1. 4spdragtop

    4spdragtop FABO Gold Member FABO Gold Member

    Messages:
    28,905
    Likes Received:
    8844
    Joined:
    Aug 28, 2009
    Location:
    Wasting time here
    Local Time:
    11:39 AM
    Maybe...but if they are lightening it, they are removing metal correct?
    I've never heard or seen a balance quote on a piece of paper. So I cant say one way or another. I can only imagine that there is a fair amount of calculations and weighing involved, which equals a lot of time=$$
     
  2. RustyRatRod

    RustyRatRod Bla de blizhibliz de blatde blizi bla bla FABO Gold Member

    Messages:
    59,754
    Likes Received:
    30811
    Joined:
    Jun 7, 2010
    Location:
    Georgia
    Local Time:
    12:39 PM
    Well it depends, Steve. They may need to remove metal from one side and add to the other. It's all about gettin the bob weight right. Sometimes it's a trick.
     
    • Thanks! Thanks! x 1
    • nm9stheham

      nm9stheham Well-Known Member

      Messages:
      11,939
      Likes Received:
      3806
      Joined:
      Dec 20, 2013
      Location:
      Waynesboro, VA
      Local Time:
      12:39 PM
      FWIW...... 50% of the piston weight change is doubled because there are 2 piston/rod assemblies represented by each bobweight. So, if you're thinking of it in that fashion, then think of 100% of the piston weight change going into the bobweight.

      The over- or under-balance creates a rocking motion in the engine at the same rate as the RPM's. Imagine passing an imaginary axle through the #3 main bearing, and the engine rocking back and forth on that... .front is going up while rear is going down and vice versa, back and forth once per crank rotation. The trannie and its mounts tends to limit this rocking motion, but then those forces all go into the front and rear of the bearings, crank, block etc.

      The balancing of the piston/rod assemblies minimizes a different imbalance around the main axis of the crank.
       
    • Wyrmrider

      Wyrmrider FABO Gold Member FABO Gold Member

      Messages:
      3,197
      Likes Received:
      1531
      Joined:
      Sep 5, 2016
      Location:
      los angeles
      Local Time:
      9:39 AM
      good on you NM
      one poster said no big deal
      going lighter maybe so
       
    • yellow rose

      yellow rose Doctor of Thinkology.

      Messages:
      21,127
      Likes Received:
      17170
      Joined:
      Jun 19, 2015
      Location:
      Living on the razors edge
      Local Time:
      9:39 AM

      I've already posted...the math is simple. Takes no time.
       
      • Agree Agree x 2
      • 4spdragtop

        4spdragtop FABO Gold Member FABO Gold Member

        Messages:
        28,905
        Likes Received:
        8844
        Joined:
        Aug 28, 2009
        Location:
        Wasting time here
        Local Time:
        11:39 AM
        Math might be simple, but the time it takes to come up with numbers to plug in??
        Gotta weigh every single piece right?
         
      • yellow rose

        yellow rose Doctor of Thinkology.

        Messages:
        21,127
        Likes Received:
        17170
        Joined:
        Jun 19, 2015
        Location:
        Living on the razors edge
        Local Time:
        9:39 AM

        Yes. But I seperate out the math from the time to weight and equal each part. Today we are pretty lucky. Most Pistons and rods are now well within a gram. So you are really just making sure something from a different run didn't get boxed together.

        Once you have the big end, pin end, piston, rings, pin, pin retaining clips and a rod bearing weighed, you take about 5 minutes to add up the bobweight.

        Then the real work begins.
         
        • Like Like x 1
        • 89on35s

          89on35s Inferno Red Duster FABO Gold Member

          Messages:
          1,656
          Likes Received:
          1561
          Joined:
          May 11, 2006
          Location:
          Martensville Sask. Can.
          Local Time:
          10:39 AM
          I can't remember who, but someone I was talking to out at the track recommended Precise Engines to me for my Car engine stuff. I have used them in the past, but it was for Snowmobile stuff. @79410aspenrt do you have a recommendation?

