Cause of my engine failure, type 4 rebuild

Discussion in 'Mech Tech' started by Joker, Mar 1, 2014.

  1. So, I found what I believe to be the main culprit of my engine failure.

    One of #1's rocker shafts had sheared completely off, the second had worked its way totally loose from the head

    So I have focused on the failed shaft to the right of this photo

    [​IMG]

    This photo shows the shaft which was almost out of the head. Again I've blurred out all but the offending item

    [​IMG]

    So #1 barrel and piston looked to be ok, as did the head, albeit a little brown.

    #2 spark plug had melted

    [​IMG]

    and the top of the piston is covered on a thick crust, but not holed. Yet.

    Here you can see #1 to the right of the picture, it's been hot in there

    #2 to the left of the picture. Exhaust valve has seen some extreme heat.
    [​IMG]

    #3 and 4

    [​IMG]

    The oil was like tar, most if it deposited in the engine bay and inside the exhaust

    [​IMG]

    Whilst the barrels look to be ok without scoring, so do the pistons apart from around the very top of the crown. More worrying is the fact everything is brown where it's seen extreme heat. Haven't cracked the case open yet. The oil didn't appear to have too many metallic deposits. I doubt I'll reuse the heads or pistons, unless any of the pro's think its worth having them reworked @Paul Weeding @holmsen @zed ?

    So, I've left it there for now, I'll take the opportunity now to clean strip out and respray the engine bay and make it a bit more pleasant with some lighting. Poor thing looks like its messed itself :(
    [​IMG]
    This gives me the push I needed to crack on and get my camper engine running or to do the 1800 AN engine.

    :)
     
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  2. rickyrooo1

    rickyrooo1 Hanging round like a bad smell

    the bus is showing it's protest from being "de-lawnmowered" @PIE never had this hassle :lol:
     
    Moons and Joker like this.
  3. The WO heads are supposed to be pretty good ....heritage used to sell the domed pistons / barrels ...or I may have a decent used one or two
     
  4. None of it appears damaged in any way, no holes in the piston crowns no scoring on the barrels of pistons. Heads don't look to be cracked, will need to look at the valve seats though and if want to change the valves at the very least. Looks like I may have gotten lucky. My only concern is with the pistons to be honest, and wondering whether they will be damaged and suffer failure later.

    The WO with the high compression pistons isn't really suited to a bus as the bus is too heavy. That and the fact I thrashed it.
    :)
     
  5. Can't figure out where all the oil in the exhaust system came from though. Im guessing (??, read don't have a clue) that the fact that neither of #1 valves were opening and closing that this out undue pressure on the other 3 and the crank case?
    :)
     
  6. It never went up a drag strip before though ;)
    :)
     
    rickyrooo1 likes this.
  7. If it makes you feel any better you're not alone fella. My tappets making a right old racket. Pulled cover off and two were mushroomed over then checking pushrods they were bent as a bent one! Whole lot had been tightened up too much and I'm lucky they hadn't snapped! Sure you'll get the 1800 sorted soon :)
     
  8. Thanks for the offer, I may come calling
    :)
     
  9. The WO compression is 8.2 -1 which is still fairly low , makes you wonder what all the scooby boys CR is as they also weren't designed for a bus ?????
    My WO supercharged is destined for the bus
     
  10. rickyrooo1

    rickyrooo1 Hanging round like a bad smell

  11. Ta
    :)
     
  12. In terms of repair I'm going to finish the tear down get all the parts cleaned up, have the crank and cam inspected. I'll take the pistons and heads to work for NDI to look for cracks before I decide whether to reuse them. Of I do I'll have new valve seats guides and valves put in, new rings, if I don't need any work on the crank or cam I have all new bearings in the shed so it 'should' be a relatively cheap rebuild
    :)
     
  13. Zed

    Zed Gradually getting grumpier

    Cripes. I wonder what came first, the chicken or the egg?
     
  14. Compression ratio is about 9.5:1, I think. About normal for a 16v engine, I thought?

    I don't think there's much of an issue about them not being designed for a bus. There's not much in it regarding the difference in kerb weight of a Subaru Legacy and a VW T2. These things were also put in Forresters, and I bet they're heavier. A fully laden T2 going camping is probably around about the weight of a Forrester.
     
  15. I'm guessing a culmination of a good thrashing without a break, my discovery that some scrote had robbed my breather system, the shaft...

    Also discovered that #3 exhaust wasn't sealed into the head, #2 the stud holding the exhaust into the head has actually pulled the nut through the j-tube, how the feck that's coming out I've no idea. All in all terminal overheating but I'm guessing the worst of it started with the rocker shaft. I blame no one but myself
    :)
     
  16. There's no real reason for building low compression engines these days!! The fuel quality is way above what it was in the 50/60/70s... Which was the only reason for low compression...

    I'd love to build a 12:1 1600, just as a point proving item ;)
     
  17. JPM is building a 1584ccm with 15,3:1 atm. :) ms 250 heads
     
    Paul Weeding likes this.
  18. PIE

    PIE

    Was that engine out a T3 or 411/410 ?
     
  19. brown is OK....white is ridiculously hot....sooty black is usually over rich....oily wet black is usually ignition related
     
  20. I've built a 13.5:1 compression 1970's Kawasaki engine, originally 90hp now 140+. Not bad for 1170cc. :)
    That runs pump fuel.
    Tis true that higher comps are easy today.
     
    Joker and Paul Weeding like this.

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