Author Topic: Yet another M90 Microcosm Hit & Miss thread  (Read 573 times)

Stoker

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Yet another M90 Microcosm Hit & Miss thread
« on: May 16, 2019, 03:36:00 pm »
Howdy All

Finally got my M90 from Jin. I won it on eBay from one of Jin's three different sales handles, just a bit before he started posting BIN listings, and got it for about 10% less than the BIN, so I'm pretty happy about that, for they were often going quite a bit higher right about then. When Nick's Aliexpress "engine" (which was more likely a ladies purse or some such), got delivered in Denver Colorado, and while my supposed engine was in flight for well over a week, I bit the bullet and bid on one of Jin's auctions, and won.  Oddly enough after cancelling my Aliexpress order, I saw it was delivered somewhere in Texas, and was also likely a pair of shoes, blouse, purse or some such that I'd been given a tracking number for to keep me engaged, while they hoped to fill their own stock backorder. Never happened, but I did get a full refund, so everything squared in the end except for the lost time and price-points.

It did take most of a month to get to me however, unlike the seven days some of the early responders reported. But it appears that most of that month was spent in U.S. Customs, which is a fairly new experience for me on this kind of thing, as most stuff from China has gotten to me in about ten days before this.

I'll not bother showing pictures or videos of this engine, as we have plenty of that kind of material already available here on the Forum.

What I do intend with this thread is to thank the many mentors who went before me on this, and offered their insights, suggestions and modifications, so that when mine got here I was in a position to fire it right up when I went to do so, and fire up it did !

So THANKS to all of you who posted your experiences with this engine, your help was greatly appreciated !!!

Here follows a host of technical details as gleaned from running my own engine:

1.) First let me say that although my expectations for the quality of this engine were quite high due to the excellent reviews offered by others, it actually exceeded my expectations far beyond that. It really is of excellent build quality, fit, finish and function. I'm officially IMPRESSED!!!

2.) The wood box that the engine sits upon, and that houses the electronics, appears unfinished in the photos on the eBay listing, but in fact has a rather tough and durable, slightly yellow clearcoat of some kind on it. Long before I received mine, I had determined on staining this box a dark shade of walnut, but upon arrival found that I would have to remove the original finish to do so. Thus I heavily sanded the original finish, or so I thought, but found upon trying to stain the box, that original finish penetrated the wood much deeper than I had surmised, such that my stain did not penetrate the wood properly, but mostly just slurried on the surface creating a rather ugly looking smear. Still, upon setting up, it seemed to make the box look more "industrial", so for now I have just waxed over the stain, and will use it as is for now. It's actually kind of growing on me, and I do have other plans to modify the mounting, which hopefully will eventually make it better yet.

3.) The electrical switch is easily turned 90 or 180 degrees, so you can have your on/off toggle work in any direction you want. Mine was set up so that "on" was toggled toward the outside of the box, which I didn't like, as reaching a finger in between a moving flywheel and the toggle to turn it off really didn't seem like a good idea, so I reversed mine to where "on" is toggled toward center, and "off" is toward the outside. Safer I think! BTW ... I do like the LED light that someone installed to show when the engine is ready to run, and will almost certainly add this good idea to mine later.

Now on to some tech-specs:

4.) Water for the cooling reservoir can be used, but I'm not totally convinced that it is actually necessary as the engine seems to run so cool. I recommend using warm water as this will aid in getting the engine started at first, and the water never gets any past warm during any of the runs that I made. I would also suggest that you don't put more than about 20-25 ml of water in the reservoir, or about half full, as the way the engine tends to bounce around it will throw any more than that out anyway, especially while starting.

5.) My engine ran well on all three of the different fuels that I tried, all mixed with a few drops of Marvel Mystery Oil (thanks Rog), so let me detail those here.
 
   A.) Zippo lighter fluid, seems to be just fine, and ran smooth, or as smooth as H-n-M can, from the very first run. A bit pricey, but for the little bit used, not excessively so, and as others have pointed out, the smell is slight and quite tolerable.

