Anatomy of a historic 8V race engine

Discussion in '8-valve' started by TonyB, Jan 7, 2023.

  1. TonyB Paid Member Paid Member

    Joined:
    Jan 6, 2010
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    317
    Location:
    Ammanford, Wales
    So on to the bits that dictate the engines character. The pistons are 82.5mm dia and look to be of the Audi 2E variety, or similar....unfortunately they are cast so probably the weak link in the whole setup. The have had the crowns machined to get the compression right one assumes. The squish measures up ok, but I need to have a measure up and check the chambers and crown volumes. Interestingly each piston in marked front on the side, although the oil squirter cut outs give you a hint.....although this block doesn't have squirters of course.

    IMG_20221228_172549_resized_20221231_061706925.jpg IMG_20221230_162106_resized_20221231_015222296.jpg IMG_20221230_162114_resized_20230108_034731897.jpg IMG_20221230_162121_resized_20221231_015222002.jpg IMG_20221230_162140_resized_20221231_015221696.jpg

    I've taken the top ring off to check the end gap in the bore. Bearings are ok, but I'll change them for some King or ACL ones as a matter of course, need to check size but look std....as you would expect. VW cranks don't wear generally.

    I did toy with fitting some new JE Tfsi pistons and IE rods I have on the shelf, as they fit perfectly, spot on clearances and have the correct squish etc. when installed, but I don't want to start maching the crowns really, need to check compression ratios to be clear. if the existing ones are too low its an option. The skirt length is far better, the cast pistons are too long really, the skirt hangs out of the bore at BDC, which is less than ideal as it will induce a rocking motion which could cause piston ring blow by or flutter etc......but we'll see. There are no marks to indicate anything to drastic at the moment.

    IMG_20221228_173802_resized_20221231_061706547.jpg IMG_20221228_173840_resized_20221231_061706171.jpg
     
    erreesse likes this.

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