Replace stock Harmonic Balancer?

Discussion in 'Small Block Mopar Engine' started by WSUTARD, Mar 20, 2017.

  1. WSUTARD

    WSUTARD FABO Gold Member FABO Gold Member

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    As some of you know, I'm in the process of digging into my 340. Or maybe screwing it up...yet to be seen.

    Anyway, I yanked the stock harmonic balancer. I'm wondering if there is any benefit to going with an after market one instead?

    I'm trying not to spend more money on the engine. However, it id makes sense then I can.

    68 340, internal balanced.
    IMG_1379.JPG IMG_1380.JPG
     
  2. rklein383

    rklein383 Well-Known Member

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    Two benefits, rubber that is not cracked and degrading and most aftermarket balancers have degree markings on them so you can dial in your advance better. I was checking this one out for my 5.9, works for all small blocks. 100 bucks
    Pro Products Street Dampener for Small Block Mopar
     
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    • 383Scampman

      383Scampman Well-Known Member

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      Agree , the single important thing is safety . If you decide to purchase a SFI balancer it will have degree markings to make your life a little easier .
       
    • nm9stheham

      nm9stheham Well-Known Member

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      Deteriorating rubber (either hardened or cracked) makes them not do the intended job, which is to damp out torsional vibrations within the crankshaft itself. If you were grandma, and never drove it revved up at all, then it wouldn't much matter. But, as said having the outer ring come off when running would be bad, even for grandma.
       
    • 72Valiant4Door

      72Valiant4Door Trouble Maker FABO Gold Member

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      Unless u plan to hit 6k+ rpms a good bit, there isnt much need for a high dollar balancer.

      Use a paint marker for timing tape.
       
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      • j par

        j par Well-hung Member

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        There's a place here in town that rebuilds those. machine shop would probably recommend refurbishing your American made one instead of buying Chinese junk like I did. My -2
         
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        • yellow rose

          yellow rose Doctor of Thinkology.

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          Your part is not useable. Replace it.
           
        • Ottmundr

          Ottmundr 68 Fastback

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          Even a really expensive one is cheaper than destroying your bottom end and then having to fix it. If that's the original, it's almost FIFTY year old rubber man!
           
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          • ScampMike

            ScampMike Damn Yankee FABO Gold Member

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            just in case you're not convinced yet - YES, there are many - IMHO - #1 being your personal safety, #2 being protecting the investment you're making in the engine. Even a straight stock replacement would be fine. (if you're not looking to hit a race track with it) The one you got there is plumb wore out.
            https://www.summitracing.com/parts/sum-163273/overview/year/1968/make/dodge/model/dart
             
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            • YoloCtyFlash

              YoloCtyFlash Well-Known Member

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              Also, the ring can slip. I've seen this twice while verifying TDC and timing marks.
               
            • WSUTARD

              WSUTARD FABO Gold Member FABO Gold Member

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            • WSUTARD

              WSUTARD FABO Gold Member FABO Gold Member

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              Is there anything I need to do to the timing marks on he block or do I just use the 0 line now?
               
            • ScampMike

              ScampMike Damn Yankee FABO Gold Member

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            • plumkrazee70

              plumkrazee70 Well-Known Member

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              If you go with this one. Get some good clear coat on it asap. It will rust in no time, ask me how I know. :(
               
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              • plumkrazee70

                plumkrazee70 Well-Known Member

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                Nevermind. Looks like you got one! Yay!
                 
              • nm9stheham

                nm9stheham Well-Known Member

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                You have a '68 340 right? That originally had the older water pump and timing cover with the timing mark on the cover over on the passenger side. Most (or all) of the newer dampers are for the '70 and up timing marks, which are on the driver's side. What you shows in the ad looks like it is for the later marks on the driver's side.

                So 1st thing it to check on which side are the timing marks on the timing cover that you have. If on the driver's side, then you are basically set. If on the passenger side, then you are going to have to make a pointer on the driver's side, or make new marks on the damper to line up with the passenger side timing cover marks.

