Horizontal Double acting Twin Self starter

[Brian Rupnow]

Still a bunch of stuff to build on this one,---valves are next.

 

[CrewCab]

Keep up the good work Brian, top class stuff 8)

CC

 

[Brian Rupnow]

I spent the morning painting over at my daughters new condo, then made it home in time to make a pair of valves. I decided to make the ends from brass, and to just turn the main bodies from some 1/4" cold rolled. I didn't spend a lot of time on the reduced diameter section of the valves, as the only important part is the two large diameters and the brass end. I can see that my tools are due for some new carbides, as the old ones are the originals that came with my lathe and are getting quite dull---thus the shabby finish---I could have put the lathe on high RPM and used a bit of crocus or emery cloth to clean them up better, but they won't show, so I'm not too worried. I departed from my usual method of attaching the ends, (silver solder), and glued them on instead with Loctite 638. Why---Well, to make a long story short, I screwed up the sequence and drilled and reamed the 1/8" holes in the brass ends first. Then I realized that if I silver soldered the shafts in place, I would end up filling the 1/8" holes with silver solder. I have used loctite before for similar types of connections with good success, so I will see how this goes. If the bond breaks, I can always silver solder it later. I coated the short section of 1/8" cold rolled with grease and inserted it through both peices as an alignment tool before I started Loctiting--I HOPE I can get it out later--- ;D ;D Next thing on my agenda will be the two eccentrics that operate the valves.

 

[Brass_Machine]

Didn't realize you weren't done yet (note to self: read all the posts before commenting). It looked almost done. But still, I am anxious to see whats next. I got some ideas if you wanna talk about them.

Eric

 

[Brian Rupnow]

A bit of extremely good news this morning!!! I made up a temporary air inlet tube , put some temporary plugs in the 0.080 holes drilled thru the side of the cylinder block, and put both valves in place. By supplying 20 PSI air to the inlet tube, and moving the valve back and forth thru its normal range by hand (which the eccentric will do eventually), I was able to get the piston and rod to kick back and forth like it will do when the engine is running. I tried this test independently on both sides of the engine, and both pistons move back and forth equally well. This proves to me that the design is correct in terms of the piston location in relationship to the valve ports drilled thru the cylinder body. In the picture you can see the temporary air inlet stack, as well as the plugs in the sides of the cylinder body. (you can also see the pivot axles with acorn nuts that I made up to connect the piston rods to the connecting rods.) This "tryout" air inlet will play a very important roll later in the development of this engine. My plan is to set the valve timing on one cylinder at a time with the other cylinder "dead",(receiving no air supply). This will let me establish the best valve timing and power profile for each cylinder individually with no false input from its other cylinder.

 

[Philjoe5]

Nice progress Brian. I like your idea about timing each cylinder independent of the other. I was wondering how I was going to do that step when I get to it (not in the near future yet ) on my current build.

Cheers,
Phil

 

[Maryak]

Brian,

Your engine is really starting to come together now and looking great.

Congratulations on a fine build and for providing us with some very useful and innovative techniques.

I'm sure you've thought of it, but just to be safe, both eccentrics must either lead or lag their respective cranks. (Easy to get one on each side

when timing individually)

Best Regards
Bob

 

[Tin Falcon]

Am Enjoying this thread also and saving the plans for later.
When I saw you running it in with the drill I too thought you were finished. but there was something like the picture telling me something was missing like valves valve rods etc. Keep up the good work.
Tin

 

[Brian Rupnow]

And for todays bit of mischief---a pair of eccentrics. I still have to drill and tap them for #10-24 set screws, but other than that they are finished. And my oh my, the size of the part bears absolutely no relationship to the ammount of work required to hog them out of a 1 1/8 diameter chunk of hotrolled steel!!! Its a good thing that I don't have any "real work" today, because it took me all afternoon to make these darn things. We are closing in on a working engine here. The only outstanding mechanical things are the rods that go from the eccentrics to the valves.

 

[Brian Rupnow]

Guess I'll go here next.---Don't worry about saving these drawings. I'm going to update all of them and save them as .pdf files in the upload setion when I get this engine fineished.---Brian

 

[wareagle]

Brian, the eccentrics look good. You are almost there!! And this has been a lightning fast build I must say.

