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The 351W Long-Rod Thread of Doom.

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    #16
    Seeing as this set up has a lot of potential in our cars, I'm wondering if the shortened piston deck height (especially with the pin located in the way of the oil ring) is gonna wreak havoc with emissions? Other than that, this engine should have a lot more accelaration than a standard 351W.



    Packman

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      #17
      Howdy, gang.....

      I have some more 302 long-rod information handy.....and have located forged pistons for this setup.

      http://www.kb-silvolite.com/feature....n=read&F_id=21

      Of interest is the KB747; it's for a stock stroke 302, with 5.4 rods. In addition, it produces 10.6:1 compression with 64 CC heads....with a little smoothing of the dome, this piston, coupled with a 5.4 rod, should let you get away with around 10:1 compression with either E7 heads, or regular GT40 units.

      Concerning rods....you don't really need much of a connecting rod with this setup, I've located some from Ebay:
      http://cgi.ebay.com/ebaymotors/ws/eB...link:middle:us

      Yeah, it's the chinese rods, and I need to do some background checking on whether or not they're worth a damn....but it's a start.

      A set of Scat I-beam 5.4 rods would work well, also.

      To be honest with you, I'm pondering building one, as I already have most of the equipment fresh and ready to go. So far as what heads to run....I'm finding a lot of AFR 165's out there that would be perfect, or maybe even just clean up my existing GT40P heads, and do some more smoothing of the pop-up dome on the KB747 pistons....

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        #18
        i have a few questions pertaining the 351w long rod setup.

        1.) as far as efi is concerned, what kind of fuel system (injectors, maf, pumps) does it require and im assuming the tuning process would be different than that of a typical performance 351. if theres an article or thread on some site about this please lead me to it.

        2.) how exactly does it let you use that kind of compression on pump gas?

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          #19
          Originally posted by 70torino429 View Post
          i have a few questions pertaining the 351w long rod setup.

          1.) as far as efi is concerned, what kind of fuel system (injectors, maf, pumps) does it require and im assuming the tuning process would be different than that of a typical performance 351. if theres an article or thread on some site about this please lead me to it.

          2.) how exactly does it let you use that kind of compression on pump gas?
          bump.

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            #20
            Why screw around with a small block??? 385 FTW!!!!!

            nothing against small block Cleveland's but everything else is a planter or boat anchor...
            2008 Mercury Grand Marquis GS Bone Stock

            The modern definition of "racist" is "someone who is arguing with a Liberal".--updated Peter Brimelow quote.

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              #21
              Possibly Larry overlooked the question above in part because any modified engine will require careful tuning and frequently fuel system upgrades to make it run well, so a longrod build would in that respect be no different than tuning any other small-block.

              Brian: 351-based motors weigh under 550 pounds. 385-series weigh closer to 700 pounds and (so far as I know) are typically more expensive to build. So why bother unless you really need to make zillions of horsepower?
              2012 Mazda5 Touring | Finally working on the LTD again!

              Comment


                #22
                Originally posted by 70torino429 View Post
                i have a few questions pertaining the 351w long rod setup.

                1.) as far as efi is concerned, what kind of fuel system (injectors, maf, pumps) does it require and im assuming the tuning process would be different than that of a typical performance 351. if theres an article or thread on some site about this please lead me to it.

                2.) how exactly does it let you use that kind of compression on pump gas?
                Sorry about the delay, but I don't have a lot of free time for dedicated replies right now, lol.

