Is this a cast or forged crank?

Slant 6 Engines

  1. C2ndLTpigeon

    C2ndLTpigeon Mopar or no Car! FABO Gold Member

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    Can someone help me id this crank. Almost looks like its steel and makes a good ring when you tap it. But I'm not to familiar with slant cranks. Heres a pic and part number.

    20210516_110004.jpg 20210516_110137.jpg
     
  2. clementine

    clementine Flight risk FABO Gold Member

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    Isn't there a difference in casting/forge seams to tell?
     
  3. krazykuda

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

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    "Is this a cast or forged crank"

    Yes....
     
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    • krazykuda

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

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      Yeah, but he hasn't posted any close-up pictures of the 'parting' line for us to be able tell....
       
    • Dartswinger70

      Dartswinger70 Only thing I ever bought new was a Fender Strat

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      Looks forged if you tap it with a wood handle of a hammer does it have a "ring" to it or a dull "thud" I also think most Slants had forged or should I say they ran a forged crank for a long span of time...
       
    • C2ndLTpigeon

      C2ndLTpigeon Mopar or no Car! FABO Gold Member

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      It has a nice ring unlike some cast V8 cranks I have.
       
    • Dartswinger70

      Dartswinger70 Only thing I ever bought new was a Fender Strat

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      Yeah the ring means forged also the "forge" marks are wide and the cast seam is thin and raised. That looks forged to me but the photo is at a distance. I dont see any thin cast marks in it where they would be. More of a wide flat appearance which would also be forged.
       
    • C2ndLTpigeon

      C2ndLTpigeon Mopar or no Car! FABO Gold Member

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      20210516_112321.jpg 20210516_112327.jpg 20210516_112414.jpg
       
    • Dartswinger70

      Dartswinger70 Only thing I ever bought new was a Fender Strat

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      yeah the marks would be out on the throws not on the journals Id zoom that photo out a bit.
       
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      • C2ndLTpigeon

        C2ndLTpigeon Mopar or no Car! FABO Gold Member

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        20210516_112657.jpg 20210516_112702.jpg 20210516_112714.jpg
         
      • Dartswinger70

        Dartswinger70 Only thing I ever bought new was a Fender Strat

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        Yeah that pic on the very left, you can make out the "wide" forging mark on the throw. That and the ring and the fact that most slants are forged I'd say its a yes.
         
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        • krazykuda

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

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          Forged...
           
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          • C2ndLTpigeon

            C2ndLTpigeon Mopar or no Car! FABO Gold Member

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            I did not know a lot of slants had forged cranks, you learn something every day. Thanks for the help @Dartswinger70 :thankyou:
             
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            • MoparMike1974

              MoparMike1974 FABO Gold Member FABO Gold Member

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              The rounded edges of the counterweights are a good indication its a forged crank. Cast cranks are usually much more squared off at the edges.
               
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              • volaredon

                volaredon Well-Known Member

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                all slants til mid '76 prod had forged cranks.
                 
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                • Valleyant

                  Valleyant Valleyant

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                  Hey, very easy to check....if the mains measure over an inch wide and the thrust about 1.25 wide then you have a Forging! The cast cranks had smaller mains/thrust.............that looks like a forged crank to me.....forge on!!!!!!!!!!!!!! and Slant 6's RULE !
                   
                  Last edited: May 16, 2021
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                  • 65 Cuda 340

                    65 Cuda 340 FABO Gold Member FABO Gold Member

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                    Besides the wide forging mark and other things mentioned above, the casting number on the crank would indicate late sixties, which would mean forged crank.
                     
                  • RustyRatRod

                    RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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                    You can easily tell from the very FIRST picture it's a forged steel crank.
                     
                  • Dartswinger70

                    Dartswinger70 Only thing I ever bought new was a Fender Strat

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                    I think so too, but the point was to get the OP to know how to tell which is why I asked him to zoom the pic. Then I hopefully informed him of what the wider forging marks looked like. I can only hope he understands. I'd post a pic of a cast crank,but right now the only one I have out of an engine is forged.
                     
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                    • C2ndLTpigeon

                      C2ndLTpigeon Mopar or no Car! FABO Gold Member

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                      And the info helped. Ive messed around with some 318's and they have all had cast cranks. I just wanted to be sure as I never would of expected there to be more forged cranks in the slants. But yes I do now understand what you meant looking at the marks, like I said I learned something new today.
                       
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                      • RustyRatRod

                        RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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                        Yeah I get that, but he didn't ask HOW to tell. He asked if WHAT he HAS is forged. It is. But, since we do all want to spread information....at least I know I do, HERE is how you tell.
                        CAST VS FORGED.jpeg
                         
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                        • 65 Cuda 340

                          65 Cuda 340 FABO Gold Member FABO Gold Member

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                          Found this pic on line. I believe top is forged, bottom cast. If that is so (and I've never had a cast slant six crank physically in my hands), they do look different, but not in the way cast vs. forged V8 cranks do. Please correct me if the bottom pic is not a cast slant six crank. The pic came from a Hot Rod article on building a hot slant six, and the cast crank was chosen because it was strong enough and a lot lighter.

                          Chrysler Slant Six Cylinder Engine - Mopar Muscle Magazine

                          mopp_0602_03z-chrysler_engine-crank_shaft.jpg
                           
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                          • RustyRatRod

                            RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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                            Both of those appear forged.
                             
                          • Hyper_pak

                            Hyper_pak Old School Chrysler Fan

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                            Check the number against this chart.
                            Crank Casting Numbers.JPG
                             
                          • 65 Cuda 340

                            65 Cuda 340 FABO Gold Member FABO Gold Member

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                            OK, I'm gonna stick my neck out and still say the bottom one is cast. Note that the center counterweight is significantly smaller. Also, the rod bearing widths are narrower. I'm not aware of any slant six forged cranks with a smaller center counterweight or smaller rod bearing widths (of course, I have been wrong before). Here's a pic that Dutra posted on Slant Six Org. a few years ago, when he was putting together an aluminum block slant six with a cast crank. Looks to me like the bottom crank above, albeit ground on (lightened) a bit:

                            crank-full.jpg

                            Another:
                            crank-weight.jpg
                             
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