Os 46 Fx Crankcase Replacement
08-03-2003 | 10:29 AM
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From: Wabahsa, MN
Os 46 Fx Crankcase Replacement
I CRASHED AND LOST THE TWO FRONT MOUNTING HOLES ON MY OS 46 FX. BOUGHT A NEW CRANKCASE.
HOW DO I GET THE PISTON AND BEARINGS OUT OF THE OLD ONE AND INTO THE NEW CRANKCASE.
I'VE BUILT LOTS OF PLANES, BUT NEVER DID THIS.
CAN ANYONE HELP?
HOW DO I GET THE PISTON AND BEARINGS OUT OF THE OLD ONE AND INTO THE NEW CRANKCASE.
I'VE BUILT LOTS OF PLANES, BUT NEVER DID THIS.
CAN ANYONE HELP?
08-03-2003 | 10:38 AM
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Os 46 Fx Crankcase Replacement
CHANGING BEARINGS
OS 46FX
The bearings are the last thing to come out of the crankcase when you are taking a motor completely apart.
First you must get the connecting rod off the crankpin. To do this you must raise the sleeve out of the crankcase. To do this, you must heat the motor up in the oven with it on a low setting. (Some where between 200-300 F.) (Make certain that you mark the orientation of the sleeve relative to the crankcase before removing.) Then you push the sleeve up with a dowel from inside the crankcase. (While the motor is still hot) When you get the sleeve up, (and the engine cools) make sure you mark the back side of the connecting rod then you can take the connecting rod off the crankpin and push it up out of the way and remove it.
Now it is best to put the crankcase back in the oven to warm it up again. While still hot, press the crankshaft to the rear and out of the crankcase. It should come out rather easy. But it’s best that you don't hammer it at all. You are trying to force the crankshaft through the front bearing and the prop drive washer. The rear bearing should most likely stay on the crankshaft. I use a drill press to do this.
Then when the crankshaft and rear bearing are hot, I generally get the rear bearing off the crankshaft by prying in behind it with a small screwdriver and then a larger one.
To get the front bearing out of the crankcase, you have to have the crankcase hot and push the bearing from the rear. It should almost fall out the front.
Look at your new bearings, generally, you remove both seals from the rear bearing and leave the front seal on the front bearing, but do whatever you want to.
To put it back together, heat up just the rear bearing and put the crankshaft in the freezer. Now put the hot rear bearing on the cold crankshaft and press it into place. Let it cool.
Heat up the crankcase and put The crankshaft and rear bearing in the freezer. Now put the cold crankshaft into the hot crankcase. if it didn't go all the way in, you might could pull it on through with a nut and washer(s) on the nose of the crankshaft.
Place the front bearing in position on the front of the crankshaft. Try to draw it into position with the washer and nut method. At some point, you can use a wrench socket as a spacer to push the front bearing home. (Do not hammer it).
Place the drive washer in position and when you install the prop, it will be locked into position.
Now you can assemble the rest of the engine by re-inserting the piston/rod onto the crankpin making certain that you get the rod oriented correctly. Now you can insert the sleeve making sure you have your mark aligned with the crankcase.
Re-install the remaining covers, carburetor, etc.
OS 46FX
The bearings are the last thing to come out of the crankcase when you are taking a motor completely apart.
First you must get the connecting rod off the crankpin. To do this you must raise the sleeve out of the crankcase. To do this, you must heat the motor up in the oven with it on a low setting. (Some where between 200-300 F.) (Make certain that you mark the orientation of the sleeve relative to the crankcase before removing.) Then you push the sleeve up with a dowel from inside the crankcase. (While the motor is still hot) When you get the sleeve up, (and the engine cools) make sure you mark the back side of the connecting rod then you can take the connecting rod off the crankpin and push it up out of the way and remove it.
Now it is best to put the crankcase back in the oven to warm it up again. While still hot, press the crankshaft to the rear and out of the crankcase. It should come out rather easy. But it’s best that you don't hammer it at all. You are trying to force the crankshaft through the front bearing and the prop drive washer. The rear bearing should most likely stay on the crankshaft. I use a drill press to do this.
Then when the crankshaft and rear bearing are hot, I generally get the rear bearing off the crankshaft by prying in behind it with a small screwdriver and then a larger one.
To get the front bearing out of the crankcase, you have to have the crankcase hot and push the bearing from the rear. It should almost fall out the front.
Look at your new bearings, generally, you remove both seals from the rear bearing and leave the front seal on the front bearing, but do whatever you want to.
To put it back together, heat up just the rear bearing and put the crankshaft in the freezer. Now put the hot rear bearing on the cold crankshaft and press it into place. Let it cool.
Heat up the crankcase and put The crankshaft and rear bearing in the freezer. Now put the cold crankshaft into the hot crankcase. if it didn't go all the way in, you might could pull it on through with a nut and washer(s) on the nose of the crankshaft.
Place the front bearing in position on the front of the crankshaft. Try to draw it into position with the washer and nut method. At some point, you can use a wrench socket as a spacer to push the front bearing home. (Do not hammer it).
Place the drive washer in position and when you install the prop, it will be locked into position.
Now you can assemble the rest of the engine by re-inserting the piston/rod onto the crankpin making certain that you get the rod oriented correctly. Now you can insert the sleeve making sure you have your mark aligned with the crankcase.
Re-install the remaining covers, carburetor, etc.
