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wavekatcher
08-11-2012, 11:38 AM
What is the proper technique for installing the thrust bearing? I noticed the shaft on the motor has some in/out play. Do I find the half way point of this play then install the collet up against the thrust bearing?

I have it installed already. What I did is, pulled the shaft to the aft position then tightened the collet down against the thrust bearing.

dana
08-11-2012, 11:47 AM
Not really the best way. The motors bearings are designed to take thrust, so IMO thrust bearings aren't necessary, but if I were using one I would just install it without trying to get rid of play.

stumblinh
08-11-2012, 01:16 PM
Install the bearing in the normal rested position, you don't want the wear from being "in the middle" with constant drag and load. Not effecient.

gyrotron
08-11-2012, 01:23 PM
Install the bearing in the normal rested position, you don't want the wear from being "in the middle" with constant drag and load. Not effecient.
Stum,
If you have one of these installed in your boat, can you show us some pics?
Thx

wavekatcher
08-11-2012, 01:57 PM
Install the bearing in the normal rested position, you don't want the wear from being "in the middle" with constant drag and load. Not effecient.


Forgive my stupidity, What is normal rested position of the shaft? Run the motor without anything attached, then connect?

Mike Caruso
08-11-2012, 04:45 PM
Before the boat ever was in the water, I was running my motor out of the boat and it made a small amount of temp. I thought that's crazy! I order the bearing I installed it in the middle of the end play. Ran the motor the same way as before out of the boat PRESTO NO TEMP build up. Time will tell but this leaves the motor bearings to just take care of rpm and not the thrust. Comes under the heading of too much time on my hands.

Basstronics
08-11-2012, 05:22 PM
Not really the best way. The motors bearings are designed to take thrust, so IMO they're useless, but if I were using one I would just install it without trying to get rid of play.

Radial ball bearings were never designed to take thrust.

dana
08-11-2012, 05:33 PM
Edit. You can take my advise on the bearing thing. They will take thrust. Thanks jay

wavekatcher
08-11-2012, 05:44 PM
So, exactly where does the thrust bearing go? I still am unclear. Btwn the drivedog and prop:banana:??

dana
08-11-2012, 05:48 PM
Between the collet and motor mount plate/motor can

domwilson
08-11-2012, 06:02 PM
Here is a pic of how mine is installed in one of my boats....

wavekatcher
08-11-2012, 06:08 PM
Thanks everyone. Looks like I did the install correctly.

domwilson
08-11-2012, 06:19 PM
Make sure you pack the bearing with plenty of grease.

Fluid
08-11-2012, 08:19 PM
Wow, lots of bad information in this thread....


Radial ball bearings were never designed to take thrust. Not so. Many of the motors we use are designed for airplanes with the prop directly attached to the motor shaft. They are not only designed to take thrust, they do it very well.


I was running my motor out of the boat and it made a small amount of temp. All electric motors build heat when run without a load because virtually all the energy goes into heat, not torque. The thrust bearing had nothing to do with heat buildup in the motor.


Install the bearing in the normal rested position, you don't want the wear from being "in the middle" with constant drag and load. A thrust bearing does nothing if it does not transfer thrust from the prop to the hull. It does this ONLY if the bearing is pinched between the coupler and the motor under forward movement - otherwise the motor's endbell bearing is transferring all the thrust (usually not a bad thing at all). When set up correctly a thrust bearing will not be loaded when the motor isn't running, otherwise it will cause unwanted friction. If a motor shaft has axial run out - end play - measure the play and install the thrust bearing so that only half the end play remains. This will insure two things - that the bearing is actually taking thrust when the boat is moving, and that the thrust bearing is not adding friction by pinching the PTO bearing between the internal shims and the thrust bearing/coupler.


Make sure you pack the bearing with plenty of grease.Many small bearings are not meant to be "packed with grease". Most will sling out any grease as soon as the motor spools up. You need to use a bearing oil that will stick to the races and balls for the few minutes the motor runs. What you have to remember is to re-lube the bearing after every use and don't let it rust.....



.

wavekatcher
08-11-2012, 09:13 PM
Thanks for the clarification Fluid. Are you sure the bearing doesn't go btwn the drive dog and prop?:roflol:

Basstronics
08-11-2012, 10:46 PM
Depends on bearings.

If its a radial ball bearing it will only take a small amount of thrust. If its angular it can take some more. However thrust loads are not what they were designed for.

A thrust bearing in larger applications is a good idea. There is no real con against using one... The added weight or rotating mass is negligible.

I know a few things about bearings. My last machine I was Project Engineer on I utilized a 126" thrust bearing special made in Thailand. I also utilized a ton of tapered roller bearings in spindles as it was a tube mill.

stumblinh
08-11-2012, 11:53 PM
Wow, lots of bad information in this thread....

A thrust bearing does nothing if it does not transfer thrust from the prop to the hull. It does this ONLY if the bearing is pinched between the coupler and the motor under forward movement - otherwise the motor's endbell bearing is transferring all the thrust (usually not a bad thing at all). When set up correctly a thrust bearing will not be loaded when the motor isn't running, otherwise it will cause unwanted friction. If a motor shaft has axial run out - end play - measure the play and install the thrust bearing so that only half the end play remains. This will insure two things - that the bearing is actually taking thrust when the boat is moving, and that the thrust bearing is not adding friction by pinching the PTO bearing between the internal shims and the thrust bearing/coupler.

.

You said nearly the same thing.. when there is no load you don't want a load on the thrust bearing.. otherwise it will cause unwanted friction :P If you have as much "play" as you are describing in your comment, I suggest re-shimming the motor, a lot of bad things can happen if you have too much play.

ray schrauwen
08-12-2012, 01:01 AM
Gave up on thrust bearings when I went to Neu & Leo/ TP power motors. Never had a need. Tried one on a 1521 1.5 in df33 4s2p and could never get it shimmed right, loud as hell. Removed it and it ragn like a dream with less heat. To each their own though.

Mike Caruso
08-12-2012, 06:23 PM
I was running my motor out of the boat and it made a small amount of temp.

All electric motors build heat when run without a load because virtually all the energy goes into heat, not torque. The thrust bearing had nothing to do with heat buildup in the motor.

This is the whole story.
Correct they all make heat, but what I was saying is MY MOTOR made less heat with the thrust bearing installed. I don't know why this motor is pulling so hard to one end plate? What I do know is lower motor temp is a good thing. I just got back from running today and I removed the 45 x 68 which ran 45 mph and installed the stock prop. No data logging today (forgot laptop) but it looks fast and sounds like higher rpm. This boat drives and runs just great, you can carve the water up with it... so cool!

Since the 70's running speed-o cable drive lines many people used the engine ball bearings for the boats thrust. Some used a propeller thrust bearing to take the load off the engines crankshaft bearings Engineering wise ...ball bearings are not designed to act as thrust bearings you are correct 100%. But they have been and still are being used that way in our boats. If they work and don't fail all the better for us.
Lets go boating