Go Back  R/C Tech Forums > General Forums > Nitro On-Road > Onroad Nitro Engine Zone
Adding castor oil to premixed fuel >

Adding castor oil to premixed fuel

Adding castor oil to premixed fuel

Reply

Old 08-13-2015, 02:23 AM
  #1  
Tech Elite
Thread Starter
 
fyrstormer's Avatar
 
Join Date: Mar 2014
Location: Maryland, Near DC, USA
Posts: 3,690
Default Adding castor oil to premixed fuel

After I bought my OS wankel airplane engine, I had to get some proper fuel for it, so I bought a quart of O'Donnell 10% nitro airplane fuel. It has 18% oil, a mix of synthetic and "degummed castor" oils. According to the OS wankel engine manual, that wasn't good enough; the engine requires 25% plain castor oil. While I realize that manual was written in the 80's and synthetic nitro oils have improved since then, I don't want my discontinued novelty engine to wear-out any time soon, so I went to the pharmacy and bought some plain castor oil to add to the fuel. I calculated how much to add to bring it up to a full 25% oil content, and dumped it in. It mixed right in, just like I'd hoped it would. (it's weird to see oil dissolve in alcohol, but that's the cool thing about castor -- it's unique molecular shape makes it alcohol-soluble.)

I have a bunch of castor oil left over, so I decided to add a little bit to my car fuel too. My cars all run on Byron 30% nitro with 11% synthetic/degummed-castor oil, so I just added enough plain castor to raise it 1%, to a total of 12%. Not a big change. However, I noticed a big difference when I opened one of my engines for a periodic checkup.

The engine internals were slathered with a thick coating of oil, unlike anything I've ever seen inside them before. The combustion chamber was also slathered in oil. I had noticed the engine made a better seal when first starting-up than it had before, but I hadn't realized just how much of the plain castor oil was remaining behind. All of the moving parts worked super-smooth with all that extra oil hanging around, and there were the early signs of varnish build-up, which I have never seen with the Byron fuel before. (varnish is bad in large quantities, but in small quantities it fill defects in the metal surfaces as the engine wears, so it helps maintain compression.)

It was interesting to see what a big difference a tiny change in the fuel composition could have. I plan to continue modifying my car fuel like this in the future. Just 1% plain castor oil, about 43mL per gallon of fuel. A 4oz/118mL bottle of castor oil from the pharmacy costs about $6, so it's good for about 3 gallons of fuel. Cheap insurance against premature wear.
fyrstormer is offline  
Reply With Quote
Old 08-13-2015, 06:56 AM
  #2  
Tech Master
 
Join Date: Apr 2010
Posts: 1,098
Default

Originally Posted by fyrstormer View Post
After I bought my OS wankel airplane engine, I had to get some proper fuel for it, so I bought a quart of O'Donnell 10% nitro airplane fuel. It has 18% oil, a mix of synthetic and "degummed castor" oils. According to the OS wankel engine manual, that wasn't good enough; the engine requires 25% plain castor oil. While I realize that manual was written in the 80's and synthetic nitro oils have improved since then, I don't want my discontinued novelty engine to wear-out any time soon, so I went to the pharmacy and bought some plain castor oil to add to the fuel. I calculated how much to add to bring it up to a full 25% oil content, and dumped it in. It mixed right in, just like I'd hoped it would. (it's weird to see oil dissolve in alcohol, but that's the cool thing about castor -- it's unique molecular shape makes it alcohol-soluble.)

I have a bunch of castor oil left over, so I decided to add a little bit to my car fuel too. My cars all run on Byron 30% nitro with 11% synthetic/degummed-castor oil, so I just added enough plain castor to raise it 1%, to a total of 12%. Not a big change. However, I noticed a big difference when I opened one of my engines for a periodic checkup.

