I haven't seen this engine posted, hoping someone could tell me if it's worth doing. It's a Jonsered Big Red-BR420, 40cc. The motor is by Efco and built between 1990-92. Needs new main bearings and rings (Dual Ring), don't want to spend$$$ if not worth it.

Whats the matter with the ball bearing on crank? How are the seals? Mostley....how is the cylinder bore? Capt,n

The Bearings feel slightly pitted, everything else is fine, someone must have thrown this in the corner of the garage for a year or two. Have you converted this???

Jonsered engines are a class act.
I understood that they were built by Husqvarna and were an up scale version on the standard Husky..

The lower grade engines had plastic lower cases, as did a few other brands.

It looks easy to convert. I say go for it.

One thing I would do is get a set of rings from frank bowman.

ringmaster46msn.com

If you sent him the cylinder and piston you would end up with a "perfect Fit"
Yes I believe franks ring are worth getting and the cost is very reasonable.

By the way, because it is a chain saw engine you will not need to do any port work.
The porting on saw engines are just about perfect for airplane use.

What are the numbers on the bearings? NO use paying more than you have to.

Frank does provide quality rings, the engine actually came off a trimmer, does this still make it a good choice in the 40cc catagory. I don't care to put $$$ in bearings and rings if the porting and run qualities of this engine don't get it done for plane use. No question Jonsered by Efco Olympus Products, is a quality engine. Anyone out their actually run this engine.

I've never ran this engine but I've owned a 40cc chain saw.

As far as performance of the engine.
What are you putting it on?
What style of flying are you planning on doing.

As you know these are the key factors in determining what engine you should choose.

String trimmer engines work pretty well for RC planes. They just have less power than chain saw engines.

Hi Ralph, I have No idea what so ever on the plane. I have probably 50+ engines I'm going through, scored big as far as quantity of engines, don't know what i have yet for quality. Having alot of fun ripping these apart. Lots of Ryobis, Echos, Stihl's, Mac's. Right now i'm just determining whats worth playing with first. You will see several posts of engines i'm unable to determine "Plane Quality". It's hard to search some of these so I'll post them up for those that enjoy the challenge or have converted some of these odd balls. Lots of fun.
Mark

As you work on those 50 engines...be sure to tag the parts so you will know what they are later! Don,t ask me how I know Capt,n

Words of wisdom! Found out after about number 10. I write up a tag first then stripe the engine. If it's worthy, I mark it so, if not i write parts on it for the screws, bearings, ect..
GOOD IDEA-thanks

I'm getting close on the Big Red 40cc. Need to finish the sensor mount and muffler. The engine as shown weighs 3lbs 3oz. This is a very solid engine and i hope it runs well. Not sure of what prop to run on it.

Hello
i am inspecting your photos and see in front of engine a label "GILARDONI" , i believe it is because the first photo hide the last letters because of angle of shooting.
If it is true , the Gilardoni label , you have a real gem, Gilardoni is famous making cylinders for motorcycle and made cylinder for world champion engines like minarelli.
I have Alpina engines, made in Italy and the cylinder is Gilardoni.
Good luck and enjoy.
Happy landings
Jose
Argentina

I posted a few lines about the new Efco Chainsaws you can buy at Menards. They are made in Italy and have a 5 year warrentee. They did have the 37cc one on sale for $209. Now if a person sold the bar & chain to someone...you might end up with a real nice engine to convert! Capt,n

Well that explains it. It is made in Italy and the quality is super. Finished the Sensor mount and installed the Magnet and locking screw for the adjustable collar last night Thanks for the post.

I placed a copy of your nice engine in my Picasa Photo albums in my computer. I have many engines ect in there. All I have to do is right click on the photo and send to my documents. From there I can view it or emal it to others. Real simple. Best Rgards Capt,n P.S. You shot the photo with a Fuji 2800 Finepix 2800Zoom Right?

Amazing Captn' what are you FBI??? Federal Bureau of internal combustion!

Hey thats pretty funny! FBI. Nope I am not brainless enough for that. I just wanted to let folks know how neat & easy Picasa is to do. Capt,n P.S. Is it getting cooler up North!!![X(]

80 mph winds and 4' of snow in western SD and moving this way. Time to put the ski's on. Ya it's getting cold, flying days for me are over. I'm a wimp!

Hi!
This is my first post here
I signed up since I see that there are many Jonsered convertors in here.

I hope you don't mind that I comment on your thread.

I've got an 49cc Jonsered engine witch I'm thinking on converting. I looked at some FTL-26 (50) parts from Hobby King that seemed to fit this engine. The "prop mont" from that engine seemed to fit right on, the ajustable collar you've got locks very good. Were did you find it?

My enginewad sadly integrated in thechassi of the rest of the saw, but it was no problem tocut out. Just need to fabricatea engine mount.

I was thinking of using FTL egnitionand prop mount, If they will fit. Are thereany downsides?

Edit: I allso wonder what muffler to use. What will fit?

Interesting to see this old thread pop up. Can't answer your question.
I have run this engine back when-very strong but needs bearings, just haven't got aroung to taking it apart-Maybe I'll go for it this week. If I remember I couldn't get the bearings off even with heat. I'll try again.

PS-took the engine apart at lunch-Yep! still needs bearing-hope to find them cheap and seals too! This engine is on the heavy side but really runs nice from what I remember. Worthy of something anyway.

EFCO is good stuff. Here is my 39cc conversion. It is one of my best conversion engines.