I cant believe it! Fully built, $7500, 700 miles, and CRANKWALK!!

[sunflashx]

Originally posted by NDgsx
If the thrust surface of the crank and main bearing were properly aligned there is no way that a clutch would cause that type of thrust play. 2600 does have the highest release pressure of any dsm clutch though. That's why I run centerforce pressure plates with an ACT disc.

That's a new one to me. Why use the ACT disc over the centerforce disc?

 

[got traction?]

Factory disc works the same if not better and is alot cheaper.

 

[GRNDSM]

2G factory disc is pretty good (better than 1G), But it is not as thick as ACT (which is stronger and lasts longer).

Of course, ACT did have have quality issues in the past...

Leon
RR

 

[umiami80]

yOU DO NOT, repeat , DO nOT GIVE THAT #@%#@%#@%#@% AT eXTREME ANOTHER CENT, YOU demand A FULLY FUNCTIONAL CAR from him and you want it now, it is not your fault in the least, it is their fault 100%. And if those #@%#@%#@%#@%s refuse to help, fine, just park your car right infront where all the customers walk by, TELL EVERY LAST ONE OF THEM WHAT YOU PAID AND HOW YOU GOT #@%#@%#@%#@%ED every day until the #@%#@%#@%#@%er caves, go to many fourms and sits as well. You got #@%#@%#@%#@%ed and now this #@%#@%#@%#@%er is gona bend you over for seconds, no way.

I did this same #@%#@%#@%#@% to SAATAN and it worked like a charm. If you pay him anything then you are just dumb and they are #@%#@%#@%#@%ing you.

 

[HighPsi91]

A couple things....

Automatics can and have caused thrust bearing issues. On very high horsepower cars torque converters can ballon and cause excessive thrust loading.

GRNDSM..
2G discs are thicker than ACT's discs... I know I have them both at my shop right now, and have used both.


One thing I noticed on the 2Gs I have worked on is the clutch hydraulic system is a bit fishy. If you grab a hold of the rod that goes between the slave cylinder and the release fork and try pushing it back into the slave cylinder you cannot. On a 1g it pushes in with very little effort. If this is the case then it means that there is always hydraulic pressure trapped in the 2G's sytem. This would cause the throwout bearing to always have some degree of pressure against the clutch. Is this just the cars I have seen or are all your cars like this??? Go out and check.

 

[Tevenor]

That's pretty much all 2G's Wes. 2G's stock have a clutch accumulator that is supposed to reduce the vibration and feel to the clutch pedal to the driver. This tends to build up pressure. But that's not all. My system had times where the pressure built even after I replaced the lower line with a SS line. It took easily twice as long to get the clutch adjusted properly on my 2G as on my 1G.

 

[HighPsi91]

I removed the accumulator on one car just to see if anything would change and it didnt. Doesnt this concern you 2G guys?? Right here is a very likely culprit in the cumulative crankwalk problems. 50k+ miles of constant thrust loading doesnt sound too good to me.

 

[BryanK]

sh*t, so you're saying I don't need to get a new block? That I just need to rebuild what I've got and get a 1G transmission, or how would I remove the accumulator on mine? Do you guys really think this is the cause of crankwalk, and if so, with what degree of certainty?
Thanks,
Bryan

 

[HighPsi91]

Its not the transmission.... its just the clutch hydraulic system. The clutch's master cylinder is what I suspect to be the problem. Like I said earlier I already ditched accumulators and saw no difference. This is what I believe is potentially the cause for long term crankwalk.

Post rebuild crankwalk is a completely different situation. This is due mainly due to thrust bearing misalignment. Aligning the thrust bearing on a 2g block is very very hard due to the fact that all the main caps are girdled together. I have rebuilt crankwalked 2g blocks in the past with only one modification. I used a bandsaw and cut the thrust cap out of the girdle. This way I could align the cap as I do for all my 1G motors. So far no problems. And this was without ANY machine work to the block... and clevite bearings which are taboo in a 2g rebuild. There, theres my little secret.

