Rotating torque for a new build?

Big Block A body Tech

  1. fshd4it

    fshd4it Squid inc FABO Gold Member

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    How much resistance is normal for spinning a new motor? Bored, align honed, everything measures fine. Moly faced Speed Pro rings, with rear main seal installed, no cam/timing chain yet. Breakaway is about 25 ft/lb, 20 ft/lb or a bit less once it's rolling. Seems a little high to me, but it's been a long time since I've worked with anything new.
     
  2. RustyRatRod

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

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    Sounds bout right. New rings are a major source of friction.
     
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    • fshd4it

      fshd4it Squid inc FABO Gold Member

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      Good deal. Now I can quit worrying about that, and start worrying about something else.
       
    • perfacar

      perfacar Well-Known Member

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      a lower tension oil ring would lower it to 10 #, way better, just food for thought.
       
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      • 70aarcuda

        70aarcuda Master Hoader of SBM FABO Gold Member

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        and ring width...1/16 or 5/64?
         
      • fshd4it

        fshd4it Squid inc FABO Gold Member

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        5/64 rings, in a 340 (yep, posted in the wrong forum before I noticed) with forged pistons. Not doing anything fancy with this motor, pretty much stock.
         
      • superfragl

        superfragl Member

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        As I recall the book Big-Block Mopar Engines (How to Rebuild): Don Taylor calls for 5 ft/lbs per cylinder. So under 40 is fine.
         
      • fshd4it

        fshd4it Squid inc FABO Gold Member

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        I've got his small block book, and thought it mentioned something about that. But I read through it a couple times and didn't find anything, maybe I just glossed over it. I'll have to go back and check again I guess.
         
      • superfragl

        superfragl Member

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        You should be fine anyway.
         
      • AndyF

        AndyF Well-Known Member

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        I always measure the rotating torque and write it down for the engine so I can keep track over time. This one says 20 ft-lbs on the ID pad.

        DSC_0073 (Large).JPG
         
      • BigBlockMopar

        BigBlockMopar BigBlockMember

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        If a good amount of assembly lube has been used the breakaway torque will be much higher.

        The 360 I'm currently rebuilding has, with a fully asembled engine (cam/heads/timingchain-tensioner/rockers/waterpump, minus sparkplugs), about 30-35 lbs/ft rotational torque. But its breakaway torque could be up to 75 lbs/ft.
        Now that I've done a few pre-lubes while setting the valves and such, some of the assembly lube has been pushed away, the breakaway torque has come down to 50 lbs/ft already.
         
      • perfacar

        perfacar Well-Known Member

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        narrow rings will lower rotation torque a lot. on street motors, we shoot for 15 # , race motors , 5 #. they do not use oil!!! your newer motors all use metric rings, which are lot narrower, try 1.2 MM , 1.5 MM and 3 or 4 MM oil rings. just food for thought.
         
      • RustyRatRod

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

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        Why? If you're not going to take stock in our answers, why in the world did you even ask here? People who write books are not the only ones who have experience.
         
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        • RustyRatRod

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

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          You cannot simply swap to a narrower ring. You must match whatever the ring land in the piston is. Otherwise, going narrower than the ring land will result in really bad things.
           
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          • fshd4it

            fshd4it Squid inc FABO Gold Member

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            So somewhere between my reply to your post, and my reply to Superfragl's, I decided not to take "stock" in your answers? If I didn't have faith in the knowledge on this board, I wouldn't ask. He referred to a book for the answer to my question, and I replied that I had probably missed that info in my similar book. Good grief. By the way, thanks for your last post, you answered a question before I even asked it.
             
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            • 70aarcuda

              70aarcuda Master Hoader of SBM FABO Gold Member

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              Actually Total Seal makes some spacers that allows the narrower 1/6 or metric rings to be placed in the 5/64 ring land on the piston. It is primary used for nhra Stock eliminator where the ring land must be stock....and they are expensive. The rings and spacers are 399 bucks...I had a set of KB107 with 5/64 ring lands was looking for an alternative for narrower rings...and hell..I can buy new pistons and rings for that price....lol
               
            • RustyRatRod

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

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              My apologies.I took what you said the wrong way. You know. A mistake. Glad to see someone not familiar with the concept. Must be nice. ;)
               
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              • RustyRatRod

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

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                Right, but you just cannot slap narrower rings on a piston and go. That's what I was saying.
                 
              • perfacar

                perfacar Well-Known Member

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                I didn't say you can throw narrow rings in wide, grooves, I know you need spacers,, the fact is metric rings are lower tension, make more power, better fuel milage, and last longer!!!! apparently, you use shuck n jive cast rings. good rings cost more. then it's up to the owner, if he wants good quality or poor quality.
                 
              • Abodybomber

                Abodybomber Breaking street machines , since 1983.....:) Legendary Member

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                They do,correct.. Sometimes a budget applies....I still use cast iron ,or moly rings.. depending on budget,& engine bore conditions. A dingle ball re ring,on tapered bores ,waste money on high dollar rings.
                It needs to be kept in check...,Would you install Hellfire rings & CP thin ring pistons,on a .002" out of round bore?
                 
              • RustyRatRod

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

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                I know that. I stated what I did to make sure the OP knew it and didn't make an expensive mistake..

                I don't know why in the world you would twist what I said into an insult back at me, but thanks. That was classy. And no, I don't use cast rings on anything anymore......but I have in the past with no problems.
                 
              • txstang84

                txstang84 Well-Known Member

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                :popcorn:

                Little bit too much booty hurt emanating from this thread...Rob are you startin shit again? :lol:
                 
              • yellow rose

                yellow rose Overnight Sensation FABO Gold Member

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                Holidays are coming quick so everyone has their knickers in a bind!!!!!!!
                 
              • RustyRatRod

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

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                Well maybe so but I didnt start it this time dammit. lol
                 
              • yellow rose

                yellow rose Overnight Sensation FABO Gold Member

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                For the life of me I can't figure why jpar hasn't chimed in.

                Last I heard he was in the woods.

                It's possible he was ate by a bear and pooped over a cliff.

                This thread is in his wheel house.
                 
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