hegedus

Editor
  • Content count

    175
  • Joined

  • Last visited

  • Feedback

    0%

Community Reputation

51 Excellent

1 Follower

About hegedus

Profile Information

  • Gender Not Telling

Recent Profile Visitors

2,435 profile views
  1. hegedus

    3D Printed Parts

    I just got with the class. It was very good. The takeaways: There are lots of different technologies, but 3 are most relevant: Filament Deposition, Stereolithography, and Metal melting via laser. All 3 are commercially available vis service bureaus and the one most often mentioned was Shapeways which can do all three. I might try out Shapeways before buying even the low end systems. The filament (FDM) technique uses a thermoplastic filament ("wire") that works like a hot glue gun. These are the low cost systems that you see offered. As low as $600 on Amazon. The parts have a somewhat rough surface and there is tendency for the part to fail between layers of filaments. It would be good for low strength parts and pieces. Not super stiff plastic and I would never use the technique for anything at all structural. The other major plastic technique is Stereolithography uses a laser to cure a plastic in a bath of resin. The parts generally have better surface finishes and are the same strength in each direction. The resin is a thermoset and is generally more brittle and clear because of the need for the laser to get to all the part. The basic lowed system is about $3000 from Formlabs and does a good job but has a pretty limited build volume of 4" cube. The resin is pretty expensive compared to bulk resin. The plastic feel and quality is similar to the plastic used in lens and turn signals. Stiff but brittle. The last one of interest are the metal systems which can do a variety of materials including SS or CoCr and Ti. These are all industrial tools that cost more than $1M. The parts can be reasonably large and can have very good mechanical properties. It was noted that post deposition was critical for the good mechanical properties and it was not clear that the service bureaus could do the anneals. As a point of reference one person built a 5 lb part and the cost was $1000. So it is an option for some structural parts but caution needs to be payed.
  2. hegedus

    3D Printed Parts

    I am going to a class on Additive Manufacturing (aka 3D printing) at MIT Summer session in July. I will report back on the state of the art.
  3. I think I was reversed. It alls makes sense now thanks.
  4. What is odd with the downstream configuration is the size of the tubing fittings. The inlet to the pump and the fittings on the expansion tank are all the same size. The outlet of the pump is larger. If the tank is meant to be down stream shouldn't the tube fitting be the same size as the outlet of the pump. Otherwise you would need a reducer. The tube size going to the engine is the match to the pump outlet.
  5. My expansion tank started to leak and I am replacing it. Double checking on installation. The tank was installed upstream of the pump - between the pump and tank. The parts images show it downstream between the pump and the engine. Which is correct?
  6. Hi, I have a '72 tii (blue) with a new issue, a bit of a stutter or hesitation at about 2500 rpm. The car starts well and idles at ~1000 as it starts to warm up a bit the idle will go to ~1800 for a couple of minutes and then quickly settled to ~1000 rpm. It surges a little bit until the car is completely warm. This is reproducible but also not the main issue. In the last week, it has developed a bit of stutter or hesitation upon acceleration between 2500-2800 rpm. The engine has good compression (~180 psi) and all the linkages have been replaced and the fuel system adjusted by A1 Motorsports in Marin ~4 weeks ago. Right after the linkage replacement and adjustment the issue was not there. Where should I start looking?
  7. 72 tii on HWY 280 in SF Bay Area. 78 Db as measured by SPL Meter app on iPhone. With 5 speed at 3200 rpm.
  8. hegedus

    Getting Pushed In L.a.

    Actually that would be Sergeant Schultz
  9. hegedus

    Welcome To The New And Improved Faq!

    One request: The tag field with white text on a blue bubble is very prominent, a bit distracting to the eye. Could it be toned down so the title of post is more prominent? Andy
  10. hegedus

    WTB Accelerator Pedal Support (SF Bay Area)

    Interested. Send me an email with $. hegedus (at) alum (period) mit (period) edu Thanks Andy
  11. Hi, I am looking for the support bracket for the accelerator pedal (part 17) in the image. I ordered from Mobile Tradition but they came back as NLA. http://bmwmobiletradition-onlinecom.x-shops.com/bmw/showparts.do?model=2583&mospid=47141&btnr=35_0200&hg=35&fg=10 Thanks in Advance.
  12. hegedus

    Body and paint in SF bay area?

    I had Paul at Auto Sports Exclusive in San Mateo do mine. Very nice job. He has a tiny shop and only does old porsches and '02s.
  13. Two ifs: 1. Access to an old one to act as template perhaps patching where there is wear or damage. 2. Router with a pilot bit (a straight cutter with a bearing to act as guide). The router with pilot bit will do a very good job copying the the original. Standard stuff in the woodworking world. Much better than tracing because the the pencil line will always be offset. http://www.rockler.com/product.cfm?page=26867&site=ROCKLER
  14. hegedus

    1973 Tii engine

    I think I bought that one about a week ago. There was a '72 tii motor offered on ebay at that time also.
  15. I am already talking with him and so far it looks good. I will post the results.