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mttpekin

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  1. I'm getting close and learned an expensive lesson: dont design in a bubble and don't make prototypes before consulting the faq. I have some very expensive wall ornaments.. Like I could have rebuilt my motor.. Live n learn. The angled heim pickup looked hard and expensive to build. This one can be done on lathe in hopefully 1 operation. (UAI suggested this on p1...) The tension rod mounting point doesn't give you too much room to play. Currently brg is 14mm ID like stock, might have to bump down to 1/2in ID. Brg w/ specifically high axial loading capacities. Pin w/ retaining rings is now a stripper screw. Will be adding camber adjustability to the LCA & cleaning stuff up over the next few days. Best MP
  2. Been a little busy. Plan on finalizing the cad this week and start figuring how much it'll take to build that new tension mount piece. That kink for LCA heim will either be coped per uai model above or bent. Will have more in a few days. Thanks!
  3. I've spent the last 20 hrs brainstorming, drafting, and now I have this. Similar to the model back in March. This is rigid. My machinist is going to kill me / make me broke. The connection at chassis/tension bar is trick. No subframe mods necessary. Subframe stock bushing carrier is transparent in all of these bottom collar is a tube welded to the cnc'd bar piece. Will provide the clamp surface that interfaces w/ subframe bushing carrier. Top clamping piece is a circular 1/4" plate steel w/ bolt circle 8x M6 cap head in gr 12.9. more low tolerance pins. left side is captured by welded ring & bushing carrier. right side has little plate fastened to retain pin. pin sees virtually no axial force so it should be good. little bit of red loctite. m5 gr 12.9. retaining plate. this is w/ a 2000lb load on the pin. will be refined what thinketh. happy friday!
  4. Tommy & uai (being able to speak technical talk in another language is super impressive), You're both right and I'm happy smarter guys than I are looking at this. I'm going to think about this and get back to you. The first revs of this were more traditional and utilized heims. I'll revisit those ideas & move that direction if that's what a majority seem interested in. That's also less $. It's easy for me to get lost designing for designing's sake. My understanding is that the original designs forces are thru the center of both the bushings on the tension arm, in line with the imaginary line connecting those two points. This design moves that imaginary line 45mm rearward on that front connection point, invoking that moment. Is adding a moment to that bushing actually that bad? I just drew a pic of part1 (clevis) and threw numbers at it. Assuming 1000lb tension force down the axis of the tension arm in my design (34deg from axis of clevis), that 45mm offset invokes an 82.5 ft*lb moment on that bushing [[(45mm/25.4mm/in)*sin(RADIANS(34deg))*1000lb/12in/ft]]. That's acting in conjunction with that 1000lb force. hmm if 1 & 5 were strictly rotational, I don't know how the 'roll' down LCA axis could be handled. I am going to get creative on that front attachment. I don't want to make something where people need to cut subframes. Rear rose joint seems like a solid idea. More later. Thanks.
  5. Gotcha gotcha. OK. Toby got me de-rusting the trig.. This is what I came up with. I think it's close. Disparities in effective length lead to the 'roll' along the axis of the LCA tube during travel. According to my chicken scratch, over the entire travel (5.5in) that total axial roll value is 20deg. The stock suspension picks that misalignment up in 3 places. The LCA bushing, and the two tension arm bushings. Mine limit that to two. That 'roll' will be picked up by the LCA bushing and tension arm to subframe bushing. Cycling the stock suspension on car just now and watching front tension bushing definitely shows a good amount of compliance made by that rubber. When parts are bolted to car in a few days I will cycle both the stock and these and photo/video the deflections achieved at all points. The green circle is the radius on the bushing carrier. They are designed to 'capture' the LCA bushing just like the stock ones do. The bushing 'ears' kinda catch within those radius'd edges. where the green is a cross section of the bushing carrier..
  6. Hi Anthony, thankyou. It's been a process forsure. I enjoy this type of work though. There is most definitely misalignment thru the sweep. The knuckle joint/bushings are tight and transfer that moment efficiently. That oscillation/misalignment is taken up by the tension mounting bushing. Just like the stock setup. https://www.engineeringtoolbox.com/us-bolts-tensile-proof-load-d_2066.html has some good info on 1/2 20 thread strength. I believe the 4140 heat treat is somewhere around the gr8 on those charts. I spec'd this a long time ago. Each of the eyebolts are rated to lift 2400lb at 0deg and that obviously includes whatever mfg safety factor they put on that number. You could lift the car with one of em was my 'safety factor' Toby, please see above ^^. The clevises are tight and efficiently transfer that moment. The plastic is not soft. It deforms 3% at 7252psi. The joints are pretty rigid in every degree of freedom except the one desired. I have kept track of every cent on this and wish I didn't. I did not keep track of hours and am glad I didn't... We're up there. UAI thanks for the feedback. If those rose joints fit the factory tension arm, you could run those with this set. You live in Germany where roads are amazing. I live in LA where roads are less than ok.. That's why I decided on stock bushings. I like comfort and shock absorption. If people want to run existing poly, I can make an LCA bushing carrier to fit them without an issue. I'll know in a bit exactly the amount of caster you can add before needing to cut. Thank you. Hi Mark, the alpina stuff definitly inspired the design as did the e21 gr 5. A friend has one of those. This is a pic of that setup: I put a e46zhp rack in my last e30 325is and might need to find a way to slide one of those into this thing... we'll see. I will make work with stock config first.
  7. Ian, These attach directly to those stock components w/ zero modification. The taper angle/length on the e30 LBJ is the same as the 02 LBJ. Best, Matt
