crankshaft endplay

[1fast97gsx]

factory spec was .002 - .0072 I believe. My play meassures out to .006. I know this is on the high side of being in spec but where do these cars come out of the factory with? I mean are they always .002 out of the box or does the factory also just shoot for the .002 - .0072 window? The reason I ask is if it's possible that my car always had .005 or .006 I'm not too worried ( this is my first time meassuring ) but if my car only had .002 when it was new I'm kinda worried. The motor is all the way apart and I just dropped the crank and a new set of bearings in and meassured. Not sure if I should continue putting the rest back together or just get a different crank altogether? I know there's another thread floating around about this but not enough people were responding .. what do you guys think??

 

[ballagsx]

im in the same boat you are, my end play is more than .008
im not shure what to do about it

 

[TSIfreek]

I wouldnt worry about it 7 thou is fine but the max I would allow.

 

[silverbulletAWD]

That's a tough call to make. Not much you can do short of new parts. I'd do some measuring to find out were the play is coming from and go from there. Personally, I'd run .006" unless the crank's a regrind or the bearings are a crap brand. Is the crank a regrind? Bearings crap?

For what it's worth, I was running mid 12's w/ 114 mph traps the last time out last season w/ .070" endplay. That's only 10x sevice limit. This was due to a worthless machine shops work on the line hone and me rushing the final assembly. Two lessons learned well.

 

[1fast97gsx]

service limit is .013 isn't it??? .008 is also over the spec ... hmm I thought I should be worried

crank has never been machined ... bearings are BRAND NEW federal mogul bearings from AMS. Oil clearances were all ok.

 

[ballagsx]

i dont think bearing brand would make that much of a difference, cheep or not they have to more precise than that, yours are a good brand mine on the other hand are not.

does a regrind involve the thrust surface? if so there would have to be bearings out there that would compensate for that.

 

[1fast97gsx]

does a regrind involve the thrust surface? if so there would have to be bearings out there that would compensate for that.

Yea that's what I'm wondering too. If it was possible to just kinda clean up the thrust surface and then actually take off material on the thrust bearing journal to fit a .010 over bearing and brind endplay back into spec that would be nice. I however always though thrust surfaces were not included in a regrind.

 

[ballagsx]

it would seem like some one would make a wider thrust bearing. you and i should ask around monday and post what we find.
we are probably fine the way the cranks are but it would be nice to have that peice of mind.

can you feel the endplay when you push or pull on your crank?

 

[silverbulletAWD]

No the thrust surface should not be touched in a regrind. I just asked because if it was a regrind then that would be one more chance to have been screwed up. The bearings quality should not be an issue per brand but you know the cliche "You get what you pay for" and yes this same phenomenon *could* apply to thrust bearings as well. Although I have yet to see or hear of it.

I've never heard of over sized thrust bearing sufaces but I think that would be nice.

 

[Dad]

When grinding a crank it is customary to bump the thrust sides. Just to clean up. There is a dimension that it is supposed to be ( i don't have it right in front of me). If you have 006-007 that should be fine as long as the thrust surfaces are not tore up.
One possible reason for thrust wear can be from a stuck oil squirter. If it is plugged less oil will fall back on the thrust bearing. Another cause is binding in the driveline.. such as clutch pushing forward on the crank. There should be no force on the crank. Just before start up check the end clearance after the engine has been installed. it should Float / pry forward and backward.. it should stay where you force it. If it springs back in either direction there is a bind and must be looked at or the thrust bearing will be damaged.

DAD

 

[ballagsx]

there must be something that can be done

 

[1fast97gsx]

When grinding a crank it is customary to bump the thrust sides. Just to clean up. There is a dimension that it is supposed to be ( i don't have it right in front of me). If you have 006-007 that should be fine as long as the thrust surfaces are not tore up.
One possible reason for thrust wear can be from a stuck oil squirter. If it is plugged less oil will fall back on the thrust bearing. Another cause is binding in the driveline.. such as clutch pushing forward on the crank. There should be no force on the crank. Just before start up check the end clearance after the engine has been installed. it should Float / pry forward and backward.. it should stay where you force it. If it springs back in either direction there is a bind and must be looked at or the thrust bearing will be damaged.

