Flywheel Identification internal verses external balance

General Mopar Tech Discussions

  1. B Bad to the Bone

    B Bad to the Bone Member

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    To all: Any help would be appreciated in confirming what flywheel I have.

    I think I have a flywheel for an internally balanced motor but want to make sure.

    This is what I think I know about this flywheel can anyone confirm if I am correct ?

    1 The casting number pictured is used on (both) internal and externally balanced motors

    2 It is a 130 tooth 6 bolt flywheel and is used on big and small blocks

    My big question is this, What are the 3 drilled holes that are pictured ? I have been told that for an external balanced flywheel that there should be 3 large circular areas taken out further in towards the center away from the starter ring.

    I have a vibration that starts a little over 2000 RPM and seems to fade way above 3000 RPM. It is a small block LA Motor with a mild camshaft backed up by a 833 4 speed trans. I have checked it it in all gears and speeds and seems to come from motor only and not the drive train.

    I have tried everything I know to resolve this. Any help would be greatly appreciated.

    Flywheel 2.jpg Flywheel.jpg
     
  2. Cranky

    Cranky Henchman #27 Staff Member FBBO Gold Member

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    Does it have a couple of scalloped cuts in it or just the holes? If it came from a 360, it's for externally balanced engines.....but that part number is used for internally balanced engines. That said, someone could have had it balanced differently.
     
    Last edited: Oct 11, 2015
  3. B Bad to the Bone

    B Bad to the Bone Member

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    Thanks Cranky for the response. I think the number on the flywheel may be a casting number and will show up on multiple applications both internal and external. Please correct me if I am mistaken.

    I see no scallopes but I am confused about the small drilled holes as pictured. Have you or anyone else ever seen them on a flywheel before ?
     
  4. 62 Dart Convertible

    62 Dart Convertible Well-Known Member

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    Those holes are for balancing, but not associated with external balancing of a 360 or B/RB with cast crank.

    Assuming you have a 360?
     
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    • Cranky

      Cranky Henchman #27 Staff Member FBBO Gold Member

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      Yes, the holes are for balancing and yes, I've seen flywheels that have the same casting number used on various engines. Do you know the history of this wheel and what type of harmonic dampener are you using on the front. Btw, if you have a external balanced wheel on an internal balanced engine or vice versa, you will notice vibration before 2000 rpm and it won't be going away by 3000 and it's pretty severe too. Does it vibrate when parked and in neutral when revved up too?
       
    • moparmarks

      moparmarks I'm just a guy with a screwdriver. FBBO Gold Member

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      That is a neutral balanced flywheel for steel crank. 360 wheel has three 15/16" holes and BB cast crank wheels has a scallop.
       

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    • B Bad to the Bone

      B Bad to the Bone Member

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      It is a 318. Very nice car. I am the third owner. I just got through converting it over from a 904 auto. It now has a 833 4 speed. It is done correctly with factory parts. Your info on what these holes are are very helpful.

      I was reasonably sure I had a internal balance flywheel but wanted to reach out to you guys that are more experienced with the Mopar line. I have had the drive shaft checked etc and all is well. I can duplicate the vibration while driving and when sitting still. The vibration is not real sever but is bad enough that you can notice it in the stick and feel it in the floorboard. As soon as you push the clutch in and reduce engine RPM it goes away. Thanks Very Much for your insight thus far.

      - - - Updated - - -

      Thanks and yes does vibrate parked and in neutral. The Engine is the factory 318 with stock harmonic dampener. I bought the flywheel off of E Bay with a truck 833 overdrive. I did not use the overdrive trans but did use the flywheel (pictured). No vibration until it is spooled up to about 2000 and then starts to go away when you get 3000 and becomes more of a harmonic vibration and starts to cycle in frequency. I have never seen anything like this before. None of the vibration is severe but it is, shall i say significant. I am really stumped on this one. The motor was rebuilt before I got the car I am wondering if it was not put together correctly.

      - - - Updated - - -

      BTW Thank you Both, MOPARMARKS and CRANKY. Though the problem is not resolved at least I know what flywheel I have. The direction of this project is to sort out the drive train and then upgrade the motor. Either a Gen III or stroker small block. I just have to identify the problem area before I move on. I was hoping to enjoy (drive) the car while I got my $$$ togeter for the next phase of the resto. Any other thoughts from you guys in the know are greatly appreciated.
       
