Magnum GP40 with 0% nitro fuel. Some question  
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All Forums >> Glow Engines, Gas Engines, Fuel & Mfg Support Forums >> RC Fuels >> Magnum GP40 with 0% nitro fuel. Some question
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Magnum GP40 with 0% nitro fuel. Some question - 3/16/2008 9:17:12 PM   
neuroza


 

Posts: 98
Joined: 11/17/2007
From: Porec, CROATIA (HRVATSKA)
Status: offline 		Hi!
I have Magnum GP40 engine with air bleed carburetor.
I use my own fuel (20% castor oil, 80% methanol, 0% nitro).
Is it possible that because is without nitro the engine sometimes just die on high RMP (the needle is set very carefully)???

Have another question, when the engine run on minimum,
I turn the nose up and the engine increase in RPM, then when I put the nose down the engine die.
Is this a air bleed problem - did need to be adjusted??? How???

Because I use 0% nitro, do I need to increase compression, how??? Can I put out the thin ring that come under the cylinder head???

Thanks for any help!

< Message edited by neuroza -- 3/16/2008 9:23:02 PM >
       Post #: 1

RE: Magnum GP40 with 0% nitro fuel. Some question - 3/16/2008 9:46:15 PM   
jetpack



Posts: 1391
Joined: 10/2/2002
From: Portage, IN, USA
Status: offline 		Not sure about the carb, but taking the head washer out is a good idea. No nitro likes a higher compression and a warmer glow plug.

(in reply to neuroza)
       Post #: 2

RE: Magnum GP40 with 0% nitro fuel. Some question - 3/16/2008 10:05:38 PM   
neuroza


 

Posts: 98
Joined: 11/17/2007
From: Porec, CROATIA (HRVATSKA)
Status: offline 		Ok, thanks!

I have another question, on some other forum i find that if there is no nitro I can add some acetone... Is that right??? How much???

(in reply to jetpack)
       Post #: 3

RE: Magnum GP40 with 0% nitro fuel. Some question - 3/17/2008 12:15:18 AM   
jetpack



Posts: 1391
Joined: 10/2/2002
From: Portage, IN, USA
Status: offline 		3% if the alcohol your using doesn't already have some in it.

(in reply to neuroza)
       Post #: 4

RE: Magnum GP40 with 0% nitro fuel. Some question - 3/17/2008 12:19:41 AM   
neuroza


 

Posts: 98
Joined: 11/17/2007
From: Porec, CROATIA (HRVATSKA)
Status: offline 		No, I use pure Methanole, and medicinal pure castor oil.


So is this the right mixture???:

20% Castor oil
77% Methanole
3% Acetone


Thanks!!!

< Message edited by neuroza -- 3/17/2008 12:35:44 AM >

(in reply to jetpack)
       Post #: 5

RE: Magnum GP40 with 0% nitro fuel. Some question - 3/17/2008 1:03:49 AM   
XJet


 

Posts: 3006
Joined: 3/31/2003
From: Tokoroa, NEW ZEALAND
Status: online 		I doubt you'll need (or notice) the effect of the acetone.

I ran a wide range of engines without any nitro for many years back in the 1960s-1980s and they all performed perfectly.

The Magnum GP40 is an engine that should run just fine on 0% nitro. I'd recommend an OS#8 plug -- they seem to work very well with low nitro levels.

_____________________________

When I'm not here, I'm at RCModelReviews

(in reply to neuroza)
       Post #: 6

RE: Magnum GP40 with 0% nitro fuel. Some question - 3/17/2008 3:56:03 AM   
downunder



Posts: 3013
Joined: 10/10/2002
From: Adelaide, AUSTRALIA
Status: offline 		It should run just fine on zero nitro but use a hot plug, even a 4 stroke plug. Small amounts of acetone (in that 3% range) is supposed to act somewhat like 5% nitro as far as starting and idling go. It won't hurt the engine so it's just a matter of trying it and see. Taking out the head shim will help a tiny bit by raising the compression slightly but you may get some leakage at the head joint because the shim is also a gasket.

The only thing I can't be sure of is how well an engine runs on zero nitro in cold weather because that's something we don't have here.

(in reply to XJet)
       Post #: 7

RE: Magnum GP40 with 0% nitro fuel. Some question - 3/17/2008 1:26:36 PM   
neuroza


 

Posts: 98
Joined: 11/17/2007
From: Porec, CROATIA (HRVATSKA)
Status: offline 		Ok, thanks!

Have another question...
I try to use several synthetic oil but every one drop to the bottom of fuel mixture (the mixture is not homogenic)...
What do I need to pay attention when I buy the right synthetic oil???


(in reply to downunder)
       Post #: 8

RE: Magnum GP40 with 0% nitro fuel. Some question - 3/17/2008 9:08:56 PM   
XJet


 

Posts: 3006
Joined: 3/31/2003
From: Tokoroa, NEW ZEALAND
Status: online 		You can't use a conventional automotive oil (synthetic or otherwise) because, as you've discovered, it won't mix with the methanol.

Your oil choices for a methanol-based fuel are far more limited than for gasoline-based fuels and since the 40GP is a plain-bearing engine it demands a good level of castor oil in the fuel anyway.

I'd try the good old formula of 18%-20% castor oil and 80%-82% methanol.

Synthetic model oils are not well suited to plain-bearing engines but if you're flying in very cold conditions you can use 10% of a suitable synthetic (Motul Micro, Aerosynth, Aerosave, Klotz Techniplate or Morgans CoolPower Blue) and 10% castor. This will make it easier to start your motor -- because straight castor gets real thick at low temps.

Regular automotive oils (synthetic or otherwise) will not mix with methanol -- you need one specifically designed for methanol use.

_____________________________

When I'm not here, I'm at RCModelReviews

(in reply to neuroza)
       Post #: 9

RE: Magnum GP40 with 0% nitro fuel. Some question - 3/17/2008 11:02:03 PM   
neuroza


 

Posts: 98
Joined: 11/17/2007
From: Porec, CROATIA (HRVATSKA)
Status: offline 		Thanks!

(in reply to XJet)
       Post #: 10

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All Forums >> Glow Engines, Gas Engines, Fuel & Mfg Support Forums >> RC Fuels >> Magnum GP40 with 0% nitro fuel. Some question
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