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Convert GMS 120 glow to Gas

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Old 12-24-2007, 01:21 PM
  #101
borna
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Default RE: Convert GMS 120 glow to Gas

Hi AV8TOR,
Yes it does have the V groove. I'm going to switch the carb. I have another carb that doesn't have the grove so I'm going to give it a test with that.

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Borna
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Old 12-24-2007, 02:22 PM
  #102
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Default RE: Convert GMS 120 glow to Gas

I bet that will fix it. When putting the new carb on, check very carefully for any possible intake air leaks as well.

Good luck and let us know how it works,

Happy Holidays,
AV8TOR
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Old 01-18-2008, 08:24 AM
  #103
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Default RE: Convert GMS 120 glow to Gas

How's the GMS working out? We haven't heard from you in a while and I am just curious. [8D][8D]
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Old 01-18-2008, 09:43 AM
  #104
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Default RE: Convert GMS 120 glow to Gas

Hi Jezmo,
I got busy again with other stuff. Will try to do another test run either this week or next.

Borna
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Old 01-18-2008, 07:05 PM
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Default RE: Convert GMS 120 glow to Gas

OK man, good luck with it.
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Old 04-11-2008, 08:09 PM
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Default RE: Convert GMS 120 glow to Gas

How's that GMS conversion working out?
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Old 04-12-2008, 11:03 PM
  #107
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Default RE: Convert GMS 120 glow to Gas

Hello all
Today I ran the GMS 120 on denatured alcohol bought from hardware store.
Initially I was trying to mix it with 2 cycle oil but didn’t mix well. Also tried mixing it with the Mobile syntactic motor oil and still didn’t mix.
Finally tried some caster oil and it mixed. Ran the engine with it and produced good strong RPM, however starting the engine with denatured alcohol wasn’t as easy as starting it with gasoline.
Of course I changed the carburetor from Walbro to original carb.

The thing I liked was no smoke or any bad smell of gas. I think that is what I want to run the engine with since I hate the smell of gas.

Now the question I have is what kind of oil is best to use with the denatured alcohol that mix well?
Beside the price, any disadvantage of running the engine on denatured alcohol vs gasoline?


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Borna
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Old 05-12-2008, 03:09 PM
  #108
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Default RE: Convert GMS 120 glow to Gas

just finished a conversion to gas(petrol) gms 120 cdi ignition walbro wa110 carb qalso lowered the comp ratio ignition timing at 28 degrees btdc, runs great on a 16x6 prop it is now installed in a seagull yak 54 was wondering if you had any thoughts on performance
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Old 05-12-2008, 06:40 PM
  #109
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Default RE: Convert GMS 120 glow to Gas

Several questions come to mind. Did you put needle bearings in the rod? What oil to fuel ratio are you using? I am also curious about lowering the C/R.

Borna, the oil's that work with methanol will work fine with ethanol. I understand there are some very fine oils available in Europe that we don't have access to here in the states. The best we have available is the oil that Coopers Fuels sells. PM Brian and he can give you a price and shipping info. I was running mine with Klotz when I was experimenting with Ethanol. (The Klotz that has both synthetic and castor, I forget the number)
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Old 05-26-2008, 05:34 PM
  #110
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Default RE: Convert GMS 120 glow to Gas

Ok, here is the latest news about my GMS. Today I did more testing with ethanol and caster oil as lubricant. I was getting good result and after about 10 mins, the engine stopped with a clicking sound. I noticed compression was lost so I know something went wrong. Tool the engine apart and noticed the piston ring broke. Luckily no damage to cylinder. The broken piece ended up in the crank area.

Question to those expert, what could have caused the ring to break? Not enough lubricant or ????

Borna
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Old 05-26-2008, 08:15 PM
  #111
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Default RE: Convert GMS 120 glow to Gas

The only thing that comes to mind is detonation. The ring will survive with ratios down to 100 to 1 or better. It's usually the piston that scuffs when the oil gets too low in ratio. Where was the timing set?
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Old 05-26-2008, 09:58 PM
  #112
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Default RE: Convert GMS 120 glow to Gas

Hi Jezmo,
The timing is set to 28 BTDC.

