Setting end play FAQ

Busstom · Posted: Thu Jan 04, 2018 3:12 am Post subject: Re: Setting end play FAQ

Kfred, I describe an easy, alternative method for isolating the thrust bearing and determining if it has any axial play in the crank saddle...it is on page 2 of this thread, reposted by Tcash.

In my method, the flywheel stays off, you indicate directly off of the thrust bearing, thus, any movement detected by the indicator is actual fore/aft play of the thrust bearing (axial play) within the crank saddles.

If you do detect any play, then you have to factor that number in to your crank end play setup. In other words, if you want 0.005 flywheel end play, and using my method you found 0.010 slop on the thrust bearing alone, then the sum of end play you need to shoot for when the flywheel is shimmed and torqued, such as in your picture, would be 0.015 (I used the above sample numbers because you said you are reading 0.0155...I'm not suggesting that this is your scenario).

So if you do have axial play (which is a form of end play) in your thrust bearing, and you plan to run the engine without tearing it down to fix it, then you need to know how much axial play the thrust bearing alone has, or you'll never know what to shoot for with the flywheel torqued, because you won't know how much of your reading is in the flywheel shims, and how much of your reading is in the thrust bearing play. Get it? A loose thrust bearing adds to your end play, because if it is loose, it has end play itself...and you can't compensate for that by tightening up your flywheel shimming because, as Wildthings said, you will lock (destroy) your motor like that.

Kfred09 · Posted: Thu Jan 04, 2018 12:34 pm Post subject: Re: Setting end play FAQ

Well yall called it: I went down and measured the axial play using the description of the post that was literally right before mine on this thread Embarassed

(I have been reading the forums so much in the last week that it has all kind of blended together)

The readings I got were .0095" of axial play on the bearing. Which means the number I am aiming for if I am going for .004" end play would be .0135", right? And if that is the case then based off of my two shim measurement of .029" the third shim I would need would be .0155". Does this all sound correct?

A few other questions. I have never taken a case apart before so I am having problems visualizing how this works.

1) How much axial movement by that thrust bearing is too much? I couldn't find a wear limit listed in the Bentley.

2)Would excessive axial movement of the thrust bearing also lead to higher oil temperatures/ Low oil pressure??? I don't want to spam this thread with my oil pressure readings, but they are a good deal past the wear limit.

Wildthings · Samba Member Joined: March 13, 2005 Posts: 50336

The general rule is that you just keep running the engine until either the oil pressure drops dangerously low or you can't control the leakage.

I am strongly contemplating having an oxyboxer built up for my Thing engine as the WBXer has a much improved thrust bearing setup. I have wondered if it would be possible to adapt such a setup to a standard Type 1 engine. 76mm stoke, a factory oil filter arrangement, an aluminium case, and a better designed thrust bearing all make this seem like a very good idea.