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Old engines, I believe petrol/gas

#1
I was wondering if anyone had info on these engines. My grandpa got these for my brothers 20+ years ago but they were young then so they don’t know anything about them (I’m only 16). Looking for any info on what they can fit on and if they are any good. The bigger one is 40cc and the smaller 20cc, planes got destroyed a long time ago.
 

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basslord1124

Well-known member
#3
Pretty sure those are some old nitro/glow engines. See if this link might help ya:

http://thelukens.net/airplanes/Accessories/OS FP Series Instructions.pdf

I have a little bit of experience with glow, back in the old days. Had a Magnum .40 engine on a trainer model. It did fine, just gotta take time to get it tuned right. OS is a good manufacturer too. There are plenty of resources/videos out there for help with glow engine use and care.

People have different feelings about these types of engines. Some love em and keep using them, others pass on them. I generally steer clear of them (older, plus glow fuel is expensive compared to gas) and focus on electric mainly, BUT if someone handed me one for free I'd take it and tinker with it.
 

Headbang

Well-known member
#4
Those are definatly glow. Not 20cc and 40cc tho. 0.40 cubic inches (glow 40), and 0.20 cubic inches (glow 20). I have a 40yr old OS engine and a 35yr old one that still run great. Old OS engines had a thicker casting and were built to last (not saying the newer ones are any worse tho)
 

Headbang

Well-known member
#5
Pretty sure those are some old nitro/glow engines. See if this link might help ya:

http://thelukens.net/airplanes/Accessories/OS FP Series Instructions.pdf

I have a little bit of experience with glow, back in the old days. Had a Magnum .40 engine on a trainer model. It did fine, just gotta take time to get it tuned right. OS is a good manufacturer too. There are plenty of resources/videos out there for help with glow engine use and care.

People have different feelings about these types of engines. Some love em and keep using them, others pass on them. I generally steer clear of them (older, plus glow fuel is expensive compared to gas) and focus on electric mainly, BUT if someone handed me one for free I'd take it and tinker with it.
Go to any field and there are guys who are glow fanatics, they have discovered how cheap you get glow engines at auctions and are die hard. Same guys make fun of electrics, just have to dish it back to them when they dead stick every few flights, or engine quits while taxiing lol

Nothing wrong with glow, or any fuel motor for that matter. Just comes down to what you personally find fun.
 

Piotrsko

Well-known member
#6
I think the little one is either .15 or .19 glow fuel, looks like my .19, and IIRC, Os max generally only made bigger than .40 but my memory of 50 years ago sucks anymore. Darn good engine, hard to kill. What are the props marked? My .19 swings a 9 / 6
 

Merv

Well-known member
#7
I agree with the others, OS makes a good engine. I don't remember the FP line, I'm more familiar with the FX line. According to this OS Engin Chart the FX had a bit more horse power than the FP. If they are not locked up and they have compression, they will run.

Both engines have air bled carburetors, that is when setting the idle, you are regulating the air, not the fuel that enters the carb. When you turn the valve in, you are making the mix richer, less air. The high side operates as normal, regulating the fuel, when you turn the needle valve in, you are making the mix leaner.
 

speedbirdted

Well-known member
#8
These are old glow motors! They do not run on gasoline rather a mixture of methanol, nitromethane and various kinds of oils (primarily castor and different types of synthetics) and achieve ignition with a glow plug, which is basically just a piece of platinum alloy wire that gets heated orange-white hot (hence the glow name) I believe these engine sizes are .20 and .40 cubic inches as you stated - usually on OS engines the displacement is on the casting somewhere.

These look like they may have not been run, or if they were it wasn't for very long. I doubt they're broken in fully yet. Since they are I think ABC engines (some early FP were ringed but I think this was only ever 40 size and above) when you do go to break it in, be sure the cylinder can reach operational temperature and properly "bed" in with the piston. ABC engines achieve good compression by having the cylinder wall be slightly tapered - this is why when you turn it over when it's cold (you shouldn't actually do this) it will have some "pinch" at top dead center. When at proper operating temperatures the top of the cylinder will expand and assume a less tapered shape.

What's sure here is you have some good motors. I have used many, many, many OS 2-strokes in my planes, LA, AX, FX, FSR and more, and I still consider the FP series superior to all. In fact, I think OS engines from the 80's are better than anything they make today. Treat them well, always run a couple clicks rich, be religious with the after run oil, and you could put a tank or two through them every day until you die and they'd still run good as new.

Another side note for me: I have a 25 FP that also came with an extended muffler with an extra baffle like the 40 FP here. Didn't know they made them for other engines!
 
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Merv

Well-known member
#10
If @speedbirdted is correct, you need to be very careful breaking in your motors. ABC motors have a very different break in procedure that other motors. They need to be run in lean, so the cylinder can get hot enough to properly seat the piston. More research may be in order before you try to start them.

I have never owned an ABC motor but I recall they are very stiff, they will not turn without effort. A normal motor turns freely, you can flick the prop & it will bounce from the compression. Not so with an ABC motor, you need to crank it all the way around, there is no compression bounce.
 

speedbirdted

Well-known member
#15
I read that some people add castor oil but others say it's fine, not sure whether or not I should, thx
For old engines, some castor is helpful. Older engines tend to live longer and run better on a little extra oil content - my newer engines all run on around 18% oil but I have some older ones that really like oil so I bump it up to around 20-22% with extra castor in some cases. Castor oil has a nice effect where after a while it will form a very thin varnish like material on the inside of the engine which will help protect the engine if you end up accidentally running it lean. Castor also stands up to high temperatures and pressures better than some synthetics, though in very cold conditions synthetics are usually a little better. For all my 4 stroke engines I buy fuel with synthetic oil but then add around 2% castor into the fuel - this is enough to provide the internal varnishing. Giving 4 strokes more castor than this from my experiences tends to just gum up the valves.
 

Bricks

Well-known member
#17
I read that some people add castor oil but others say it's fine, not sure whether or not I should, thx

It is not really necessary to add extra oil it is more of a personnel thing. My gassers call for 32-1 but with the new synthetics I run them 50-1 one of the guys at the field is running his gassers at 75-1 for two years now and not a problem even on a bushed engine. The newer synthetics oils are so much better then a few years ago it used to be synthetics would break down when they got too hot good quality 2 stroke oils will take more high temperature then castor oil.
 

Merv

Well-known member
#18
Determining and following the correct break in procedure is critical. The break in procedure for an ABC motor will ruin a standard motor. The break in procedure for a standard motor will ruin an ABC motor.