$18.00 Crankwalk (Temporary) Fix
2G Eclipse Crankwalk
DSM = Dumb Stupid Mitsubishi - yes, I'm pissed!
What brought on the need for me to make a crankwalk page?
I bought this car with 30K miles. I thought the clutch was out of adjustment, and I would simply adjust it. Well, after replacing every clutch
related part on the car: pedal bushings, master cylinder, slave cylinder, had the flywheel cut, and made sure the step was
exactly in spec, new pressure plate, disk, and throwout bearing. The clutch was still acting funny. I bought the car July of '99, and have only heard of crankwalk, but, never dreamed it could happen to my car.
How wrong I was. Read on:
12/18/01 UPDATE:
The car now has just under 76,000 miles.
I am still measuring 0.009" of end play with the "Swiss Cheese Bearing".
I was getting skeptical of my bearing not wearing past the 0.009" in 11,000 miles just by changing to 20w-50 oil, STP oil treatment, and bringing the oil pressure up by revving the engine prior to pressing the clutch, so I pulled the oil pan and installed a new set of bearings.
Prior to removing the "swiss cheese bearing" I measured wear with a feeler gauge to test measurement accuracy - something I shold have done long ago. The feeler gauge measurement of the swiss cheese bearing was only 0.0065" ( a 0.006"
feeler gauge
would fit and 0.007" feeler gauge would not while preloading the crankshaft with a pry bar. This shows a 0.0025" error in my measuring technique when measuring outside of the oil pan using :AWD crankwalk check
or the FWD crankwalk check
. I thought I would bring that to everyone's attention. My external measuremnts showed worse than the bearing was really worn. I guess I was moving the engine in it's mounts a little when measuring the bearings and was pretty consistent at it.
The new (replacement bearing#3) measures 0.0035". I figured since I was there, I'd install a fresh bearing. I made no modifications to this bearing.
(Replacement Bearing 2 "swiss cheese bearing") 7/24/01 update:
I now have 68,750 miles on the car.
The bearing play has stayed at 0.009"
The changes I made in oil, driving technique, and hardware adjustments are helping out a bit.
Negatives: There has to be a negative, nothing is all good, at least in my world. The 20w-50 oil makes the lifter tick like an angry mother tapping her foot on the floor. I'm sure the knock sensor is loving this. I did a little test with straight 30W oil and the ticking stopped, and the power increase was amazing, so I'm sure timing was getting pulled. The other negative is sick high oil pressure at 3500 rpms (my cruising rpms on the way to work in 5th gear). If I had to guess, a lot of the oil might be using the oil pump bypass and not going through the filter.
I know that we aren't supposed to use the 20w-50 oil due to lifter tick etc., but, so far it's working pretty good with reguards to bearing wear.
5/10/01 UPDATE: How is the "Swiss Cheese Bearing" holding up?
I now have 65,700 miles on the car.
The car is now mostly stock with the exception of a upper intercooler pipe, 1G BOV, and I still run 17 psi of boost.
The bearing play has increased from 0.0055" to 0.009" (0.0035" of bearing wear already - ouch!)
*note* I got lazy for a few oil cahnges and did not check crankwalk since the bearing was fresh. The last oil change is where I switched to the 20w-50 and STP oil treatment, 3k miles prior to finding 0.009" of end play.
I measured how far I can safely wear into the bearing before absolutely having to replace the thrust bearing. (soft copper part of the bearing that hopefully won't damage the crankshaft too badly) I feel safe up to 0.015" of end play. Why that number? I measured 0.020" of copper on each side of the bearing. The clutch side wears much faster so I can only count on one side of the bearing to wear. I gave myself 0.005" of error combined in measuring crankwalk and bearing tolerances with the dimensional amount of copper used. This should allow plenty of room for error with out risk of totally trashing what is left of the crankshaft.
I also noticed that the oil pressure would drop to almost nothing at redlights, and hot engine starts. I now rev the engine to bring the oil pressure up prior to pressing the clutch. I don't press in the clutch with the engine revved up, I wait for the rpms to come back to near idle. The oil pressure will stay up long enough to allow for this. This is a pain to to all of the time, but, I was planning a bearing change yesterday, and didn't have too. I credit this toward bringing the oil pressure up a little prior to stepping on the clutch.
I also switched to 20w-50 oil and one can of STP Oil Treatment to increase my oil pressure. *see above note for more info* That helped the oil pressure quite a bit, but, it still drops off, and I still have to rev the engine to build a little oil pressure prior to pressing in the clutch.
I also adjusted the clutch pedal stop (with foot off of pedal, position the pedal returns too). I backed it out almost all of the way. Now there is no chance the throwout bearing can "ride" and cause unnecessary wear. The clutch tolerates the sloppy crankshaft movement much better now too.
Hopefully, the above steps will extend my bearing replacement intervals until we can get Mitsibushi to make good on our defective engines - I'm not holding my breath.
(Replacement bearing 1) How is the $18.00 crankwalk fix holding up after the first 5,000 hard miles?
The new bearings measured more than 0.002" of thrust play, but, less than 0.003" of thrust play after installation.
The new bearings have seen 130 mph three times.
They have also been down the 1/4 mile 12 times. Eight of the passes were in the high 12's.
We drove to the 2000 DSM shootout in Norwalk and competed in drag racing (best of 12.8@109) and the autocross (what a blast!), then drove back to eastern PA again (10 - 12 hours with traffic).
The bearing have also survived two more autocross races. 12 laps total.
You can see that I have not babied the $18.00 crankwalk (temporary) fix at all. In fact, I have purposely been beating on it to see how well it will hold up.
Result is: after 5000 very hard miles the thrust clearance has increased to 0.003"
NEW Result is: after 8000 miles, the last 90 going around Pocono Raceway as fast as I could resulted in the thrust clearance increasing to 0.008! Out of spec! Ahhh, so what. I did another autocross after that anyway!"