  8. Hi all, My name is Matt. I've been a long time faq lurker and always been into the 02. This forum has helped me way too many times to count so thanks for that. I fixed up my first '74 the summer of 2013 after my first year of college up in SLO and since then have had 90 & 91 e30is cars and an 88 e24. There's something about a good old bimmer.. I've always been into the idea of building an 'ultimate 02' to my vision of what that means. I've got some 3d printed heater valve brackets and have fully designed and 50% built a honda S2K 6 speed into my car, but that's not what this topic is about. February '19 I picked up a '72 auto car that sat in a barn in New Mexico for 23 years prior to me (crazy to think it's been there since I was 4) and that's what really kinda started me down the road on this idea. Since then I've designed, built, and pretty much finished setting up mfg for some adjustable lower control arms for our cars. My design criteria was: be able to play with camber and caster and utilize cool machines and technologies. This is what I came up with: Specs: Material: 4130 Chromoly Lower Ball Joint: E30, Lemfoerder, PN: 09 3010 101, pressfit. It's the same taper and everything and fits perfect on stock pitman arm LCA & Tension Arm Bushings: stock rubber (if you really needed to run poly I could adjust LCA bushing carrier, I like compliance for street cars) Innermost Adjustment: -2deg camber Outermost Adjustment: -5deg camber (w/ approx 1.25" threaded in bung) Caster Throw: 5.5degrees (stock is 4, so max on these is something near 9.5) The main LCA tube is cnc laser cut for the rosette weld holes & the notch that the ball joint seat slides into. The plate pieces (all tabs/lbj seat) are waterjet. That LBJ seat is 5/8" 4140 plate. The arms are not held together by bolts but rather pins of 0.5" (+0", -0.0005") diameter. Between pins and metal components are German engineered polymer bushings (I did tech sales for the company). An AN washer under a spirolox retaining ring on both sides round out the connections. The connections are light, strong, smooth, and have zero (a couple tenths?) play. They are not heims. My design philosophy was a knuckle joint but with 'cartilage' kindof like a human finger or knee. The bushings provide dry lubrication as well as some level of vibration damping and are unaffected by sand/road grime or water etc. It looks something like this: From the top down on the pin (stainless) you have: - spirolox (stainless) gold - AN washer (stainless) black - bushing (plastic) yellow - tension mount (CNC'd 4130) transparent - bushing (plastic) yellow - eyebolt (4140 heat treated to 125ksi tensile) transparent and the mirror of that ^^ stackup on the bottom. This is the design I am offering: Over the last couple months I've been building the prototypes. Here are some pictures so you get an idea of how it all goes together. This shows the waterjet LBJ carrier sitting in the lasercut notch in the tube. There is a little keyed cap piece that gets TIG'd to keep gunk out. Disregard smaller tube. The prototype doesn't utilize eyebolts on both ends of the tension rod but the production version will. I stared at the design too long and made it too complicated... Notch for cap quite apparent in this picture. CNC tube lasers are cool. Initial layout Next to the stockers. I appreciate their simplicity and elegance in terms of strength where needed but have always wanted to take a crack at making them adjustable. 2 of a kind.. Don't look too close at welds on the prototypes. My machinist welded these and he's not a welder. I grew up with my welder in SD. He's a structural welder for work and a rock crawler chassis fab guy for play. Production models will look like a robot welded them. Pins in. Note no AN washers. They should be arriving today 7/28. The slot cutting operation for the top tension rod clevis is being finalized on CNC. The tension rod clevis is 14x1.5mm thread and same shank diameter and length as stock tension arm for easy installation in the stock rubber bushings. Pins close up. The CNC lathe produces them in short order. In the coming weeks I will have these on the car and know exactly how they go. I will go to West End Alignment here in Gardena and verify the camber/caster angles. I'd like to get an idea of the interest and potential buyers, so please chime in if you'd like to give them a go and with any questions/comments, I'll answer best I can. I am confident that this product is good and am excited to offer it to you all. It's been quite a long time coming. I have a few other things I've been working on that'll emerge soon if this goes well. They are $1200 for a pair which includes what is in this model below but x2 (L&R). Plus shipping and tax and all that fun stuff. Made in the USA Redondo Beach, CA. Lastly, the barn car after I cleaned it up and made it run but before I ripped it all apart again. Straight and zero rust. I have better wheels now. Will make a post on it sooner or later. Thank you!
  9. mttpekin

    mttpekin

  10. Hi, Project necessitates a 228 flywheel. Will be custom surfaced and drilled to accept a honda clutch so slight surface imperfections are likely OK, but do need a good ring gear. Please let me know. 6sp getting pretty close... Located in San Diego Many thanks. Matt
  11. Hi Brandon, Looking for a pedal box. In rebuild condition is fine as long as it's all there. Preferrably no rust. I work for a german engineered plastic bearing company called igus so I'm gonna go thru it and make those available to everyone while im in there. . Doing manual swap from an auto. Got any interesting shift levers laying around? There's a rare factory catalog piece a rear fender guard. stamped aluminum I believe. I have a set but the passenger one has seen some life.. Inside mirror for a 72. Just the mirror piece if possible. Still have bracket. Broke mounting cup plastic trying to pull out.. Many thanks
  12. Came out of a 74' but vin didnt match so I dont exactly know what it came out of. I never turned it over or heard it ran. I was told it ran but smoked when I bought the car. I planned on rebuilding it because it has and E12 head but my priorities have changed and I no longer have the car. I'm located in San Diego. The best way to contact me is my email, [email protected]
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