Hi Folks,
I just got my hands on a never run OS 46 SF ABC. What kind of performance can I expect from this engine> What kind of prop is best, what kind of break-in method? Does anyone have the specs. on this engine? I purchased it for 75.00 dollars.

thanks,
Frank

Frank,


OS introduced ABN pistons and sleeves in the SF series.

The entire (?) SF ABN series of engines were called ABC, without actually being ABC.

ABN is weaker and less durable than ABC.
ABN sleeves sometimes loose (peel) the nickel coating on them, while ABC sleeves last virtually for ever. OS has supposedly improved its ABN sleeves, by adding a copper flash coat, between the brass and the applied nickel, in the late FX and the new AX version of their .46.

The FS obviously doesn't have it.

The best break-in process is detailed in [link=http://www.rcuniverse.com/forum/Tapered%2DBore_Engine_Break%2Din_%2D_Upgraded/m_1850473/tm.htm]this thread[/link].

You can expect power similar to the new FX model, but this engine will be louder.

George Aldrich (RIP) had a lucrative business chroming peeled OS liners. He reported that of 300 engines only one (1) came from a CL flyer. He put this down to the fact that CL flyers almost invariably use much more oil (and mainly castor) in their fuels so he concluded that the OS ABN survives better with at least 22% oil. That's the advice of the engine Master, take it or leave it

To run it in, use a small prop (9x6 is good) preferably, use around 25% oil and set the mixture so it's running just barely above a 4 stroke setting for the first couple of tanks then slowly lean it out a little for the next few tanks. Contrary to popular opinion I don't think an ABx is a "one tank and go fly" engine although they survive this treatment surprisingly well.

HI Folks,
Thanks for your help on the break-in issue. One question comes to mine. Once the motor is broke- in using 25% fuel, then can I use standard 18% oil for flying?
thanks,
Frank

The break in is the most critical part of an engine's life which is why the higher oil content is desireable. Once it's run in then you can use whatever you like but 18% oil might shorten its life a bit.

Downunder you have to stay consistant with the information you are giving in order to have the same results. The first quote you made in a thread yesterday. The second quote you made this mourning at least here in the US it's mourning.

IMHO, the OS46 SF engines are among the best OS engines ever. I have several 46SF engines, ringed and non-ringed, and have never experienced any problem with liner peeling. That's a problem that occured with later OS engines.
18% oil is O.K. as long as you don't run it lean. I use 15% oil in my fuel and have had no problems whatsoever with wear. One of my SF:s has been run for more than 300 hours in different aircraft and the only thing I have ever changed is a rear bearing.

One problem that some people experienced was that the engine didn't run well with muffler pressure. I run my engines with no muffler pressure and it works great. Apparently it had something to do with the position of the muffler pressure nipple position relative to the baffle inside the muffler.

Good luck with your SF! It will be with you for a long time if you take good care of it.

/Red B.

RC-FIEND
First up I'll just repeat that it's good to have a lot of oil flowing through a new engine. That's where Dar and I are in complete agreement on using 25% with some castor.

But that first quote was for an entirely different question where he wanted to know if it was OK to run in using 20% nitro then switch to 15% for flying. But where's the inconsistency? If you use higher nitro during running in then you have to richen the mixture which means you're letting more oil into the engine which is a good thing (although not as good as actually adding oil to the fuel).

I'm not trying to test your experience with engines , so lets keep it civil . The first quote printed in this thread you are talking about running it in (in my book it's the same as breaking in the engine) In the second quote it's obvious you are talking about 'break in'.

Then in the first post you say 'with the rather low oil content of some fuels a high nitro might even be better because you have to open the needle more which means a higher rate of oil flow. ' which I understood you were trying to say low amounts of oil good be good. Or only more oil comes out when the needle is opened wider.

Then in the second post you said 'The break in is the most critical part of an engine's life which is why the higher oil content is desireable ' I understood you were saying higher oil content is better for break in period.

I can only speak for myself and I believe you contradicted yourself or you didn't explain enough for a newbie to understand the difference you were trying to make. Or better yet you were trying to stay in the middle as far as how to break in an engine.

If you could explain further what you mean, maybe I would understand differently from what you typed.

Oops, I thought I was being civil
Yeah, "break in" and "run in" are the same thing. I usually like to use "run in" but if someone uses the other term in a question I'll generally go along with it so there's no confusion.

Yes, higher oil content is preferable during run in/break in because this means that for the same amount of running more oil passes through the engine. But to try to answer as best I can I'll give a real life example.

