# Back to work on my UFO



## Sprocket (Jun 1, 2020)

My wife is a quilter, and their term for any incomplete project that has been put aside is a UFO, UnFinished Object. She also figures that what I make are quilts, of a kind
because we both take big pieces of material, cut them up into smaller pieces, then put them back together. And we both use threaded fasteners of a sort.
Years ago, I started the Gearless Hit and Miss engine by Philip Duclos from plans in Home Shop Machinist. I got the base and side plates cut out and the pillars made but not cut to exact length



I had also finished the crank shaft, but for some reason I can't recall, I put it aside.





With the stay at home order this spring, and finally being retired I started to work trying to remember why I'd stopped.
I think the crank shaft bushing holes were the problem, because my mill drill wouldn't keep register as I raised the head to change drill to reamer. But somewhere in there I acquired an old Bridgeport that makes a lot of things easier. So I drilled the bushing holes and other mounting holes and started back in.

There was a thread on making split bushings, and another on two piece con rods, all of which was sounding familiar.






Then I started on the cylinder and liner. Started with a chunk of aluminum about 2 3/4" dia. and 3" or so long, and removed a lot.



 mounted on the rotary table to drill and square the base

 I guess that's all the files I can attach right now. More later

Doug


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## ku4qb1 (Jun 2, 2020)

I think a lot of UFOs are finally getting some much needed attention, lately. My oldest one is a 1/2 scale Maytag, 18 years old. I think, this time, I'll get those last couple of parts finished and get it running. Connecting rod, timer and carb....
Just a few more stitches!


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## Sprocket (Jun 2, 2020)

There are a couple of reliefs in the sides of the cylinder before you cut the fins, spaces for the intake and exhaust valve housings, and the valve lifter for the exhaust




Cast iron cylinder sleeve   


pressed into the cylinder  


And a mandrel to hold it all so you can cut fins. I didn't have a tapered mandrel that big, so I made one that squeezed end to end.










When you stack up the parts, it starts to look like a motor!


   The cylinder fins are rounded on the ends. Plans give instruction for making the cutter to cut that shape.

The cylinder head has fins in both directions


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## awake (Jun 4, 2020)

Very nice work!


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## Sprocket (Jun 4, 2020)

Thanks, Andy.
Some more pics:

  Fins, top and sides, ports for intake and exhaust,


 That last little fin on the right is really sharp! Don't ask.


 I'd made the plug with guidance from either Steve Hucks Or G.Britnell, can't remember who wrote that one up.
Plans called for a 1/4" plug, but it looked too small in the picture, so this one is 5/16" 

There also was a thread on making valves. This is how I've done it in the past. Stem is 1/8" piano wire, top is stainless silver brazed on






I sand it down .0002 or so it fits well in a 1/8" reamed hole.
Another trick some one here had was (Mark maybe?) for cross drilling the valve stems. Worked great. Can't remember how I did it before. It used a little fixture to drill the #60 hole 1/8" from the end. Guess I haven't transferred that photo yet.





Valve bodies required cutting the seats down inside, which is blind. There are instructions for making that cut, but they depend on your cross feed in the lathe being a reliable measure, mine is not, so I ended up using a dial indicator to move to the point of being able to cut the seat with the compound.

Guess I'd better transfer those other pictures.

Doug


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## Sprocket (Jun 5, 2020)

Some more bits and pieces.

 I found the picture of the fixture for cross drilling the valve stems. Again, it was something mentioned on this forum, but I can't think by whom. It worked well though. I annealed the valve stems before drilling because the piano wire seems pretty hard

The valve bodies both have finned covers, exactly the same, attached with 4- 3-48 shcs. 






 Round, to rectangle, counterbored, finned and mounted on the valve bodies

I changed the intake pipe to add a cone for more of a venturi, and a bug strainer. ( it's really not an air filter)




 Ran out of room!


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## Sprocket (Jun 5, 2020)

A couple more that didn't fit in the last post...


  with the spray bar and needle valve


 Attached to the valve body


  And attached to the cylinder.

