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Old Aug 25, 2012, 10:39 AM
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United States, IL, Crete
Joined May 2007
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Who's running synthetic fuel ?

I am seriously considering switching to all synthetic 10-15 % nitro blend fuels and was wondering who is actually running straight synthetic fuel currently and how do you like it ?

What brand ?

How clean is the inside of the motor after hours of running ?

I ask because I run regular 15 % cool power castor mix currently and the motor is always carboned up (piston, sleeve, head, etc...) and would like to see if the straight synthetics keep the motor clean while protecting and doing its job.

Appreciate all replys !

Dan
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Old Aug 25, 2012, 06:10 PM
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United States, CA, Norco
Joined Feb 2007
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Ah oh! Here we go again.

If your engine is getting all gunked up you are probably running it to lean or running it peaked out for maximum power so it's getting too hot..

Using Byrons/caster I had fifty runs on 50FSR before a prop strike during a bad landing destroyed the ceramic bearings and in turn destroyed the engine. When I took apart the engine to see the extent of the damage there was no carbon buildup at all just broken ball bearings that dented the piston and head. In my case I always run my engine a few clicks rich for longevity and to keep the piston and liner for carboning up e.g enigine running cooler. Had I not been lured into running ceramic bearings that engine would have lasted for ever.

As far as Castor or Synthetic if you run a engine peaked or it runs lean regularly it's going to carbon up. If this is the case with your engine you might want to put a little larger engine in your plane so that you don't have to run it so hard.

Another point you'll have to decide on is although the claims that synthetic does lube better and is cleaner than castor there is tendency for synthetic to destroy the engine during a lean run as compared to castor due to castors higher flash point. If your engine is already carboning up you'd probably wish you ran castor due to this higher flash point if your engine is indeed running on the peaked or lean side (too hot).

Bryan
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Old Aug 26, 2012, 04:53 PM
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Australia, TAS, Burnie
Joined Jul 2008
64 Posts
Hi Dan,

The carbon build up is more likely attributed to the castor oil rather than running too lean. In my opinion full synthetic does not give the same protection as castor based fuel does, especially if you have a lean run.
I use Cool Power synthetic oil, but add 1% castor oil. The 1% castor is not enough to cause excessive carbon build up, but enough to help protect the engine during normal flying and in a lean run situation.
I also run my engines slightly on the rich side to look after the engine.

Scott
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Old Aug 26, 2012, 05:41 PM
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Kaiapoi , New Zealand
Joined Jun 2007
562 Posts
I have never used any other oil than cool power for the last 15 years.methanol and 20%cool power and the engine a notch on the rich side no problems.
I have an os25,two OS 46LA an OS40LA and a super tiger 61.
Both the 25 and the 40 are now 10 years old and still nice and clean inside and out.The 40 has round 57 hrs time on it.
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Old Aug 26, 2012, 09:16 PM
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doxilia's Avatar
Montreal, Canada
Joined Mar 2008
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In my experience, engine design and materials also have an effect on whether the engine is prone to carbon build up. Simpler design engines such as the K&B's and some Italian engines tend to produce build up more easily than Japanese engines such as YS/ OS. I've never given much thought to why this is the case...

Higher revving engines such as smaller 10-40 size also are more prone than larger 60-120 size engines. On the other hand, I never noticed any build up on engines such as Cox TD's (ran a boat load of those as a kid) no matter how peaked and cooked we ran those engines. I still have a ST G 20/15 that I ran in CL wings, mostly, that built up carbon standing still... The engine however still looks new after 35 years and a little regular TLC ;-)

David
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Old Aug 27, 2012, 12:31 AM
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Australia, TAS, Burnie
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I've used Cool Power with 1% castor for years in all my engines, from OS.32 size engines to the YS DZ170. I have never had any problems with carbon build up. Either 2 stroke or 4 stroke.

Scott
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Old Aug 27, 2012, 02:28 AM
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Izegem/Belgium
Joined Sep 2003
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only synthetic

Many years ago, I used to run 20% castor ( no nitro), then after some years, I switched to 50/50 castor and synthetic because of carbon build-up and just plain sticky goo all over the engines and mufflers. I went further down to 30/70 ( still 20% total lubrication) ... maybe the castor oil that I could find was not good enough ( not de-gummed enough).

Nowadays, my 2-strokes run with 16% Carbulin oil, no nitro ( OS, Enya). My 4-strokes with 14% Carbulin, up to 15% nitro ( all OS older Surpass types). Sparkling clean engines, no flame-outs ( dry methanol helps most there), no corrosion ( not even after winter storage without after-run oil), always a nicely loose feeling of the crankshafts. I can't say anything wrong about the synthetic that I use.