 

[Beemer]

GRNDSM - You are correct about different causes. However, if you just replaced the clutch, and all clearances are correct, the only way you could misadjust a hydraulic clutch are:
a: Not properly bleeding the hydraulic master or slave cylinders (IE never being able to fully disengage the clutch)
b: Fooling around with the pedal height adjustment and screwing the pooch
c: Having a bad clutch pedal assembly (rounding out the square hole and getting slop in the pedal pivot
d: Having a worn clutch pivot ball or throwout bearing arm that is bent or worn (which the pivot ball and arm should be replaced when you change the clutch anyways)
e. An improper flywheel step (I believe that .610 is the proper step height, or .610- .612 or so, although if you call SATAN or Mitsu, they will never tell you. If I remember right, I got that figure off of the Centerforce website for my mitsu dealer since they had no clue. That was an awd flywheel btw, dunno for a fwd)

You are correct about oil flow over the bearing also, and heat buildup as a consequence of the lack of oil.

Now for a wee bit of engine engineering talk
from what i have seen, 4g63 motors tend to push towards the balancer under accelleration and back towards the clutch at decelleration. Am I correct here? Part of the problem, and this is my firm belief, is that when the 7 bolt motors came out, why were they produced? Primarily, a lack of failure of the old 6 bolt motors. So mitsu says...gee we over built the motor (Chevy did this as well with the 327 and 283 v8 in the 60's) We have to meet stricter emissions requirements as well..
Hmmm.. turbo motors with low compression are well known for dumping lots of unburned gas at idle...7.8 compression ratio...hmmm.... lets bump the ratio to 8.5, lighten everything up, use a cheaper alloy in the reciprocating assembly since it is swinging less weight around due to smaller lighter rods, and use cheaper bearings. We save 30 bucks per engine, and over a hundred thousand engines, we add 3 million bucks to the bottom line for more horsepower and better torque. No matter that the engine is stressed more and is now less sturdy than before.

Has anyone checked the figures on AUTOMATIC TRANS equipped T/E/L's for crankwalk?
(I admit I have not, but it would be interesting to see the results...since the majority sold may have been automatics in the second gen cars)

Also, you have to remember that Buscher sold Sheppard that car. It was pretty well sorted, although John really has done THE BEST job with that car the world has ever seen. It would be an honor to spend a year working with him, as I have been learning "seat of the pants", since i am an old ass mustang and GTO racer from the 70's (60's cars of course, they were cheap in the '70's with the gas crunch)

Like the sign says tho. DSM makes a decent mechanic out of anyone who owns one (at least any turbo model...ever wonder why there are no big time 3000 gt vr4 draggers out there? Thank Getrag for that spindly ass transmission that can barely handle stock HP. I saw one with a chevy LT1 and the awd system from an awd astro van lay down some pretty good times once, but I never found the guy to ask him about the setup)

Also, you are correct about Buscher and the mitsu trannys. Again, he could have picked any trans out there running rwd.. a 700R4, a TH400 or 350, a Ford C6 or C4. But he picked the powerglide, even tho they are getting way harder to find (since most of us pitched them in favor of the TH350 or 400 back in the day) and the cast iron cased powerglides (the really tough ones) are getting like gold nowdays, you wonder why he picked it?) Lack of shifts + less spool down (I'm guessing, since I don't know Dave personally). Now if he could find a way to make a lockup converter invalid in first, but clamp down in secondat about 6 grand, he would wipe out all that 30% slip with the flip of a switch and be even faster. I don't care how fast you can shift, the turbo will spool down with a Manual Trans compared to an automatic.

Enough for now, my brain hurts from having to remember all this stuff. Let's just call it a design deficiency and leave it at that.

 

[696]

High PSI 91: So should you use clevite bearings in a 2G after your mod?
696

 

[dsmntc]

beemers comments about using a roller thrust bearing are intriguing. I rebuild marine transmissions and drives, and these are used in great numbers. the question would be how to maintain a min amount of preload so the rollers retain traction when not under load. and how to lube them. i can provide quite a few different sizes of RTBs and mating thrust washers if your interested in trying. Also might have some ideas about keeping them alive as i have seen many different failures of these bearings e-mail me at [email protected]

 

[GRNDSM]

Beemer wrote:

>An improper flywheel step (I believe that .610 is the proper step height,
>or .610- .612 or so,

You got the step right. The thing is that there are enough other variables (in addition to getting that step right), which often require you to re-adjust clutch engagement point after ACT install. I adjust them to grab as close to the floor as possible with out hindering shifting (full disengagement). Many people do not like the feel of that low engagement and adjust them to grab half way up the travel. This leaves you much more likely to have slight T/O bearing pre-load on the pressure plate. Which is bad for two reasons: continuos thrust load on the crank and your pressure plate never fully grips and can slip under high torque.

