Author Topic: Horizontal Air Cooled Engine  (Read 12304 times)

Offline Brian Rupnow

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Re: Horizontal Air Cooled Engine
« Reply #165 on: December 30, 2021, 04:43:22 PM »
So, here we are. The culmination of a two month thrash!!! I had a few problems sorting out a reliable head gasket, but solved that by going to a Viton o-ring head gasket instead of the treated cardboard that I have used on previous i.c. engines. I had major issues getting the engine to fire, but traced that back to leaking threads around the sparkplug. There was nothing wrong with the sparkplug, it was my funky threads in the cylinder head that were causing me grief. Once I got that sorted, the engine ran like a race-horse. These Traxxas carburetors have the touchiest throttle lever in the world. That throttle is intended to be operated by a servo, so is very touchy indeed. That is why during the video my finger doesn't leave the throttle lever--if I take my finger off the throttle the engine tries to run wide open and scares me half to death. I miss-spoke in the video and said the motor has a 1" stroke---that's not correct, it is actually 1 1/4" stroke. I will sell these plans (about 50 sheets) for $25 paid to my Paypal account. Contact me if you want to purchase a set of plans. Thank you for following my build on the forum.---Brian Rupnow

Offline crueby

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Re: Horizontal Air Cooled Engine
« Reply #166 on: December 30, 2021, 06:01:45 PM »
Wonderful sound to it!  Glad you got it sorted.   :ThumbsUp:

Offline Laurentic

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Re: Horizontal Air Cooled Engine
« Reply #167 on: December 30, 2021, 07:50:22 PM »
Glad you got it fixed Brian, sounds really good, runs very nicely

Chris

Offline Admiral_dk

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Re: Horizontal Air Cooled Engine
« Reply #168 on: December 30, 2021, 10:32:06 PM »
Glad to see your success with this engine - congratulations, you have a fine runner  :cheers:

Offline Brian Rupnow

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Re: Horizontal Air Cooled Engine
« Reply #169 on: December 31, 2021, 02:14:42 AM »
Tomorrow I'll make up a "Casey Jones" throttle lever and linkage from it to the carburetor. A couple of Belleville washers between the throttle lever and the baseplate will add enough friction to keep the throttle from vibrating out of place.

Online Art K

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Re: Horizontal Air Cooled Engine
« Reply #170 on: December 31, 2021, 05:10:17 AM »
Brian,
Glad to see you sorted out the problems and have it running!
Art
"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: Horizontal Air Cooled Engine
« Reply #171 on: December 31, 2021, 07:17:55 PM »
Today, after some minor tweaking and tuning and the addition of a Casey Jones style throttle lever, the engine is running much more sedately. The folks who I generally buy Belleville washers from are temporarily out of stock, so even with the addition of my throttle lever the engine wants to "creep" to a higher rpm.--That gets scary as heck when the engine pulls the throttle wide open. My next trick will be to add the piston with cast iron rings and see how well it runs.---Brian

Online mikehinz

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Re: Horizontal Air Cooled Engine
« Reply #172 on: December 31, 2021, 09:14:43 PM »
Brian, another great build!  I'm glad you found the issue and that the engine is running so well! 

I really like the looks of it!

Mike
MIke
Wichita, KS, USA

Offline Brian Rupnow

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Re: Horizontal Air Cooled Engine
« Reply #173 on: December 31, 2021, 09:19:48 PM »
Thanks Mike. I'm really interested in what it will do with the other piston with cast iron rings.---Brian

Online mikehinz

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Re: Horizontal Air Cooled Engine
« Reply #174 on: December 31, 2021, 09:34:06 PM »
Thanks Mike. I'm really interested in what it will do with the other piston with cast iron rings.---Brian

Brian, I'll certainly be interested in your testing of cast iron piston rings vs the Viton o-rings.  I've only build 2 I/C engines so far and I've used Viton o-rings on both of them and they've run really well.  I do use a much lower 'squeeze' on the o-ring than you seem to though and I wonder if that make a big difference.  I've heard the claim that C/I rings are lower friction and work better, but I'm not sure about that.  I'm guessing that there's no doubt that they'll last longer, but I do wonder about the friction.  I've followed the advise of Bob Nawa and I size the o-ring groove diameter for very minimal squeeze which is definitely not what Parker or National recommend. 

Again, great work and I'll be watching your tests!

Mike
MIke
Wichita, KS, USA

Offline Brian Rupnow

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Re: Horizontal Air Cooled Engine
« Reply #175 on: January 01, 2022, 01:56:13 AM »
Mike---I've built model engines now for about 13 years, and always used Viton o-rings, because they are so easy and work so well. It's only within the last year that I've gotten serious about cast iron rings. For me that was a huge learning curve and the cost of a heat treating oven and controller. You heard right---Viton rings seal well, but have a much higher "stiction" than cast iron rings. Cast iron rings slide in the cylinder much easier, but for me it was a difficult learning curve. I have two 1" bore engines working very well with cast iron rings, and this will be my first 7/8" bore with cast iron rings.---Brian

Offline Brian Rupnow

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Re: Horizontal Air Cooled Engine
« Reply #176 on: January 02, 2022, 12:15:33 AM »
Today I removed the piston with the Viton ring on it and installed the piston with the two cast iron rings. The engine tried it's best to run, but never quite made it. The engine would fire and start, but after I removed the drill/starter the engine would gradually slow down and quit. I thought that perhaps if the flywheels were a bit heavier it would let the engine "carry thru" from one power stroke to the next and help the engine to keep running. I dug around in my "shorts" bin and found a piece of round cast iron that I set up in the lathe and bored it to fit over the drive pulley on the back side of the engine, held in place by a 1/4" set screw. It didn't help. Tomorrow I will investigate why the cast iron rings aren't holding compression properly and see what  can do about that.

Offline Roger B

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Re: Horizontal Air Cooled Engine
« Reply #177 on: January 03, 2022, 11:30:26 AM »
It takes a very small leak to loose compression. My diesel is of similar size to your engine (20cc) and leakage through the  0.2 mm (8 thou) injector nozzle hole when the needle is removed destroys the compression.
Best regards

Roger

Offline Brian Rupnow

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Re: Horizontal Air Cooled Engine
« Reply #178 on: January 03, 2022, 02:46:56 PM »
When you can take a heat treated ring and bend it like this, it's a pretty good indicator that you have used the wrong cast iron to make the ring. It will also bend like that before heat treat. It will work as rings---I have two engines operating quite fine using rings made from this material.  Today I am going to use the two remaining cast iron rings that were made in that batch to see if they will run my engine. I am also going to take steps to buy the correct cast iron for ring making. My local supplier doesn't know squat about the cast iron he is selling.

Offline crueby

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Re: Horizontal Air Cooled Engine
« Reply #179 on: January 03, 2022, 03:07:29 PM »
Brian, what is the proper type to use?