OS 25fp from 1988, with better pictures

i have some, i am trying to remember my pass word for my servimg acc, i changed my email and deleted the old one so... i think i need a new account there but cant find out how

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Not looking for a pee wee are you?

nitroairplane wrote:Not looking for a pee wee are you?

meeebe, can i see a picture?

Hello Mitch, the engine you have pictured there is a terrific control line engine if your interested in using it. They made two versions of that engine. The earlier version was a iron piston steel sleeve, while the other was aluminum, brass with a plated cylinder. The stock muffler like some claim, works better that anything. I personally couldn't throw it out fast enough. The engines however are strong runners and if you wanted to venture into a larger control line model, this is a great long lasting engine. Both versions run strong, I prefer the ABC as it can be abused a bit more and run harder in my opinion. Venturi's from the OS LA series engines are a direct fit into the case and needle valve assemblies are currently available. These two items would run about $27. Even though the design is from the 80's it has modern technology and quality that you don't find in newer OS engines such as 6 headbolts compared to 4, and a full bushed bronze bearing crank and casted backplate instead of plastic. That engine would be a keeper in my opinion. Ken

Ken Cook wrote: Hello Mitch, the engine you have pictured there is a terrific control line engine if your interested in using it. They made two versions of that engine. The earlier version was a iron piston steel sleeve, while the other was aluminum, brass with a plated cylinder. The stock muffler like some claim, works better that anything. I personally couldn't throw it out fast enough. The engines however are strong runners and if you wanted to venture into a larger control line model, this is a great long lasting engine. Both versions run strong, I prefer the ABC as it can be abused a bit more and run harder in my opinion. Venturi's from the OS LA series engines are a direct fit into the case and needle valve assemblies are currently available. These two items would run about $27. Even though the design is from the 80's it has modern technology and quality that you don't find in newer OS engines such as 6 headbolts compared to 4, and a full bushed bronze bearing crank and casted backplate instead of plastic. That engine would be a keeper in my opinion. Ken

thanks, i just wonder why os would switch to the 4 head bolt design? and then they change the head bolts to extremely soft phillip head scews?

Ken Cook wrote: I prefer the ABC as it can be abused a bit more and run harder in my opinion.

The FP and LA engines are only ABN as far as I know. There are only a few car engines from OS that are ABC.

mitchg95 wrote:

Ken Cook wrote: Hello Mitch, the engine you have pictured there is a terrific control line engine if your interested in using it. They made two versions of that engine. The earlier version was a iron piston steel sleeve, while the other was aluminum, brass with a plated cylinder. The stock muffler like some claim, works better that anything. I personally couldn't throw it out fast enough. The engines however are strong runners and if you wanted to venture into a larger control line model, this is a great long lasting engine. Both versions run strong, I prefer the ABC as it can be abused a bit more and run harder in my opinion. Venturi's from the OS LA series engines are a direct fit into the case and needle valve assemblies are currently available. These two items would run about $27. Even though the design is from the 80's it has modern technology and quality that you don't find in newer OS engines such as 6 headbolts compared to 4, and a full bushed bronze bearing crank and casted backplate instead of plastic. That engine would be a keeper in my opinion. Ken

thanks, i just wonder why os would switch to the 4 head bolt design? and then they change the head bolts to extremely soft phillip head scews?

Cheaper to manufacture. The downside is stripped head bolts, which I have seen plenty of.

microflitedude wrote:

mitchg95 wrote:

Ken Cook wrote: Hello Mitch, the engine you have pictured there is a terrific control line engine if your interested in using it. They made two versions of that engine. The earlier version was a iron piston steel sleeve, while the other was aluminum, brass with a plated cylinder. The stock muffler like some claim, works better that anything. I personally couldn't throw it out fast enough. The engines however are strong runners and if you wanted to venture into a larger control line model, this is a great long lasting engine. Both versions run strong, I prefer the ABC as it can be abused a bit more and run harder in my opinion. Venturi's from the OS LA series engines are a direct fit into the case and needle valve assemblies are currently available. These two items would run about $27. Even though the design is from the 80's it has modern technology and quality that you don't find in newer OS engines such as 6 headbolts compared to 4, and a full bushed bronze bearing crank and casted backplate instead of plastic. That engine would be a keeper in my opinion. Ken

thanks, i just wonder why os would switch to the 4 head bolt design? and then they change the head bolts to extremely soft phillip head scews?

Cheaper to manufacture. The downside is stripped head bolts, which I have seen plenty of.

i hate there new screw, i mean common spend the extra couple bucks and have happier customers

The problem with OS screws is they are not a standard philips design. They are JIS screws and that is why the philips bit strips them out easy as the contact angles are different. JIS is Japanese Industry Standard. Get yourself a set of JIS bits and most of your problems will be over.

Just for the record, OS made an iron version and a ABN or ABC which is what the instructions referred it as even though it was incorrect. The way to tell the difference other than taking out a magnet to touch the piston is by the bypass on the muffler side of the engine. I believe the iron has the bigger bulge. The other way to tell was the casted letters were different. One was somewhat italicized which is the version Mitch is showing. The other version the lettering was slightly different. OS also made a FP.20 which also had the same differences. Both iron and aluminum versions were offered up to the .40 FP. The Tower .40 was true ABC and not ABN. The Tower .40 is an identical clone to the FP.40 and all parts interchange. I have both versions of engines and power is almost identical. The iron piston doesn't like the lighter pitch props like the aluminum version does and I also run the iron version with slightly more castor. The problem is I know the differences, I just can't tell you which version you have. Ken

bump

If it was a .40 I'd spring on it. I don't have any planes in the 25 range.

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