Author Topic: Design and build side shaft hit and miss engine from bar stock  (Read 22924 times)

Online Admiral_dk

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Re: Design and build side shaft hit and miss engine from bar stock
« Reply #435 on: February 19, 2019, 10:23:14 PM »
Congratulations Brian - it's a nice runner  :cheers:

Do you think that the second head would have worked just as well with this latest cam ?

Offline Brian Rupnow

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Re: Design and build side shaft hit and miss engine from bar stock
« Reply #436 on: February 19, 2019, 11:08:05 PM »
No, I don't think it would have. I actually had both cams, the good one and the bad one on the previous head at different times, but it wasn't going to work no matter what I done. I think there was simply too much space in the burn chamber of that previous head.

Offline Craig DeShong

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Re: Design and build side shaft hit and miss engine from bar stock
« Reply #437 on: February 20, 2019, 02:05:54 AM »
 :cheers:  I knew you'd figure it out.  Runs nice now.    :ThumbsUp:
Craig

Online crueby

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Re: Design and build side shaft hit and miss engine from bar stock
« Reply #438 on: February 20, 2019, 02:06:55 AM »
So it was actually a medical issue with the engine... It had good compression, but with that exhaust cam it had a Decompression problem...  It had the bends!   :Lol:




Sorry, couldn't resist...

Offline Brian Rupnow

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Re: Design and build side shaft hit and miss engine from bar stock
« Reply #439 on: February 20, 2019, 04:12:28 PM »
Okay fellows---This is it. Engine starts, runs, hits, and misses. I will continue to fiddle with things which should provide less hits and longer misses, but the engine and hit and miss features are completed. This has been an interesting 9 week thrash, I've learned a few things, been surprised a couple of times, and been frustrated beyond all belief at times. All of the difficult stuff has been sorted out, and drawings updated as I went along. If you are a skilled engine builder with two or three internal combustion engines under your belt, this would be a great engine to build. No castings are involved, just bar stock. Thank you all for following the build and commenting. If you want to buy a set of plans (there are about 50 drawings), Send $25 Canadian funds to my Paypal account where I am registered under my email address  brupnow@rogers.com  I send out my drawings electronically, as .pdf files soo that you need no proprietary software to open and read them.---Brian Rupnow
t=5s

Offline Brian Rupnow

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Re: Design and build side shaft hit and miss engine from bar stock
« Reply #440 on: February 20, 2019, 11:43:06 PM »
Synopsis---I'm glad this engine is finished. I'm somewhat disappointed that it doesn't have a better hit and miss ratio. Biggest finding is that when you add in a set of helical gears for the sideshaft and a set of bevel gears for the governor, the engine "coasts" like a lead balloon. With or without the Viton o-ring on the piston this engine does not coast well.--at least not with 6" diameter flywheels. On a full size engine or on a larger scale model with possibly 8" flywheels and a 1.25" bore piston I'm sure that the "coasting" would be greatly improved. The governor works very well. It is rather complex, but it does function better than I had thought it would, and is very sensitive to changes in rpm. I have always had a sense of great "mystery" when it comes to face cams, but after the first rendition of this engine with a face cam, and thanks to help from a couple of forum members, I wouldn't be afraid to design and machine a face cam again. This is the first engine I have ever built with an "internal" fuel tank mounted in the engine base. It worked out very well, and the anti backflow valve I designed and built really does work well, and keeps the fuel from draining back into the tank when the engine is in "miss" mode. The strange "Frankenhead" I designed and built to allow installing the valves from the top of the cylinder head didn't work. I never really come up with an exact answer as to why it didn't work, but I surmise that the burn chamber created was simply to large. The third and final cylinder head, in which the valves, valve cages, springs and retainers were inserted as "sub assemblies" really did work out well. I had never thought of doing it that way, and I give thanks to "Ringo", a relative newcomer to one of the forums I post on for suggesting it. The basic structure of the engine including the water reservoir, sideplates, base, crankshaft, and ball bearings is pretty standard fare for this type of engine, as are the cylinder piston and connecting rod. It's been an engine which provided me good entertainment for two months or so, and made me stretch my machining abilities to a higher level. Thank you to everyone who stopped by, said Hi, or even had a look at what I was doing.---Brian Rupnow

Offline 10KPete

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Re: Design and build side shaft hit and miss engine from bar stock
« Reply #441 on: February 21, 2019, 02:24:17 AM »
Congratulations, Brian! The engine runs very well I think and it's likely that you could tweak it a bit more but you're at the 99% point so I don't blame you for "giving it a rest".

This has been a very interesting build to follow and I did learn a few things from it. Never too old to learn! :old: :happyreader:

Thanks again for your wonderful and entertaining posts.

 :cheers:

Pete
Craftsman, Tinkerer, Curious Person.
Retired, finally!
SB 10K lathe, Benchmaster mill. And stuff.

Offline John Hill

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Re: Design and build side shaft hit and miss engine from bar stock
« Reply #442 on: February 21, 2019, 02:51:14 AM »
Brian, I can only imagine the short miss duration is due to friction more than anything else and assuming everything is free in a mechanical sense I wonder what part  pumping losses in and out of the exhaust port have to play.  I wonder if a bigger diameter exhaust pipe might make an improvement?

John

Offline Roger B

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Re: Design and build side shaft hit and miss engine from bar stock
« Reply #443 on: February 21, 2019, 11:22:02 AM »
Nicely done  :praise2:  :praise2: There's always a reason things don't work like they should, the challenge is finding it  :)
Best regards

Roger

Offline Craig DeShong

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Re: Design and build side shaft hit and miss engine from bar stock
« Reply #444 on: February 21, 2019, 01:33:16 PM »
 :cheers: looks and runs great Brian
  Nice job !
Craig

Offline cheepo45

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Re: Design and build side shaft hit and miss engine from bar stock
« Reply #445 on: February 21, 2019, 05:29:24 PM »
Thanks, Brian for bringing us along this journey with you.
I have been checking MEM a lot more than usual for the last few months!
 Scott

Offline Brian Rupnow

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Re: Design and build side shaft hit and miss engine from bar stock
« Reply #446 on: February 22, 2019, 01:58:30 AM »
When I built this engine, I "borrowed" a carburetor from one of my other hit and miss engines. Now that the main build fever has tapered off a bit, I will build a new carburetor specifically for this engine. I had a few issues with carburetor placement, necessitated by going rapidly thru three different head designs. I don't really want to make any more changes to the final third head, but I do want a carburetor that sets up really close to the head and has adequate clearance from the sparkplug. This design, although it requires a clearance notch on the land which centers the sparkplug in the head and a couple of tapped #6 holes, gives me everything I wanted. It sets up close to the head, it has adequate clearance form the sparkplug, and it's not going to get whacked by the revolving cam.--And best of all, I found a piece of brass big enough to make it in my "brass drawer".


Offline Brian Rupnow

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Re: Design and build side shaft hit and miss engine from bar stock
« Reply #447 on: February 22, 2019, 04:03:59 PM »
The carb body, while small, ends up being quite complex.


Offline Brian Rupnow

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Re: Design and build side shaft hit and miss engine from bar stock
« Reply #448 on: February 22, 2019, 08:12:07 PM »
This isn't exactly micro-surgery, but it's darn close. I will make up the two 1/4" plugs and solder them in later today.

Offline gbritnell

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Re: Design and build side shaft hit and miss engine from bar stock
« Reply #449 on: February 22, 2019, 09:08:22 PM »
Brian,
If you had a Venturi in the carb it would help both with the fuel draw and the atomization.
gbritnell
Talent unshared is talent wasted.