i think my engine could be toast

Discussion in 'Mech Tech' started by wendygun, Dec 6, 2015.

  1. I just had a bit of time to do it. Popped off no 3&4 piston con rod.
    both look very similar so im going to take it 1&2 are going to be the same.
    shells are toast so ill have to look at grinding

    Cheers for info. Shells are grooved slightly so needs to be replaced.
    Cheers
     
  2. been allowed back into the garage today.....
    for tonights instalment lets see what we found.
    able to remove the barrel studs with brute force, nuts and washers. all tight and one above no3 piston is just turning and not out.
    split the case(virgin aircooled moment) so I think I know whats broke and making a noise
    [​IMG]

    this is the camshaft thrust bearing, well part of it.

    [​IMG]
    the cam bearing web
    [​IMG]

    the b ig end main bearings are slightly marked and I take it something has had work on it, crank or case
    [​IMG]

    anybody got any ideas on which way to progress @zed @Robert Parry @Fish
     
    Fish likes this.
  3. Has the cam been chewing the case where the thrust bearing goes?

    If it has, then pretty much game over for the case... You could technically run the thrust in the other half of the case, and mod the thrust side to take the bearing from the opposite side... :thinking:

    But it's really going to depend on whether the case has worn and bearing tightness in the case....
     
    Fish likes this.
  4. the cam web where the bearing sits.... look third pic up in my last post, is it crackered then
     
  5. 4 bolts and sorted
     
    wendygun likes this.
  6. New case time. You cannot have any wear on that part of the case.
     
    Fish likes this.
  7. so you cant do like you can on the main bearings and get thicker thrust part on the cam bearing.:(
    for future info, any ideas of why this happens......cheers
     
  8. No they do not make oversize on the thrust. I can machine for 0.50 oversize on the bore, I have never seen bearings that could repair a case worn there. The reason for the wear is two fold. Firstly because of the helical gears there is always loading at that point, hence the thrust ring on the bearing, the second reason and the cause of the failure would have been the excessive play on the thrust, allow it to have to much and you let the cam do just what it wants to do, and that is to push long and hard on the cam bearings.
     
  9. so I need a new case.........................well complete engine then, start from scratch with it and turn the old one into an ornament. looks like I'm not having any holidays this year, damn para will be on the road before I get this fixed...
    right another scotch needed before I go tea total and save the pennies. other half has gone to bed in a huff because I've knackered the engine, it wasn't me, honest....

    I noticed when turning engine the helical gears moved the cam forwards...
     

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