          Cley
           
        • Mopar Sam

          Mopar Sam Well Fed Member

          Messages:
          910
          Likes Received:
          1213
          Joined:
          Jul 18, 2008
          Location:
          Indiana
          Local Time:
          12:39 PM
          I really wish the crank manufacturers would make cranks unbalanced for machine shops, especially the cast versions. I hate when you need to add weight right where they drilled a hole. Usually this is on stuff with hyper pistons and cast cranks.
           
        • nm9stheham

          nm9stheham Well-Known Member

          Messages:
          11,939
          Likes Received:
          3806
          Joined:
          Dec 20, 2013
          Location:
          Waynesboro, VA
          Local Time:
          12:39 PM
          FWIW...... Getting the end weights for stock rods matched can be time consuming.
          They will vary a fair amount. Checking 1 set of light SBM rods yielded bobweight variation of over 20 grams across the set if the piston and pin weights were all identical. So yes IMHO, lots of labor there.

          And for info.... The rod end weighing part is the area most subject to errors.
           
          • Thanks! Thanks! x 1
          • rumblefish360

            rumblefish360 So close, yet so far away FABO Gold Member

            Messages:
            37,774
            Likes Received:
            9470
            Joined:
            Jun 21, 2005
            Location:
            New York, on a Island
            Local Time:
            12:39 PM
            I agree, but what RRR is saying is that IF you need to add metal...... I don’t think anybody will give a quote on the dollar amount and much less stock to it. Typically, I get, it starts at $ XXX ....

             
            • Thanks! Thanks! x 2
            • 79410aspenrt

              79410aspenrt Well-Known Member

              Messages:
              226
              Likes Received:
              124
              Joined:
              Nov 23, 2010
              Location:
              Saskatchewan
              Local Time:
              11:39 AM
              i have used Precise Engines in the past. i don't think i will go back there. i recommend Bruce from ABS in regina. but he's a one man show and it takes time, lots of time. i have used Northside Engines for some small stuff.
               
            • 89on35s

              89on35s Inferno Red Duster FABO Gold Member

              Messages:
              1,656
              Likes Received:
              1561
              Joined:
              May 11, 2006
              Location:
              Martensville Sask. Can.
              Local Time:
              10:39 AM
              Was it a particular issue with Precise? I know they are expensive but I have been happy other than that.

              Cley
               
            • oldkimmer

              oldkimmer FABO Gold Member FABO Gold Member

              Messages:
              14,830
              Likes Received:
              3903
              Joined:
              Nov 11, 2006
              Location:
              Kindersley, Saskatchewan,
              Local Time:
              11:39 AM
              I guess it all depends if u want to ship or travel. Yes, Bruce is the best. I hear Northside does good work but I haven’t used them. Kim
               
            • 70aarcuda

              70aarcuda Master Hoader of SBM FABO Gold Member

              Messages:
              15,372
              Likes Received:
              3870
              Joined:
              Jan 16, 2005
              Location:
              las vegas
              Local Time:
              9:39 AM
              this is what i get from the machine shop along with the bill....print out of the balance job...plus he keeps one on file for the future should something needs to be fixed. This a 360 .070 small block cast crank that had been previouly internally balanced. New pistons weight pretty close to old pistons but went from a 660 gram H beam rod to a 595 gram I beam rod. Weight had to be removed from the crank....I wonder if i could have gotten a rebate on the mallory metal...lol

              20171031_210729_resized.jpg
               
            • 70aarcuda

              70aarcuda Master Hoader of SBM FABO Gold Member

              Messages:
              15,372
              Likes Received:
              3870
              Joined:
              Jan 16, 2005
              Location:
              las vegas
              Local Time:
              9:39 AM
              I can not find the second sheet where they spin it and shows the numbers.....
               