    • Vince kf

      Vince kf Member

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      hey brother help having vibration issue with my 73 Charger 400 - 4speeds ( originally auto someone convert it this engine/trans combo ) i have a flywheel with casting numbers #2843212 , someone even told me if i don't have a pilot bushing it will make this vibration . is this is my correct flywheel numbers? ( this is an old photo of my engine before installing it )

      my 400 engine flywheel.jpg
       
    • Vince kf

      Vince kf Member

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      hey brother having vibration in my 73 Charger 400 with A833 4 speeds ( originally318-904) i swamped the 400 and 4 speeds from another 73 Charger that was also originally auto . some told me that i don't have the pilot bearing on my flywheel ( judding by an old photo of my engine before installing it ) m but i think i have the wrong flywheel for my engine , mine have the casting numbers #2843212 . also does my flywheel in the photo below has a pilot bushing installed ?any help would be much appreciated

      my 400 engine flywheel.jpg
       
    • Vince kf

      Vince kf Member

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      hey brother i have a vibration in my 73 Charger 400 4 speeds ( originally 318-904) i took the engine and transmission from another 73 charger that was also convert it to a 4 speeds . my vibration increase when i raise the RPM ( even standing still in neutral ) been told that a missing pilot bushing could do that, but am not sure if i have the right flywheel for my application . my current one does have the casting #2843212 , 1st question is what the right flywheel for my engine/transmission combo , and second does my flywheel have a pilot bushing/bearing in this photo ? ( old photo of my engine before installing it in the car ) any help would be much appreciated !

      my 400 engine flywheel.jpg
       
    • Daves69

      Daves69 Well-Known Member

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      Either, a bearing or bushing will work.
      The crank in this picture does not have a pilot "bearing". One cannot discern whether or not a bushing is installed from this picture.

      upload_2021-3-12_12-49-55.png
       
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      • Vince kf

        Vince kf Member

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        many thanks Dave for your help brother , does this missing bearing makes a vibration ? and what is the better to use
         
      • Daves69

        Daves69 Well-Known Member

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        You need one or the other. If neither are in there I would think it possible as the disc would not be centered. I remarked in your other post how one "might" try to check for a missing / loose bushing issue.
         
      • Cranky

        Cranky Henchman #27 Staff Member FBBO Gold Member

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        Has the input shaft of your transmission been shortened/sawed off shorter? If it's been shortened, it might not reach in far enough to use a factory style bushing so the bearing will be needed instead. Casting numbers don't really mean too much but the one you have is for an externally balanced engine. If the balancing holes are 31/32" in diameter and .66" deep the flywheel is for a cast crank 383/400/440 but if they are larger, it's for a small block. The small block drill holes will be around 1 13/64ths in diameter (same depth) based on what I'm finding on the net......which seems to be pretty corn fusing.....
         
      • Vince kf

        Vince kf Member

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        i don't think my input shaft was shortened , i was trying to find any picture during the restoration of the car . the flywheel i have now on the car doesn't have any holes or weights , i looked at it the other day from underneath the car and i was able to take the casting numbers cause i saw a similar casting number one here on this page but WITH holes that's why i'm confused . also saw 2 comments about the 400 flywheel that it should have a cut . i don't have much infos on these am still learning thats why i ask you guys
         
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        • Cranky

          Cranky Henchman #27 Staff Member FBBO Gold Member

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          Can you post of pic of the nose of the input shaft....side view and end view please.....
           
        • Vince kf

          Vince kf Member

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          that was a very helpful photo brother thanks for the help sadly the engine is on the car , however i met an old mechanic he told me you have the wrong flywheel for the engine , he said he can balanced right for my application also told me that i might have the 11 inch clutch which is wrong and makes my pedal much stiffer than a smaller 10.5" one
           
        • Vince kf

          Vince kf Member

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          am trying brother to find a picture sadly i can't find any , i assembled the car 3 years ago , but as far as i remember it was a compete input shaft and not being cut , but the pilot bearing is not there ( judging by the picture i've posted above ) not sure if i have a pilot bushing tho
           
        • Daves69

          Daves69 Well-Known Member

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          You do have an 11" flywheel in that picture. If it's balanced for the rest of the team it's OK to run. Pedal pressure is typically a result of pressure plate load differences, not diameter of the clutch.

          24 teeth X 6 = 144 teeth, 143 for Mopar is an 11" flywheel.........

          upload_2021-3-13_12-47-13.png

          .....a 10-1/2" flywheel will be 130 teeth. 21.5 teeth between bolt holes.


          The '73 Dodge and '72 Plymouth FSM may be available to downlod here. Best price anywhere. The site is being updated right now so not all links are ready..............

          Service Manuals – MyMopar


          One of these can be helpful.............

          Mopar Performance Mopar Chasis 8th Edition | eBay
           
          Last edited: Mar 14, 2021
        • Crash520

          Crash520 Well-Known Member

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          Just for giggles, drop your alternator and ps drive belts off so that the only thing turning is the crank, I was chasing a similar vibration, could not see out the rear view mirror, turned out to be a bad alternator balance !!!!
           
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