7 bolt crankwalk rebuild with pics

H@xtGSX · 06-04-2012, 07:12 AM

I have a 95 GSX that has been my second wife for about a year now. I bought it as a bent valve special from the first owner. He wasn't exactly a stickler for maintenance and treated the car like a Jeep. It was lucky to have the oil changed on time, much less anything else. I bought it, rebuilt the head, did all the needed maintenance, and added a bunch of the crap we all tend to add to our cars... bigger turbo, clutch, etc. I have been driving it daily ever since.

At 126,000 I started to notice the clutch was changing it's engagement position. When I let my foot off the gas and it was engine braking, the clutch would chatter on the flywheel real bad. In an effort to deny reality, I thought maybe I just hadn't adjusted the clutch correctly and fiddled with it in hopes that maybe I was just too stupid to understand the Jack's Transmission clutch adjustment video. It was adjusted correctly, and when it started disengaging near the floor after a hard turn, I decided to push on the harmonic balancer, hoping it wouldn't move... *thunk* ... I can see it move about a 1/16 of an inch. Lovely. I have crankwalk. I can't afford a new motor, I don't want to risk a JDM motor, and I don't really want to do a 6 bolt swap. Rebuild is the only option left, so I start buying parts.

I knew the crank would be trashed along with the bearings, so I bought a new one. $243.99 at Oriley's got me a new crank and a full set of King bearings matched to the crank. I also bought a "conversion gasket kit" that has all the gaskets and seals for the bottom end in it for $45.

Time to get dirty... what better way to show your car you care than by ripping it's guts out?

You have to get it mounted on an engine stand. This requires flipping the motor upside down, so it's mandatory.

Since it's out of the car, clean the motor. I don't want to be doing this again because I was a lazy ass and some little bit of dirt accidently got into one of the bearings before assembly... and while I'm at it, might as well clean the bell housing out too. That Purple Power cleaner works wonders. Yes, that is a 17 year old transmission.

While disassembling the motor, I found a spot where you are supposed to use one of the Mitsubishi special magic tools only the dealer normally has. Screw that. I find that a 2.5" 2 piece exhaust flange, a wrench handle, and a bolt work just as well.

The source of the problem... but look at that main bearing girdle. That's a beefy piece of reinforcement that makes me happy to be keeping my 7 bolt.

Here's what I found with .014" of end play.

...destroyed...

I'm lucky to have done this repair when I did. If I had waited any longer, that block would have been trash too. The crank was already just barely starting to nick the block. The nice thing about doing this though is that all the seals and gaskets are new now... no more leaks, anywhere. Here's the one that is a major source of annoying clutch problems, the rear main. Make sure you take care doing this one right.

It's very important to use assembly lube when replacing something like a crank. You do not want the journal bearings to get scored in the first second it is running when you fire it up, or you will be doing this all over again real soon. As a side note, is it strange that I always laugh when I have a huge tube of lube in my hand?

After carefully dropping in the crank, bolting it down with a good torque wrench, and reversing the whole removal process, I now have a working motor within factory spec. The manual says normal crank end play is .002 to .007. Mine is now .005 with me really pushing on it hard with a pry bar. It's not as tight as a brand new motor is, but it's close enough... Plus, this cost me 1/3 of the next cheapest option for fixing this problem. I am hoping to get at least another 50,000 miles from this bearing set. That would be long enough that I won't mind having to do this again. The 7 bolt motor is built tough enough to take some severe punishment, with the exception being the main thrust bearing, and I am happy to be keeping it... crankwalk or not. It's not nearly as big of a deal as people make it out to be.

jjrock5 · 06-04-2012, 07:27 AM

Photos aren't showing up.

I think you have the IMG tags wrong. It should look like this:

[IMG]http://www.dsmtuners.com/gallery/files/1/3/0/6/8/7/imag0713.jpg[/IMG <---add in the final bracket to show image...

H@xtGSX · 06-04-2012, 07:31 AM

Crap.... that explains it. Thanks.

Fixed.

kidtsi · 06-04-2012, 07:41 AM

How long did you did this ?

