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  1. Sierra Charlie

    Sierra Charlie Member

    Messages:
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    Location:
    Norfolk
    Just wondering if anyone could offer any advice or help please. I have decided to change the head gasket on my 2001 Y regn Astra 1.7 diesel due to water in the oil giving me a milky dipstick and sludge in the rocker cover.

    Stripped everything out, got a replacement head gasket and head gasket set together with new bolts etc. Put the head back on together with the camshaft carrier and two camshafts before refitting the cam belt and timing up. Tried to turn the engine over by hand but it appears that the pistons are just touching the valves.

    I`ve checked, rechecked and checked yet again and all the timing marks line up correctly. The only conclusion I can come up with is that I`ve been given the wrong gasket ( possibly the wrong thickness? ) meaning that the head is not far enough away from the block.

    Has anyone else experienced these symptoms after a rebuild?

    Would appreciate any help or advice please.
     
  2. Fire26662

    Fire26662 There can be only one.

    Messages:
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    Location:
    Hereford
    There are several thicknesses of head gasket, and I think they are identified with a notch or a small hole (can't remember sorry) I am sure you have the 1.7DTi with the Y17DT engine, these suffer with the oil to water cooler failing too, which produces the exact same symptoms. Anyway examine the old gasket for identification, did you have the head checked and skimmed? as it will need a different thickness.
     
    Sierra Charlie likes this.
  3. Sierra Charlie

    Sierra Charlie Member

    Messages:
    34
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    Location:
    Norfolk
    Many thanks for your reply.

    I`ve already investigated and bypassed the oil cooler including flushing the coolant system four or five times over a period of about three weeks. The head gasket (patterned part) was matched using the "one hole reference", never thought to double check the thickness with the old gasket prior to fitting.

    Didn`t bother with getting the head skimmed or checked as the engine never boiled or got hot.

    I assume the only option open to me is to remove the head again to check the new gasket?
     
  4. Fire26662

    Fire26662 There can be only one.

    Messages:
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    824
    Location:
    Hereford
    yup
     
    Sierra Charlie likes this.
  5. rick45

    rick45 Well-Known Member

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    Location:
    gainsborough, lincs, uk
    Drives:
    2008 zafira exclusive 19cdti 120 bhp in silver
    HI,
    CHECK TO SEE HOW MUCH THE PISTONS STAND ABOVE THE BLOCK AND GET A GASKET THAT MATCHES THE HEIGHT OF THE HIGHEST STANDING PISTON.
    sorry had caps lock on.
     
    Sierra Charlie likes this.
  6. Sierra Charlie

    Sierra Charlie Member

    Messages:
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    Location:
    Norfolk
    Hi, Many thanks for your reply. I basically did that and got a gasket 1.5mm thick (previous gasket was actually 1.35mm). Have refitted the head, camshaft housing and camshafts etc. When trying to retime the engine using a Haynes manual instructions the pistons are touching the valves when the engine is turned over by hand. Have checked and double checked timing marks but no matter what I do or try the pistons are still touch the valves.

    Would appreciate any advice or helpful suggestions please.
     
  7. 19eddie82

    19eddie82 Active Member

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    Location:
    liverpool, england
    It may sound silly but are you sure that the camshafts were pot back the right way round if uve checked every thin else with no look it may be worth a try. also i usually make sure that the hydraulic tappets go back in the same way they came out otherwise that could cause issues unless u have de-hydrualiced them. also the diameter or the piston holes in the gasget could be a bit smaller then they need to be an could be stopping the pistons rather than the valves or vice versa.
     
    Sierra Charlie likes this.
  8. Sierra Charlie

    Sierra Charlie Member

    Messages:
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    Location:
    Norfolk
    Yes, checked the camshafts for correct fitting, can`t really fit them wrongly as camshaft sprocket is fitted onto the camshaft with a locating dowel and the other end has two gears which have a single dot and twin dots on them, you fit the camshafts into the camshaft housing and line the single dot between the twin dots.

    The hydraulic tappets stayed in the head and were not removed. I also checked the size of the gasket piston/bore holes against the bores before fitting the head.

    Al the timing marks appear to line up correctly with number one piston at TDC but when you hand turn the engine the pistons still touch the valves.

    Really struggling to understand why and what could be causing this problem.
     
  9. 19eddie82

    19eddie82 Active Member

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    Location:
    liverpool, england
    Could the cams be in wrong as in exhaust for inlet and inlet for exhaust?
     

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