Doug


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## awake (Jun 6, 2020)

Looks like this will be an atmospheric intake valve?


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## Sprocket (Jun 6, 2020)

That's right, Andy. The exhaust has a cam and lifter, but part of what makes it gearless is the way the lifter is made. Haven't gotten to those parts yet.


  I had some ring material already turned to size, and even a couple of spares cut from the last 3/4" bore engine I made.The rings were a little thick, by a couple of thousandths, but I've used a little holder to sand them to thickness.





Just before Memorial Day, the VFD that runs my mill failed spectacularly. Loud POP, the Magic Smoke all escaped, and  a little fire started inside. I tried to blow it out a couple of times, but it just kept coming back. I guess that's why I have a fire extinguisher. I gave it the shortest blast of dry chemical I could, and it still made quite a mess. But the fire was out. Really stunk!

  I got another one from Wolf Automation, came in a few days. Of course, nothing is the same shape or mount as the 10 year old one so, new mounting plate, etc.


 But it's working again and life goes on. Never miss a machine so much until it's down!
I made the piston today, pictures later.

Doug


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## Sprocket (Jun 8, 2020)

I finished up turning the piston, and moved it to the mill for drilling the wrist pin hole and inside space for the connecting rod. There was a little stub left after turning, so i set it up in a V block, vertically,






Squared off the stub, which gave me  a good place to grip in the vice, and a way to get my con rod slot perpendicular to the wrist pin, and drill and tap the set screw holes. 












With the piston finished, I split the rings, heated and opened them up, gapped them, made a wrist pin, and put the whole thing together. That's all the parts for now. I started the exhaust cam, but didn't get too far.

Thanks for looking,

Doug


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## Sprocket (Jun 30, 2020)

It's been a couple of weeks, but I've been working on some strange little pieces. This is a gearless engine, and something has to replace the gears to only open the exhaust valve every other revolution.
The  exhaust cam doesn't look like a typical cam, and it's milled on the rotary table.





  There is a half inch wheel that rides on this cam, and sits in the lifter


  with an unfortunately shaped indexer at the other end.






  Between these and three different kinds of springs (one flat, one straight wire, and one wound), every time this piece goes up and down, the indexer rotates 1/4 turn and the long sides lift the valve, the short sides don't. Also the governor acts on this lifter to hold the exhaust valve open.
More later.
Thanks for looking.
Doug


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## Sprocket (Aug 2, 2020)

I guess it's been awhile since I added anything new, but I've been busy making parts. At this point, I think all the parts are complete, except maybe the governor springs. Two of the springs on the exhaust lifter are just spring wire, one a coil, the other a straight piece. But the third was a leaf spring either .008 or .016 of different widths. I didn't have either, and couldn't see buying the amounts suppliers wanted to sell, so I made one from a saber saw blade. 




and the little piece to hold the spring at 10 degrees the the pillar shelf and a toggle bracket





Also the governor weights, arms, and governor bracket






I think that's all I have room for tonight. I finished the flywheel yesterday, there was a bit of time making a broach, which was another project.
I might put that one in a different thread.
Thanks for looking,

Doug


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## awake (Aug 3, 2020)

Intricate work!


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## Brian Rupnow (Aug 3, 2020)

I was so entranced by the gearless mechanism that I made it as a "stand alone" model a few years ago. It was very impressive.---Brian


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## Sprocket (Aug 4, 2020)

Brian;
I can't quite imagine it moving at a few hundred RPM. Got to be nothing but a blur. Playing with it as I was fitting parts, it is a fascinating mechanism.
My first model engine was Philip Duclos' Maverick, another gearless, with a different mechanism. That was easier to build.  You can almost see that one work as it's running.
Doug


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## Steamchick (Aug 5, 2020)

Fascinating and the parts look good! - I'm sure the accuracy is just as good. (Which is why I admire the finished engines when running, as too many of mine have the imperfections that prevent running).
K


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## Sprocket (Aug 8, 2020)

I think the last major part is the flywheel. I used a 5"x1" cast iron disc. The plans call for 3/4" thickness, but I feel like a  little extra weight in the rim is a good thing. So mine finished just under 1", still 1/4" thick web, and 1/4" high hub in the back so it won't interfere with the governor function. I think this piece of cast iron had some hard spots or inclusions that I haven't run into in these discs in the past.