                1. So far as fuel system/tuning goes with a long-rod setup....as in regular-rod-length engines, it's all in the camshaft, intake, and heads so far as fuel demands and tuning go. This setup works well for smaller heads, cams, and intakes, as the long-rod engine requires less air and fuel. This isn't some bizarre engine combination that has to have some special tune thrown at it, the only concern one should have is that you need to run a conservative timing curve due to the compression ratios involved.
                If you're looking to me to provide you with a build sheet, I can't, because I have absolutely no idea what heads, cam, or intake you plan on, or wish to be using. I've given a basic outline of what could be a suitable combination for the typical car seen within the realm of GMN, and therefore gave some baseline suggestions (GT40 iron heads, or AFR 165's, stock H.O. camshaft, GT40 intake, etc.). Even in stock rod-length form, an engine combo utilizing a mix of these components wouldn't be too difficult to tune for, as either head mixed with the stock H.O. cam would provide an excellent vacuum signal....the vacuum signal being probably the one thing to worry about (especially with carbs) concerning low-speed driving. In addition, this possible combo isn't something requiring rocket sicence in the fuel delivery department, either, as a basic upgraded fuel pump and 19 or 24-pound injectors (depending on cam and heads used) should be enough to supply this engine, based on a mild H/C/I seup.

                2. Increased piston dwell time, and the piston taking more time to reach TDC. Compressing air heats the air, and if you compress it more slowly....it doesn't get as hot....allowing more compression.
                This isn't a scientific explanation, this is simply a vague idea of how it works.

                3. Concerning the 385-series of engines: They are heavy, overweight monsters that have no practical purpose, short of providing the foundation for a 500+ C.I. stroker engine for all-motor drag cars. A stroked 351W-based engine will provide enough power for almost any streetable engine combination, and most drag-car applications. It simply isn't necessary anymore. It's not to say that I don't love these engines....it's just that with what you can do with a 351W block nowadays....there's no point.

                Comment


                  #23
                  Originally posted by RugerP97DC View Post
                  Why screw around with a small block??? 385 FTW!!!!!

                  nothing against small block Cleveland's but everything else is a planter or boat anchor...

                  That wasn't exactly a helpful response to the guy's question.

                  And in case you hadn't noticed, Clevelands (no apostrophe!) aren't discussed particularly often on this site....and since the thread is about Windsor motors.....sheesh
                  Originally posted by gadget73
                  There is nothing more permanent than a temporary fix.
                  91 Mercury CP, Lopo 302, AOD, 3.08LSD. 3g upgrade, Moog wagon coils up front, cc819s in the back. KYB GR-2 police shocks. Energy suspension control arm bushings. Smog deleted.
                  93 F-150 XLT, 302, ZF 5-spd from 1-ton, 4wd.
                  Daily--07 Civic Coupe. Bone stock with 25k miles
                  Wife--14 Subaru Outback. 6-speed.
                  95 Subaru Legacy Wagon--red--STOLEN 1/6/13

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                    #24
                    Originally posted by 91waggin View Post
                    ....and since the thread is about Windsor motors.....sheesh
                    I just noticed that.....lol.

                    Comment


                      #25
                      Originally posted by Pirate View Post
                      Sorry about the delay, but I don't have a lot of free time for dedicated replies right now, lol.

                      1. So far as fuel system/tuning goes with a long-rod setup....as in regular-rod-length engines, it's all in the camshaft, intake, and heads so far as fuel demands and tuning go. This setup works well for smaller heads, cams, and intakes, as the long-rod engine requires less air and fuel. This isn't some bizarre engine combination that has to have some special tune thrown at it, the only concern one should have is that you need to run a conservative timing curve due to the compression ratios involved.
                      If you're looking to me to provide you with a build sheet, I can't, because I have absolutely no idea what heads, cam, or intake you plan on, or wish to be using. I've given a basic outline of what could be a suitable combination for the typical car seen within the realm of GMN, and therefore gave some baseline suggestions (GT40 iron heads, or AFR 165's, stock H.O. camshaft, GT40 intake, etc.). Even in stock rod-length form, an engine combo utilizing a mix of these components wouldn't be too difficult to tune for, as either head mixed with the stock H.O. cam would provide an excellent vacuum signal....the vacuum signal being probably the one thing to worry about (especially with carbs) concerning low-speed driving. In addition, this possible combo isn't something requiring rocket sicence in the fuel delivery department, either, as a basic upgraded fuel pump and 19 or 24-pound injectors (depending on cam and heads used) should be enough to supply this engine, based on a mild H/C/I seup.

