Dumb impeller question(s)
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Dumb impeller question(s)

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    Senior Member H20MOFO's Avatar
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    Default Dumb impeller question(s)

    O.k so I have a detailed bronze (agressor)b cut coming in the mail. I'm wondering if I do have to have it cut smaller, will the "detailing part" be erased by cutting it down??? Also on the wear ring side of a rebuild.. Do they come std., .030 under,ect? Or do they(wear rings) come in .010 increments? I may try this myself and can use any advice I can get. I'm a little confused, sounds like I need to be concerned with the impeller to wear ring clearance in 2 directions. 1) the dia. and 2) having the impeller pulled/shimmed? far enough fwd. BTW it's a berk split bowl I'm working on. Right now if I stand on it out of the hole, she slips bad.
    Another Hot Boat refugee

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    Senior Member Cowboy_Mike's Avatar
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    Do you have an inducer? What is the current impeller?

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    Senior Member H20MOFO's Avatar
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    Quote Originally Posted by Cowboy_Mike View Post
    Do you have an inducer? What is the current impeller?
    No inducer..spinning an a/b cut aluminum impeller right now. Fwiw ...guys if you want to upgrade your impeller, just tell your wife if the aluminum one breaks, we'll all have to swim=broken suction housing= bye bye boat. It worked for me.
    Another Hot Boat refugee

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    Sit N' Spin Jetaholic's Avatar
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    They make wear rings in 0.010" undersize increments.

    When you cut an impeller down, you're basically dropping the impeller's efficiency. Detailing makes the impeller more efficient, cutting it down makes it less efficient. So I guess you could say to a point yes it will "erase" the detailing. The long and short of it is -

    The better an impeller flows/the more efficient an impeller is, the more water it flows.

    The more water it flows, the greater the pressure head.

    The greater the pressure head, the more thrust you make.

    However that pressure/thrust comes with a price (nothing's free). If you don't have the horsepower to pull through it, there's no point in getting your impeller detailed since you're gonna have to cut it down anyway to match your motor's horsepower peak.

    And yes you have clearances in actually 3 different spots, but unless you're drag racing we usually don't worry about the 3rd (i.e. the impeller - bowl clearance).

    The clearance between the wear ring shoulder (or the thrust lip of the housing if you run a stock ring) and the front edge of the impeller wear ring surface area is your "thrust" clearance, aka "axial" clearance.

    The clearance between the side of the wear ring surface area and the wear ring itself...some call it "side" clearance. But the "professional" term for this is "radial" clearance. You need a 7"-8" ID and OD micrometer to measure that.



    Quote Originally Posted by HammerDown
    Kendall L-427 Super Blu...extreme-pressure (ep) lithium complex keeps my thrusting balls happy
    Quote Originally Posted by back2k5 View Post
    Well I am putting in a nice stereo system in the Carrera...maybe Ill put on some rap and turn the scoop sideways

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    Senior Member H20MOFO's Avatar
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    Quote Originally Posted by Jetaholic View Post
    They make wear rings in 0.010" undersize increments.

    When you cut an impeller down, you're basically dropping the impeller's efficiency. Detailing makes the impeller more efficient, cutting it down makes it less efficient. So I guess you could say to a point yes it will "erase" the detailing. The long and short of it is -

    The better an impeller flows/the more efficient an impeller is, the more water it flows.

    The more water it flows, the greater the pressure head.

    The greater the pressure head, the more thrust you make.

    However that pressure/thrust comes with a price (nothing's free). If you don't have the horsepower to pull through it, there's no point in getting your impeller detailed since you're gonna have to cut it down anyway to match your motor's horsepower peak.

    And yes you have clearances in actually 3 different spots, but unless you're drag racing we usually don't worry about the 3rd (i.e. the impeller - bowl clearance).

    The clearance between the wear ring shoulder (or the thrust lip of the housing if you run a stock ring) and the front edge of the impeller wear ring surface area is your "thrust" clearance, aka "axial" clearance.

    The clearance between the side of the wear ring surface area and the wear ring itself...some call it "side" clearance. But the "professional" term for this is "radial" clearance. You need a 7"-8" ID and OD micrometer to measure that.
    As long as I'm on a roll what's a shouldered wear ring, and why would you want to use one or not????????
    Another Hot Boat refugee

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    Sit N' Spin Jetaholic's Avatar
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    Shouldered wear rings are a must in every pump. Without them you cannot run a thermostat.

