Opposed Twin I.C.

Shop deals on ebay
Advertise with us
Find deals on amazon
Home Model Engine Machinist Forum

Help Support Home Model Engine Machinist Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
canadianhorsepower said:
Brian,
to my opinion the intake runner are way to long for
such a small AND low RPM engine.
GOOD LUCK
Click to expand...

Hi Luc - if that were the case my Aeronca E118 shouldn't run at all ... and its carb is under the engine! <grin>

Sounds like you're on to it Brian! Tomorrow should be THE DAY.
Charlie
 
Last evening while trying to start the engine out in my main garage, I noticed that it was occasionally sending out a puff of smoke between the right side cylinder head and the cylinder. I was away all day today on a design job, and when I got home tonight I squirted some liquid dish detergent on the joint and turned the engine over with my variable speed drill. Sure enough---bubbles, bubbles everywhere. Will now pull the head off and have a look.
 
And yes, boys and girls---it happens just that fast!!! I have work to do yet, but this truly is the first run. I was surprised when it started right up and ran after I changed the head gasket on one side, and fortunately my camera was setting within reach. YAHOO--YAHHOO---YAHOO---more later after some serious tuning.---Brian
[ame]https://www.youtube.com/watch?v=Jhgla-362jo&feature=youtu.be[/ame]
 
... and there you go!
Congratulations on a successful run. Everything from here on out are just niceties.
Sounds great Brian!
Charlie
 
Some quick observations--The right hand cylinder with the new head gasket seems to be the dominant cylinder right now. I think the valves could still use a bit of attention in the left hand cylinder. It is firing and getting hot, but I can tell when turning the engine over by hand that the compression isn't as strong in the left side cylinder, and there don't appear to be any leaks in the left side cylinder head gasket. The "vanes" on the flywheel are blowing a good draft of air directly across the cylinders. The engine doesn't want to idle down to a slow "tick over" right now, and I think that is due to the one weak cylinder. The gas tank looks great where I have it, but I just ran the engine out of gas, and I'm afraid to fill the tank because of the hot cylinders directly below the tank. When trying to start it with my variable speed drill, the right hand cylinder was firing like crazy, but simply didn't have enough power to run the engine by itself. When the left hand cylinder kicked in, you could really hear and feel the difference. The heavy brass gear case seems to soak up all of the noise made by the timing gears. This is very exciting, as it is my first twin cylinder engine.---And I don't see any puffs of vapour coming back thru the carburetor like my clone of Malcolm Stride's Bobcat or Jaguar engine.
 
Last edited:
In the first video it sounds like it runs fairly slow already but will surely improve as it is run in. Remember it will sound twice as quick as you think it's running because of the two cylinders - you're only used to hearing one fire so 500 RPM will sound like a thousand.
 
Well done Brian, although I've been quiet during your build, I've been following along with every post. It's a great feeling when an engine runs for the first time.

Paul.
 
Thanks guys--I can't really feel a difference in the exhaust gas temperatures between the right and left hand exhaust stacks, but I can't really feel any compression on that left hand cylinder when rotating the crankshaft by hand. I'm about to dive into that left hand cylinder and do a quick rework on the valves and maybe replace the headgasket. One of my goals when I built this engine was to have an open crankcase so the inner workings would be visible. This works great in theory, but in practice all you really see is a grey blur in there. I think I will make a polished brass top for the engine that sets in place with a locating register and 4 small super magnets Loctited into the underside which mate with 4 steel slugs set into the top of the angle crankcase. That way it will be easy to remove to oil the inner works with a squirt can, but will give a more "finished look to the overall engine.
 
Brian Rupnow said:
One of my goals when I built this engine was to have an open crankcase so the inner workings would be visible. This works great in theory, but in practice all you really see is a grey blur in there. That way it will be easy to remove to oil the inner works with a squirt can, but will give a more "finished look to the overall engine.
Click to expand...

Hi Brian,
Great project , I have followed your work for years now.
I was thinking a while back a 0.5 " clear acrylic cover would be a nice touch to your design! Figured I would toss that idea out and praise your work at same time!
Enjoying your threads and all the eye candy pictures you post "I love drawing"
Lane
 
burkLane said:
Hi Brian,
Great project , I have followed your work for years now.
I was thinking a while back a 0.5 " clear acrylic cover would be a nice touch to your design! Figured I would toss that idea out and praise your work at same time!
Enjoying your threads and all the eye candy pictures you post "I love drawing"
Lane
Click to expand...
I considered that.--But--clear acrylic isn't anywhere as pretty as polished brass and there is enough oil flying around in there that it would only be "see through" for seconds after starting the engine.---Brian
 
"Awesome" is a word that is often overused!--However, after a quick relapping of the valves on the left hand cylinder and a new head gasket for that side too, there aren't many other words to do this engine justice!!! My God---It is "awesome"!!! I will post a better lighted and better planned video tomorrow. I can now feel lots of compression on both cylinders when turning it over by hand.
 
Charles, I have done that, and I wasn't happy with the result. When you can no longer see into the crankcase, you really have no idea of what the oil in there is doing. The amount of oil is so very small that it's hard to check with a dipstick. Either you don't have enough oil and bearings burn out as a consequence, or you end up like Jason, who built basically this same engine (although his was far more streamlined than mine), and found out that the rotating crankshaft picks up oil and slings it straight into the bore of the right hand cylinder causing it to burn oil and foul the plug because of so much oil in the cylinder barrel. My engines are not ran for hours and hours at a time. I much prefer being able to readily access the crankcase and give a few squirts with my trusty squirt oilcan. There is a drainhole that is open in the bottom of my crankcase to let excess oil out!! This way I know how much oil is reaching the bearings and can give it a squirt of oil before running it.---brian
 
As I promised, here is a better lighted and better planned video. I do a bit more "voice over" on this video to explain some things about the engine. You get to see the start up procedure, the low speed, and the higher speed it is capable of. Thank you again to everyone on the forums who have followed my build threads and offered advice and information. This engine is a complete success, and the results are everything I had hoped for.---Brian Rupnow
[ame]https://www.youtube.com/watch?v=whXt2ZTvw1c&feature=youtu.be[/ame]
 
Last edited:
You must log in or register to reply here.

Similar threads

Longboy
Longboy's "TWIN REDEMPTION" Model Engine.
Replies
6
Views
852
Longboy
Longboy
Brian Rupnow
Electric Starter System for Model Engines
2 3 4
Replies
61
Views
8K
Petet Fernell
Petet Fernell
B
Online twin gas or 4 stroke build
Replies
1
Views
983
ruben
ruben
pat_pending
Crankshaft for opposed twin 5cc CI aero engine
2
Replies
31
Views
3K
pat_pending
pat_pending
Tony Bird
Twin Cylinder Oscillating Steam Engine
Replies
1
Views
2K
Cymro77
Cymro77

Latest posts

Back
Top