Installing crank bearings using heat may not be for you!
If you have to follow a manual word for word then this method may not be for you, this thread is just for info. I have used the method described here for over 45 years now and had no problems show up by doing the install this way.
A source of heat is required, a hot plate with a piece of plate steel on it, a hot air heat gun ,a oven of any sort or even a torch will do.
Have the two bearings and the crank cleaned and ready.
I place a heavy piece of angle iron and clamp it in the vice, mine is 3/8"X4X4X 12" long and leave 6" of it stick out from the vice jaws. The throw of the crank sits on over the end of the angle iron and supports the crank, either end up will do.
Heat the bearing up to 200-220*F and with a welding glove I pick it up and drop it over the end of the crank that is sticking up, it will almost fall into place but if it does not I have a length of 3/4" black iron water pipe cut to length and a hammer ready, slide the pipe over the crank end and a light tap will seat the bearing. The pipe must contact the inner race only.
Do both bearings this way and let them cool.
Next heat the PTO crankcase half up, the heat gun will do but an oven is better, 210-220 *F is plenty hot. I have a set of blocks set up that supports the case half up about 6" off the bench.
When the case half is hot pick it up with the welding gloves on, sit it on the blocks and then drop the crank with the bearings already on it into place, you won`t have to hit it.
Let that side start to cool down and start heating the opposite side up to 210-220*F . Turn the crankcase open side up. Place the case gasket on the case half and I use the dowel pins for the Stihls or a couple of long case bolts with the heads cut off, these need to be long enough so that they can be removed later, threaded rod pieces work well also. These studs work very well as a guide to help guide the case halves together.
After the case gasket is in place put the gloves on and pick up the the hot flywheel side case and drop it down over the upended crank. They will usually go all the way into place with a hollow clunk sound if done right. Once in a while I have to bap the case with the side of my fist to settle it but not always.
I now install the case bolts and draw the cases tight. Let the assembly cool for 5-10 mins and then try the crank for axial stress, if it needs relief then tap each end a good rap with a brass hammer. That usually relieves the stress and if the assembly is now cool enough start to put the seals in place. I have pieces of pipe cut to length that clears the end of the crank by at least an inch and fits the outside diameter of the seal, very easy to drive the seals this way.
Now reassemble the rest of the saw as required. Happy sawing.
Pioneerguy600
If you have to follow a manual word for word then this method may not be for you, this thread is just for info. I have used the method described here for over 45 years now and had no problems show up by doing the install this way.
A source of heat is required, a hot plate with a piece of plate steel on it, a hot air heat gun ,a oven of any sort or even a torch will do.
Have the two bearings and the crank cleaned and ready.
I place a heavy piece of angle iron and clamp it in the vice, mine is 3/8"X4X4X 12" long and leave 6" of it stick out from the vice jaws. The throw of the crank sits on over the end of the angle iron and supports the crank, either end up will do.
Heat the bearing up to 200-220*F and with a welding glove I pick it up and drop it over the end of the crank that is sticking up, it will almost fall into place but if it does not I have a length of 3/4" black iron water pipe cut to length and a hammer ready, slide the pipe over the crank end and a light tap will seat the bearing. The pipe must contact the inner race only.
Do both bearings this way and let them cool.
Next heat the PTO crankcase half up, the heat gun will do but an oven is better, 210-220 *F is plenty hot. I have a set of blocks set up that supports the case half up about 6" off the bench.
When the case half is hot pick it up with the welding gloves on, sit it on the blocks and then drop the crank with the bearings already on it into place, you won`t have to hit it.
Let that side start to cool down and start heating the opposite side up to 210-220*F . Turn the crankcase open side up. Place the case gasket on the case half and I use the dowel pins for the Stihls or a couple of long case bolts with the heads cut off, these need to be long enough so that they can be removed later, threaded rod pieces work well also. These studs work very well as a guide to help guide the case halves together.
After the case gasket is in place put the gloves on and pick up the the hot flywheel side case and drop it down over the upended crank. They will usually go all the way into place with a hollow clunk sound if done right. Once in a while I have to bap the case with the side of my fist to settle it but not always.
I now install the case bolts and draw the cases tight. Let the assembly cool for 5-10 mins and then try the crank for axial stress, if it needs relief then tap each end a good rap with a brass hammer. That usually relieves the stress and if the assembly is now cool enough start to put the seals in place. I have pieces of pipe cut to length that clears the end of the crank by at least an inch and fits the outside diameter of the seal, very easy to drive the seals this way.
Now reassemble the rest of the saw as required. Happy sawing.
Pioneerguy600
opcorn:
