O.S. Engine question
 

I have a NEW OS .40 LA engine that I recently got from a guy who is no longer in the hobby. It was new in the box and he purchased it in 1993. I want to use this in a Kadet LT40 that I am currently building. My question is this, Can I replace the bushings with bearings and essentially turn it into a .40 FX? I used to be into nitro trucks and had an engine that I replaced the bearings on. It had bearings to begin with however (Not a bushing to bearing conversion). My LHS told me to put the stripped down crankcase in the oven and heat it up and then remove the bearing. This method worked. Can I do the same with this engine? If I am going to do this modification, I would like to do it before the initial breakin proceedure. Thanks All:D

Shaun

RE: O.S. Engine question
 

Bearings won't fit in that engine.

Look at this picture of the 40 LA crankcase:

http://www2.towerhobbies.com/cgi-bin...?&I=LXCG67&P=Z

... and this one of the 46 FX

http://www2.towerhobbies.com/cgi-bin...?&I=LXCG74&P=Z

See where the bearing go in the 46FX? One at the front of the case, and one between the carb and the
cylinder. No room for bearings in the 40 LA.

RE: O.S. Engine question
 

Thanks Jim, You answered that question quickly...Now is the .40 LA going to be addequate for the LT-40? When I got the airplane kit, the LHS said the .40 LA would be perfect but I heard someone else say that I would at least need a .46 sized engine? Wondering what the more experienced pilots here on RCU have to say? Thanks again!!!

RE: O.S. Engine question
 

It depends on what you want to get out of it. It won't take off in 5 feet and pull out vertically, but do you want that with an LT-40???

I've flown that combo (not my model, I was helping) and it was fine.

I have one under construction that will have 10+ year old OS 48 Surpass four stroke. Not too powerful either, but I also expect it will be fine.

RE: O.S. Engine question
 

not very important, but:

The 40LA was designed in 1996. He can't have bought it in 1993...

RE: O.S. Engine question
 

I flew the LT-40 with a K&B 40 for a year. The K&B had about the same performance as an LA40. It flew the LT just fine, very docile, easy flyer. I have since put an OS 46 FX on it, and man what a difference. I wouldn't recommend that combo to a newbie, but thats why you have a throttle lever.

RE: O.S. Engine question
 

I could be mistaken about the .40 LA...The receipt came with it in the box and had a date of 3-xx-1993. It is an O.S. engine and has a .40 on the crankcase. It only has a bushing and not bearings. Was there a different .40 motor in 93 that O.S. put out? Anyways, does anyone know if the "footprint" for this motor and a new .46 is the same? I have already mounted the motor to the engine mounts and was wondering if I would need new motor mounts if I were to try a .46 instead.

Thanks,

Shaun:D

RE: O.S. Engine question
 

What color is the box that the motor came with? Per chance you might have the earlier and more desirable plain bushing model 40FP rather than a 40LA. If it is silver and has a front mounted needle rather than a rear remote mounted needle valve then I would say you've got the FP version. Either engine is plenty for the LT40.

RE: O.S. Engine question
 

Ok, I dug the box out and it is a .40 FP.

What is more desirable about the FP over the LA? Just curious.

Thanks,

Shaun