Gear ratio question

Discussion in 'Sterndrives' started by Kentj, May 26, 2006.

  1. Kentj
    Joined: May 2006
    Posts: 1
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Twin Falls, Idaho

    Kentj New Member

    It is a long story but I have ended up with the wrong gear ratio for a repair job on my outdrive.

    I purchased a used top end sold as setup for a V8 turns out the splines on the gears count out at 17/19 which as I understand is 1.84 - my question is can I run this ratio on my 5.7 which was setup at 1.5:1 and what is the down side? - I boat mostly at altitude near or above 4000 feet.

    Thanks in advance for your help
     
  2. Jango
    Joined: Aug 2005
    Posts: 519
    Likes: 7, Points: 0, Legacy Rep: 63
    Location: Mid Atlantic

    Jango Senior Enthusiast

    Not really a problem, unless you run W.O.T.

    With a 1:84 to 1 gear in place of a 1:50, your engine can run up to 1000 rpm higher than with the 1:50 gear. In order to get back to desired RPM range of 4200 - 4400 you will need to change props ADDING about 5" of pitch to what you now have. i.e. from 19P to 25P or if you have a 21P go to 26P. Going to a 4 blade prop will also help - same as adding one inch of pitch if same dia.
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.