Thanks
Borna
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Old 05-26-2008, 11:55 PM
  #113
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Default RE: Convert GMS 120 glow to Gas

Is the ring pinned?? If it was, maybe you got the piston in backwards and the ring gap caught a port.
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Old 05-27-2008, 08:08 AM
  #114
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Default RE: Convert GMS 120 glow to Gas

If the timing was at 28 btdc then I agree with Terry (tkg) on the ring catching a port. Only other thing that makes sense.
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Old 05-27-2008, 08:33 AM
  #115
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Default RE: Convert GMS 120 glow to Gas

Humm that could have been the cause. Also what do you mean by "maybe you got the piston in backwards"? Anyway I'm going to order the ring from Tower Hobbies, but want to make sure when I put it in, I put it in correctly this time, if this is because I didn't install the ring correctly the first time.


Thanks again
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Old 05-27-2008, 09:39 AM
  #116
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Default RE: Convert GMS 120 glow to Gas

A ring is pinned so that the end gap is ALWAYS on a solid part of the cylinder wall. If you installed the piston turned 180 degrees when you reinstalled it, then maybe the end of the ring was passing a port opening and finally caught.
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Old 06-02-2009, 06:13 PM
  #117
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Default RE: Convert GMS 120 glow to Gas

WOW, after waitting for over a year, finally Tower hobbies has the ring in stock. I just order it today so soon I can do more testing.

Borna
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Old 06-03-2009, 01:20 AM
  #118
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Default RE: Convert GMS 120 glow to Gas

Great, let us know how it runs when you get it going again.[8D]
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Old 06-05-2009, 09:03 PM
  #119
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Default RE: Convert GMS 120 glow to Gas


Quote:
ORIGINAL: borna

WOW, after waitting for over a year, finally Tower hobbies has the ring in stock. I just order it today so soon I can do more testing.

Borna
Not sure....but I think you could have got the piston ring right away and maybe less $$$ from Frank Bowman. Good luck Capt,n
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Old 06-15-2009, 08:35 PM
  #120
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Default RE: Convert GMS 120 glow to Gas

Just to give you a reference for power.  I have a GMS 1.2 on glow and I am getting 9000 rpm on am APC 16/6 and the same
on a 15\8 APC.  this may not be as good as some as I am at 5000 feet in Denver, but it seems pretty good.
Jack
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Old 06-17-2009, 04:24 PM
  #121
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Default RE: Convert GMS 120 glow to Gas

this is all very interesting !! and 9570seams to bepretty good considering we are running our AX 46right at12,000 on 15%,,
borna,, if you do feel you need more power you could buy a gallonof say 30% heli fuel and add some toeach gallon ofgasoline, mixing this way a gallon of heli fuel should last you a few years..
Gass/Glow mix how-to,,
with the ignition I myself would be concerned about weight unless the plane was tail heavy to beginwith,, Iwould like to do the crank bearing mod and burn the Gasoline/Glow Mix with a 4st Plug and not use the ignition, I got to get my 4-Star 60 back together LOL
Jim
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Old 06-25-2009, 06:11 PM
  #122
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Default RE: Convert GMS 120 glow to Gas

Hi
I am converting a os 160.
What did you set the timing at befor TDC ?
Alos did you try to use the glow fuel carb?
Thanks Mike
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Old 06-25-2009, 06:18 PM
  #123
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Default RE: Convert GMS 120 glow to Gas

Hi
I am converting a os 160.
What did you set the timing at befor TDC ?
Alos did you try to use the glow fuel carb?
Thanks Mike
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Old 06-25-2009, 10:15 PM
  #124
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Default RE: Convert GMS 120 glow to Gas


Quote:
ORIGINAL: borna

Ok, here is the latest news about my GMS. Today I did more testing with ethanol and caster oil as lubricant. I was getting good result and after about 10 mins, the engine stopped with a clicking sound. I noticed compression was lost so I know something went wrong. Tool the engine apart and noticed the piston ring broke. Luckily no damage to cylinder. The broken piece ended up in the crank area.

Question to those expert, what could have caused the ring to break? Not enough lubricant or ????

Borna
I sure would like to see a photo of that broken piston ring! The broken part must have traveled back to crankcase through a port. If not ....seems like a scratched cylinder wall would be for certain. If no damage....you are one lucky guy!!! Capt,n
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Old 06-26-2009, 04:38 PM
  #125
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Default RE: Convert GMS 120 glow to Gas

Hi Guy
Where did you get the spark plug wire.
I have the rim fire plug and have it rigged up and it works but it may come off in the air.
Thanks Mike
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