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  • Engine girdles

    A question regarding engine girdles, but first some background.

    When I embarked on my Road Runner rebuild project I decided that the engine would be a stroked 440. I was aiming for something in excess of 500 HP. My mindset was I wanted a strong running engine that would stay together, and I wanted to build it right. (Yeah, I know you can explode any engine if you try hard enough, LOL.) So, as part of the build I installed a girdle.

    Fast forward to dyno day - my goal of 500+ HP was achieved: 574 HP @ 5600 RPM & 632 Lbs Ft torque @ 3700 RPM. This was more than any of us expected from the parts we chose. As Marc Viau, the person who supplied most of the internal parts and assisted me in building the engine, said about the engine as built - "Overbuilt for the street and under built for the track." (see the build thread "(Yet another) Road Runner build" in the Car Builds (Progress Threads) forum for complete details.)

    I've heard the opinion that on engines of less than 600 HP girdles aren't really necessary, but they don't hurt. Which leads to my question, was installing the girdle in what is basically a high horsepower street engine a good idea or over kill? On a build such as mine, is spending the time/money/necessary machining well advised or not really needed?
    Paul, aka 'zij576ca'
    Lifer #49
    Member & webmaster, The Mopar Club of San Diego

  • #2
    Damon from Diamondback Engines never liked them. Said they were ineffective and a PITA. He preferred to half fill iron blocks, but that won't work well for a street car.
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    • #3
      I know a few who ran half fills on the street with good results. Most of the heat is higher up in the cylinder so the bottom isn't really affected by high temps that much. On the girdle, I've heard lots of pro vs con. If you have it in there already, may as well leave it in. If you hook up on the street and are pulling the fronts up, I'm sure you will be putting some stress on everything but how many street legal tires can hook well? With a 3400 lb car, you can run 10.60's with that much power. My old car was pulling down that ET and at tear down there was evidence of cap walk but it also had the heavy Hemi rods but with light weight ask can Jahn's pistons. The stock stroke 440 saw 7300 at the top end on every pass and did NOT have a girdle (had some nice shoes though ). I guess you could call it an old school build complete with max ported 906 heads In my opinion, a girdle will help reduce cap walk and the hard block half fill helps to make the cylinders more rigid while a full fill is even better for cylinder support but more heat buildup can become a problem....
      Last edited by Cranky; 08-27-2016, 09:38 AM.

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      • #4
        Originally posted by BK View Post
        Damon from Diamondback Engines never liked them. Said they were ineffective and a PITA. He preferred to half fill iron blocks, but that won't work well for a street car.
        Yeah, the girdle was a pain. A full day of measuring, girdle on & off the block, to get the right combination of shims for each of the main studs. But I figured that the added protection was worth the day's effort it took.

        Originally posted by Cranky View Post
        ... If you have it in there already, may as well leave it in. If you hook up on the street and are pulling the fronts up, I'm sure you will be putting some stress on everything but how many street legal tires can hook well? With a 3400 lb car, you can run 10.60's with that much power. ...
        Girdle is in and I'm going to live with the tiny oil drip that it has. For rear tires I'm using Mickey Thompson et street radials - 10 1/2"W x 30" T. Advantage - they hook better than "normal" street tires; disadvantage - they last around 5,000 miles, so I've been told.

        After the build was finished we weighed the car - came in at 3660 lbs. Ran the car at the MATS in Vegas past March and ran a best of 13.14. Time was more due to the driver (me) than anything else. I thought I did alright considering I hadn't been on a track in more than 10 year and haven't shoed a 4sp in a lot longer than that. In its' current configuration consensus is it should run high 11's. Of course that'll probably involve a driver change, LOL.

        All in all, after driving the car for a year, I love it. Car has enough torque to spin the tires in 4th gear, is a beast out of the hole, and a ball to drive. I've surprised more than one BMW.
        Paul, aka 'zij576ca'
        Lifer #49
        Member & webmaster, The Mopar Club of San Diego

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        • #5
          Right now I'm beginning my 499 build for the Demon. It's a 400 block with a 4.150 stroke crank. We're going with a half filled block and a girdle. There will be a 4 speed in this car and I'm planning on more than a few missed shifts. Therefor I feel the girdle will be a good investment.
          If it takes a day to set it up, well like said above it will be time well spent. One more thing to add is that I'm going to be using a crank scraper as well so that will add a few more hours to the set up.

