play in new crank bearings

[Upbasher]

Okay so I just rebuilt my whole engine. Was checking the crank and it had a tiny amount of up and down play on the drive gear side. If you grab the drive gear and wiggle it up and down there is a TINY but of play. I mean like so tiny its about the width of a human hair. In fact the only way you can really notice it is if you shine a bright light at the crank seal and look at the grease on it to see the light on it change. You cannot physically FEEL anything. I'll be very clear in stating that both crank bearings are brand new, never used. I am hoping this is not a problem and its normal. Am I right?

 

[jus_me]

Can you make a video of it? There should be NO up and down play at all.. Is it the big end crank bearing? nm you said the crank bearing in the trans side? If so there should be no play.

What brand bearings are they and is the crank new as well?

When you replaced the bearing was it a tight fit or did it slide right into the case? Is it the bearing that moves or is it play between the crank and the inside of the bearing?

 

[Upbasher]

Yeah its the clutch side one. I cant make a vid because its so small you'd never be able to see it.

 

[Upbasher]

Its almost impossible to see it in PERSON

 

[Upbasher]

OEM koyo bearings, brand new wiseco crank, everything is brand new. The bearing was very tight in the case as was the crank in the bearing. The play (if you could call it that even) is in the bearing itself

 

[jus_me]

Up and down play? really? So if the hold the shaft for the clutch and move it up and down there is play in it?


I dont know man,, I have never seen that nor ever felt any play. I guess wait n see what others say but it doesn't sound right to me. That bearing should have no play at all..

 

[Upbasher]

If you grabe the drive gear and try to wiggle it up and and down you cannot feel or see any play in it. The only way you can even tell is if you shine a light at the seal. I have soke grease in between the inner and outer lip of the seal if you can picture what im talking about. anyway if you shine a light on it you can just make out the grease being compressed and decompressed. Its very hard to see you almost have to use a magnifying glass to be able to see it.

 

[Upbasher]

I have to apologize I misnamed this thread Im talking about the crank bearings not the clutch bearings here

 

[jus_me]

Im going to say there should be no play at all other than some side to side play on the crank big end bearing and not even much in that case. No play in a main bearing. Over time a little play turns into something big.

You say up and down play. It only has play up and down and not in any other direction?

 

[Upbasher]

no play in any other direction.

 

[Larry's Shee]

Width of a hair? Blond or red head?
Have to think there would be a "hair" of movement just so it can even spin free.
A hair is 17-181 micrometers (millionths of a meter)

 

[joeak47]

All sealed and un-sealed ball bearing assemblies have clearances built into them. Its not much, but its there. Lubricant has to get in there to lubricate the bearing.I believe that all is well. I think your splitting hairs.

 

[Upbasher]

thats what i figured and i also read that there has to a miniscule amount of play to compensate for heat expansion?

 

[Upbasher]

Still not sure what to do on this. Is it normal or is it screwed up. I have another brand new bearing (exact same bearing) and it felt exactly the same before i assembled the engine

 

[joeak47]

I say roll with it. You need clearances in a bearing to compensate for heat, lubricant, misalignment, etc. Don't over analyze.

 

[jus_me]

I did allot of reading about bearings and all after you posted this. Frankly because I wasn't sure and I didn't want to give you bad info.. From all have read and understand you are perfectly fine.

 

[Blaner]

Im with Joeak47 here, Koyo factory tolerances, they have to have SOME movement or else the bearing would wear excessively to "bed" itself in.

 

[Upbasher]

Thank you guys!!! I appreciate it !