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Engine basics => Engine set up tips => Topic started by: frank mccune on April 26, 2016, 06:53:07 AM
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Hi:
Before one gets his knickers in a knot by the title of the post, I am asking about the minimum amount of castor in a blend of oil to prevent damage caused by a lean run in the old style engines with c.i. and steel p&c with bushings in the crankcase. There are times, for some reason, an engine will be run in a very lean flight. Stuff happens!
I have really fried a couple of O.S. plain bearing circa 1960-70 stunt engines and they are still are one flip starting engines. I also never damaged a Fox .35 Stunt after very hot and lean Foxberg runs. Perhaps, it was due to fuels having about 27% castor for lube. I was told many years ago, that it is difficult to ruin an engine by running it with a very high percentage castor oil mix. To this date, I have found this to be true. The inside and outside of the engine turned a very dark brown but there appeared to be no damage to the engines.
Now to the meat of the question. I have ringed engines that have iron and steel p&c combination and some with steel cylinders with a ringed aluminum piston. Can I mix something like 13% castor,11% synthetic, 7% nitro. 2% prop and the remainder alky to use in all engines safely? A friend of mine has been running 11% castor, 11% synthetic in all of his engines for 40 years, and has never had a problem. Perhaps he has ben lucky. I am attempting to avoid having to have two mixes for flying.
Yes, I have read Randy's notes re. engine fuels. If I have to have two mixes, then so be it. One thing else, I have changed to using the Metric System for mixing fuels and have found it to be vastly superior to using the "American" method of measurement. "Try it, you will like it."
Have a great day,
Frank McCune
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Frank I know I think backwards on some things in comparison to others but rather worry about how little oil I can get away with I work with the idea of how much can I get away with without issues. Castor is cheaper than new engines and my engines last nearly forever. I won't put anything less than 23% oil in any engine I have and 28-29% in all the older vintage engines, Fox, McCoy, Torps, Enya, etc. Many years ago the Japanese team of about 4-5 guys came to our Nats. When they left they gave me 12-13 gallons of fuel they couldn't take home. I naturally added oil to that fuel as usual and it took about two years for me to burn it. I didn't know till it was about gone they had already added oil to it. Final oil content was about 34%! It all ran superbly in everything including my piped Wiley .40.
Dave
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Depends on the weather .
the QUALITY is as important as the QUANTITY .
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You don't need any propylene oxide until you get to 40% nitro and then 1% for every 10% nitro is a good rule of thumb. This works out good because prop is really dangerous and it evaporates out of fuel rather quickly.
You can protect your engine and have it run dirty or you can wear it out quickly and have it run clean. There is no combination of synth and castor that will lube your engine and let it run without deposits. Castor is much better than the snyth made for alky. I run 20% castor in ABC engines and 25% castor in iron and steel engines. people will tell you different things because you can get away with darn near anything in a rich stunt run. I don't run snyth in anything I care about. YMMV
MM
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Hi MM:
What makes propylene oxide dangerous?
Take care,
Frank McCune
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Hi MM:
What makes propylene oxide dangerous?
Take care,
Frank McCune
https://en.wikipedia.org/wiki/Propylene_oxide
"Propylene oxide is a probable human carcinogen,[12] and listed as an IARC Group 2B carcinogen.[13]"
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I have several PA65's and several RO Jett's of various sizes. I have never run more than 20% total oil with at most 5% castor in any of them.
They all stay very clean inside except for the slight brown coating on the top of the piston that needs to be cleaned off about ever 200 flights or so. This is probably due to dirt more than anything else.
I have one PA65 that has between 600 and 700 flights on it using 12 to 20% nitro and 20% total oil with 17% Klotz and 3% castor. It still pops like it was new and runs very, very well! Except for the occasional cleaning of the top of the piston it has needed no replacement or repair and the inside of the engine is clean and shows no visible wear!
I fly mostly in Tucson AZ where the temperatures sometimes reach 110 degrees or more (the reason for the nitro increase in summer) and do not have any problems with these engines!
Randy Cuberly
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Hello Chris:
Thanks for the reply.
I researched prop for awhile and found that it can be lethal in some animals and cause weight loss in others. The term probable carcinogenic is a bit vague. It is used in the processing of almonds and pistachio nuts for food so I doubt that it is too scary. I had heard so many terrible things about it that I thought that I would check it out for my own safety. Perhaps I did not do enough research.
I really do not care if I mix it into my fuel or not but I was concerned about any health hazards that it may possess.
Be wall,
Frank McCune
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Frank: I run ALL my 2 stroke engines on 10% nitro, 22 or 23% oil, 50/50 castor/synthetic.
This includes both ringed and lapped piston engines from as far back as the EARLY 50s.
Fox, Johnson, Atwood Triumph (ringed), McCoy (both ringed and lapped) and VECO.
I have NEVER experienced a failure, even after some screaming lean runs.
Bob Z.
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I have several PA65's and several RO Jett's of various sizes. I have never run more than 20% total oil with at most 5% castor in any of them.
They all stay very clean inside except for the slight brown coating on the top of the piston that needs to be cleaned off about ever 200 flights or so. This is probably due to dirt more than anything else.
I have one PA65 that has between 600 and 700 flights on it using 12 to 20% nitro and 20% total oil with 17% Klotz and 3% castor. It still pops like it was new and runs very, very well! Except for the occasional cleaning of the top of the piston it has needed no replacement or repair and the inside of the engine is clean and shows no visible wear!
I fly mostly in Tucson AZ where the temperatures sometimes reach 110 degrees or more (the reason for the nitro increase in summer) and do not have any problems with these engines!
Randy Cuberly
Randy, What do you use and how do you go about cleaning the top of the piston? I have had my Profi combat engines apart for cleaning after stuffing them in the dirt. They are both showing brown goo on the tops of the pistons. I have been hesitant to use anything to remove it for fear of ruining the piston. What is a safe way to do it? Thx.