I've got an ST G51 which (for reasons completely unknown to me) is by far the most economical engine I've ever had. It runs for 6 minutes on a 3 ounce tank using 20% all castor and zero nitro. Now this should have been more than enough oil but it continually overheated and gave erratic runs. Then the light bulb went off over my head. With 20% oil, that tank held 0.6 ounces of oil which had to last for 6 minutes. In other words, only 0.1 ounces of oil was going through the engine every minute.

It was plain that 0.1 ounces/minute wasn't enough so what to do? First there's the obvious...add oil which I did (to 25%) and that transformed the engine. Now there was something like 0.125 ounces/minute flowing through it. *

But there was another way and that would have been to up the nitro content (from zero to whatever) and increase the fuel consumption. Let's say that now it could only fly for 5 minutes on that same tank with that same 0.6 ounces of oil so it's using oil faster...at about 0.12 ounces/minute or almost the same as what happened by adding oil.

So what I was saying in that quote wasn't that low amounts of oil could be good but that by using a higher nitro content could make the engine believe there was more oil in the fuel.

* I can't help myself when it comes to things like this
At the 8000 ground revs (4 stroking) that I was running this engine it means that every rev there was 0.0000156 ounces of oil going through it (or in real measurements 0.00046 cc). If my maths are right then this is the same as a ball of oil 1mm across going into the engine every rev. And seeing the engine doesn't fill up with oil it also means a ball 1mm across comes out of the exhaust every cycle (one mm is about 1/25th of an inch). Imagine how much heat this can take out of the engine

[X(]IMHO this is HORSE CHIT ! Why can't you just say you contradicted yourself and move on from there? At least, if not anyone else, I know not to take what you post as face value.

Good Luck on your next magic trick because this one failed terribly.

P.S. you are so blind , you probably don't even see you contradicted yourself in the first quote.

Really...?

RC-FIEND, you have three engines, you think your glow plug runs on 60 volts, and that dirt and/or dust just disintegrate in your engines.

Take one of your three engines, and run some fuel blends through it. Start with zero nitro, and go all the way to 50% nitro in 5% nitro steps. Keep the oil % constant. Record the needle settings at which you engine runs best for each fuel blend.

PS you might want to run a spell checker om this one

Rudeboy , I just don't know what to do with you If you don't see the bold face contradiction downunder made that is your problem . Yes I have three engines and I have never posted having a problem with blown plugs, broken rods, engine seize ,etc. When i bought my first engine OS .40 LA it was used and I didn't have a clue what the settings should be for the engine. Other than that I may have ask advice about an engine I was going to buy .

You can ride me all the way to hell but the only difference will be I will know when to turn around because I will recognize the devil when I see him, you on the other hand are the type of guy you follows blindly so you won't make back my friend.

P.S. I like the way you answer a post just to agree with the person who answered the post before you . [X(].

Sure.. I'm riding you... and you should just sit back and enjoy the ride... you might just learn a thing or two in the process.

It is sunday morning... nice weather... guess where I'm going...? I'll see you later.

Yea good Idea , I have 5 more hours before I can rev up the engine. have fun.

Glad I'm not going to be at the same field with any of you guys!!! If I ever ask any of you for help, please tell me you can't.

Soko,


Arguments are a natural part of expressing ideas.

Although you are not likely to ever ask for my help (unless you come to fly in Israel...), I will gladly give it to you.
Most of the participants here will too, unless you try playing the 'know it all' and 'brush off' any good advice you are given.

People unlikely to get sincere help, are those that 'spit into the well they just drank from', so to speak...


Welcome to RCUniverse!

Well, the above advice is dead wrong for an ABC engine.

I would have thought that, by now, it is rather common knowledge that a non-ringed engine needs to get up to operating temperature QUICKLY on the first run it avoid "squeezing" the piston.

skrez, I bought a pair of these engines in 1988, one ringed and one ABC (or whatever). They both ran flawlessly for many, many hours, and the ringed one is still flying. I sold both some time back, but I know where the ringed one ended up at and I saw it in a Sig Somethin' Extra just last month. I replaced the ring at over 50 hours, back in the mid-90s; AFAIK it still has the original bearings.

Red is correct; the liner peeling problem did not emerge until later. I have had four SF series engines, all purchased in 1987-88, and still run one of the 40 SFs in a Sig Kougar. Much of the run time I accumulated in all of them was with 15% Cool Power fuel with 17% all-synthetic oil. I'm not going to get into a castor/synthetic urination competition, but rest assured that normal oil contents in every brand of model airplane fuel I am aware of are sufficient to the task; unless YOU mis-use/abuse the engine. An exception to that could well be the crap plating that OS used on a a lot of engines a few years back that had all the peeling problems, that downunder referred to. No doubt that heavy castor use prevented many of those peeling instances; but since you, the modeler, have no control over how the engine was manufactured, you have to hope for the best and operate the engine sensibly.

