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Technical Olds Rocket flywheel interchange

Discussion in 'The Hokey Ass Message Board' started by tubman, Apr 18, 2018.

  1. tubman
    Joined: May 16, 2007
    Posts: 5,737

    tubman
    ALLIANCE MEMBER

    I have a '51 Oldsmobile engine with an iron stick flywheel. It is the 145 tooth version. I would like to get an aluminum flywheel for it, but it seems the 145 tooth version is scarce. I have seen 2 176 tooth aluminum flywheels on eBay, but passed on them because of the tooth count. I did a little research, and on the "Rocket Oldsmobile" thread on which has some flywheel information. It looks like both the 303 and 324 starters had 9 teeth. Does this mean I can use a 176 tooth flywheel in place of a 145? I wouldn't think so, but the available information seems to suggest it. Does anyone know for sure?
     
  2. Not without changing the starter. The flywheel teeth and starter gear have teeth that are matched depending on the number of flywheel teeth.
     
  3. tubman
    Joined: May 16, 2007
    Posts: 5,737

    tubman
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    That's what I was afraid of. Thanks for the information. Now to be on the lookout for a 12 volt starter.
     
  4. You can run the 6V starter on 12. It'll just spin faster.
    Or, if you don't care about keeping things original, you can get a high torque mini starter from Ross Racing (@GOATROPER02 on here)
     

  5. tubman
    Joined: May 16, 2007
    Posts: 5,737

    tubman
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    Wait a minute. I know I can run a 6 volt starter on 12 volts (I've done it before), but I thought the gears had a different pitch and wouldn't mesh correctly. Are you saying that the starter gears interchange?

    I won't mind converting the whole thing to 12 volts if that's what it takes. It ain't for no restoration.
     
  6. 42merc
    Joined: Dec 19, 2010
    Posts: 766

    42merc
    Member

    '49 thru '52 are 6 volt & used with a 145 tooth flywheel, '53 used a 12volt starter with a 145 tooth flywheel, '54 & later used a 12 volt starter with a 176 tooth flywheel.
    Starter must match flywheel.
    Depending on how my time goes I'll try to get a starter tooth count for you.

    I measured & counted both starter gears :
    6 volt & & '53- 12 volt is 1- 5/32" diameter with 9 teeth.
    '54 & up 12 volt is 1" diameter with 9 teeth.
    Measurements are +or-.
     
    Last edited: Apr 18, 2018
  7. 1941coupe
    Joined: Jul 4, 2010
    Posts: 401

    1941coupe
    Member

    tony at ross racing can supply you with a 12v mini starter with 176t or 145t starter drive,thats what im running 46 merc w/ 50 olds 303 never had a problem
     
  8. You are correct that the gears have a different pitch depending on what flywheel they are designed for. I am not sure if the starter gear interchanges or not.
    I forgot that the voltage changed before the flywheel tooth count changed. Double checking, I have a same information recorded that @42merc does, that the 53 starter is 12V but is for 145 tooth flywheels. Sorry for the confusion.
     
  9. tubman
    Joined: May 16, 2007
    Posts: 5,737

    tubman
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    Thank you gentleman for the information. I now know exactly where I am.
     
  10. BJR
    Joined: Mar 11, 2005
    Posts: 6,998

    BJR
    Member

    Does anyone know if you can just change the starter drive between the two starters and make it work?
     
  11. 42merc
    Joined: Dec 19, 2010
    Posts: 766

    42merc
    Member

    .The 176 tooth wheel is slightly larger in diameter, so if the drive is interchangeable between 6 & 12 volt starters , it should work.
     
    Last edited: Apr 19, 2018
  12. GOATROPER02
    Joined: Mar 22, 2006
    Posts: 2,059

    GOATROPER02
    Member
    from OHIO

    Not on an original starter...... drive shaft sizes are different

    My starters can be used with either drive gear


    Sent from my iPhone using The H.A.M.B. mobile app
     
  13. GOATROPER02
    Joined: Mar 22, 2006
    Posts: 2,059

    GOATROPER02
    Member
    from OHIO

    I may have a old 145 t wheel.... all of the ones I’m making now are 176

    Ring gears are not interchangeable


    Sent from my iPhone using The H.A.M.B. mobile app
     
  14. tubman
    Joined: May 16, 2007
    Posts: 5,737

    tubman
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    If it's aluminum, I would be interested. Let me know. I'm trying to save as much weight anywhere I can.
     
  15. GOATROPER02
    Joined: Mar 22, 2006
    Posts: 2,059

    GOATROPER02
    Member
    from OHIO

    I’ve 2 145t
    A used schiefer and a mildly used Howard’s



    Sent from my iPhone using The H.A.M.B. mobile app
     
  16. tubman
    Joined: May 16, 2007
    Posts: 5,737

    tubman
    ALLIANCE MEMBER

    Tony,

    I'll send you a PM.
     

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