   B.) Coleman camp fuel otherwise generally known as White Gas, ran just as good as the lighter fluid, with perhaps just a bit less smell, as it is designed to be used in stoves, heaters and lanterns that are often used indoors and around foodstuffs, so odor is an important concern. Of possible note here is that the fuel I used was the last dregs from a gallon can that has been open and in use for several years, and may have lost some of its volatiles sitting so long in a near empty can, such that a newer can may well offer better performance.

   C.) Denatured Alcohol, Ethanol and probably Methanol too (though I didn't test it), seem to work well, so there may be no reason to buy a special fuel for these engine, as we all probably have some laying around for our steam engines. I will note that the engine ran noticeably weaker on the alcohol fuel, but that could be because I was using alcohol from a bottle more than half empty that has been sitting for a long while, and alcohol actively absorbs water from the atmosphere diluting it, which may well have happened here. While it did run noticeably weaker (guessing, maybe 5-10%), it still ran, and perhaps a bit smoother for the softer "kick", so it may actually be a preferable fuel in some ways.

6.) Fuel tank capacity seems quite small at just over 14 ml, but in fact is far more than adequate in my opinion. My first run on the Zippo fuel lasted for quite a bit more than forty minutes on a measured 6.4 ml of fuel, with perhaps about a ml still left in the fuel line when it did die. My second and third runs with Coleman fuel and Alcohol respectively, where both just 3.2 ml, and each ran for about half an hour. On my fourth and final run, I filled the tank to the top, with the old "stale" Coleman fuel, and proceeded to run a bit in excess of two & one half hours. I should note that during all of these runs, there was no part of the engine, that I could not easily touch, without any discomfort, for extended periods of time, including the cylinder head and the cooling water, which was never more than barely tepid.

7.) Speed seems always to be a consideration, as people typically want to know how fast it is going. With a hit and miss engine of this type there really is no set speed, as it is quite load dependent. I ran my RPM tests with an old style L.S. Starrett Speed Indicator held against the end of the crankshaft for six seconds, as near as I could gauge from my stop watch, and multiplied the reading by ten to get RPM. The range I saw was from around 1250-1420, so would say that my approximate average "speed" was about 1325 RPM. Of note is that this instrument does require putting a bit of pressure on the end of the crankshaft to get a good reading, and no doubt I did push harder on some readings than others, yet I doubt very much that my taking the reading affected the RPM my more than a few revs. I do know that trying to slow the crankshaft by pinching it as a brake between my thumb and fingers seemed to have little effect on speed, but only caused the engine to fire more often to keep pace with the governor's setting. So there is some real power available here!

8.) Which brings to mind the governor .... which is a very interesting aspect of these engines, and really fun to watch how the entire mechanism works together to achieve the engines function. I gathered from reading other's comments, that the springs on the governor's fly-plates were a little too strong from the factory, so I glibly stretched mine shortly after arrival, and as it turns out, stretched them a bit too much, such that they no longer "hugged" the flywheel center hub, and thus were almost permanently in coasting position and could only just pull in enough to get a fire signal through to the valves on occasion, which was not usually often enough to keep the engine running. Springs do not re-compress well at all normally, so I was faced with the alternatives of cutting a coil or three off in hopes of hitting it right, or finding some other way to shorten the distance over which these springs could act. The first offers few alternatives if over done, so I went with the latter technique, and arched the springs out from a straight line tension pull in such a way that I now have some adjustment available, and should be able to slightly vary the engines speed by increasing and decreasing the tension on these springs by changing the amount of arc that they are set at. A rather cool, if totally unintended, outcome!

