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  1. Brian Rupnow

    Building a twin cylinder inline i.c. engine.

    Elvis has not left the building!!! I am currently troubleshooting the engine and waiting for the first run. The intake manifold that fed two cylinders and used a single carburetor did not want to seal against air leaks, so finally I made up two individual intake manifolds and used two Traxxas...
  2. Brian Rupnow

    Looking for hex wrenches with hardened ends

    I have a tough time with my hex wrenches. The brand I use is generally Bondhus, which have a good reputation. However I find that after about 3 weeks the ends get the corners rounded off and then I have to go out to my industrial belt sander and grind back the ends until I get past the rounded...
  3. Brian Rupnow

    Building a twin cylinder inline i.c. engine.

    Engine is timed and all is reassembled. Had a slight leak at one end of my see-thru gas tank, but a disassembly of the leaking end and a new o-ring stopped the leak. Engine is firing as it is rotated by my electric starting table but not running on it's own yet. I won't be posting any more now...
  4. Brian Rupnow

    Building a twin cylinder inline i.c. engine.

    Well---the good news is that although the set-up looks rather unorthodox, it works very well. The bad news is that I have managed to thoroughly confuse myself. It's not a problem to set the valve timing on the first cylinder. For some reason it's much more difficult/confusing to set the valve...
  5. Brian Rupnow

    Building a twin cylinder inline i.c. engine.

    Okay!!--In the world of wild and wacky set ups, this may win a prize. First thing I did before any of the set up was to set the valve lash so that there is 0.005" clearance between the rocker arm and the end of the valve stem when the tappet is not up on the cam. Did this once for each valve...
  6. Brian Rupnow

    Building a twin cylinder inline i.c. engine.

    I can design an order of magnitude faster than I can build, but I'm going to make a fixture like this. The orange bracket will screw to my tabletop and to the engine, using the sump bolt threads. This gets the engine up on its side so I can get at the individual cam segments. Lots of room on the...
  7. Brian Rupnow

    Building a twin cylinder inline i.c. engine.

    The old cams which were made with a flank radius are out!!!. The new cams with no flank radius are in. What a nasty, nasty job it has been. All of the rocker arms are rocking their little brains out when I turn the crankshaft. Now, once again I am ready to set my valve lash and cam timing...
  8. Brian Rupnow

    Looking for photo & drawings on Flame / Candle Engine.

    Here is my build thread.---Brian https://www.homemodelenginemachinist.com/threads/senft-poppin-engine.27555/
  9. Brian Rupnow

    Building a twin cylinder inline i.c. engine.

    And, at the end of what seems to have been a long day---We have four new cams with no flank radius and an extra set of set screws. I had a terrible time getting a picture of these little rascals, finally took them outside to get this shot. They are made from 01 steel, flame hardened and...
  10. Brian Rupnow

    Building a twin cylinder inline i.c. engine.

    Today it was time for another kick at the can---So--I made four new cams without radiused flanks. The point of the cam nearest to the chuck is pointed the other way, because I had to take the workpiece out of the chuck, then put it back in. The angular orientation doesn't matter at this point...
  11. Brian Rupnow

    Building a twin cylinder inline i.c. engine.

    George--I remember asking you this before a couple of years ago. I agree--I think I am over complicating the whole thing. I'm going to do up a set of cams with flat flanks and see what happens.---Brian
  12. Brian Rupnow

    Tabletop CNC

    Toolsrul--Send your email address to [email protected] and I will send you a .dxf file.---Brian
  13. Brian Rupnow

    Building a twin cylinder inline i.c. engine.

    Some more 3D CAD shows me that yes, I could build a fixture to turn the flanks on my cams. In fact, I could do one side of all four cams at once. Then I could flip all the cams over 180 degrees and do the other four sides all at once. Mind you, that would only machine the flanks. Then a second...
  14. Brian Rupnow

    Tabletop CNC

    Toolsrul--- There seems to be enough interest from people following this thread that we can bore them and they'll like it. I have always had trouble machining cams. My machines are all manual, and I struggle thru and do make my own cams, but they are not masterpieces. I have been researching...
  15. Brian Rupnow

    Building a twin cylinder inline i.c. engine.

    01 steel is an oil hardening steel. In it's unhardened state it machines almost the same as cold rolled steel.
  16. Brian Rupnow

    Building a twin cylinder inline i.c. engine.

    Can you "unharden" 01 steel that has been heated to cherry red and then quenched? I want to add two more threaded holes for set screws to my cams, but right now they are harder than the devil's horn. After the threaded holes have been added I want to reharden them. Seems to me that I've read...
  17. Brian Rupnow

    Building a twin cylinder inline i.c. engine.

    Forgive me--I've spent the morning playing on my cad system. One of the pioneers of model engine building Graham Meek did an excellent presentation of how he machined a cam with flank radii. This looks a bit crazy, but it works. Machine one side of the cams, flip them over and machine the other...
  18. Brian Rupnow

    Tabletop CNC

    All very, very interesting, fellows. I had not ever seen the video posted by Timo_Gross
  19. Brian Rupnow

    Building a twin cylinder inline i.c. engine.

    Petertha--Thank you for bringing that to my attention. Today I have been rushing around getting info on tabletop cnc machines. Although a lot of tabletop machines say they will cut metal, they really don't do well at all on anything other than aluminum or brass. I don't really have the budget to...
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