DAD

yea I will double check that once the engine is done and in the car. I actually did have my number 3 oil squirter fall out so maybe that was part of it? I guess I will just put it together and hope for the best and tripple check clutch adjustment. Just got kinda worried when I wiggled the crank and could physically see it go in and out ... however if it moving .006" is ok I suppose then I'm ok.

 

[1fast97gsx]

can you feel the endplay when you push or pull on your crank?

yes I can feel it a tiny bit ... after meassuring it I guess it seems normal but it just kinda worried me.

 

[Colossus]

My endplay was around .005, and I could grab the crank and push it back and forth. You'd never notice by feeling it that it moved, but upon moving it one direction, you could hear a fant "clang" noise, so it can be moved..just slightly. Don't be afraid if it jiggles just a teny tiny bit.

 

[1fast97gsx]

My endplay was around .005, and I could grab the crank and push it back and forth. You'd never notice by feeling it that it moved, but upon moving it one direction, you could hear a fant "clang" noise, so it can be moved..just slightly. Don't be afraid if it jiggles just a teny tiny bit.

alright thanks ... that just totally reassured me because what you are describing is exactly what mine is doing. Thanks

 

[ballagsx]

mine moves alot

 

[1fast97gsx]

well what is your measured endplay? If it's over .007 its time for a new crank imo.

 

[Strm Trpr]

I just checked mine about a month ago, and I'm at .0071"....
Mitsu's specification for Crankshaft Endplay is .002" - .0071".
This is their manufacturing assembly spec.
Your engine can fall in this range out of the box.

.009" is the Crankshaft Endplay service limit according to my Chiltons Manual.

 

[1fast97gsx]

at what point is it when the crank will start chewing up the sensor? I heard like .013?

 

[Strm Trpr]

Not too sure about at what point it will chew your Crank Angle Sensor, but if you've been down there doing a timing belt, then you probably noticed that it can't be much to start hitting the Crank Angle Sensor.

 

[ballagsx]

well what is your measured endplay? If it's over .007 its time for a new crank imo.

mine is somewhere between .008 and .009

the crank was macheaned and the whole rotating asembaly was balanced so i am sort of stuck in with the crank unless i want to get the whole thing ballanced again

 

[ballagsx]

if i absolutly have to get a new crank i would just stroke it. and ballance it again

 

[1fast97gsx]

mine is somewhere between .008 and .009

the crank was macheaned and the whole rotating asembaly was balanced so i am sort of stuck in with the crank unless i want to get the whole thing ballanced again

hmm yea that sucks man. Well you can either put it together and just keep an eye on it and save money for when endplay gets even greater, or just wait with the buildup until you have another crank and have it rebalanced. Sucks either way though. :thumbdown

 

[ballagsx]

did you decide what to do with yours?

 

[half-cocked]

OK, I have been reading alot lately on thrust bearing and alignment lately because I am paranoid about crankwalk and I am building a 6 bolt, and here s a few things. When a crank is ground they are supposed to machine the the thrust face to compensate for the bigger bearings. Problem with this is they have to be machined with the side of a grinder and the thrust face must be perpindicular with the journal or thurst failiure can result.

FSM states standard values are .002" - .0071" with max of .009". Traditionally electroplated babbut on bearings is approx. .01" thick. Give you an idea of what kind of margin you are dealing with. If a crank gets into the hard part of the bearing, its usually trashed or needs machining. If the crank gets beynd that there is a chance you can scrap the block but it should be obviously presenting itself by then. ope some of this helped

Now, if someone could just explain a way to confirm thrust bearing slignment to me I would be really happy.