    Just kidding . Actually a shouldered wear ring is a wear ring with a front lip on it to take up some of the front clearance without having to machine the shaft and move the impeller forward. Due to the thickness of the shoulder, you end up having to shim the impeller back to get the right front clearance, which not only tightens up the axial clearance, but also tightens up the impeller-bowl clearance, making it tighter all the way around.

    For some, it is the preferred method of tightening up front clearance because by doing the "move the impeller forward" method, you end up with more clearance behind the impeller than you had stock.
    Last edited by Jetaholic; 08-31-2009 at 09:16 PM.



    Quote Originally Posted by HammerDown
    Kendall L-427 Super Blu...extreme-pressure (ep) lithium complex keeps my thrusting balls happy
    Quote Originally Posted by back2k5 View Post
    Well I am putting in a nice stereo system in the Carrera...maybe Ill put on some rap and turn the scoop sideways

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    Senior Member Futs's Avatar
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    Another reason to run a shouldered wear ring is to hide a dinged up suction housing..IE dings or gashes on the surface area on the impellor W/R edge that meets the suction housing. You would install the shouldered W/R to basiclly make it a smooth surface again so your not letting the "water seal" suck air and cavitate. You must cut the lip off the isolator and seat the lip flush against the S/H and adjust with shims to get your tollerances.

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    Senior Member Delemorte's Avatar
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    Something else to think about with a shouldered wear ring. If you put one in and did not have one previously you will have to shim the hell out of the front of the impeller…. My bowl has been cut to bring the bowl closer to the impeller so I’m not sure I could run one even if I wanted to but I didn’t really see the point in my specific set up.. Maybe in something with more HP and faster than my tub.



    Edit: Damn it futs already brought up shimming.. Didnt read his responce all the way thru.
    Quote Originally Posted by jetboatperformance View Post
    the ensueing fire would likely be extinguished by the sinking however

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    Senior Member Widetrack's Avatar
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    I had the problem of cavitation before and found that the packing was not the best and was sucking air around the shaft from the bearing side! JFYI! WT


    SOMEONE SAID YOU CAN'T TAKE IT WITH YOU! SO,IM BURNING IT UP ONE GALLON AT A TIME!
    WT

    WFL Crew!!!

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    Sit N' Spin Jetaholic's Avatar
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    Quote Originally Posted by Delemorte View Post
    Something else to think about with a shouldered wear ring. If you put one in and did not have one previously you will have to shim the hell out of the front of the impeller…. My bowl has been cut to bring the bowl closer to the impeller so I’m not sure I could run one even if I wanted to but I didn’t really see the point in my specific set up.. Maybe in something with more HP and faster than my tub.



    Edit: Damn it futs already brought up shimming.. Didnt read his responce all the way thru.
    I only had to shim mine 0.025"-0.035". That's not all that much.



    Quote Originally Posted by HammerDown
    Kendall L-427 Super Blu...extreme-pressure (ep) lithium complex keeps my thrusting balls happy
    Quote Originally Posted by back2k5 View Post
    Well I am putting in a nice stereo system in the Carrera...maybe Ill put on some rap and turn the scoop sideways

  13. #11
    Cas
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    Quote Originally Posted by Jetaholic View Post
    However that pressure/thrust comes with a price (nothing's free). If you don't have the horsepower to pull through it, there's no point in getting your impeller detailed since you're gonna have to cut it down anyway to match your motor's horsepower peak.
    don't you mean torque?

  14. #12
    Sit N' Spin Jetaholic's Avatar
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    Quote Originally Posted by Cas View Post
    don't you mean torque?
    Torque per RPM



    Quote Originally Posted by HammerDown
    Kendall L-427 Super Blu...extreme-pressure (ep) lithium complex keeps my thrusting balls happy
    Quote Originally Posted by back2k5 View Post
    Well I am putting in a nice stereo system in the Carrera...maybe Ill put on some rap and turn the scoop sideways

  15. #13
    Senior Member H20MOFO's Avatar
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    Quote Originally Posted by Futs View Post
    Another reason to run a shouldered wear ring is to hide a dinged up suction housing..IE dings or gashes on the surface area on the impellor W/R edge that meets the suction housing. You would install the shouldered W/R to basiclly make it a smooth surface again so your not letting the "water seal" suck air and cavitate. You must cut the lip off the isolator and seat the lip flush against the S/H and adjust with shims to get your tollerances.
    Thanks for the info guys... As far as measuring for the wear ring, I guess I need some giant calipers???
    Another Hot Boat refugee

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