The engine internals were slathered with a thick coating of oil, unlike anything I've ever seen inside them before. The combustion chamber was also slathered in oil. I had noticed the engine made a better seal when first starting-up than it had before, but I hadn't realized just how much of the plain castor oil was remaining behind. All of the moving parts worked super-smooth with all that extra oil hanging around, and there were the early signs of varnish build-up, which I have never seen with the Byron fuel before. (varnish is bad in large quantities, but in small quantities it fill defects in the metal surfaces as the engine wears, so it helps maintain compression.)

It was interesting to see what a big difference a tiny change in the fuel composition could have. I plan to continue modifying my car fuel like this in the future. Just 1% plain castor oil, about 43mL per gallon of fuel. A 4oz/118mL bottle of castor oil from the pharmacy costs about $6, so it's good for about 3 gallons of fuel. Cheap insurance against premature wear.
try novarossi castor oil,it is 1L pack,may cheaper than the price in pharmacy
kyosho malaysia is offline  
Reply With Quote
Old 08-13-2015, 03:55 PM
  #3  
Tech Elite
Thread Starter
 
fyrstormer's Avatar
 
Join Date: Mar 2014
Location: Maryland, Near DC, USA
Posts: 3,690
Default

Possibly. Food-grade castor oil has to meet stricter requirements, but for this one circumstance all I needed was a small bottle. If/when I start running the airplane engine on a regular basis, I'll need to buy castor oil in larger quantities, and then I'll start looking for a lower price.
fyrstormer is offline  
Reply With Quote
Old 08-13-2015, 04:02 PM
  #4  
Tech Lord
iTrader: (24)
 
wingracer's Avatar
 
Join Date: Nov 2007
Posts: 12,977
Trader Rating: 24 (100%+)
Default

Klotz Benol. Easy to find, readily available in the US, as good as anything else out there and cheap.
wingracer is offline  
Reply With Quote
Old 08-13-2015, 06:32 PM
  #5  
Tech Elite
Thread Starter
 
fyrstormer's Avatar
 
Join Date: Mar 2014
Location: Maryland, Near DC, USA
Posts: 3,690
Default

Are you sure that stuff has no additives in it?

Last edited by fyrstormer; 08-18-2015 at 12:26 PM.
fyrstormer is offline  
Reply With Quote
Old 08-14-2015, 03:48 AM
  #6  
HHH
Tech Regular
 
HHH's Avatar
 
Join Date: Aug 2008
Location: Singapore
Posts: 423
Default

I used castor oil from a pharmacy once and engine was gummed up with little brown balls after.

I have the nova 1N1 castor oil and works great.

Be careful what you add.
HHH is offline  
Reply With Quote
Old 08-14-2015, 06:46 AM
  #7  
Tech Champion
 
Roelof's Avatar
 
Join Date: Aug 2007
Location: Holland
Posts: 7,130
Default

We use Eurol Racing-1
http://www.eurol.com/en/37-products/...1-ricinus.html

Works wonderfull!

But if you look around you will find a racing castor oil.
Roelof is offline  
Reply With Quote
Old 08-14-2015, 11:35 AM
  #8  
Tech Elite
Thread Starter
 
fyrstormer's Avatar
 
Join Date: Mar 2014
Location: Maryland, Near DC, USA
Posts: 3,690
Default

I'll keep that in mind, thanks.

Really I was just adding my personal experience to the mass of other users' experiences with adding castor to premixed fuel.

I haven't seen any little gummy brown balls as a result of using pharmacy castor oil, either in the airplane engine or the car engine. In both cases, the castor oil is mixed in with other oils, so I doubt it's capable of fully gumming-up unless the engine were running WAY too hot. All it really seems to be doing is maintaining a thicker coating of oil on the internal parts.
fyrstormer is offline  
Reply With Quote
Old 08-18-2015, 07:41 AM
  #9  
Tech Elite
iTrader: (85)
 
lil-bump's Avatar
 
Join Date: Aug 2006
Location: The Cold Great Lakes
Posts: 2,992
Trader Rating: 85 (100%+)
Default