Roughed out in the 3 jaw                                     Round  and smooth                                          Both sides are the same





Drill holes every 90 degrees             Expand to 1"                                                        Rotate 23 degrees for each, and reliefs for the
                                                                                                                                      governor arms




Broach a keyway                                     Drill and tap for a set screw at 20 degrees

I did some balancing with the crankshaft and exhaust cam on the flywheel, but until I know exactly where the exhaust cam sits, I can't be certain I've really got the balance right.
I wanted to get this much done so I can sand and paint some of the big pieces, then start putting it together.
Won't be long now... (famous last words)
Thanks for looking,
Doug


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## Sprocket (Aug 12, 2020)

I painted the parts that will be painted, then finished the surface of the flywheel with the tool post grinder. I like the look of the ground
finish, and doing on a mandrel should help it be true and concentric.

  Before


 in process


  and finished

there were weights that I added to the back of the wheel, and the governor bracket


And mounted on the motor with the governor arms set in place.


I feel like I do alright at prep and painting, but I get really impatient for things to be dry enough to continue. Had a couple of minor mishaps
that it was good no one was in hearing distance.
Anyway, maybe soon it will run. Just some fitting, lapping, finishing.........
Thanks for looking
Doug


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## Sprocket (Oct 24, 2020)

Well, it's been a while, but I've gotten a lot done. Seemed like it took a month, but I put a DRO on my mill, X,Y,Z, and K. The K (quill) was the most difficult, because it's not obvious how to attach it, and there were few mounting parts with that scale. But it all works, and after calibrating, it seems very accurate. No more .030 of play in the X lead screw to try to deal with.
But back to the motor.
It ran today for the first time!
I had tried before, but got very little compression, a few pops, but that was it. Even after running it in, it didn't get better. After measuring, and looking at the rings, I decided to make a new piston a couple of thousandths bigger, and make rings by a different method.
I had looked at the Strictly IC articles by George Trimble, but couldn't see going through all that when I had had good success just heating rings with a torch. This time, when I looked at the rings after break in, you could see the areas that didn't touch the cylinder wall, and that  the shape was not round. So I went back and did it Trimble's way. The rings, by his calculations should have been .017" wide and .032" thick, although width is less of a concern, and he says in model use they are typically 1 to 2 times thickness. I couldn't see trying to make them .017" wide, so I went with the 1 times thickness, about.
I made the fixture and annealed the rings. . Somehow those files are too big to load here. Never been a problem with phone pictures, but these are from a digital camera and probably more pixels. (If any one has a suggestion on that, please tell me)
After annealing and gapping, they seemed to fit well, still had trouble with compression,  it turned out to be gaskets. An O ring under the head gasket and spark plug has improved compression quite a lot. I tried gasket material, paper and grease,  and some silicone stuff. The O ring seems to work, and compression is adequate.
Guess I'll go see if I can figure out how to post videos


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## Cogsy (Oct 24, 2020)

Congrats on a runner. For videos, the easiest thing is to upload them to youtube then simply insert the youtube address into your post. The video will then magically appear in your post.

I'm curious about your 'running in' procedure. The way I was taught, the pressures of combustion drive the rings against the cylinder wall and this facilitates the running-in (or bedding in) of the rings. If spun for a long time without significant combustion then it's likely the rings will never be able to achieve a good seal (effectively wearing them out before running them in). This could have been the issue with your first set of rings having a poor contact area.