                      2. Increased piston dwell time, and the piston taking more time to reach TDC. Compressing air heats the air, and if you compress it more slowly....it doesn't get as hot....allowing more compression.
                      This isn't a scientific explanation, this is simply a vague idea of how it works.

                      3. Concerning the 385-series of engines: They are heavy, overweight monsters that have no practical purpose, short of providing the foundation for a 500+ C.I. stroker engine for all-motor drag cars. A stroked 351W-based engine will provide enough power for almost any streetable engine combination, and most drag-car applications. It simply isn't necessary anymore. It's not to say that I don't love these engines....it's just that with what you can do with a 351W block nowadays....there's no point.
                      ok, thats all the questions ive got for now. and as usual, you provided a very helpful and logical answer. it makes sense to me now.

                      Comment


                        #26
                        Potentially-interesting linky as this pertains to stroker motors ..... I'm not getting how the gasses are compressed more slowly, though - if the piston spends more time at the top and bottom of the stroke, it'll have to move faster during the stroke, which ought to actually compress the gas *faster* .....

                        Now I've got to go re-read my Physics II junk about adiabatic compression and expansion. Gasses compressed more quickly logically experience conditions closer to adiabatic (less heat escaping through cylinder walls), which actually retains *more* heat inside the cylinder ....

                        http://www.fordmuscle.com/archives/2...ker/index2.php
                        2012 Mazda5 Touring | Finally working on the LTD again!

                        Comment


                          #27
                          Originally posted by 1987cp View Post
                          Potentially-interesting linky as this pertains to stroker motors ..... I'm not getting how the gasses are compressed more slowly, though - if the piston spends more time at the top and bottom of the stroke, it'll have to move faster during the stroke, which ought to actually compress the gas *faster* .....

                          Now I've got to go re-read my Physics II junk about adiabatic compression and expansion. Gasses compressed more quickly logically experience conditions closer to adiabatic (less heat escaping through cylinder walls), which actually retains *more* heat inside the cylinder ....

                          http://www.fordmuscle.com/archives/2...ker/index2.php
                          Folks, I've gone back to da' books on what this does exactly, because, to be honest, I forgot.

                          The piston hangs around at TDC longer, raising the detonation point. In addition....(copied) The longer rod allows the piston to come to a stop at the top of the bore and accelerate away much more slowly than a short rod engine. This slower motion translates into a lower instantaneous velocity and hence lower stresses on the piston. Another strong effect on mechanical stress levels is the angle of the connecting rod with the bore centerline during the engine cycle. The smaller the centerline angle, the less the side loading on the cylinder wall. The longer rod will have less centerline angle for the same crank angle than the shorter rod and therefore has lower side loadings.

                          There's more to it....but this is a nice bit of info.

                          Comment


                            #28
                            Yeehaw! More pistons available!

                            KB725, forged....it's .01 taller in compression height, but it has a dish, which will allow GT40P heads to be used with a 351W long-rod motor, and keeps the compression right at or just under 10:1....woot....

                            http://kb-silvolite.com/forged.php?a...etails&P_id=10

                            Comment


                              #29
                              Originally posted by 1987cp View Post
                              Now I've got to go re-read my Physics II junk about adiabatic compression and expansion. Gasses compressed more quickly logically experience conditions closer to adiabatic (less heat escaping through cylinder walls), which actually retains *more* heat inside the cylinder ....
                              This isn't an ideal situation. It most definitely is not adiabatic, even given the elevated cycle speed.
                              **2012 Ford Mustang Boss 302: 5.0/ 6 spd/ 3.73s, 20K Cruiser
                              **2006 MGM,"Ultimate": 4.6/ 2.73/ Dark Tint, Magnaflows, 19s, 115K Daily Driver
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                              **1976 Ford F-150 4WD: 360, 4 spd, 3.50s, factory A/C, 4" lift, Bilsteins, US Indy Mags, 35s Truck Duties

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                                #30
                                What kind of fuel economy could you possibly see with this kind of motor, say with 3.55's?

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