Author Topic: Vertical hit and miss engine  (Read 11203 times)

Online Art K

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Re: Vertical hit and miss engine
« Reply #240 on: September 06, 2019, 03:31:14 AM »
Brian,
Good to hear that you dieted hard and lost 30Ibs, that is impressive. If I lost that much I'd weigh about what I did when I graduated from high school. I enjoyed the video of the hit & miss at work. I could picture you doing that half the day watching it go up & down. :lolb:
Art
« Last Edit: September 08, 2019, 11:09:20 PM by Art K »
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Offline Brian Rupnow

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Re: Vertical hit and miss engine
« Reply #241 on: September 08, 2019, 05:32:29 PM »
After much playing about with this engine, under both load and no load conditions, I have come to notice this phenomenon that I have seen before on other hit and miss engines. When the engine is running very slowly, with a good number of "misses" between "hits", the fuel in the line running to the carburetor wants to all run back down in to the tank during long "miss" cycles. Then when it finally does "hit" again, there is no fuel at the carb and the engine stops. I use clear neoprene gas line, and I can see it doing this. The answer of course is my venerable one way valve, as shown in the .jpg. This one way valve only works well in the vertical position, and the best location is immediately below the carburetor fuel inlet. Experience has shown that a 3/32" diameter ball is the optimum size. If the ball is larger, the venturi vacuum from the carburetor may not be strong enough to lift the ball consistently.
« Last Edit: September 08, 2019, 05:36:46 PM by Brian Rupnow »

Offline Brian Rupnow

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Re: Vertical hit and miss engine
« Reply #242 on: September 08, 2019, 08:17:17 PM »
That fixed it!! You can see it setting directly below the carburetor fuel inlet. (there really isn't much to see, because the gas-line pushes on from both ends of it). Now when the engine is on "miss" cycles, the fuel doesn't run back from the carburetor at all. The engine starts a lot easier too, with much less manual choking.--Also of interest to some will be the gear reducer with the piece of tape on the output shaft. I built that reducer about ten years ago, using gears from a couple of dead electric drills. It has an 8:1 overall ratio. That reducer was built back before I purchased my own complete set of 24DP gear cutters.


Offline Ye-Ole Steam Dude

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Re: Vertical hit and miss engine
« Reply #243 on: September 09, 2019, 09:05:08 AM »
Hello Brian,

Great job on the overall design and build on this engine. Watching the last video I really like the sound when running without the "miss", sounds smooth and strong.

Have a great day,
Thomas

Offline Brian Rupnow

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Re: Vertical hit and miss engine
« Reply #244 on: September 11, 2019, 10:19:09 PM »
One of the people building the engine from my plans has discovered an error in the con rod drawings. I will be sending new corrected drawings of the con rod and cap out to all who purchased the plans later this evening.---Brian

Offline Brian Rupnow

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Re: Vertical hit and miss engine
« Reply #245 on: September 11, 2019, 11:19:16 PM »
For those of you who are building this engine-----The crankshaft endplay ends up being controlled externally by the ignition cam on one side and by the small bevel gear on the other side. My original plan was to have it controlled on the inside by having the two registers on each side of the crank-throws riding against the ball bearings. There are enough accumulated tolerances to make this a very iffy thing. The real story is that the crankshaft is centered by the con rod, which is positioned by the piston, riding in the bore of the cylinder which is bolted to the crankcase.  Originally I had made no provision on the crankshaft for the sideplate gaskets. Then when I went to assemble everything and seen exactly how the crankshaft was being centered as explained above, I was glad that I had left that
.030" clearance on each side of the crank throws to the ball bearings. You may find that you have to put a small spacer washer between the small bevel gear and the shoulder on the crankshaft. That is something that you won't know if you need or not until final assembly.

Offline Brian Rupnow

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Re: Vertical hit and miss engine
« Reply #246 on: September 27, 2019, 01:47:58 PM »
I've had all of the fun I can have with this engine. Today it's going up on a shelf with all of it's friends. This is the first engine I have built with cast iron rings, and I must say, they do coast a lot better than previous engines with Viton rings. I will probably use cast iron rings from this point on for any new i.c. engines that I build. I don't really think that I have learned anything new building this engine, but knowledge is cumulative, and every engine does get a bit easier as I go along. I may go back and revisit some of my existing engines, but right now I'm a bit burned out on machining in general. One of the people who purchased a plan set from me asked if it would be reasonable to remove the inner grease seal from the crankshaft bearings and wash out the grease, as the engine has an oil sump and the bearings would get lubricated that way. I think that would be a good thing to do in terms of how long the engine would coast, but I don't know if the one remaining outer grease seal on each bearing would be sufficient to prevent crankcase oil from leaking out. this is something that would be good to know if it made an improvement to the engines coast time, and whether or not it made the engine leak crankcase oil around the bearings. Thanks again to the many people who followed this build.---Brian

Offline Brian Rupnow

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Re: Vertical hit and miss engine
« Reply #247 on: October 07, 2019, 10:36:16 PM »
I forgot to dimension the depth of the piston ring groove.---Here is the drawing
---Brian

Online Art K

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Re: Vertical hit and miss engine
« Reply #248 on: October 08, 2019, 12:21:27 AM »
Brian,
My experience with removing the inner oil seal and using splash lube inside the crankcase to lubricate the bearings is. It does work very well and doesn't leak unless you don't have proper crankcase ventilation. If not you cant imagine where  all the oil comes out at.
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King