              • Thanks! Thanks! x 1
              • 89on35s

                89on35s Inferno Red Duster FABO Gold Member

                Messages:
                1,656
                Likes Received:
                1561
                Joined:
                May 11, 2006
                Location:
                Martensville Sask. Can.
                Local Time:
                10:39 AM
                Well I got it tore down completely now. I'm going to follow along with @krazykuda and his awesome how to that he was kind enough to put together. So far the crank bearing surfaces look awesome. Both the crank and bearings are marked .010 so I know what main bearings to get now. The rod bearings are not marked but I can read the part number. I have yet to try and find what they are.
                20191201_151035.jpg 20191201_151043.jpg
                The bores look good at .030 over. I'll hone them up and drop new pistons in with the stock rods and ARP rod bolts. I ordered most of the stuff I need like pistons, rod bolts, oil pump, etcon Summit's black friday sale saving a whopping 50 bucks but free shipping to Canada is always sweet!
                20191201_155400.jpg
                If anyone wants a used MP 508 cam it's out and available too.
                20191201_160614.jpg
                Looks like a new double roller in it so that is a bit of a bonus too! All in all it was a good couple hours in the shop!

                Cley
                 
                • Like Like x 1
                • rumblefish360

                  rumblefish360 So close, yet so far away FABO Gold Member

                  Messages:
                  37,774
                  Likes Received:
                  9470
                  Joined:
                  Jun 21, 2005
                  Location:
                  New York, on a Island
                  Local Time:
                  12:39 PM
                  Good bracket cam.
                   
                • krazykuda

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

                  Messages:
                  52,410
                  Likes Received:
                  17241
                  Joined:
                  Aug 20, 2007
                  Location:
                  Orland Park, IL
                  Local Time:
                  11:39 AM
                  If there are no size markings on the bearings, they are usually standard, however I would recommend measuring the journals to be sure....
                   
                  Last edited: Dec 1, 2019
                • oldkimmer

                  oldkimmer FABO Gold Member FABO Gold Member

                  Messages:
                  14,830
                  Likes Received:
                  3903
                  Joined:
                  Nov 11, 2006
                  Location:
                  Kindersley, Saskatchewan,
                  Local Time:
                  11:39 AM
                  Cley, u can buy new rods on Speedmaster 79. For less than $200.00
                   
                • 89on35s

                  89on35s Inferno Red Duster FABO Gold Member

                  Messages:
                  1,656
                  Likes Received:
                  1561
                  Joined:
                  May 11, 2006
                  Location:
                  Martensville Sask. Can.
                  Local Time:
                  10:39 AM
                  I've got 2 sets of stock rods and the ones in my car as well. Is there a benefit to new rods?

                  Cley
                   
                • oldkimmer

                  oldkimmer FABO Gold Member FABO Gold Member

                  Messages:
                  14,830
                  Likes Received:
                  3903
                  Joined:
                  Nov 11, 2006
                  Location:
                  Kindersley, Saskatchewan,
                  Local Time:
                  11:39 AM
                  No cycles on them and ur stock ones will be as much once u resize them and new bolts
                   
                • 89on35s

                  89on35s Inferno Red Duster FABO Gold Member

                  Messages:
                  1,656
                  Likes Received:
                  1561
                  Joined:
                  May 11, 2006
                  Location:
                  Martensville Sask. Can.
                  Local Time:
                  10:39 AM
                  Good to know! If you're in town some time you should stop by for a Christmas drink and give me a second opinion on what I have!

                  Cley
                   
                • oldkimmer

                  oldkimmer FABO Gold Member FABO Gold Member

                  Messages:
                  14,830
                  Likes Received:
                  3903
                  Joined:
                  Nov 11, 2006
                  Location:
                  Kindersley, Saskatchewan,
                  Local Time:
                  11:39 AM
                  Cley, U got it buddy. Kim
                   
                • krazykuda

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

                  Messages:
                  52,410
                  Likes Received:
                  17241
                  Joined:
                  Aug 20, 2007
                  Location:
                  Orland Park, IL
                  Local Time:
                  11:39 AM

                  However, I prefer to use rods with oil squirt holes and many of the aftermarket rods do not have them... That's why I prefer to recondition old rods and have new bolts installed so I can have squirt holes....


                  but if you don't want oil squirt holes then look into new rods...
                   
                  • Agree Agree x 2
                  1. This site uses cookies to help personalize content, tailor your experience and to keep you logged in if you register.
                    By continuing to use this site, you are consenting to our use of cookies.