How to tell if flywheel is iron or steel

Transmission and Drivetrain Tech

  1. MoparMike1974

    MoparMike1974 FABO Gold Member FABO Gold Member

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    I have a 11" flywheel from a 69 383 that i'm thinking about using. I'm sure its not the original wheel but i'm not sure if its iron or steel. It has the numbers 40 30467 stamped into it but I haven't been able to find anything online. The pressure plate was yellow and diaphragm type.
    Is there any easy way to tell what its made of?
     
  2. George Jets

    George Jets 1967 Dart 2 Door FABO Gold Member

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    Hit it with a grinder. If it sparks should be steel.

    Steel is 3x the money vs stock ductile iron flywheels.

    Screenshot_20220617-013941_Firefox.jpg

    Screenshot_20220617-014711_Firefox.jpg
    Screenshot_20220617-014641_Firefox.jpg
     
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    • 66fs

      66fs FABO Gold Member FABO Gold Member

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      Magnet. Count the teeth on the starter ring. You need 130 or it will not work.
       
    • krazykuda

      krazykuda Well-Known Member FABO Gold Member How-To Section Editor

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      If you paid for it, it's iron...

      If you took it without paying, it's steal....
       
      Last edited: Jun 17, 2022
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      • Daves69

        Daves69 Well-Known Member

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        FWIW...........
        upload_2022-6-17_8-27-8.png
         
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        • 67Dart273

          67Dart273 FABO Gold Member FABO Gold Member

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          LOL what?? Both steel and iron are magnetic.
           
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          • cudascott

            cudascott It’s a sickness!

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            :lol: Yes and make sparks when ground on with a grinder although different colored ones but sparks none the less. Bright yellow sparks Steel and Red to Orange iron
             
          • Scody21

            Scody21 Just send it

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            Just buy a new one. Do you really want a 50+ year old non SFI cert 30 pound disk spinning up to say 6500 rpm’s 6 inches from your feet coming apart?

            Scatter shield also…. Just a thought…
             
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            • Outsder

              Outsder way back when

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              Well to answer the poster's question, an iron FW will typically not be fully machined all over and show some rough cast surfaces on one or both sides. In addition, if there are raised cast numbers or letters, it's iron. Steel FWs are fully machined all over, have no rough pebble like cast surfaces, and if there are any numbers or words they are stamped in.
               
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              • 66fs

                66fs FABO Gold Member FABO Gold Member

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                LOL, I was thinking Aluminum or Iron.
                 
              • CudaFactHackJob

                CudaFactHackJob Well-Known Member

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                Iron sparks are shorter and darker orange. Steel sparks are longer; with a lot of split ends; and lighter in color; yellow. If you take a pic of the sparks you can count the splits and determine the exact hardness.
                 
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                • mopowers

                  mopowers Well-Known Member

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                  Yeah, hit the machined surface with a grinder and tell us what the sparks look like. :rofl:
                   
                • 33IMP

                  33IMP Well-Known Member

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                  That's what I was gonna say. If it has texture like a cast iron head or block, likely cast. Smooth on the non clutch side, probably steel.
                   
                • Dfr360cuda

                  Dfr360cuda Diagnosis... Plum Crazy.

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                  Hit it with a grinder.
                  How will that affect the balance ?
                   
                • MoparMike1974

                  MoparMike1974 FABO Gold Member FABO Gold Member

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                  Thanks for the reply's. I will post some pics this evening. Im leaning torwards buying a new wheel since my goal is around 600 hp. Not sure im willing to chance it. I will sell this wheel for someone who is doing a mild build as its in great shape.
                  These 11" wheels are expensive. Cheapest ones come in close to $400.
                   
                • barbee6043

                  barbee6043 barbee 6043 FABO Gold Member

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                  Is it heavy??
                   
                • CudaFactHackJob

                  CudaFactHackJob Well-Known Member

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                  Okay, never hit the machined surface with a grinder. That is very poor advice.
                   
                • MoparMike1974

                  MoparMike1974 FABO Gold Member FABO Gold Member

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                  Yeah dont worry, I wasnt going to grind on my flywheel.
                  Here are a couple pics of the flywheel. Its fully machined so no obvious rough areas like a cast part would have. Additionally, the numbers are stamped in.
                  Heavy? Hell yeah. I was thinking about 35 lbs. Threw it on my scale and its a whopping 40.2 lbs.

                  Flywheel_Front_A.jpg

                  Flywheel_Front_B.jpg

                  Flywheel_Back.jpg
                   
                • MOPAROFFICIAL

                  MOPAROFFICIAL FABO Gold Member FABO Gold Member

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                  Pick it up, you'll know.
                   
                • 33IMP

                  33IMP Well-Known Member

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                  Looks like a steel wheel with a fresh Blanchard grind. I'd run it.
                  Though, I did LOVE my aluminum flywheel. Need a lot of gear to make an aluminum wheel work well.
                   
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                  • MoparMike1974

                    MoparMike1974 FABO Gold Member FABO Gold Member

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                    Yes, I just had it resurfaced. Second pic is cosmolined since it will be in storage a while.
                    I will probably buy a new one because its heavier than I need.
                     
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                    • RAT ROD AL

                      RAT ROD AL I know just enough to be dangerous FABO Gold Member

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                      Your box is full. I may be able to help you out ! PM me.
                       
                    • MoparMike1974

                      MoparMike1974 FABO Gold Member FABO Gold Member

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                      Try again
                       
                    • toolmanmike

                      toolmanmike Moderator Staff Member FABO Gold Member

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                      Does it ring when you tap it with a hammer it is steel. If it is a dull ring or almost a thud it is cast. Just like a crankshaft.
                       
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                      • CudaFactHackJob

                        CudaFactHackJob Well-Known Member

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                        Excellent point.
                         
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