>That was an awd flywheel btw, dunno for a fwd)

There is no difference between FWD and AWD flywheel steps. However, flywheel castings have different outer diameters and can not be interchanged. Also, ACT clutches are identical for both applications.

>from what i have seen, 4g63 motors tend to push towards the
>balancer under accelleration and back towards the clutch at
>decelleration. Am I correct here?

No idea… I have never heard this discussed… What forced would be there to cause such pre-load?

>Part of the problem, and this is my firm belief, is that when the 7 bolt
>motors came out, why were they produced? Primarily, a lack of failure
>of the old 6 bolt motors.

Well, 7 bolt motors were definitely cheaper: smaller rods, looser tolerance cranks and blocks (thus so many factory bearing combinations), then, 2Gs also got much cheaper oil squirters. This general change was made across the Mitsubishi product line. In late ’92 all 4G63 and 4G64 engines (turbo and not) became 7bolt/small rod/loose tolerance.

>Hmmm.. turbo motors with low compression are well known for
>dumping lots of unburned gas at idle...7.8 compression ratio...hmmm....
>lets bump the ratio to 8.5,

Higher compression ratio, along with smaller intake ports, smaller throttle body and smaller turbo, were mainly implemented to address one of general public’s biggest concern: turbo lag. 2G’s definitely have much less of it! And they did not come for two years after the 7 bolt motor design was implemented.

>Has anyone checked the figures on AUTOMATIC TRANS equipped
>T/E/L's for crankwalk?

Yes, they also crankwalk. This seems to happen less frequently, but it happens. The problem is that most of these forums are performance oriented, so the majority of people have 5sp cars. This might skew the real world number. But when I talked to a good service manager at a local dealership he said that number of crankwalk in automatic cars was representative of their percentage. Of course, he was dealing with 5sp cars which had stock clutches . He might have seen higher percentage of crankwalking cars if most of them had performance clutches (as they tend to be with people on these forums).

> (since most of us pitched them in favor of the TH350 or 400 back in the day)

Actually, David also build a RWD Starion with TH350 and did not it at all. I recall him saying that everyone he talked to prior to building his first RWD cars told him that 2sp powerglide would not work with a 4 banger engine. Well, he took a chance and proved them wrong.

BTW, thanks to Bruce, I got to drive BR’s original RWD Talon a couple of weeks ago, WHAT A BLAST!

Leon
RR

 

[sunflashx]

Originally posted by GRNDSM
2G factory disc is pretty good (better than 1G), But it is not as thick as ACT (which is stronger and lasts longer).

Of course, ACT did have have quality issues in the past...

Leon
RR

I think you missed the point of the question. No one even mentioned the Centerforce disc. The factory disc / act disc thing with a act clutch is pretty common, but the centerforce pressure plate with the act disc is not. What is wrong with the centerforce disc?

 

[NDgsx]

Originally posted by GRNDSM
Beemer wrote:

>from what i have seen, 4g63 motors tend to push towards the
>balancer under accelleration and back towards the clutch at
>decelleration. Am I correct here?

No idea… I have never heard this discussed… What forced would be there to cause such pre-load?

If you have any old stock pistons laying around go take a look at the wrist pin, it is just slightly offset.

I use the centerforce disc does not like getting very hot. You have to let them cool off forever in between runs if you want it to last. The ACT disc takes the abuse very well. Centerfore pp has either 2400 or 2500lb clamp load (can't remember now), but it has a much lower release pressure.

 

[ILOSE]

Originally posted by NDgsx
If the thrust surface of the crank and main bearing were properly aligned there is no way that a clutch would cause that type of thrust play. 2600 does have the highest release pressure of any dsm clutch though. That's why I run centerforce pressure plates with an ACT disc.