Again, from my observations (and reading between the lines on posts here), most folks who toast model engines are either clueless in the first place or are trying to extract the absolute last bit of power out of an engine. That latter is a big culprit. There are all sorts of suggestions on just what is the proper "slightly rich" mixture, to avoid engine overheating, but since each engine is different you cannot go by rpm reading, etc. If you follow this rule of thumb, you'll probably be okay... make sure that the engine is blowing a faint smoke trail at all times. That smoke is really unburned oil, which means that the engine is getting enough to cool/lubricate itself.

Enjoy your new engine. They really aren't "making them like that anymore". OS does still make quality stuff, but it appears to me that their "mass market" engines are now built to a price point instead of a level of quality. The SF engines were built to a level of quality, and were rather expensive in their day.

As far as I know I'm the only one curious enough (or silly enough ) to actually take a brand new ABC and run it slobbering rich for 45 minutes then pull it to pieces to see how much damage was done. Absolutely none, the piston looked brand new with no signs of "squeezing" whatsoever and the pinch was the same as at the beginning. The following 20 minutes of running in using the "accepted" manner gave far more wear on all parts including the rod bush.

As for the advice I gave in the quote above, the mixture setting is exactly the same as in the instructions for my Irvine 40 (I just checked ).

downunder,
Actually no, you're not the only one silly enough to test thoroughly. Chuckle.... There are at least two of us.

And I found exactly the same thing as you. And btw, your "contradictions" aren't even close to being contradictions. And there also isn't a word in your posts that is un-cordial. Some people can't read too good, don't understand complex stuff very well, and are less than cordial from the git-go. The internet is an amazing and often silly place. It's funny that you've given good advice to two different people, yet are attacked by someone who missed the point (twice), and then a third guy jumps in and paints you both with the same paintbrush.

I've also found that 4-cycling a plain piston engine during running-in ain't a big deal. Heck, it isn't even a deal at all. The idea that 4-cycling "squeezes or whatever" or beats anything to ruin appears to be one of the myths that has really gotten blown up by some of the more excitable, less experienced, wanna be experts. Hey, fuel flow cools. And 4 cycling still "allows" the mating parts to rub against each other and locally heat up. And an engine at say 8,000 rpm "feels" almost exactly the same "pounding" at 4-cycle as at 2-cycle and that "pounding" is way far less than at 12,000 and the suckers are designed to stand even higher rpm. The 4-cycle to 2-cycle break is an excellent "tool" to give you an idea about your gas mixture into the engine. And about the only thing the 4-cycle does for/to you is greatly slow down the break-in. But it's extremely sensible to use early on to make the break-in safer for the components. None of this stuff is simple and isolating the 4vs2cycle issue out as a make or break detail is actually sorta dumb. but what the heck....

BTW, I was tearing down motors after break-in and a bench test because a buddy and I were making our own pistons to try different timing, tolerances, shapes, weights etc etc. And we usually measured off (and visually judged) the sleeve and piston before break-in, after break-in, and after testing.

Aldrich was a heck of an engine man. And his observation that CL flyers didn't encounter the same problems as R/C flyers was extremely telling... and subtle.... CL guys ran more oil... and more castor... and usually more than half the flight at 4-cycle... and our engines lasted forever (wanna buy a Johnson Stunt Supreme that still has decent compression after thousands of flights?), that is, when they were made of halfway decent metals... and seldom saw a lean run.

BTW, have you ever noticed that the first person in an argument who bleats about being civil usually isn't and usually gets shriller and shriller?

Steve,
Actually, ABC engines will get up to a useful temperature quickly, whether at 4cycle or at 2cycle. The temperature that is "useful" is the temperature of the parts that need to be broken-in. Such as the "high points" around the piston that break-in needs to wear away. And those places are going to rub no matter what you've got for mixture into the engine. Actually, all engines, ABC or ringed, will rub the most out of tolerance high spots first. And ignoring the detail about the high spots.... The entire engine gets up to useful break-in temp very fast, whether at 4cycle or 2cycle. Obviously, it gets to the temp faster with a leaner fuel flow. But then.....

The "pounding" these engines get is really associated with the rpm way more than with the fuel mixture or 4vs2cycling. Truth is, the real pounding comes from the cylinder pressure that hits the piston on the firing cycles. And that's often greater with higher rpm. So...

I think a bunch of people who embrace the idea that 4cycling beats the engine up are getting excited with the idea that 4cycling is something like flooding the cylinder. They've seen a flooded engine lock up when being turned over by hand and make the leap that 4cycling must be like that. It isn't.