9.) Adjustable speed brings us back to a combination of other factors, such that Governor tension vs RPM vs Load becomes of interest. Thus somewhere down the road I'll be making myself some form of pulley wheel to attach to the crank's endshaft, and trying to find a "standard" load that I can test against. But that is all for another day. For now, I'll simply say that without significant load, and with my governor set at some fixed point by my arched springs I was getting approximately 1325 RPM while getting just a bit less than one second interval between the engine firing, which averages out to something like one hit every twenty or so revolutions. Double hits were fairly common, typically something like one in ten, but often seemed to come in groups of two, and occasionally even three, but oft times nary a one for perhaps a minute or two at a time. All part of the fun of these little beasties!

10.) For a final note I'll simply say that mine seemed to "dance" in different directions at different times, for no apparent reason that I could fathom. There was a tendency to rotate clockwise, that was fairly consistent, and also more tendency to move to the right when viewed from the cylinder end, but left movement was occasionally observed. Front to back movement seemed to favor going backwards, but not exclusively as forward movement was at least fairly common as well. All mysteries worth looking out for and looking into, in my opinion at least.

So in conclusion I will simply say ... Did someone suggest that these engines were fun? ...  well Boy-Howdy, let me tell you .... they are a Ton o' Fun, to say the least!!!
"Information is not knowledge, Knowledge is not wisdom, Wisdom is not truth, Truth is not beauty, Beauty is not love, Love is not music: Music is THE BEST...   
Wisdom is the domain of the Wis (which is extinct). Beauty is a French phonetic corruption of a short cloth neck ornament currently in resurgence..."
F. Zappa ... by way of Mary, the girl from the bus.

classixs

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Re: Yet another M90 Microcosm Hit & Miss thread
« Reply #1 on: May 16, 2019, 04:19:21 pm »
Good news that one finally decided to move in with you Daniel, cool little buggers these

Great write up, and definitely more observations from you already, than i have made here after many hours of fun.
Will try to pay more attention to details myself...just as soon as i stop grinning like an idiot when running it.
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IndianaRog

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Re: Yet another M90 Microcosm Hit & Miss thread
« Reply #2 on: May 16, 2019, 07:27:26 pm »
Daniel, your write-up was superb and covered most of the idiosyncrasies of these wonderful engines.  One additional point made by Bruce and I definitely concur...the needle valve on the carburetor top is very sensitive and has a major impact on how the engine runs.  I have mine "set" at approx. 1/2 turn from closed position, but I mess with it regularly seeking the perfect wave so to speak.  I have clocked mine at roughly 55 hits per minute when dialed in well.

I have experimented a bit with Zippo...first using 5 parts Zippo to 1 part Marvel Mystery Oil...TOO much pink oily residue resulted.  Currently using 10 parts Zippo to 1 part MMO, but enough pink residue collects that next batch of fuel I make up will be 15 parts Zippo to 1 part MMO. I want to keep backing down the oil content to avoid fouling the spark plug and have a spare spark plug on order should mine fail me.  I like to make "batches" of 50 ml mix as I have a nice screw lid container with graduations on the side (similarity to a urine sample bottle is purely coincidental)

Like you, I would like to add an LED like one of our members showed.  I have looked on eBay and Amazon for a source in the range of 4-5 volts...but lowest I have found is 12 volt.  Any suggestions from anyone on a source would be appreciated.  I personally need the LED to warn me to shut off the switch when I am done.  I have now left it on twice and wasted 2 sets of batteries for the oversight...an LED would avoid this dumb mistake.

I think Jin has given us a quality engine for the money... smiles per dollar are off the chart!

Rog
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Stoker

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Re: Yet another M90 Microcosm Hit & Miss thread
« Reply #3 on: May 16, 2019, 08:06:59 pm »
I wholly agree on the critical nature of the needle valve setting Rog, but didn't figure I needed to included it as it had been well covered before. For the record I did all of my running at between 1/4 or just a little under, and 1/2  turns from closed, with most of the running done closest to the 1/4 turn mark. I did find that as it started to run out of fuel, with air showing in the fuel line, opening up toward the 1/2 turn mark seemed to help it drink just a little bit more out of the line.

