Crankwalk cause

I dont know if this holds true in all or any dsms but I know what caused mine to walk. Well I know why it walked but not what caused it to walk. The thrust bearing was worn down to pure copper and that is what gave it the extra end play causing it to get a funky crank signal causing it to run like ass :) BTW all I need to do is time the motor and its ready to be dropped back in

Good luck, hope that what is it.

Thank you captain obvious! ;) Ha ha, just playin Scott. Now you would be a popular man if you could figure out why there wasnt sufficient oil there causing the bearings to get worn down that far.

I didnt think it was that obvious :P I hear alot of people saying how it fucks up the block and that its the cranks fault and such. I'm going to take the bearings to school tomorrow and see if between my teacher and I we cant figure out the cause

From what I have gathered, CW is another name for "thrust bearing failure" and the most likely (or definately) is caused by lack of oil on the thrust bearings surfaces. We just dont know why theres not enough oil getting in there.

Thats what I've always thought also but I've been told that I'm wrong so I guess I should go back to those people and tell them I'm right...I couldnt think of anything better

From what I have read lately the 2g oil squirters suck...and get clogged really easily...or also the oil pump is clogged and you dont get enough oil pressure...have you read the write up on Magnus Motorsports...that was the most in depth article that I have read on the subject....here is the link... http://www.magnusmotorsports.com/tech/crankwalk.htm

There are lots of theories on the cause of "crankwalk" (thrust bearing failure)... but no definites, and no one has taken the money/time to diagnose/cure the problem... most people will just swap the motor...
Any car (not just 2g DSMs) can experience thrust bearing failure...

Here are a few links that address this problem and offer some diagnosis/possible cures (not DSM specific)
http://www.aa1car.com/library/2003/eb50331.htm
http://www.gnttype.org/techarea/transmission/trantsb.html

well if the oil squarters fail... i guess a regular 15K miles engine flush would be worth while? thats what i've been doing anyway... just to keep shit in the motor as clean as possible... :2cents:

I really dont think it has anything to do with that. 1. because the bearings get pressurized oil from the crank and 2. not all cars that walk have oil squirters

I would have to agree with pr_ricer...

(steps on soapbox, prepares to repeat others' rant)
I believe it has a lot to do with the crankshaft, I believe it was not manufactured within spec, I also believe that with an upgraded clutch, the pressure exerted on the bearing would be greater than intended by the manufacturer...
I believe that pressing in the clutch to start the car causes the two surfaces to mate without lubrication, which may be fine while sitting still, but when the car is started, that causes the two surfaces to come into direct contact, and causes accelerated wear on the two surfaces. Over time with repetitive actions, the two surfaces begin to wear until they are out of spec, by the time the clutch pedal drops; it is too late...
Some people may even go through the clutch and transmission, which may temporarily patch the symptoms, but have not fixed the cause. When the crank position sensor is shredded, then the block gets looked at a little closer, but all the damage is done...

You may be able to salvage it by dropping in a new crank and bearings, but I would simply suggest swapping...
either swap or get a fresh block and build it with aftermarket bearings,etc...

(steps down)



On a side note, has anyone ever pulled out the mitsu blue prints and checked every inch of the motor... maybe the transmission sits in a way to put pressure on the flywheel/crank assembly?!?

who knows...

So far so good with a polished crank and new bearings on the 7 bolt

How many miles do you have on your new crank and bearing pr_ricer?

Good deal!

How many miles do you have on your new crank and bearing pr_ricer?
0 :lol:

lol then i would expect it to not have walked yet with 0 miles... :thumbsup:

I ment my end play is within specs :P

From what I have read lately the 2g oil squirters suck...and get clogged really easily...or also the oil pump is clogged and you dont get enough oil pressure...have you read the write up on Magnus Motorsports...that was the most in depth article that I have read on the subject....here is the link... http://www.magnusmotorsports.com/tech/crankwalk.htmThat theory is not that the squirters get clogged(that would be fine), but that they get stuck open and lower oil pressure sufficiently. So when you are sitting at the light at idle with your foot on the clutch, all your oil is going to your squirters instead of your bearing surface and the pressure of the clutch on the flywheel causes the crank to ride against the bearing. So with low oil pressure at idle and pressure from disengaging the clutch you wear it down.

I believe the cranks are not hardened deeply enough, and if someone were to send one off to be nitrided, they would never experience "CW" again. :2cents:

I know with my crank all the wear was on the bearing the crank had little to no damage and just got a polish and it was perfect

I know with my crank all the wear was on the bearing the crank had little to no damage and just got a polish and it was perfect
UMMMMM.......Maybe I put that badly. You will not ruin the crank if it is nitrided, only the bearing, and/or block. :icon16: My crank was totally ruined when I walked. Not just the bearing journals, but the crank was eaten up into the counterweight.


OOOPS!

I have also read alot on the cranks not being hardend deep enough, calling them inferior. I have seen some cranks worn and not the thrust bearing.

Well, most would agree... crankwalk isn't caused by one problem; or it would have been found. The problem stems from multiple causes...

Someone needs to take and nitride their crank, remove/block the oil squirters, disable the clutch switch, replace the bearings (even upgrade them)... and drive the car... checking the tolerances at set intervals, say 3k, 6k, 15k, 30k, 60k, 100k, 120k, 150k... see if the car crankwalks... report the results... and if it works, everyone (w/a 2g) follow their recommendations... and voila...