                Either way, with your heads off the engine as the are you are going to have to find EXACT TDC on #1 cylinder. Use a dial indicator with the heads off on #1 piston to find exact TDC, and carefully locate your marks so that zero is EXACT TDC on #1. Since you are going to be messing with cams and/or timing them, you need to be spot on with this to have a solid, accurate reference.

                Once you have that zero reference, then you just read the timing on the damper against you zero mark.

                It may be confusing a bit, but hang in there; we're all pulling for ya.
                 
              • WSUTARD

                WSUTARD FABO Gold Member FABO Gold Member

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                The previous owner swapped out the pump and timing cover for the one with the marks on the driver side. I guess I don't follow with finding the zero mark. Once I find TDC will the 0 mark on my timing cover point to 0 on the dampener? Or are you saying it might point to a different number on the dampener and then I use that as zero from that point forward?
                 
              • nm9stheham

                nm9stheham Well-Known Member

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                Good that you know all of that. If things are perfect on all parts, then the 0 on the new damper will line up on the 0 on the timing cover marks. If they are off a bit, then the 0 on the damper will line up on some other timing cover mark. Use that other mark as your new reference, and read the timing tape numbers on the new damper against that new reference point.

                BTW, I can't emphasize enough to use a tool like a dial indicator to find exact TDC; eyeballing it is iffy at best. This is the baseline for everything else so it needs to be spot on. 3-4 degrees off on cam timing will show right up in the engine's performance.
                 
              • 70 DUSTER CRATE

                70 DUSTER CRATE Well-Known Member

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                You're right! This one is made in China, but they do make a SFI approved one. If that's any help.

                http://www.corvetteforum.com/forums/c6-corvette-general-discussion/3452723-
                ati-balancer-vs-summit-sfi-harmonic-dampers-sum-c2501.html
                Professional Products Harmonic Dampers... Any good? • Speed Talk
                Here's some failures on this subject.
                Hope this helps.
                 
                Last edited: Mar 22, 2017
              • WSUTARD

                WSUTARD FABO Gold Member FABO Gold Member

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                Hmm, that thread makes me question my decision. Im not going to be racing, just a street/cruise vehicle looking for low end performance. If I get up to 6k rpm I'm doing something wrong...

                Anyone know of a sub $100 US made one that is reliable?
                 
              • yellow rose

                yellow rose Doctor of Thinkology.

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                Again, it's not a place to skimp. What does RPM have to do with it? You can have frequency issues at any RPM. Not just high RPM. Don't step over a donut to pick up a dog turd. You see what happens to rubber over years. Now, change the bob weight, change the RPM, change the load. All those change the frequency where issues can occur. The harder you work the rubber, the quicker it becomes hard and fails.
                 
              • WSUTARD

                WSUTARD FABO Gold Member FABO Gold Member

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                Do they make single piece ones? Maybe I should go for that.

                What if I'm on a diet and don't want the donut but I need to get the turd off the lawn?
                 
              • nm9stheham

                nm9stheham Well-Known Member

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                No single piece ones... the outer ring connected through the rubber ring is what makes the damper actually damp.

                I suspect there are a lot of the PP dampers running OK out there. The issue is what gets damaged IF they fail. Other damper brands have problem from time to time.

                The stock ones can be rebuilt as suggested earlier....it is all in the rubber used, and the care of installation of the ring to keep it centered.
                 
              • Marcohotrod

                Marcohotrod Well-Known Member

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                I think I will keep running my Chrysler made in USA 340 damper, maybe someday I can afford an ATI DSCF0179.JPG
                 
              • yellow rose

                yellow rose Doctor of Thinkology.

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                See post 23.

                In 2002 I was still replacing cranks that were junk from Moroso single piece dampers. And I'm talking nice, aftermarket cranks.

                The two biggest deals with dampers like you are using is overall diameter (weight) and the durometer of the rubber used between the outer ring and the hub.
                I would rather have what you have rebuilt if and its a big IF they can tell you the durometer of the rubber is OE.
                I've never seen an OE Chrysler damper fail, but I did see a couple of GM ones fail back in the early 80's and it was a hell of a mess. Not as bad as a clutch but bad enough and that's where the SFI damper rule came from. NHRA had to decide when you use an SFI damper they picked 9.90 at the beginning. I don't know where it is now but I think it's slower than that.