Agreed! I also run and have run a centerforce plate and an act 6 puck solid hub disc on my fwd. Talk about some sick launches, and it always asks for more.

 

[ILOSE]

Originally posted by got traction?
Factory disc works the same if not better and is alot cheaper.

Utterly and Totally incorrect! Try and launch a stock disc over 500 rpms and then do it over and over again. It ain't gonna happen. Once you overheat a stock or center force disc they turn to puddy and willl not grab. Even if you let it cool down between launches, it'll heatsoak as so as you try to launch again.

All discs are not the same, they are made up of many different
materials.

I have tried a gazzillion combinations and I am gonna try a new disc next year. Not for more grip or strength, but for some secret (wink, wink) tranny reasons.



As for GSX4life, man you are insane if you even think about giving them anymore money! Someone said it before, Take them to court and sue their asses! As a supposed respectable dealer, they should honor their work and correct *THEIR* screw-ups! You say you trust them, or believe them, and yet you already trusted them to give you a top of the line product the first time around. If you let this slide, they and other vendors will only continue to rip people off in the future.

 

[696]

So by using a ACT 2600 disc and a Centerforce Pressure Plate you can get good clutch and not have to worry about or lessen the risk of crankwalk? Is this correct? If not someone please correct me.
696

 

[NDgsx]

I'd say "lessen the risk" would be more accurate, but yes that's basically it.

 

[696]

Ok, So it the thrust bearing misalinment or clutch pressure or both that contribute to crankwalk? I've heard alittle from both sides. Is it hard to properly aline the thrust bearing? And by starting the car without pushing on the clutch (bypass) and allowing oil to get on the bearing to help with the pressure from the clutch on the bearing?
696

 

[BryanK]

whatever happened to GSX4Life? What ended up happening with SATAN? Did you nail those bastards? I really really hope so.... I would do exactly what UMIAMI88 said... park it outside their shop and let the whole world know how they screwed you. You might even try unhooking the exhaust some to make it sound just horrible, then sit outside so not only can they see you, but they'll hear you as well. Yeah, its misleading, but they mislead you when they told you they'd build you a nice engine for $7,500. Bottom line... GET THEM, ONE WAY OR ANOTHER, MAKE THEM GIVE YOU WHAT YOU PAID FOR!!!

 

[GSX4LIFE]

Im still here. Its not as simple as parking outside and discouraging other customers that enter.(BTW. Thats illegal. Its called loitering, or solicitation.) I live about 2 hours away from Extreme. And I have a full time job, and a family. The car is at Extreme now. Sean should have it done by next Monday. Yeah its another $2000. And that sucks AZZ. But Im stuck. I need my car, and I need it now. No one else will touch it because Extreme has aleady worked on it. So if I take it somewhere else and something else goes wrong, then that person will say its not thier fault because Extreme already Fugged it up. I already made it quite clear, that I want it right this time. I told them I will be expecting the car by next Monday. And I told them that I dont want to have to call them in another 700 miles with the same problem. They have no loop holes now to hide behind. If it hppens again, Extreme will be 100% liable for any repairs. And if it does happen again, I will take them to court.

 

[Tuff02Ranger]

I actually did a search on Crankwalk and found a good article. Sound like this guy is headed in the right direction. See page two for results of testing after research.

http://www.magnusmotorsports.com/crankwalktheory.htm

 

[NDgsx]

Originally posted by 696
Ok, So it the thrust bearing misalinment or clutch pressure or both that contribute to crankwalk? I've heard alittle from both sides. Is it hard to properly aline the thrust bearing? And by starting the car without pushing on the clutch (bypass) and allowing oil to get on the bearing to help with the pressure from the clutch on the bearing?
696

Yes it's normally a combination. Yes with the full main girdle on 7 bolts it's very hard. Yes that will also help a lot.

 

[696]

I believe I will order that kit to accept the 1G oil squirter. Also can I just call up a Centerforce dealer and order the pressure plate and do the same for the clutch disc? I already know they will want me to by the whole kit and say that I will have to in order to get one of those pieces.
696