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## Sprocket (Oct 24, 2020)

These should be the exhaust lifter functioning, and the engine running


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## Sprocket (Oct 24, 2020)

Thanks Cogsy.
I found the magic!
And yes, the ring wear might have been from trying to break them in with the lathe spinning the motor, but I'm not sure they were ever going to work. Strange, because that method has worked for me before. (torch heating, not running in that way)


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## Cogsy (Oct 24, 2020)

I've only ever done the torch heating also - it was the first way I tried and it's always worked out well (so far...).


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## teeleevs (Oct 25, 2020)

Thanks Doug, lots to think of, beautiful job, worth the time and effort.
Cheers Ted


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## minh-thanh (Oct 25, 2020)

Hi *Sprocket !*
Can you take a picture to show me the position of the lobe when the valve closes and when the valve opens?
 I've never seen a camshaft like that .
Thanks !


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## Sprocket (Oct 25, 2020)

Thanks Ted, Minh Thanh,  
That is a very different cam shape. There is a 1/2" wheel that rides on the came and , I think, helps to smooth out the motion. It does drop off suddenly, but the indexer needs an abrupt motion to turn it. So the cam drops off, the spring pulls the lifter down, the indexer catches on the flat spring on the right side, and turns 90 degrees. Straight wire spring on the left stops it at 90
Some pictures, although the cam is behind the flywheel and governor, and a little hard to get a clear look


  the roller just as it comes on top of the cam,


  as it is about to drop off the cam


  A bit dark, but the same position from the other side


  Maybe this one is better


   with the cam lobe and lifter all the way down, almost no contact with the cam.
The instructions say to turn the cam so the exhaust valve is closed 3 degrees after Top Dead Center  (TDC) .

I hope that explains well enough, it is an interesting mechanism, and I think it is smoother than the cam would make you think.
I had a slow motion video, but when I transferred it, it came out as a still.
Thanks for looking,
Doug


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## minh-thanh (Oct 27, 2020)

Hi *Sprocket !*
Thanks for your images!
Can you explain how the engine works?
Is it a 2-stroke or 4-stroke or another .. ??
I don't understand the sequence : intake -compression - explosion - exhaust


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## Steamchick (Oct 27, 2020)

When I saw Hepworth and Grandage piston ring manufacture, they took the near-fished rings and "barrelled" them by running in a cylinder (the size and material of the engine's cylinder) - just with oil - NOT carborundum! - using a machine that rotated the cylinder slowly while oscillating the rings in and out with a slight eccentricity of motion so the edges of the rings were slightly pre-worn - thus when the car engine was built almost no running-in was required. - NO back pressure from combustion there - just the reciprocation motion to simulate an engine. I think they had 1/2 to 1 hour of that treatment - but can't be sure.... (notes were archived at work about 20 years ago). They had a lot of machines, as the rings were built onto packs of 20 or 30 and run - and a bloke managed many cylinders - loading and unloading the rings onto the mandrel and fitting into the bores and linking to the driving rod - then engaging a clutch to continue the lapping.
May be of interest?
K


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## Sprocket (Oct 27, 2020)

Steamchick,
Were the rings split at that point, or still complete rings? It seems like a good idea (must have worked), though I'm not sure how I'd accomplish it in my shop. I think the idea of running in an engine on the lathe would be similar, but the rings are in their grooves so can't float as much.
It's worth some thought...
Thanks
Doug


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## Sprocket (Oct 27, 2020)

Minh Thanh,
It is four cycle. The exhaust valve lifter goes up and down every revolution of the crankshaft, but the indexer on top rotates 90 degrees to a shorter side and doesn't contact the exhaust valve every other turn. I got a video slowed down enough so I think it will explain itself.




I hope this clarifies . there is a lot of motion going on
Thanks for looking,
Doug

I found another good one. Use the little gear (settings) in the lower right to slow it down more.


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## minh-thanh (Oct 28, 2020)

*Sprocket .*
Thanks for the slow motion video., Nice to see how it works
One more way to make an engine !
Thanks for sharing !


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