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Thread: short nose, big nose question

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    Idling - Listen to it purr... alexlula's Avatar
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    Question short nose, big nose question

    Alright guys, Ive got a few questions for you! Last week i busted my timming belt on my big nose engine so i bought a short nose engine, the head on that engine was rebuilt amd machined to new! And timming components are almost new, thing is, it dosnt have a crank pulley. so first question is dose bignose engine crank pulley fit on short nose block, if not i will exchange heads and timming components to my bignose block, second question is, is there any other bolts that gets unusable once unbolted? I know that the crank pulley bolt should be replaced once unbolted but like head bolts and studs?

    Thanks
    Alex

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    6,000 rpm - mere mortals would shift Demon I Am's Avatar
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    New crank bolt and Head studs are needed.

    The crank pulleys have different part numbers when looking on a Mazda part's site, so I'm not sure that they swap over.

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    Ninja Messiah kung fu jesus's Avatar
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    These are non-nterference engines, so unless something went really, really wrong, you can break a timing belt and simply replace it without any damage to the engine.

    Big nose (BNC) and small nose crank (SNC) interchange everything EXCEPT the crank pulley, crank pulley bolt, woodruff key, and oil pump. The crank nose seal might be different, too.

    OE head bolts stretch, but *can* be re-used. Generally, they should be replaced after one use though. An upgrade is to use ARP head studs, which CAN be reused and offer more strength if you plan to test the forced induction waters in the future.

    You can swap pistons, rods, heads, etc. between BNC and SNC engines, just not what I mentioned above.

    Good luck!

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