Author Topic: My Little Hit Engine from bar stock (mostly) update  (Read 1918 times)

Offline dwulfe

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My Little Hit Engine from bar stock (mostly) update
« on: July 16, 2018, 09:47:03 PM »
This was inspired by the Tiny IC posts and various others especially Rudydubya's.
It has 3" flywheels with a .5 inch bore by .75 inch stroke. It hand starts on Coleman camp fuel.
The valve springs are from retractable ball point pens. The gears where bought cheap (< $10) and modified.
It has cast iron piston and sleeve without rings. The crank is .25" with .188" rod journal.


Here is a video. It's running a bit rich but I like the slower speed. Notice how it picks up when I pull the draw tube out of the fuel.


I've been experimenting with a mixer. This video is the second variation. I have since found that I can lean it out by inserting a .015" wire in the .020" id draw tube (brass bushing stock for clock maker).  Not quite finished but getting close.
« Last Edit: August 31, 2018, 04:29:23 PM by dwulfe »

Online b.lindsey

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Re: My Little Hit Engine from bar stock (mostly)
« Reply #1 on: July 16, 2018, 09:57:50 PM »
Very nice a a good runner too. They are fun little engines for sure. Nicely done!!

Bill

Offline Brian Rupnow

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Re: My Little Hit Engine from bar stock (mostly)
« Reply #2 on: July 16, 2018, 09:58:53 PM »
Very nice little engine. I have a couple of similar hit and miss engines that are running Viton O-rings on the piston. The Viton gives amazing compression, but it also creates a lot of "drag" in the engine, so I have never been able to get them to hit and miss the way I'd like them to. If I ever build another hit and miss engine I will try and do it with a lapped piston and cylinder, no ring, and see how that works.---Brian

Offline Ye-Ole Steam Dude

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Re: My Little Hit Engine from bar stock (mostly)
« Reply #3 on: July 16, 2018, 10:02:21 PM »
Beautiful little engine and a nice runner.

Have a great day,
Thomas

Offline Sleddog

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Re: My Little Hit Engine from bar stock (mostly)
« Reply #4 on: July 16, 2018, 10:31:53 PM »
Very nice! :ThumbsUp: Thanks for posting.

Offline zeeprogrammer

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Re: My Little Hit Engine from bar stock (mostly)
« Reply #5 on: July 16, 2018, 11:15:24 PM »
Beautiful job.  :ThumbsUp:
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
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Offline propforward

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Re: My Little Hit Engine from bar stock (mostly)
« Reply #6 on: July 16, 2018, 11:39:58 PM »
Superb engine! Nicely done.
Stuart

Offline 90LX_Notch

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Re: My Little Hit Engine from bar stock (mostly)
« Reply #7 on: July 17, 2018, 12:54:01 AM »
Nice!

-Bob
Proud Member of MEM

My Engine Videos on YouTube-
http://www.youtube.com/user/Notch90usa/videos

Offline rudydubya

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Re: My Little Hit Engine from bar stock (mostly)
« Reply #8 on: July 17, 2018, 08:20:08 AM »
Nicely done!  Looking forward to seeing it finalized.  Will you be showing us any build pictures?

Regards,
Rudy

Offline dwulfe

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Re: My Little Hit Engine from bar stock (mostly)
« Reply #9 on: July 17, 2018, 01:08:48 PM »
Thanks Bill, Brian, Thomas, Sleddog, Zee, Propforward, and Bob for your comments.

Sorry Rudy, I didn't take any photos along the way. I would like to add a governor at some point but I need to finish the fuel system.

Brian, thank you for all your posts. I learned a lot from them. I had to make a 2nd piston for this one. I failed in my first attempt. I lapped the fresh off the lathe piston and sleeve with brasso on the first one. It was leaky. I could see fuel bubbling out from the back of the piston when I flooded it while attempting to get it started. I then spent an hour and half lapping the cylinder with a commercial lap and 320 grit. I took about 2.5 mils off. Went from .505 to .510. It took that much to get a uniform gray finish in the bore. Then I snuck up on the piston od using the sleeve as a gauge. Once the piston would wiggle in an few tenths of an inch I then parted off the blank and finished the other features. I then used brasso and oil to lap the two together until silky-smooth full stroke. Took a maybe a couple hours. It is a very good fit with enough compression to hand start.

Offline dwulfe

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Re: My Little Hit Engine from bar stock (mostly) update
« Reply #10 on: September 01, 2018, 02:04:18 PM »
I added a C.Fellows type carb and a fuel tank.

Offline dwulfe

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Re: My Little Hit Engine from bar stock (mostly) update
« Reply #11 on: September 01, 2018, 02:09:54 PM »
It runs to my liking now with the ignition timing slightly retarded and a silicone boot over the plug to prevent arcing.

I tried to count pops per 5 seconds and estimate about 400 rpm.



Online b.lindsey

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Re: My Little Hit Engine from bar stock (mostly) update
« Reply #12 on: September 01, 2018, 02:26:43 PM »
Sure has a sweet sound to it!! Even your shop buddy seems to like it  :)

Bill

Offline zeeprogrammer

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Re: My Little Hit Engine from bar stock (mostly) update
« Reply #13 on: September 01, 2018, 02:45:21 PM »
Sounds great! Congrats!  :ThumbsUp:
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
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Zee-Another Thread Trasher.

Offline propforward

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Re: My Little Hit Engine from bar stock (mostly) update
« Reply #14 on: September 01, 2018, 03:00:45 PM »
That's a gorgeous engine, runs and sounds superb. Good to have a shoppe dawg in there too!
Stuart