I've only got about four hours on mine so far, as yesterday was the only day I have run it, so it is just getting broken in I'd guess. My best runs seemed to be giving me about 60 beats per minute, but only the very first run on Zippo was on a "quality" fuel, as both of my other fuels were old remnants and likely somewhat compromised.

I've only been using a few drops of the oil mixed in with my fuel as it seems to hang around pretty well, much like steam oil seems to linger in the cylinder for several runs.

Where are you sourcing the spare parts from (ie: sparkplug) as I'd like to order up some spares myself?
"Information is not knowledge, Knowledge is not wisdom, Wisdom is not truth, Truth is not beauty, Beauty is not love, Love is not music: Music is THE BEST...   
Wisdom is the domain of the Wis (which is extinct). Beauty is a French phonetic corruption of a short cloth neck ornament currently in resurgence..."
F. Zappa ... by way of Mary, the girl from the bus.

IndianaRog

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Re: Yet another M90 Microcosm Hit & Miss thread
« Reply #4 on: May 16, 2019, 08:13:24 pm »
Daniel, here is a link to a source on eBay for the replacement spark plugs that fit this engine:

https://www.ebay.com/itm/1pcs-Rcexl-Advance-1-4-32-Spark-Plug-for-Nitro-Turned-to-Gasoline-Engine/113682699073?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

Given your review and having just watched a YouTube video by Ron Walters regards this engine...I definitely need to back my needle valve off a bit to closer to 1/4 turn.

Check out Ron Walter's YouTube...very teachable in the ways a Hit and Miss actually functions.

https://youtu.be/ZCrjj4niyto

Rog
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Jim

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Re: Yet another M90 Microcosm Hit & Miss thread
« Reply #5 on: May 16, 2019, 09:19:41 pm »
Great review Daniel.
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Jim

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Stoker

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Re: Yet another M90 Microcosm Hit & Miss thread
« Reply #6 on: May 16, 2019, 09:21:45 pm »
Thanks for posting that video Rog. Interesting that he's running his ignition coil at 3 volts instead of the 4.5 volts that it came set up for, with a three cell battery pack. Wonder what makes him think that is better?

Also interesting that he mentions no top oil in the fuel, nor specifically pre-oiling the cylinder walls, but I'm certainly not sorry that I do those things.

Sort of odd he felt he had to open the other side of the box too, instead of just sliding it out the bottom.

He does give a nice explanation of the four cycle system, though I'm sure most of us are fully aware of how it works.
 
All in all, I remain extremely impressed with the quality of this model for the price, or most any price really, and I definitely like your analogy of "smiles per dollar" .... a real bargain for certain and for sure!!!

All Electronics is my usual go to source or most surplus electronic type stuff, so you might have a look there. They do have a nice flashing red led that seems to handle 3-5 volts so might be an option as seen here:

https://www.allelectronics.com/item/led-4/red-flasher-led-t-1-3/4/1.html

Oh yeah ... and thanks for the link for the spark plugs, I'll definitely place an order if Jin doesn't have a better deal on these. May even see if I can get some replacement governor springs (Oops!!!) at the same time.

"Information is not knowledge, Knowledge is not wisdom, Wisdom is not truth, Truth is not beauty, Beauty is not love, Love is not music: Music is THE BEST...   
Wisdom is the domain of the Wis (which is extinct). Beauty is a French phonetic corruption of a short cloth neck ornament currently in resurgence..."
F. Zappa ... by way of Mary, the girl from the bus.

classixs

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Re: Yet another M90 Microcosm Hit & Miss thread
« Reply #7 on: May 17, 2019, 01:46:15 am »
Quote from: Stoker

...Interesting that he's running his ignition coil at 3 volts instead of the 4.5 volts that it came set up for, with a three cell battery pack. Wonder what makes him think that is better?...


He does mention Myfordboy as inspiration for this mod, and Myfordboy claims that his Banggood engine tends to cut out with three batteries, and not with just two.

