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OS Gemini Twin Rear Walbro Gas Conversion

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OS Gemini Twin Rear Walbro Gas Conversion

Old 07-30-2022, 10:04 AM
  #126  
mitchilito
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Yes, indeed fellas - I've been recirculating my waste oil like this for YEARS without any problems. As I said earlier in this post, I introduced the crankcase discharge on this engine into the intake of the carb to avoid any hydrolock issues, although it would probably run fine ported directly into the manifold.

With that said, I got to the bottom of this problem I've had basically from the beginning although it was most alleviated by the Rimfire plugs. Apparently they would tolerate fouling better than these RC excels I put in there because that is the problem: the left cylinder fouls and once fouled won't clear itself. Now, the reason it fouls and not the right one is because it is getting more of the waste oil (and undoubtedly fuel mixture) from the intake manifold. I just found (sort of again) that a narrower gap is more resistant to fouling so I cleaned the plug throughly, tighten up the gap some and it fired right up and ran great.

My induction system is obviously unbalanced (which is hard to ovoid in these types of single carb installations) so I need to figure out some way to balance it - at least better than it is. In the mean time I'm going to order some iridium plugs from Adrian (when he gets back) and also carry a spark plug wrench in my kit so I can clear the plug at the field if it fouls out. I'm hoping the iridiums will be more resistant to fouling. The Rimfires only did it once in all the flights I had - but I don't really want to buy new ones: they're $32 bucks a pop!!
Old 07-30-2022, 11:10 AM
  #127  
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Originally Posted by mitchilito View Post
Yes, indeed fellas - I've been recirculating my waste oil like this for YEARS without any problems.
Please don't take this wrong, but... now you HAVE a problem and you're going to solve it with more expensive wear items. Just saying.

The valve lube thing CAN'T go wrong (it literally is impossible for that rerouted oil to influence anything) and costs nothing...
Old 07-30-2022, 07:28 PM
  #128  
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Originally Posted by mitchilito View Post
Yes, indeed fellas - I've been recirculating my waste oil like this for YEARS without any problems. As I said earlier in this post, I introduced the crankcase discharge on this engine into the intake of the carb to avoid any hydrolock issues, although it would probably run fine ported directly into the manifold.
!

The recirc system serves just fine, best when ahead of the carb from what I have seen. I have cured several uneven running O.S. Alpha series engines by re-routing the vent, feeding the discharge back at the velocity stack.
A few years ago on another forum I posed the possibility of rocker box oiling using either case vent or exhaust pressure tap. Half in jest, for benefit of the compulsive types out there. In short order it was taken up.
Nothing new even back then, I had seen people trying it back in the early 1980s.


Having run the Gemini beginning with the original 120 up thru the late 160 series as well as servicing all sizes for local fliers. Personally, with the Gemini, I had never seen a rocker box that was short on oil.
Cam bearings are another deal however
First clue is difficulty setting rocker clearances.
In every instance, cam bearings were an instant cure.


Keep up the good work.


Last edited by Jesse Open; 07-30-2022 at 07:51 PM.
Old 07-31-2022, 01:11 AM
  #129  
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Originally Posted by 1967brutus View Post
Please don't take this wrong, but... now you HAVE a problem and you're going to solve it with more expensive wear items. Just saying.
Eh, what's the expense of a couple of plugs, Brutus? Not too much. And personally, I like the idea of your rocker chamber oil lines. I just don't like the way they look.

That's the fun of this segment of the hobby - doing things your own way
Old 07-31-2022, 06:19 AM
  #130  
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Originally Posted by mitchilito View Post
Eh, what's the expense of a couple of plugs, Brutus? Not too much.
True, not too much. It's just that I am trained and focused on solving issues with changes to the system, not by using different consumables. I mean, I could in a few years change to a different fuel and a different ignition method and claim that I re-invented the methanol fuelled glow engine as the solution to all my problems, now couldn't I? Now that last part is just a joke of course, but the first part is real: As a seafarer I do not have the luxury of a change in consumables, so I have to solve issues in a more permanent way. That is all I am trying to convey.
Originally Posted by mitchilito View Post
rocker chamber oil lines. I just don't like the way they look.
That makes two of us. Whichever way I turn it, I cannot find even the slightest bit of aesthetical beauty in them. They're ugly and all I can do is minimize the ugliness. You should have seen the prototype that did not have the bent Alu tubing, but loose loops of Tygon tubing. Hideous!

