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    #31
    Big block is now a narrow rib. Weight loss in the transformation is about 27 grams. Upon closer examination of the big block on the cap, I believe it's main purpose was to balance/equalize the weight of the rods.
    I've been machining 16 rods (6 race, 6 spare motor, 4 spares for balancing) during this adventure. All 16 of the rods weigh within 9 grams, 14 are within 6 grams of each other. I haven't started to equalize the end weights as I will be polishing the forge finish and have some hand work to blend the machined areas. I'm not sure how much material will be removed by that process, but I've trimmed about 75 grams per rod so far. After the equalizing, polishing, and blending I estimate that another 10-15 grams will be removed. That's a 85-90 gram loss on a 600ish gram rod (w/bolts).
    Very happy with how everything looks so far, and can't wait to be done with the rods.

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      #32
      Been busy polishing the rods. It takes me a little more than an hour per rod. Ugh. Polishing removes another 7 grams per (82grams/rod so far). I've also built the 2 rod balancing fixtures and will try and get the rods balanced this weekend.

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        #33
        Although I made fixtures to help with the rod balancing process we struggled to get consistent numbers especially when weighing the large end of the rods. After much head scratching and process modifications we were able to get some consistent results of the smaller ends. All of the smaller ends varied less than a gram from one another, which was probably due to that end being mostly machined. Rod caps were placed in the CNC, programs written, and material machined off to balance the rod weights. Woo Hoo the connecting rods are 95% done! Total weight removed is about 85grams per rod. Now I'll have them stress relieved (bead blasted) and they'll be ready for assembly.
        The wrist pin EDM fixture is in need of modifications as the grit from the process is making it impossible to fit subsequent pins in the fixture. that should yield another 10ish grams of weight loss.

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          #34
          Almost wish I'd bought aftermarket rods. After all of the machining, balancing and polishing I just dropped $340 to have the 12 rods shot peened and magna-fluxed. The good news is that I have a fair amount of experience working rods... Bad news is that I'm getting frustrated by the pace and amount of work involved. Wrist pins are being finish EDM'ed and the lower edge of the piston skirts have been radiused for better oiling.

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            #35
            12 wrist pins completed. I estimated a 10 gram loss per pin. I am happy to say I was wrong. Wrist pins lost 15 grams each. They went from 105 to 90. :)

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              #36
              We've been working on our heads as well. The valve guides have been replaced in our 3 heads with longer guides. This is to allow enough material to machine the ports and guides smooth. Basically eliminating the casting "bump" and valve guide unevenness near the valve stems.
              Word of warning, be sure to measure the O.D. of the valve guides before you order custom replacements... It seems that BMW had some casting issues and had to adjust the hole size. One of my heads guides measured the "correct" dimension of .514". Two of the heads guides measured .521".
              The intake ports are oval shaped and I'm opening them up by .025"/side. The transition radius by the valve seat is also being re-cut, blended and smoothed.
              Exhaust ports are round and will have the valve seat transition area re-cut, blended and smoothed. There is a bump that must be left intact or you will thin the wall thickness too much by the spark plug channel. A 10 degree taper was cut to open up the exhaust diameter to 1.5" which is about what my flea bay headers measure. Next year I plan on building headers to better match up with the exhaust ports, but opened them up now while I had the heads set up in the CNC.

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                #37
                Got a bit sidetracked with the head work. But since I've been removing metal I guess it still qualifies as "engine lightening" Intake and exhaust ports on all 3 heads have been machined and polished (intakes getting remachined due to overly aggressive polishing). As I type this, the heads intake/manifold surface is having an o-ring groove machined so that the manifold and head will be metal to metal (no gasket) and the ports can be matched to the manifold. Pics on our facebook page "Squidrope Racing"