Cutting out is not a problem with mine here, but i will however try running my own with 2 as well, since there has been a few reports of the hall-sensor being easily fried.
My hope is that feeding less voltage through hall-sensor unit on these engines, will reduce heating of it slightly and minimize that risk?
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St Paul Steam

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Re: Yet another M90 Microcosm Hit & Miss thread
« Reply #8 on: May 17, 2019, 06:13:13 am »
very interesting read Daniel, great detailed information there, thank you.
Bruce
St. Paul Indiana , USA

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Re: Yet another M90 Microcosm Hit & Miss thread
« Reply #9 on: May 17, 2019, 06:33:10 am »
Thank you for the great write-up, Daniel. I am glad to see you are having an off the charts level of fun experience!


Regarding fuel, while most hit and miss engines can run on alcohol, I recommend strongly against it. Alcohol delivers a clear path to collecting water inside the fuel tank and inside the engine.


Gil

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Re: Yet another M90 Microcosm Hit & Miss thread
« Reply #10 on: May 17, 2019, 08:38:42 am »
Are these engines strong enough to run accessories (with gearing if needed)?

Nick

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Re: Yet another M90 Microcosm Hit & Miss thread
« Reply #11 on: May 17, 2019, 09:03:48 am »
Yes, but they don't have a lot of power... here is Bruce's with a Baker fan

https://youtu.be/xnzGWIIQ2e8
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Re: Yet another M90 Microcosm Hit & Miss thread
« Reply #12 on: May 17, 2019, 09:04:32 am »
And that was a very interesting read, thanks Daniel  :)
Nick

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Re: Yet another M90 Microcosm Hit & Miss thread
« Reply #13 on: May 17, 2019, 10:21:04 am »
Thank you for the great write-up, Daniel. I am glad to see you are having an off the charts level of fun experience!


Regarding fuel, while most hit and miss engines can run on alcohol, I recommend strongly against it. Alcohol delivers a clear path to collecting water inside the fuel tank and inside the engine.


Gil

Good point Gil ... thanks for chiming in with that!

Perhaps one only needs to make a final run with one of the less hygroscopic fuels, after running with alcohol, to clear the system of any residual water, and store the engine away safely.

On the other hand, don't we pour alcohol into our fuel tanks to get any residual water to be absorbed out of them?
"Information is not knowledge, Knowledge is not wisdom, Wisdom is not truth, Truth is not beauty, Beauty is not love, Love is not music: Music is THE BEST...   
Wisdom is the domain of the Wis (which is extinct). Beauty is a French phonetic corruption of a short cloth neck ornament currently in resurgence..."
F. Zappa ... by way of Mary, the girl from the bus.

Stoker

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Re: Yet another M90 Microcosm Hit & Miss thread
« Reply #14 on: May 17, 2019, 10:32:04 am »
Yes, but they don't have a lot of power... here is Bruce's with a Baker fan

https://youtu.be/xnzGWIIQ2e8

I would make two observations regarding this:

First is that the Baker fan with its flat paddles offers significant resistance, far more so than a propeller that cuts through the air.

Secondly, Bruce's engine is not hitting on every stroke by far (or rather every other stroke, as it is a 4 cycle), so there is still a lot of potential energy that engine is not yet applying, thus it hasn't nearly reached its max power threshold yet.
"Information is not knowledge, Knowledge is not wisdom, Wisdom is not truth, Truth is not beauty, Beauty is not love, Love is not music: Music is THE BEST...   
Wisdom is the domain of the Wis (which is extinct). Beauty is a French phonetic corruption of a short cloth neck ornament currently in resurgence..."
F. Zappa ... by way of Mary, the girl from the bus.

 

...Engine of the month winner is Nuvolari's Bing 8048-2 ....  photo A late 19th century Bing 8048-4 2 - Copy 493x640.jpg Congrats, Danny!