But they comply with the idea above and that prevails.
.
Originally Posted by mitchilito View Post
That's the fun of this segment of the hobby - doing things your own way
100% agreement on that. Ol' blue eyes would be proud

Old 07-31-2022, 08:21 AM
  #131  
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But we aren't at Sea.
Here on Terra Firma, more suitable "consumables" are an option in many regions.
Having zero interest in seeking patents nor fame we may use the materials and methods that best deliver our desired outcomes. Based on real experiences, one fellow may decry the various shortcomings of wet fueled engines and simply take advantages of clean, reliable electric flight.

Mitch, good job. The fine tuning can cover many areas. Make use of whatever you like out whatever is available.


I like what I see.









Really

Last edited by Jesse Open; 07-31-2022 at 08:25 AM.
Old 07-31-2022, 03:39 PM
  #132  
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Default Problem solving

Post removed.
Not having any part of it.










Last edited by TheEdge; 08-01-2022 at 05:22 AM. Reason: Not having any part of it
Old 08-01-2022, 01:46 AM
  #133  
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Originally Posted by TheEdge View Post
I think Brutus's point was regarding problem solving and solutions, not about being at Sea
He knows that... He understands that... He simply can't help himself. He HAS to pry and prod until there's a response. He has been doing that for 10 years on RCG, and despite me totally ignoring him here from the first day I signed up here, he simply can't let go.

Very unpleasant if you ask me, and my polite and humble request to you is not to quote him whenever he does things like this, because I really don't care for reading his manipulative style of posting.



Old 08-01-2022, 02:20 AM
  #134  
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Now now, boys. Let's all try to get along. . . . .
Old 08-01-2022, 04:01 AM
  #135  
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Presenting diverse backgrounds and experiences may present different perspectives.


Seldom do we get clones who agree 100%, but even that does happen


Last edited by Jesse Open; 08-01-2022 at 05:30 AM.
Old 08-01-2022, 04:09 AM
  #136  
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Originally Posted by mitchilito View Post
Now now, boys. Let's all try to get along. . . . .
Between the two of us, one of us is desperately trying to ignore the other, and the other one keeps prying and prodding without any provocation. Going on now for 10 years. And why? Beats me.
Old 08-01-2022, 05:17 AM
  #137  
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Regarding iridium plugs and waste spark ignitions.

Waste spark sytems have two plugs, driven with a single coil, one has the center electrode at the positive end of the ignition coil secondary, the other at the negative. As a result the electrode erosion wear is unequal.

As cautioned by NGK:

" The use of nickel-alloy or single precious metal spark plugs in vehicles equipped with waste spark ignitions will result in more aggressive gap erosion and shorter spark plug life."

Not certain if the difference here will really be a factor, just thought you may want to be aware


Last edited by Jesse Open; 08-01-2022 at 05:31 AM.
Old 08-01-2022, 05:26 AM
  #138  
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Originally Posted by 1967brutus View Post
He knows that... He understands that... He simply can't help himself. He HAS to pry and prod until there's a response. He has been doing that for 10 years on RCG, and despite me totally ignoring him here from the first day I signed up here, he simply can't let go.

Very unpleasant if you ask me, and my polite and humble request to you is not to quote him whenever he does things like this, because I really don't care for reading his manipulative style of posting.

Humble request granted. I edited my post and will not play into any of this.

Really enjoy reading your comments and hope you carry on.
Old 08-01-2022, 10:49 AM
  #139  
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Originally Posted by TheEdge View Post
Humble request granted. I edited my post and will not play into any of this.

Really enjoy reading your comments and hope you carry on.
Really appreciate that, thanks!
Old 08-02-2022, 02:10 AM
  #140  
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Originally Posted by 1967brutus View Post
Between the two of us, one of us is desperately trying to ignore the other, and the other one keeps prying and prodding without any provocation. Going on now for 10 years. And why? Beats me.
As the OG of this thread I have to say I've always appreciated Jesse's input. He obviously has an extensive background in this field. At no time in any of these threads did I get the feeling he was "prodding or prying." On the contrary, his advice has always been helpful.

Please don't turn my thread into a personal vendetta.
Thanks,
Mitch

Old 08-02-2022, 02:16 AM
  #141  
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Originally Posted by Jesse Open View Post
Regarding iridium plugs and waste spark ignitions.

Waste spark sytems have two plugs, driven with a single coil, one has the center electrode at the positive end of the ignition coil secondary, the other at the negative. As a result the electrode erosion wear is unequal.

As cautioned by NGK:

" The use of nickel-alloy or single precious metal spark plugs in vehicles equipped with waste spark ignitions will result in more aggressive gap erosion and shorter spark plug life."