A big hearty thanks for all of the time you have taken with documenting and posting progress pics. I almost feel like I have been building this along side you!!

 

[Brian Rupnow]

Well boys, Onward and upward!!! I had real work in my engineering office today, and I have to travel to see a customer tomorrow, so I'm a bit late accomplishing anything tonight. I got the eccentric straps machined and mated to their respective eccentrics (there is about .001 difference in the diameters). I was so excited that I had the holes in the eccentric straps reamed to .187 before I realized that "Damn!!! That was supposed to be threaded!!!" Oh, well, God hates a coward---I'll put the threads in the other end that isn't made yet.

 

[ksouers]

...I had the holes in the eccentric straps reamed to .187 before I realized that "Damn!!! That was supposed to be threaded!!!"...

Brian,
You are not alone!
I needed to drill 3 blind holes in a line. When I finished the last hole I realized I'd just drilled 3 of the purtiest thru holes you've ever seen.

Are you going to solder them?

 

[kvom]

Brian,

Does Solidworks compute the angle of the tangents for the eccentric strap? That is, the angle the sides of the large end and make with the centerline? For machining these using a rotab that would be useful to know on the plans.

I did some math/trig calc. and got 26.255 degrees.

I noticed that this part is a duplicate of that on the double scale beam engine, and I will be making this part soon.

 

[Brian Rupnow]

Brian,

Does Solidworks compute the angle of the tangents for the eccentric strap? That is, the angle the sides of the large end and make with the centerline? For machining these using a rotab that would be useful to know on the plans.

I did some math/trig calc. and got 26.255 degrees.

I noticed that this part is a duplicate of that on the double scale beam engine, and I will be making this part soon.

Kvom--Your math is right on!!!---Brian

 

[Brian Rupnow]

Well, I got back from the Big Smoke (Toronto) this afternoon, and managed to get the OTHER ends for the valve control rods finished. (And yes, I threaded them!!) then I drilled and tapped the eccentrics, and had a little assembly party. However, things did not go as swimmingly as I had hoped.--Oh, it all went together, and I was entertaining thoughts of maybe a test run, but---Not quite yet. I seem to be suffering from a stack up of tolerances, which is not that unusual when a whole whack of parts fit tight against one another. You can see in the picture that the valve control rods are not running parallel to the center of the machine---instead they angle outward from the crankshaft to the cylinder body. This was cause for a bit of head scratching, and for a minute (a very short minute) I thought about firing up the oxy acetylene torch and putting a small dog leg in each rod. then sanity prevailed, and after studying what I had for a few minutes I determined that I have lots of room to shave about .090" of the end of the eccentric hub that sits tight up against the inside of the flywheel hub This will let the valve control rods set parallel to the center of the machine like I intended, and will take any induced "bind" out of the system. It will also give me the opportunity to machine a couple of "retaining rings" that I will Loctite in place on the end of the eccentric (the bit that sticks out past the eccentric strap)--This will keep the eccentric strap from wanting to wander off of the eccentric.

 

[Philjoe5]

Looks like you've entered the "Tweak Zone" Brian. Since I haven't really built an engine yet exactly from plans, I seem to always get to where you are at now. A spacer here, a washer there, trim a few thousandths off this n' that, then put it all back together again. I may be a real "sicko" but I actually enjoy this phase of building the engine. For me, it really brings to the forefront, where the tolerances have to be. Good luck in getting the engine ready for the first run. We're all anxiously awaiting

Cheers,
Phil

 

[wareagle]

Brian, the little engine looks great. :bow: :bow: I know that you will get the tweaks sorted out in short order and soon will have a very nice running model!!

 

[Brian Rupnow]

I am in the final stages of assembling my twin horizontal engine, and simce I had to tear everything down after a preliminary fitting, I decided to go with my original idea of turning a 0.060 thick steel ring, heating it cherry red, and shrinking it onto the eccentric to keep the strap in place. It calls for having 3 hands at once, one to hold the torch, one to hold the pliers with the hot ring in it, and one to hold a small hammer to "persuade" the ring into place, but it seems to work very well.

 

[Brian Rupnow]

Everything is finally lined up and reassembled. The engine is stiff, but I've got thr drill on it again, "running in" the friction points. Whats really unbelievable is the ammount of air its pumping out the inlet stack!!! If I've lived right I'll have this thing running on its own power before the day is over.