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                  #38
                  I'm finally done with the lower end work. Rods have been lightened, polished, balanced/matched, magnafluxed and shot peened. Wrist pins have been lightened. Piston skirts are radiused, and pistons have been cleaned up and walnut blasted. Rod set assembly weights have been weight matched. Each rod assembly for the 2 engines vary by 16 grams. The rods and pistons varied from set to set. Rod sets varied by 3 grams/rod. and piston sets varied by 13 grams per piston.
                  The ARP rod bolts are 3 grams lighter than stock bolts. That's 6 more grams of weight off the assemblies. After weight matching and all the other fun stuff each assembly weighs approximately 110g less than stock. 110g x 6 assemblies is 660g weight loss. Plus the crank will need to be lightened to maintain its balance.
                  Very glad to be done with the lower ends, and pleased with the results so far. Now I can focus on the heads/intake/exhaust.

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                    #39
                    The 2 engine's lower ends are being assembled this weekend. The 3 heads are 90% done, just need to shorten and install exhaust and intake studs. Hopefully we'll have the engines and car running this month. Can't wait to see how the motors run.

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                      #40
                      glad I came back into this thread. Not glad that there are no pictures! This is definitely a cool approach. Looking forward to seeing the effects once the engines running.
                      1984 Delphin 318i 2 door

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                        #41
                        Originally posted by wworm View Post
                        glad I came back into this thread. Not glad that there are no pictures! This is definitely a cool approach. Looking forward to seeing the effects once the engines running.
                        facebook has lots of pictures... Sorry I'm learning engine stuff and don't have time to figure out how to post pics here. Facebook Squidrope Racing

                        Thanks for your interest!

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                          #42
                          Originally posted by wworm View Post
                          glad I came back into this thread. Not glad that there are no pictures! This is definitely a cool approach. Looking forward to seeing the effects once the engines running.
                          Will post videos on youtube when we first fire the engine.

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                            #43
                            Everything is taking longer than expected. Forgot about having to fit the crank scraper. Hoping that both lower ends should be done tomorrow.

                            Highly recommend Yothers Teflon crank scrapers. Great quality and service. Fairly easy to install. Pics on facebook page (Squidrope Racing)

                            Teflon crank scrapers are the balls.
                            Installation hints. (keep metal chips outside of the engine and leave enough material to be worn away by the crank)
                            1)Install CS(without Teflon) and oil pan with oil pan bolts.
                            2)Drill and ream 2 holes (12"+ apart) I used 3/16" dowels.
                            3)Remove oil pan and CS
                            4)de-burr holes and press dowels into block.
                            5)Ream CS holes .002" oversize
                            6)drill OP holes 1/16" oversize
                            7)place CS (without Teflon) onto dowels (no bolts)
                            8)slowly spin motor and look for any metal to metal contact between CS and crank assembly
                            9)Dremel or bend CS as needed to allow crank to spin freely
                            10)tighten CS to block with oil pan bolts
                            11)rotate crank to be sure no metal-metal contact
                            12)place Teflon onto CS at 1 end only
                            13)Cut leading edge of Teflon with tin snips to allow slight interference fit with the leading edge of the counterweights. Cut sharp wedge shaped pieces off of teflons *leading edge only* The Teflon cut out will be tapered on both sides. Do not cut the entire depth of the pocket. Leave radius' so the Teflon won't crack.
                            14)Rinse and repeat working your way in from both ends.
                            15)You should have an interference fit between the crank and CS but the crank should be able to spin without catching the edge of the Teflon.

                            Let me know if you have any questions.

                            Disclaimer-I'm not an expert just a DIY guy. If you screw up or things go bad, it's on you. Always contact a professional before attempting this foolishness.

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                              #44
                              Arrrggghhh still working and hope to fire race engine this weekend. Engines in but have lots of little details to get wrapped up Saturday morning

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                                #45
                                After many weeks of 1 step forward 2 back. I'm happy to say that we fired one of the modified engines today. Slight valve train ticking at start up but that went away quickly. The engine is very smooth and seems quieter and revs quicker than the stock motor. Didn't do anything but take it for a quick drive around the block. Will update when we get to push it a bit.

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