Admittedly, I am careful about lean runs.

I won't switch back to castor.

KrisG

P.S. It's the heli-guys in our club, who run their engines so hard, in those tight cowled helis, that pointed me towards this Carbulin.
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Old Aug 27, 2012, 02:17 PM
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Australia, TAS, Burnie
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Carbulin has 3% castor in it.
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Old Aug 28, 2012, 08:50 AM
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pathfinder's Avatar
walterboro s.c.u.s.a
Joined Jun 2004
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Is this type castor oil ok to add to glow fuel?.The only thing it says about the ingredients is castor oil and nothing else.Has anyone tried anything like this with good results?
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Old Aug 28, 2012, 09:18 AM
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Illinois
Joined Sep 2001
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HA! That's what we used when we were kids. My father worked at a chemical plant at the time so methanol and nitro were easy to get.

Andy
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Old Aug 28, 2012, 10:20 AM
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Los Angeles
Joined Jun 2010
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I use Sig, AAA Baker or something like that. I've used it since i was a boy with no complaints.
Chris...
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Old Aug 28, 2012, 03:56 PM
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United States, IA, Rockwell
Joined Jul 2011
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I WAS running pure synthetic in my helicopter and other engines. I stopped because of no protection from rust. I had to replace bearings in two engines after they set for two weeks without running. The jug said "No after run oil needed". All I can say is "BULL". I am now back to Sig fuel. 50% caster in the mix. Engines set without issue now. I will tear down and clean for winter storage though, as I've done since 1975 when I started the hobby.

Ken

ps. A little residue on the outside of the engine is a small price to pay for clean well lubricated internal parts
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Old Aug 28, 2012, 10:33 PM
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If you're running high nitro, then you'll find that you'll be replacing bearings regularly unless you flush all the by-products of running out. Nitromethane breaks down into nitric acid, and it loves steel, like bearings.

I don't have many issues in my engines running on FAI fuel or those that don't stand too long, but any that run on higher than 15% nitro get at least a throat full of ATF (auto trans fluid) and good flicking to get it all around. The only bearings I've replaced recently are from old engines that I've been given that have not seen fuel since the 70's
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Old Aug 29, 2012, 07:06 AM
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United States, CA, Norco
Joined Feb 2007
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I used to rebuild my own hot rod transmissions and ATF is a very high detergent lube oil as compared to regular engine oil and will turn silicone gasket sealer and materials to goo.

ATF won't hurt most RC engines but will ruin the silicone diaphram in YS engnies.

IMO the best way to store your engines after running is to run them dry at idle then cycle the engine with an electric starter 20-30 seconds with or without afterun oil. Methonal loves to bind with water so leaving fresh fuel in the crankcase is a formula for rust. If methonal collects moisture from the surrounding air and Nitromethane turns into nitric acid, well it's a doulbe wammy for rust, not to mention that some of the Synthetic fuels produce a corrosive substance after being burned in the the combustion chamber. Any of these will certainly reduce the life on an rc engine.

DarZeelon over on RCU posted the quintessential thread on Castor vs Synthetic oil
http://www.rcuniverse.com/forum/fb.asp?m=10150963
and for max temp comparison of Castor vs Syn later in the same thread
http://www.rcuniverse.com/forum/fb.asp?m=7911008

Bryan
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Old Aug 29, 2012, 09:35 PM
KE your cub.
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Quote:
Originally Posted by Roguedog View Post
I used to rebuild my own hot rod transmissions and ATF is a very high detergent lube oil as compared to regular engine oil and will turn silicone gasket sealer and materials to goo.

ATF won't hurt most RC engines but will ruin the silicone diaphram in YS engnies.

IMO the best way to store your engines after running is to run them dry at idle then cycle the engine with an electric starter 20-30 seconds with or without afterun oil. Methonal loves to bind with water so leaving fresh fuel in the crankcase is a formula for rust. If methonal collects moisture from the surrounding air and Nitromethane turns into nitric acid, well it's a doulbe wammy for rust, not to mention that some of the Synthetic fuels produce a corrosive substance after being burned in the the combustion chamber. Any of these will certainly reduce the life on an rc engine.

DarZeelon over on RCU posted the quintessential thread on Castor vs Synthetic oil
http://www.rcuniverse.com/forum/fb.asp?m=10150963
and for max temp comparison of Castor vs Syn later in the same thread
http://www.rcuniverse.com/forum/fb.asp?m=7911008

Bryan

Ahh, well there you go, I don't own any YS engines. No doubt, if I had I would have probably found that out for myself!
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