          Ted

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          • #6
            Would love to know how it runs once it's built.
            Paul, aka 'zij576ca'
            Lifer #49
            Member & webmaster, The Mopar Club of San Diego

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            • #7
              Damon has told me that while the fill is to stiffen the block, that the girdle s really to keep the crank and caps right. On a Mopar, aluminum caps will do a better job of keeping the crank from moving around.
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              • #8
                All good information. For my purposes, I may have gone overboard in installing a girdle, but what's done is done; I'm not tearing it apart.
                Paul, aka 'zij576ca'
                Lifer #49
                Member & webmaster, The Mopar Club of San Diego

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                • #9
                  Originally posted by DemonTed View Post
                  Right now I'm beginning my 499 build for the Demon. It's a 400 block with a 4.150 stroke crank. We're going with a half filled block and a girdle. There will be a 4 speed in this car and I'm planning on more than a few missed shifts. Therefor I feel the girdle will be a good investment.
                  If it takes a day to set it up, well like said above it will be time well spent. One more thing to add is that I'm going to be using a crank scraper as well so that will add a few more hours to the set up.

                  Ted
                  Missed shifts!! No reason for that. If your shifter is good along with the trans, clutch and all the linkage, it shouldn't be a problem. It can take some practice but if things are right to start with, you shouldn't have a problem.

                  Originally posted by BK View Post
                  Damon has told me that while the fill is to stiffen the block, that the girdle s really to keep the crank and caps right. On a Mopar, aluminum caps will do a better job of keeping the crank from moving around.
                  Any high horse power engine can and usually does benefit when using aluminum caps. What they do is help absorb some of the shock from the process of combustion and if the engine detonates/pings, they can be helpful with that too but they can only do so much lol. A Hemi engine has the cross bolted mains which help tie things together more than a 2 bolt motor but they can benefit from aluminum main caps too....so I'm told.

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                  • #10
                    I was kidding around about the missed shifts. Although it's been a while since I rowed a 4-speed.

                    Ted

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                    • #11
                      Originally posted by DemonTed View Post
                      I was kidding around about the missed shifts. Although it's been a while since I rowed a 4-speed.

                      Ted
                      A nephew came over not too long ago with a Porsche Boxster that was decently modified. After driving it around for bit he asked me when I was going to get on it. Asked him if I could drive like I stole it and he just laughed. Been awhile since I rowed gears too but I still have it The car surprised me it took it. I guess they have a much better setup for having the shifter so far from the gear box than most others with a similar setup. Only went part way with 3rd since the car was already breaking the speed limit by nearly double lol

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                      • #12
                        I like the crank girdles. your engine has enough hp ant TQ to warrant it and the insurance is good piece of mind.

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                        • #13
                          I've missed (first to third) shifts when I had a Cheatea shifter, and I'm far from the only one. I have a rachet shifter in Vitamin C and PPP in all others. No miss shifts with them.
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                          • #14
                            Engine Girdles .... revisit:

                            I went back and re-read all the above posts with particular attention to my own. In the year since posing the question, my 'small leak' has developed into an unacceptable large one. It'll be fixed later this week. Back to the shop in Lake Elsinore. If the girdle needs to be pulled to correct things I'm leaning towards leaving it removed. I've been told by a few 'people in the know', including you guys that the girdle isn't really needed on an engine that will rarely (if ever) be buzzed to more than 6000 rpm.
                            Paul, aka 'zij576ca'
                            Lifer #49
                            Member & webmaster, The Mopar Club of San Diego

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                            • #15
                              I've buzzed mine past 8000 in the past, and never had an engine with a girdle. I've had plenty f engine problems - but all were rotating oriented and not block stiffness.
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                              Members are encouraged to be Participants, by posting.
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