juice_evo_VII

iTrader: (5)

We'll never know why, my block was not going to get taken apart. But it moved about a half inch when you pulled on the crank pully. I was told the block was bad, the crank was bad etc.

I lost my trans to the clutch about 1000 miles before the crankwalk.

The crankwalk (later diagnosed) sympton presented itself as stalling between gears and trying to stall when taking off from a stop. The AEM covered it up for a while and we thought we had fixed it at one point when it mysteriously went away. The trigger plate was being eaten by the force thus shutting the car off when the clutch was pressed in.

We were told it was the result of the clutch. But when my trans went out the clutch came out of the car as well so the damage might have already been done before then.

I only had 4.5k miles on that motor, so about 1500 of that was boosting, but yes I was making a lot of power for that dyno.

fugiwara

iTrader: (124)

I thought 三菱 solve the 7-bolt 4G63 crank walk problem...

94AWDcoupe

iTrader: (125)

it doesnt matter if clutch is pull or push. the force on the thrust bearing is the same in both. so possibility of crank walk is same as well. . push type is easier to check as crank pulley will move out from engine when clutch pedal is depressed. with pull type clutch the crank pully is pulled toward engine. the thrust bearing wear will be on opposite sides of crank for push and pull.

to answer your other question about twist. if head is warped by more than a few thousand it will need to be straightened before it is machined flat again. if you head surface is warped ten thousands then your cam journals would be warped by same ten thousand. if you just machine head flat your cam journals will still be warped. high possibility of cam journals being galled from this. The block is not different. if the crank journals are off by 12 thousand, that means block was severely warped from heat. wasnt a good idea to use it if that was the case. to line hone the crank bores back straight wont correct all the other problems of having a block warped that much.

I have said many times the less things you machine during a rebuild the better off your results will be. your local machine shop (everyones) is a bad joke compared to the machining your engine received from mitsu. you local machine shop uses a 3000$ machine he got from local auction. mitsu uses a 1,000,000$ dollar machine to do thousands of block with amazing precision. I have horror stories out the ying yang from machine shops Fookin up my parts.

MRfabolous

iTrader: (17)

i know of a person that had his motor built and had his motor put together and the thrust bearings were put in backwards and they dropped out and that caused his crankwalk he pulled the oil pan and the thrust were sitting in the pan. maybe you should try to pull the pan and check and see whats going on in there. and while you have the pan off have someone press the clutch in and see how much the crank moves.

JohnBradley

iTrader: (30)

We havent seen any crankwalked Evos in the whole time we have been dealing with them. That includes the White Evo, Lucas Evo, all the customer Evos we have done motors or clutches for. I think the crankwalk issue is less clutch related since they have really light presure plates overall versus the DSMs that had issues because of the 2900# and 3200# singles. 98.5+ 2Gs do not suffer from crankwalk like the 95-97sm, and the 1G 7 bolts dont seem as prone either (not saying they dont).

What we have been seeing lately with thrust issues is people that spin bearings, metal goes through the motor and hangs out in the oil cooler. Every customer car that has come to us with this scenario and hasnt replaced the oil cooler ends up with problems. Problem number 2 is the thrust washers themselves. I can open 5 packets of TW677S from clevite and see 5 different thicknesses. Yes it might be 1 thou or 1/2 a thou difference but everything adds up. If you have loose thrusts and then have some metal particulates go through it it will be done.

Lastly, while in general everyone that came from DSMs seems to know you dont ever turn a 4G crank you intend to use at high horsepower, it seems far less Evo guys know this. The days of the 10/10 crank is best left in the past with domestics and a time when we didnt know better. Technology and metallurgy are our friends, no reason to mess with it.

If all 4 of these QM cars have issues, came from the same shop, I would think its because of how they set up the TOB stop (or didnt). Hydraulic TOB can overrun the clutch and the piston will just keep ramming the thrust until its done.

While the exact cause might be debatable it seems that the common denominator is shops that dont have enough experience (or a clue in general) doing things they shouldnt based on that lack of information.

my thoughts anyway

rolly1818

the older evos 1-4 suffered from crankwalk a lot more, i believe it was due to the bearing design (flanged) VS the new design on the later evo engines.

PS: my friend got crankwalk on an evo 4 last week for the non-believers.

whitemonster

well my horror stories are starting to add up as well. there is clearly no definative answer to this issue but i finally got around to pulling the oil pan today and aside from the shavings all over the bottom of the pan, i was looking at the crank and it clearly moved towards the tranny. i got a pry bar and it slid back over with ridiculously easy. and to clarify i used a new oil cooler and oil pump, i am thinking that the machine shop got a little carried away with the line bore. i called to see how the work was actually performed and the cut .010 off the main caps and line bored it back to the standard bore size and when they checked clearance it was .002 on the mains @ 60 ft/lbs. i dont know like i said i am no expert with machining motors but the theory that the less you do the better.