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Content tagged 'hydralic lifter issue'

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  1.  
    I think I have posted about this before, but it needs repeating.
     
    I have pulled the heads on my Jabiru 2200 several times and each time I have had this problem.
     
    The hydraulic lifters on the pulled head do not relax after reinstalling the head.
     
    This causes the valves, sometime only one, but many times both to be partially opened.
     
    You will be able to see this by comparing the position of the valves on the head you didn't work on. They will not be as far out and near the edge of the rocker box edge as the untouched head. 
     
    So when you turn the prop by hand you will find one cylinder with no compression. If the intake valve is held open too, you may see one of the other cylinders with no compression because of lack of vacuum.
     
    If this happens you have a couple choices:
     
    A) remove the head again and pull the lifters and soak them to get all the oil out. You should be able to compress them when they are clean.
     
    B) Start the engine and let it run roughly until the oil temperature builds. This can take 5-10 minutes. You should see the EGT start to build on the soft cylinder and then after the oil is heat soaked the hyd lifters will relax and the engine will smooth out.
     
    C) Turn the engine until one of the valves is open and leave it compressed for several minutes. This will usually allow the lifter to bleed down.
     
    John M