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Main cap girdle's....do they work??

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  • Main cap girdle's....do they work??

    any one have experience with them? I just fitted my 408 small block Mopar with one after finding some main cap walk and I am curious.

  • #2

    Re: Main cap girdle's....do they work??

    Re: Main cap girdle's....do they work??

    Yes, they work. Sometimes take a little fitting work, though.

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    • #3

      Re: Main cap girdle's....do they work??

      Re: Main cap girdle's....do they work??

      Yes, they work. Sometimes take a little fitting work, though.
      Who make some for a BBC? Got a couple of 2 bolts, cheaper than converting to 4 bolt.

      Comment


      • #4

        Re: Main cap girdle's....do they work??

        Re: Main cap girdle's....do they work??

        Girdles work, but I prefer a corset. Oops, my ignorance is showing.

        Dan

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        • #5

          Re: Main cap girdle's....do they work??

          Re: Main cap girdle's....do they work??

          they will hold the parts together. I think there are way to many people using them w/o knowledge of how it affects torquing the mains down and other clearance issues they can cause. If you spend the time then they have a potential to help......but how much is still up in the air.

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          • #6

            Re: Main cap girdle's....do they work??

            Re: Main cap girdle's....do they work??

            so how does it affect the torqueing of the main cap's/stud's,, according to Hughe's you torque to 90ft# with ARP moly lube.

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            • #7

              Re: Main cap girdle's....do they work??

              Re: Main cap girdle's....do they work??

              You have to make sure all the bolt holes perfectly align so they are not pulling on each other and preventing a true torque reading. Also make sure the girdle is not interfering with any other engine parts, like touching the block so it does not sit perfectly level. I'd also use more steps approaching the final torque number, making sure it all snugs down evenly.

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              • #8

                Re: Main cap girdle's....do they work??

                Re: Main cap girdle's....do they work??

                Well, I have used plenty of them on BB Mopars.. I believe in them, I am the FIRST guy that was selling the current style of main girdle for the BB Mopars.. I came up with the current simple design and sold them on Ebay about 5-6 years ago, I wasn't making crap on them, a friend of mine was cutting them on his CNC machine outta 3/8 cold rolled. They were more of a PITA to make then they were worth, it didn't take long for the word to get out and they were popping up all over the place as the greatest thing since sliced bread. Now a dozen or so people make them for the BB Mopar.

                My theory is that they help to reduce the harmonics going through the mains, harmonics are like current, it goes in the direction of least resistance. I believe on the BB Mopar with its deep oil pan rails act like a bell and the harmonics go down the rails and shake the mains out of the block, with the main girdle attaching the mains together and tying them to the oil pan rail, it helps to keep the harmonics from traveling down the oil pan rails.

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                • #9

                  Re: Main cap girdle's....do they work??

                  Re: Main cap girdle's....do they work??

                  I think it is very simple geometry, and all the rest is BS. XYZ axis, span of the cap in one axis, bolts and "bridge" of cap in another, and near nothing in the third until you put the girdle on it. I don't know what you mean by the harmonics but I guess is sounds good.
                  -dulcich

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                  • #10

                    Re: Main cap girdle's....do they work??

                    Re: Main cap girdle's....do they work??

                    I think it is very simple geometry, and all the rest is BS. XYZ axis, span of the cap in one axis, bolts and "bridge" of cap in another, and near nothing in the third until you put the girdle on it. I don't know what you mean by the harmonics but I guess is sounds good.
                    -dulcich
                    Well, I fully understand what your saying, but harmonics are very destructive and I feel that harmonics are reduced in the main cap area with the girdle tying the mains together, furthermore on the BB Mopar I feel those same destructive harmonics travel down the oil pan rail and amplify like harmonics resonating through a bell, the main girdle that I worked up a number of years ago helps to dampen all that.

                    I guess so much of what we do is not always cut and dry, its theories that some of us believe that advance things and over time become fact. How many times did some very smart people out in the World feel that some of the stuff that Smokey believed in was nuts, he proved those rocket scientists wrong many of times.

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                    • #11

                      Re: Main cap girdle's....do they work??

                      Re: Main cap girdle's....do they work??

                      well in your theory wouldnt the girdle give a new path for the harmoics to travel?

                      Main cap movement is more prevalent at higher RPM, the crank speed is reaching points where it "floats" in the mains and one hint of detonation will interrupt that..... The support will help control the "hit" of that detonation by letting it travel across the area instead of being focused on one main.

                      Keep RPMs lower and keep it safe and you wont ever have to really worry about tearing up a block.

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                      • #12

                        Re: Main cap girdle's....do they work??

                        Re: Main cap girdle's....do they work??

                        Yeah, I guess it will dampen by tying the caps together, and the pan rail too. When I think of a damaging harmonic it is a vibrational disturbance of a certain sufficient amplitude to be damaging dependend upon the frequency of the vibration and the resonant frequency of the material or structure.
                        -dulcich

                        Comment


                        • #13

                          Re: Main cap girdle's....do they work??

                          Re: Main cap girdle's....do they work??

                          well in your theory wouldnt the girdle give a new path for the harmoics to travel?

                          Main cap movement is more prevalent at higher RPM, the crank speed is reaching points where it "floats" in the mains and one hint of detonation will interrupt that..... The support will help control the "hit" of that detonation by letting it travel across the area instead of being focused on one main.

                          Keep RPMs lower and keep it safe and you wont ever have to really worry about tearing up a block.
                          Well, I feel that on the BB Mopar it travels down the oil pan rail and back and helps to rattle the bottom end apart.. Ever see the outside of a BB Mopar crack right where the oil pan rail meets the bottom of the block, I feel that area that cracks supports my theory...

                          Comment


                          • #14

                            Re: Main cap girdle's....do they work??

                            Re: Main cap girdle's....do they work??

                            Yeah, I guess it will dampen by tying the caps together, and the pan rail too. When I think of a damaging harmonic it is a vibrational disturbance of a certain sufficient amplitude to be damaging dependend upon the frequency of the vibration frequency and the resonant frequency of the material or structure.
                            -dulcich
                            See, now your getting to "scientific" for me.. lol I'm just a silly engine guy that doesn't always go along with conventional thinking..

                            Comment


                            • #15

                              Re: Main cap girdle's....do they work??

                              Re: Main cap girdle's....do they work??

                              I don't have any doubt that a girdle helps. A lot.
                              -dulcich

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