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Why a Triumph sludge tube ???

Discussion in 'Triumph (Classic)' started by nortriubuell, Mar 8, 2013.

  1. nortriubuell

    nortriubuell

    Joined:
    Aug 29, 2010
    Triumph unit 650s and 750s have a sludge tube in the crankshaft. And, the ones I've stripped and rebuilt had lots of crud that did need cleaning out. However, THE Commando crankshaft does NOT have a sludge tube. :shock: And yet, all the (several) Norton crankshafts I stripped had very little "sludge" in them ??? :? :? :? Of course I cleaned them out, and cleaned the Triumph ones out as well. I've even heard horror stories of Triumph sludge tubes getting so clogged up, that the motors seized from lack of oil to the big ends ! (Never heard about a Commando doing this though)

    Which brings me to my question ... since I'm rebuilding a 1971 Triumph 650 motor that is now completely stripped, why even bother to install the sludge tube ??? Although I've not heard of anyone leaving it out, seems to me it would be better (like the Norton Commando) to just omit installing the sludge tube ??? Maybe it would even stay much cleaner between rebuilds as well. ALL comments and opinions are much appreciated :D
     
  2. swooshdave

    swooshdave

    Joined:
    Apr 15, 2009
    Oil filters on the Nortons?
     
  3. kommando

    kommando

    Joined:
    May 7, 2005
    I would say it was down to the shape of the trap, the Triumph is long and small in diameter the Norton is the opposite. Maybe as the Triumph fills up the oil pressure needed to keep the channel open is higher than the pump can supply due to it length and the Norton pump can keep a passage open as it only a short length. We need a fluid engineer to give us the answer.
     
  4. grandpaul

    grandpaul VIP MEMBER

    Joined:
    Jan 15, 2008
    For every story of a Triumph seizing up due to a clogged sludge trap, there is a story of a Norton crank blowing up and sending rods through the case for whatever reason. I have heard of only 2 Triumphs blowing through cases, one due to an idiot over-revving a new engine, the other a drag racer trying to win at all costs.
     
  5. nortriubuell

    nortriubuell

    Joined:
    Aug 29, 2010
    The plunger type oil pump and the passage size, those are most excellent points kommando !!! Never thought about that. :shock: Anyone else wish to chime in ???
     
  6. Triton Thrasher

    Triton Thrasher

    Joined:
    Feb 10, 2009
    Interesting that ( if) the Norton crank doesn't centrifugally deposit stuff somewhere.
     
  7. grandpaul

    grandpaul VIP MEMBER

    Joined:
    Jan 15, 2008
    Yes, of course Norton cranks build up sludge; it's just allowed to be washed into the bearings easier.

    [​IMG]

    [​IMG]
     
  8. swooshdave

    swooshdave

    Joined:
    Apr 15, 2009
    I've seen porn that wasn't that dirty.
     
  9. acotrel

    acotrel

    Joined:
    Jun 30, 2012
    The crank in my short stroke 500 triumph was made out of a billet - no sludge trap. However it was raced , not used slowly over thousands of miles of public roads .
     
  10. dave M

    dave M

    Joined:
    Oct 19, 2005
    Nortibuell, I would not leave the sludge trap out under any circumstances, it must be there for a reason otherwise Triumph themselves could have saved a significant amount of money by leaving them out over the years. I don't know the technical reason why but I'm sure there are sound engineering reasons involved.
     
  11. nortriubuell

    nortriubuell

    Joined:
    Aug 29, 2010
     
    nattres likes this.
  12. nortriubuell

    nortriubuell

    Joined:
    Aug 29, 2010
    I appreciate your input as well dave M :D As this is why I started the thread, to get opinions and information. Many thanks to all who chimed in. I will install the sludge tube, and not second guess Triumph engineering on this. Cheers all.
     
  13. dave M

    dave M

    Joined:
    Oct 19, 2005
    Another thing to bear in mind is that the main British motorcycle designers seemed to move from one company to the next from time to time, so there would have likely been an opportunity to delete this part if it was simply a different design philosophy. They are cheap and fairly easy to clean out and or replace, so let someone else try it and report back while you enjoy your bike secure in the knowledge that it is as per the factory built it.

    I recently put a new one in a 1965 Bonneville that I am restoring and had to file a bit off the inner face to get it to fit properly.
     
  14. swooshdave

    swooshdave

    Joined:
    Apr 15, 2009
    I always assumed that the sludge trap was just that. A pre-oil filter filter.
     
  15. dave M

    dave M

    Joined:
    Oct 19, 2005
    Swoosh, As far as I'm aware Norton only used remote oil filters in their later Commando iterations, the bolt up crank had been around since the early Dominators.
     
  16. Bernhard

    Bernhard

    Joined:
    Apr 20, 2011

    The correct description for the Norton Dommis/Commando is a centrifugal oil filter, hence why you have to strip the whole crank apart every so often, to clean the hard crud inside it.
     
  17. phillyskip

    phillyskip

    Joined:
    Sep 15, 2013
    The Triumph Sludge trap acts as a centripetal oil filter that works much like the oil filters found on Honda CB 450s. It needs to be there and it also needs to be serviced every time the engine is totally taken apart. I have never seen a clean one in any Triumph mill. Period.
     
  18. phillyskip

    phillyskip

    Joined:
    Sep 15, 2013
  19. B+Bogus

    B+Bogus

    Joined:
    Jun 28, 2009
    When I rebuilt my T140 I binned the sludge tube, but I also fitted a paper element filter in the frame sump-plate, and converted to a gear-type Morgo pump.

    Back in the day these engines ran mono-grade oil which didn't contain the detergents found in multi-grade, so particles weren't held in suspension, but would be more easily removed from the oil by centrifugal force. Multi-grades carry the particles better and work better with full-flow filters.

    It's what I've been told anyway :wink:
     
  20. Triton Thrasher

    Triton Thrasher

    Joined:
    Feb 10, 2009
    You reckon "detergents" counteract centrifugal force?
     

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