast Eddie

    Fast Eddie VIP MEMBER

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    Oct 4, 2013
    The ‘rest’ of a Vincent always looks surprisingly little doesn’t it?!

    Looking forward to the progress reports and riding impressions soon...
     
  9. Buellingvincent

    Buellingvincent

    Joined:
    Oct 1, 2014
    Yes that's true. Only like the head lamp, rear fender, speedo, carbs and some small bits are missing. Surely the engine package is the main thing of a Vincent.

    Thought again that "now I've done with all the fixing phase", but of course yet another problem needed to be solved. I knew I would have to cut the clutch shaft but did not expect to have problems with the C20 nut. Otherwise the preassure plate won't fit. Had to reduce the height to approx 1/2". Now need to create flats for a wrench.

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  10. Buellingvincent

    Buellingvincent

    Joined:
    Oct 1, 2014
    Quite some good progress. Tomorrow ignition timing and mounting generator voltage regulator. Hopefully also attaching swing arm (rear frame member - RFM).

    [​IMG]
     

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