Not certain if the difference here will really be a factor, just thought you may want to be aware
Wow, I did not see that coming. Although I'm not sure I get the connection. Why wouldn't the standard electrodes wear faster as well? Intuitively, one would think the harder (nickel for example) electrode would last longer. . . .
Old 08-02-2022, 03:19 AM
  #142  
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I am fully aware of the fact that you are OG of this thread, and I respect that. The proof of that is that I have "Jesse" on ignore and haven't responded to him at all.
Originally Posted by mitchilito View Post
As the OG of this thread I have to say I've always appreciated Jesse's input. He obviously has an extensive background in this field. At no time in any of these threads did I get the feeling he was "prodding or prying." On the contrary, his advice has always been helpful.
That is because most likely, you are unaware of the history of 10+ years on another forum. After a while it gets tiring really quick.
Some people here ARE aware, one of them is "The Edge" and he pointed out exactly what Jesse is always doing: Taking my words in a direction they are not intended to, in hopes of getting an emotional response. It is his MO.

Originally Posted by mitchilito View Post
Please don't turn my thread into a personal vendetta.
Thanks,
Mitch
As said; I am here for a fresh start, am VERY desperately trying to ignore him, and IF there is any kind of personal vendetta being carried out, it is NOT me that is doing that, but I am also not going to keep silent if it gets to a point where others, like The Edge, start taking notice.
What I did was politely asking him to not quote if that happens, because I am sick and tired of this crap after 10+ years and I want nothing of it. For any clarification on the matter, maybe you can ask The Edge over PM. He might be able to tell you why he posted what he did.
I responded to The Edge, not to Gary's post.


But what am I to do? Refrain from posting alltogether? I think not...
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Old 08-02-2022, 04:44 AM
  #143  
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Originally Posted by mitchilito View Post
Wow, I did not see that coming. Although I'm not sure I get the connection. Why wouldn't the standard electrodes wear faster as well? Intuitively, one would think the harder (nickel for example) electrode would last longer. . . .
Here is the complete NGK article that I only partially quoted earlier. :

https://ngksparkplugs.com/en/resourc...park-ignitions

Yet another issue involves possible catalytic action with methanol fuel and Iridium plugs. Not really a concern with the gasoline however.
Old 08-02-2022, 08:22 AM
  #144  
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Originally Posted by Jesse Open View Post
Here is the complete NGK article that I only partially quoted earlier. :

https://ngksparkplugs.com/en/resourc...park-ignitions

Yet another issue involves possible catalytic action with methanol fuel and Iridium plugs. Not really a concern with the gasoline however.
This was an interesting read and now I get it. One of my plugs is going to wear the plain metal ground conductor and one is going to try to erode the hard iridium center conductor due to opposite polarity. Should be interesting to see if I notice this phenomenon during the limited operation of this little jewel. Its nice to know about this so THANKS!
Old 08-02-2022, 10:11 AM
  #145  
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Originally Posted by mitchilito View Post
This was an interesting read and now I get it. One of my plugs is going to wear the plain metal ground conductor and one is going to try to erode the hard iridium center conductor due to opposite polarity. Should be interesting to see if I notice this phenomenon during the limited operation of this little jewel. Its nice to know about this so THANKS!
If that were to happen, I'd say just change your plugs left and right every once in a while makes them wear even. But I would not expect so, because although I have no diagrams or other ways to be sure, I would expect both the CH and RcExl ignitions NOT to have a single coil firing two plugs, because that also means double voltage (higher insulation requirements), a larger coil and a larger capacitor and charging circuit. I have never opened one, but it would not surprise me in the least if there were just one processor triggering two separate HV circuits simultaneously, each HV circuit energized by its own capacitor and charging circuit. That would be manufacturing-wise the more clever thing to do (less typespecific parts, just generic HV circuits and capacitors).
That's not a fact, merely my suspicion, in part based on the fact that both RcExl and CH do not warn against the use of Irridium plugs in combination with dual ignitions.
Old 08-02-2022, 11:34 AM
  #146  
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Originally Posted by mitchilito View Post
This was an interesting read and now I get it. One of my plugs is going to wear the plain metal ground conductor and one is going to try to erode the hard iridium center conductor due to opposite polarity. Should be interesting to see if I notice this phenomenon during the limited operation of this little jewel. Its nice to know about this so THANKS!
Nothing carved in stone. As I said earlier "usually" ... a single coil.... with both ends of the secondary terminated at plug. One plug electrode positive, the other negative.

This is by far the predominate method in waste spark, dual pluggers as it makes sense from a manufacturing and power supply standpoint.
Driving two coils requires added capacitors as well as the driver needed driver circuitry. These are operating at high power levels, as opposed to the triggering which takes place at low levels.

Jury is still mixed on iridium or not for RC. Just thought you may care to ponder the details a bit.

Assumptions seldom lead to informed decisions. A phone call to Adrian at CH could clear up the issue of one plug or two.