What's the difference in "pounding" between the "missed" stroke and a firing stroke when your engine goes from 4cycle to 2cycle? The missed stroke's pounding is minus the cylinder pressure from the charge firing.

And remember, the difference in fuel charge into the cylinder when your engine goes from a 4cycle to a 2cycle is what? one click? So the change in "impact" the piston feels from it's having to compress the charge obviously isn't significant.

You know, very often, "what everyone knows"........ isn't actually true.

Darock,


George Aldrich was one heck of an engine man, as you wrote.

The whole theory of tapered-bore break-in, being done at a rich, two-cycling setting has his copyright written all over it.
It is not my idea, nor that of anyone else in this forum.

But we do base what we write, on his notes.

I also base it on my own experience.


George Aldrich reached his conclusions when a tapered-bore engine was actually designed to last 100 hours; not 15 hours like some current "Nobody ABC" engines produced today (like the ones Brian experimented with...).

He actually saw these tight engines break their crankshafts, con-rods and wrist-pins and measurably wear away their piston's crown's fit in the top of the sleeve, by pounding the piston into the cold, tight bore top, during what was then considered to be the only right way to do the break-in; i.e. slobbery rich four-cycling.

I actually saw ABN engines that peeled their nickel as a result of the same and others, especially people with car engines, realized that with 'hobby-shop-and-engine-manufacturer recommended' slobbery break-in, their engines last for 3 gallons, before needing a new P+L set. And yet, they held up for 12-20 gallons, with the DarZeelon recommended, slightly rich break-in.

I believe that says it all, as well as saying some engine manufacturers and the hobby shops want to sell us a lot of expensive spare parts...

And the idea that an un-broken-in ABC's tolerances are going to increase the pounding a new engine feels doesn't stand up either.

Those engines break in from what? One or two rich two cycle runs?

Tight tolerances in ABCs piston/sleeve actually don't resist much at all, and wear away in a heartbeat. How much pounding could they actually give an engine even if they were the major source of this pounding thing?

Dar,
Yup.... You're right on some of that.

BTW, George was a funny guy. Or maybe strange is a better word. And serious too. And sometimes hard to talk to.

But the engines back then (wanna buy some?) actually weren't designed to last 100 hours. A few might have been, but most weren't actually designed for much more than to sell at a profit in that market place. McCoy comes to mind. K&B was sorta that way too. A Fox wouldn't last 10 flights unless it saw half those first flights at 4cycle for most of the flight. The first Enya's... The first OS's..... chuckle.... I happened to be there then.... chuckle.... trust me, them puppies.... ALL of them puppies weren't designed to last 100 hours. Some did because an iron piston in an iron sleeve, running on 25% castor, if the tolerances had come out right to begin with, wound up lasting 100 hours.

Hey, George was one of the original modeling gods, but let's put him into perspective. He actually didn't originate all the things we've discovered independently to be true.

Those broken rods etc... Remember that the tolerances back then were a major contributor when one or two of those engines broke rods. Every taper bore back then didn't break a rod when broken in slobbery rich. Remember that back then a BUNCH of those taper bores WERE broken in slobbery rich and lived. Truth is, most of them were broken in successfully the same way everyone broke in engines back then, slobbery to begin with. After all, most of us hadn't found out that what everyone knew as a fact (that a model airplane engine should be broken in slobbery rich) wasn't really true for some engines. Actually, because Glen Lee hadn't published it.

Back then, I think Lee was one of the first engine columnists. Actually, everyone didn't learn what everyone knows today from George because George wasn't writing much yet. George didn't get widespread following as an engine man until later. And if I remember correctly, George didn't even start writing until way late in his career. He actually wasn't the root source of all our notes.

But whatever.... good talking with you. It's pleasant to converse about the old days.... which is what us old guys seem to do a lot of.

Thanks Dar, that gave me a good laugh seeing you had no idea what the engine was or how well it was made. Now I have no idea how you treat your engines, but 15 hours??? I like the modest way you're now saying "the DarZeelon recommended, slightly rich break-in."

Now back to reality. Darock, I see you've just joined this merry group so welcome. But you probably haven't seen the thread I started about the test I did.
http://www.rcuniverse.com/forum/New_...2875125/tm.htm

As for the CL engines, I must have done thousands of flights with my Enya 45 (model 6001 of course ) and so far my Stalker 61 ABC has about 30 hours on it, all in a 4 stroke of course, and the piston is unmarked except for the compression band at the crown. Hey, that's twice as much as a "Nobody ABC" already!