Thrust bearings

[kookie_guy]

What is the purpose of adding thrust bearings? Where do these bearings get added? Does size matter?

It's for a stock BJ26 motor, with 5mm shaft.

thanks for the help. Oh, and if anyone has pics, can you please post them?

[electric]

The thrust bearing goes between the motor and the collet. So if you did it in order it would be Collet, thurst bearing and then motor.

The purpose is to transfer the load off of the motor shaft and onto the motor housing. When you hit the throttle all the thrust is transferred up the motor shaft and "pushes" on to the motor shaft. This puts stress on the motor bearings.

I have used them on bigger boats 33", but really not sure how much value they have on smaller boats. I am sure others, who have used them much more than I can comment.

[FloatDaBoat]

Here's a photo . . . .

[kookie_guy]

Here's a photo . . . .

picture is worth a thousand words. thank you.

[Unsullied_Spy]

Basically, the prop pushes the driveshaft into the motor and ends up pressing the motor shaft back against the rear bearing and you're basically propelling the boat by the rear endbell of the motor. By transferring that load to either the front of the can or the motor mount you eliminate premature bearing failure and on motors that don't have the rear endbell secured you can actually pop the endbell off.

[BakedMopar]

Yep unless your motor is pinned always use it. I just had my Neu push the rear endbell out! It's an older one so it wasn't pinned like they are now.

[JimClark]

I just tried one on my BJ-26 motor and the shaft is really short on the BJ-26 so I was figuring on not using it

[Mel279]

I usually put the thrust bearing between the drive dog and the strut, so it doesn't stress the motor and the shaft, Im not sure if it really works, but I doing that because I had no teflon washer so i'd replace it with the thrust bearing instead.

[Zephrus]

I have one on my Feigao motor for my SV27. As I understand it, it unloads the stress from the main motor bearings which are only supposed to handle the rotational load of the motor shaft. The coupler/collet pushes against the bearing, the bearing pushes against the motor housing. If the thrust bearing weren't there, the coupler/collet would push on the motor shaft directly and thus the motor bearings, causing premature wear and failure of the motor bearings.

[Basstronics]

Im just curious if anyone has had these bearings self destruct?

The ball bearing types for 5mm shaft are rated to 12,000 RPM... Thats a far cry from 30,000 Heck the cheaper ones are only rated to 2,500...

So which ones are you guys using?

Or just not looking at the ratings?

[Jeepers]

I never had a thrust bearing destruct , I have had the same one on the motor for years.

[Jeff Wohlt]

I run the one that OSE and I sell and they are great. Never an issue with one but would think they would grove out pretty good after so long. I always put one drop of think lube on them for the day. They wear like anything else so replacing after so long should be needed. A slight space is also needed...like two paper thick space.

[m4a1usr]

Im just curious if anyone has had these bearings self destruct?

The ball bearing types for 5mm shaft are rated to 12,000 RPM... Thats a far cry from 30,000 Heck the cheaper ones are only rated to 2,500...

So which ones are you guys using?

Or just not looking at the ratings?

There are different ratings for the multitude of designs of thrust bearings available. But you will not find a thrust style bearing constructed from roller style ball bearings with a rotational speed as great as radial bearings. Thats because compression cannot be controlled (thru a fixed structure) during any loading phase of rotation. They are all down rated due to this phenom. Unlike the bearings on our electric motors where compression is contained due to bearing housing construction the worse they suffer is tension forces and even they are relatively minor.

With all that having been said the short duration of run time we apply the bearings in the configuration being used the forces are not enough to cause immediate failure. Since ultimately heat or friction is the bearings enemy we simply dont take them there in our application unless you are doing something terribly stupid.


John

[BakedMopar]

Well I blew two of them up this week. I don't know why, maybe it's just this type of brass cage? All my 5mm stuff is going strong but this is the second 8mm one that the cage disintegrate on me. I thought the first one gave out because I was running in 6-8" chop but today it was like glass with no hopping in and out of the water. I guess I'm terribly stupid.


BTW. Coupler is setup with around two paper clearance.

[Basstronics]

Thats because the bearings are not rated for the RPMs they are being used on...

The brass probably got hot and gave way. Actually Im willing to bet thats bronze and these are the bearings:

https://www.mcmaster.com

Type in 7806K53 in the search then hit enter.