Mk2 golf CL 1.6L big end bearings

Discussion in '8-valve' started by muppet9966, May 23, 2020.

  1. muppet9966 Forum Member

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    Hello guys,
    Recently I have had various problems with my engine, from low oil pressure buzzer and bottom end of the engine sounding faintly like a tractor.
    I initially replaced the oil pump and 1.8bar oil pressure sensors, which had cured the oil pressure buzzer going off, but the bottom end of the engine still didnt sound right.

    I have just dropped the sump again, and checked the big end bearings (piston 1 so far only).
    I replaced the big end bearings on piston 1 (with standard Kolbenschmidt bearings), however I can feel theres movement of these bearings when fitted (I did smear some new oil on the bearings).
    Or is this normal and I am worrying about nothing?

    I havent measured the tolerances yet, which i will do, but what would my next steps be?

    Old bearings are here, the left one is the bottom one, the right one is the top (piston end) one.

    IMG_20200523_182909.jpg

    Many thanks,
     
    Last edited: May 23, 2020
  2. Jon Olds Forum Junkie

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    A cheapo digital Vernier is one of those tools that once you have had it and measured 10 things, you will wonder how you ever did without one.
    Drop the sump, pull the BE off and measure the crank. You will get a rough and ready go/no go answer. try and measure in different 'plains' if that makes any sense.. (across bearing journal, side to side, end-end) Haynes will give you the tolerances. Take the oil pumpout and to bits, look for wear, scoring etc.
    Jon
     
  3. muppet9966 Forum Member

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    Cheers mate,
    I'm collecting a digital Vernier tomorrow to measure the crank.
    The oil pump is new, and only covered 10 odd miles, but I will check this.

    Am I correct in thiinking the crankshaft connecting rods diameter from Haynes is 47.80mm?

    Haynes manual mk2 golf engine specs crankshaft.JPG
     
    Last edited: May 23, 2020
  4. Jon Olds Forum Junkie

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    Looks like the right number. VW have been very kind to us engine builders with compatibility, over the years.
    Basically the BE size hasn't really changed over a range of engines. (yes, I know...)
    Jon
     
  5. muppet9966 Forum Member

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  6. Jon Olds Forum Junkie

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    I would look at the shells, inside edge. They will be marked STD, or 0.25 (undersize) etc.
    VW etc quote undersizes, so once your crank gets worn, you takeiot to a machinist who grinds it 1/4mm undersize, to recover
    the journal shape. Then you use undersized (oversized) shells.
    Sorry, if all this is obvious.
    So, if your crank is STD shell size, and you are outside OEM minimum tolerance, that's why you haver poor pressure.
    Its then a crank out job, off to the machine shop (engine rebuild)
    Your machine shop will grind off the amount needed to get std undersize, and you buys shells to match
    So, first, see what size shells are fitted (engine may have been rebuilt)
    If it has a new set of shells (at the correct size) may get the job away.
    At this stage you can get a crushable plasticine material to measure the gap, well worth doing, as its cheap (plastiguage)
    Othe wise its an engine out rebuild
    Jon
     
  7. muppet9966 Forum Member

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    Thanks Jon,
    Nothing is obvious, I am new at this and all useful information, but just want my golf working again, hehe

    I totally forgot to check the shells.
    The outside edge of the shells are VW marked with also 0.5.
    Could I get away with 0.5mm undersized shells?

    I dont believe the engine has been rebuilt at all (my uncle brought the golf at 2 years old, then gave it to me in 2005) :o

    FIngers crossed its not a crank out job, engine is still in the car, hehe.
     
  8. Jon Olds Forum Junkie

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    So its been ground 0.5 undersize. Take the original measurement and tolerance and subtract 0.5. This gives you the number to compare with you Vernier measurement(s).
    VW cranks are rock hard, the best of production stuff I have played with. For it to have had a 0.5 grind in the past tells a story
    Hope it goes ok.
    If it were me in your position, I would also pull the rocker cover off and check a few cam bearings, for piece of mind.
    Jon
     
  9. muppet9966 Forum Member

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    Could this have been done in the factory during production?
    The shells do have VW Audi stamped too, so look original.

    I did the headgasket 2 odd years ago, so have had the rocker off, but do have some new tappets to fit (as i had rebuilt my orginal tappets).
    Although the cam bearings isnt something I checked but will do.

    Haynes manual mk2 golf engine specs crankshaft.JPG

    The standard diameter is 47.80mm, so with 0.5mm off is 47.30mm.
    Ive measured 47.35mm & 47.36mm with a Vernier on two jornals.

    When I had the Standard shells in, I could feel it loose, so it looks like I need 0.5mm undersized ones?
     
  10. Jon Olds Forum Junkie

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    0.5mm clearance is massive, so, yes you need shells to match.
    Unlikely (IMHO) VW supplied new under sized cranks
    Jon
     
  11. muppet9966 Forum Member

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    This could explain why I could feel the conrod moving when I fitted standard shells.
    Seems strange, but my shells look orignal and definately VW...

    IMG_20200524_234940.jpg IMG_20200524_235009.jpg

    Seacrhing for 026 713 for the 026 713 part number on google doesnt come up with bearing shells.

    From the VW Hertiage website (https://www.heritagepartscentre.com/uk/034105713-big-end-bearing-set-1-6-1-8-0-5mm-undersize.html)
    Ive found the oem part number is 034-105-713, which there are some Kolbenschmidt bearings around with the part number 87 200 620: https://www.ebay.co.uk/itm/BIG-END-BEARINGS-KOLBENSCHMIDT-87-200-620-/253212514202
     
  12. Jon Olds Forum Junkie

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    size looks right, main obvious difference I have found on BE bearings is whether they have the little end oil feed hole, or not. Second, look at the shape size of the location tang. This must be 'right'
    Jon
    Sounds like you are now on the right track. Make sure everything mega clean, buy and use some plastiguage if you have the time/inclination. Its really good stuff, and relatively cheap
     
  13. muppet9966 Forum Member

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    Thanks Jon,
    Seems strange this may have been like this from factory, or work possible carried out within 2 years by VW, god knows.

    Its funny, the current bearings in the car doesnt have the oil feed holes, where are the new standard ones I purchased do.
    Hopefully the new 0.5mm undersized ones will too.
    The location tang looked okay on the new standard ones, and I will check the he new 0.5mm undersized ones when I get them.

    Two old bearings on the left & middle (with no oil hole), and the new standard one on the right:
    IMG_20200525_205328.jpg
     
  14. Jon Olds Forum Junkie

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    the hole is the oil feed to the little ends, most of the early stuff didn't have a rifle drilled rod.
    important its there if you need it, if your rods aren't drill I woulnt worry about it
    Jon
     

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