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Cam specs

Discussion in '"Stock" Alpine' started by jmahall, Oct 6, 2020.

  1. jmahall

    jmahall Donation Time

    Is there an appreciable difference in timing between a stock 1600 and 1725 cam?

  2. RootesRacer

    RootesRacer Donation Time

    Not a huge difference. For series alpines, there is a degree or 2 more overlap on the 1725 compared to 1600 due to lobe center difference. The lobe durations are about the same.

    This of course fully ignores the difference in the number of teeth to drive the oil pump which makes them incompatible with one another.
  3. alpine_64

    alpine_64 Donation Time

    As jarrid said, not a huge amount of difference in spec.

    As for the interchanage between them you can do it but it requires changing the drive gear on the distributor also the cam bearing width is different iirc
  4. RootesRacer

    RootesRacer Donation Time

    Its not the distributor drive gear but the oil pump gear that needs swapped (the pump gear drives the distributor through an offset dog).
    Cam bearings are the same part number for all series alpines 1600/1725 so the bearings are no different, perhaps the cam journal widths differ but not enough to have caused Rootes to produce different bearings.
  5. alpine_64

    alpine_64 Donation Time


    Jarrid my bad.. Yes oil pump drive.. Applogies.. Was thinking about the change i made on my car when switching 1725 oil pump into the 1494 and mod to the distributor.

    I'm sure the cam journal widths are different...but you can switch them if you change the drive.
  6. jmahall

    jmahall Donation Time

    Thanks all for the quick reply.
  7. RootesRacer

    RootesRacer Donation Time

    No apologies needed.
    It would have been wonderful if Rootes had made the cam drive the distributor. Then we could have been able to prime the oil pump as nearly all engines can.

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