I had a shop clean up my thrust surface on my crankshaft after I roasted the thrust bearing. I got it back and measured the gap between the thrust faces on the crank. I'm seeing a .0015" variance between the closest and furthest points, at opposite sides of the crank flange. It's hard to find detailed information about thrust bearings, and I'm wondering if there are any tolerances for these things? The way it is now, I imagine it putting a pressure point between the crank and the thrust bearing.
Thrust bearing surface axial runout?
- Thread starter xtreme_exploder
- Start date
I think what you're asking is for crank shaft end play? Factory spec is .005 - .011" or .13 mm to .301 mm.
So if you're seeing .0015" you need to file/sand down your trust bearing a little to increase clearance.
So if you're seeing .0015" you need to file/sand down your trust bearing a little to increase clearance.
No, I'm asking for something far more obscure that many people probably wouldn't even think about lol. I'm measuring the gap between the thrust faces on the crank itself. There's a .0015" variance in the gap between the faces when measured at opposing points of the circumference.
How confident are you in your tools to measure 1.5 thou? That's an awfully small distance to fuss about.
If it were me I'd check end play and if all is good, send it.
If it were me I'd check end play and if all is good, send it.
I have machinist micrometers, so they're definitely accurate. Thrust bearings can be super fussy when it comes to surface finish and geometry. There are very few shops that will touch them for this reason. I'll have to call some people tomorrow to see what they think. I did some research and it worries me that people are calling for flatness within .0002" as the limit.
I can't imagine the runout gap between the thrust bearing and crank surface has to be within .0002". Where did you get this? When setting crank end play you sand down the surface of the thrust bearing to get the clearance you want. I can guarantee nobody can sand or file in the clearance you need within .0002" from end to end.
That's from bearing manufactures like Clevite or Mahle. Note that I'm not talking about endplay, I'm talking about the dimension of the machined thrust face. Look at page 33 in the attached document.
Right I figured out what you're talking about. What I was saying is when you clearance the thrust bearing to adjust your end play it's going to be difficult to clearance that bearing and retain a .0002" runout between the bearing and crank surface.
Usually when setting crank end play the engine builder will remove the thrust bearing and place on a flat block of fine sand paper and take off tiny amounts, re-install and check end play again. I can't imagine that process keeps a .0002" runout between bearing and crank.
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