Old 08-02-2022, 12:07 PM
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[QUOTE=Jesse Open;12738062]
Jury is still mixed on iridium or not for RC. Just thought you may care to ponder the details a bit. QUOTE]

While I'm enjoying the heck out of this conversation I have to admit that I'm not really concerned HOW the ignition is wired. To be honest I'm just hoping the iridiums are going to be more resistant to fouling. I'll be getting them soon now that Adrian is back so I'll let you all know how it worked out.
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Old 08-02-2022, 01:19 PM
  #148  
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Originally Posted by mitchilito View Post
While I'm enjoying the heck out of this conversation I have to admit that I'm not really concerned HOW the ignition is wired.
Nobody is as long as a spark is a spark but if it could potentially cause uneven wear, at least it is nice to know why it does that instead of looking for the cause of that in the conditions in the engine, right?
Originally Posted by mitchilito View Post
To be honest I'm just hoping the iridiums are going to be more resistant to fouling.
I know of only ONE guy that uses them and he does so on Methanol. OS 55 HZ in a heli to be precise. I don't know the fuel composition he uses, other than that it is a fairly common 5% Nitro helimix but I don't know what oil or how much. From what I understood he did not so much notice difference in fouling, but a slightly better running behaviour, less misfiring in the inevitably rich midrange that is caused by the engines demand for a leaner mix, what that particular heli carb was not designed for.
FWIW he runs his engine around 18K and I don't remember him complaining about plug wear with Irridium, so I assume they hold out better than the standard plugs, which go pretty rapid at that RPM (25 hrs max or so).
I am still a bit puzzled about your plugs fouling. Mine never do despite running 10:1. In 7 years I had exactly only ONE case of an engine shutting down because the carbon deposits bridged the spark gap and that was early on when I still ran 5:1 fuel oil mix, and that with a carb set blubbering rich in a .50 class heli. Seen plenty of deposits when pulling plugs, but never even noticed they were there when running an engine. Not in starting, not in running, no "after dieseling" (if that is the term in English), no nothing. Plenty times that I thought there might be something with the plug or the ignition, but it always turned out to be something else, like the time my radial appeared to eat plugs and needed at least 2 or 3 fresh ones every 2nd run. Turned out to be a too weak ignition battery

I hope you get an answer to that fouling one day
Old 08-02-2022, 02:36 PM
  #149  
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[QUOTE=mitchilito;12738068]
Originally Posted by Jesse Open View Post
Jury is still mixed on iridium or not for RC. Just thought you may care to ponder the details a bit. QUOTE]

While I'm enjoying the heck out of this conversation I have to admit that I'm not really concerned HOW the ignition is wired. To be honest I'm just hoping the iridiums are going to be more resistant to fouling. I'll be getting them soon now that Adrian is back so I'll let you all know how it worked out.
Understanding the functions helps in making decisions. The benefits of Iridium are mainly related to slowed electrode erosion, not so much about anti-fouling.

I mentioned the polarity issue as your situation seemed to be related to one side over the other.

Mind the plug gaps as wide gaps raise the firing voltage. This can lead to flashover across the carbon deposits on the insulator.
Operating nearer the minimum gap holds that voltage lower by providing a lower potential path for the spark energy. As the gap grows, the spark energy will seek other paths.

The reports of issues with Iridium and methanol are mostly related to catalytic reaction.
Seems rare but supposedly the very small , reactive electrode tip under certain conditions can work somewhat like a glow plug, leading to auto-ignition. Some say it never happened other swear it has. Zero reported problems with gasoline that I know of.


Good luck

Last edited by Jesse Open; 08-02-2022 at 02:51 PM.
Old 08-03-2022, 02:41 AM
  #150  
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[QUOTE=1967brutus;12738075]
I am still a bit puzzled about your plugs fouling. Mine never do despite running 10:1. In 7 years I had exactly only ONE case of an engine shutting down because the carbon deposits bridged the spark gap and that was early on when I still ran 5:1 fuel oil mix, and that with a carb set blubbering rich in a .50 class heli. I hope you get an answer to that fouling one day[/QUOTE

Bert, two things are contributing to my fouling: 1) I'm re-breathing the (significant amount of) crankcase discharge oil and 2) my intake setup is imbalanced to richer on the left side. The fresh fuel load wouldn't foul the plug but combined with the rebreathed oil it will. Once running properly it will continue to clear itself and run fine but if it fouls (always at low throttle) it can't clear itself. As I mentioned, the American made Rimfire plugs I originally ran were much more resistant to fouling than this current set. In fact I'm not sure they ever did foul out. I only changed them because one insulator came loose.

If the iridiums don't fix the fouling I will disconnect the rebreathing system - at least until I can figure out the intake imbalance. In the mean time - Im having fun!

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