If your using Byrons fuel I would try Byrons lube boost degummed castor. This is what I use. I bring my 9% Byrons fuel up to 10%
lil-bump is offline  
Reply With Quote
Old 08-18-2015, 12:26 PM
  #10  
Tech Elite
Thread Starter
 
fyrstormer's Avatar
 
Join Date: Mar 2014
Location: Maryland, Near DC, USA
Posts: 3,690
Default

But I *want* a little extra gumming. Varnish fills in microscopic defects in the piston and sleeve surfaces. Besides, the Byron's fuel already has degummed castor oil in it, and whatever they did to de-gum the castor oil also made it less adhesive, so it doesn't stay inside the engine as long.
fyrstormer is offline  
Reply With Quote
Old 08-18-2015, 12:59 PM
  #11  
Tech Elite
iTrader: (85)
 
lil-bump's Avatar
 
Join Date: Aug 2006
Location: The Cold Great Lakes
Posts: 2,992
Trader Rating: 85 (100%+)
Default

Originally Posted by fyrstormer View Post
But I *want* a little extra gumming. Varnish fills in microscopic defects in the piston and sleeve surfaces. Besides, the Byron's fuel already has degummed castor oil in it, and whatever they did to de-gum the castor oil also made it less adhesive, so it doesn't stay inside the engine as long.
Ok...Here is some good reading on castor oil.

http://www.go-cl.se/castor.html
lil-bump is offline  
Reply With Quote
Old 08-18-2015, 03:26 PM
  #12  
Tech Elite
Thread Starter
 
fyrstormer's Avatar
 
Join Date: Mar 2014
Location: Maryland, Near DC, USA
Posts: 3,690
Default

That was fascinating. Thanks for the link!

Btw, I suspect the real reason why castor oil was used as the benchmark in those old lubricant-comparison tests is because it's the only readily-available, inexpensive oil that dissolves easily in alcohol. Glow engines became popular in Europe after WW2; synthetic oils were in their infancy and terribly expensive, and petroleum wasn't readily-available again after the war had ended. But normal people *could* get their hands on methanol and vegetable oils, and of all the commonly-available vegetable oils, castor oil dissolves in alcohol the best. It's a happy coincidence that it also decomposes into *even better* lubricants when it overheats.
fyrstormer is offline  
Reply With Quote
Old 08-19-2015, 02:26 AM
  #13  
Tech Champion
 
Roelof's Avatar
 
Join Date: Aug 2007
Location: Holland
Posts: 7,130
Default

For real performance a full castror based pre-mix is a bad choice. The stickyness and the thickness of the castor oil is slowing down an engine. That is why you have to get a fuel with both castor and synthetic oil to get the best of both worlds.
Roelof is offline  
Reply With Quote
Old 08-19-2015, 04:02 AM
  #14  
Tech Elite
 
blis's Avatar
 
Join Date: May 2008
Location: Brisbane
Posts: 3,456
Default

Originally Posted by lil-bump View Post
Ok...Here is some good reading on castor oil.

http://www.go-cl.se/castor.html
Great read
blis is offline  
Reply With Quote
Old 08-19-2015, 11:13 AM
  #15  
Tech Elite
Thread Starter
 
fyrstormer's Avatar
 
Join Date: Mar 2014
Location: Maryland, Near DC, USA
Posts: 3,690
Default

Originally Posted by Roelof View Post
For real performance a full castror based pre-mix is a bad choice. The stickyness and the thickness of the castor oil is slowing down an engine. That is why you have to get a fuel with both castor and synthetic oil to get the best of both worlds.
All premixed fuel (that I can find) is made with synthetic oil nowadays, so that's not really a concern.

I have to add a lot of castor to my wankel airplane engine fuel, but that engine doesn't run as fast as a little ground-vehicle engine does (17000 rpm vs. 30000+ rpm), and the design of that engine is such that the excess oil gets swept out through the exhaust port by centrifugal force -- there is no crankcase for oil to build up in.
fyrstormer is offline  
Reply With Quote

Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service