H@xtGSX · 06-04-2012, 08:05 AM

This entire rebuild took two ~8 hour days. A weekend project. That's with me really nit picking everything and going slow, really paying attention to every detail. I wanted to get it absolutely correct the first time. Now that I've done it, I think I could probably do the whole thing over again in about 12 hours.

kthackst · 06-04-2012, 08:13 AM

Don't use that graphite Moly Lube. It gums up the pickup tube. I have a picture proving it. Let me see if I can find it.

kidtsi · 06-04-2012, 08:24 AM

Quote:

Originally Posted by H@xtGSX

This entire rebuild took two ~8 hour days. A weekend project. That's with me really nit picking everything and going slow, really paying attention to every detail. I wanted to get it absolutely correct the first time. Now that I've done it, I think I could probably do the whole thing over again in about 12 hours.

the question was how long ago you did this???

My friend used the same block with a new crank and new everything after a crankwalk problem and he rebuilt 3 times in 15k miles. i would never use the same block, atleast get a 97+ block.

H@xtGSX · 06-04-2012, 08:33 AM

Quote:

Originally Posted by kthackst

Don't use that graphite Moly Lube. It gums up the pickup tube. I have a picture proving it. Let me see if I can find it.

Ok.... well.... that sucks. I hope I am avoiding that with the oil change schedule. I ran it for 15 minutes right after rebuild with 10W30 in it, drained it, and changed the filter. At 200 miles, I'll change the oil and filter again. At 1000 miles I'll change the oil again to some 0W20and another new filter. Routine changes after that.

As for how long ago I did this: Last weekend. I don't think 3 rebuilds in 15K is faulty parts alone. Something else is going on there...

black_eclipse96 · 06-04-2012, 08:41 AM

well this kinda sucks! I used the same lube. How long did it take for it to gum up. What made you decided. To check it?

kthackst · 06-04-2012, 08:50 AM

Quote:

Originally Posted by black_eclipse96

well this kinda sucks! I used the same lube. How long did it take for it to gum up. What made you decided. To check it?

That is 15 minutes of idle. It is a 2.3 stroker and we used the non oem pan from graveyard and the crank was hitting the pan, just slightly. We thought it was rod knock and come to see there was a small mark on the pan where the crank was hitting. But the Moly lube buildup was quite noticeable. So we got an OEM pan and cleaned the pickup tube.

I know it was only run for 15 minutes but I dont care, I NEVER want my oil pickup to look like that so I avoid the stuff like the plague now.

jjrock5 · 06-04-2012, 08:53 AM

I recommend this stuff:

H@xtGSX · 06-04-2012, 09:21 AM

Well, I have a bore scope I can stick up the oil drain plug hole. I will take a good look at the pick up in another 100 miles. It doesn't take pictures, but I'll let you know if it is gummed up. If it is, I'll be dropping the pan again... I do not want my pick up to look like that, especially considering that there's a very good chance that crankwalk is directly related to poor oiling.

kidtsi · 06-04-2012, 10:55 AM

The rule of thumb is when a block crankwalked once, it will keep doing it, hopefully not in your case man hope everything stays together on yours, and no all the parts were withing spec even balanced with clutch and balancer installed on the rotating assembly, after that he got a 98 block and being 30k miles no problem with a HTA 3586.

Like i said hope everything last longer on yours.

EDIT: i forgot to tell you, yo should replace those oil squiters, another probable cause, i built 7 bolts almost for a living.

H@xtGSX · 06-04-2012, 11:06 AM

Quote:

Originally Posted by kidtsi

The rule of thumb is when a block crankwalked once, it will keep doing it, hopefully not in your case man hope everything stays together on yours, and no all the parts were withing spec even balanced with clutch and balancer installed on the rotating assembly, after that he got a 98 block and being 30k miles no problem with a HTA 3586.

Like i said hope everything last longer on yours.

EDIT: i forgot to tell you, yo should replace those oil squiters, another probable cause, i built 7 bolts almost for a living.

Thank you. Me too. I wish I could get those damn squirters machined out, but $ is an issue. Whoever it was over at Mitsubishi that thought taking the oil from the main bearing for ANYTHING else was a good idea needs to be kicked in the nuts. If it starts sloshing around again though, I will be doing exactly that... finding a 97+ block. I did the filing the edge of the thrust bearings modification, hoping that'll get a little more oil on the face of the bearing. I'll also be running 0W20 oil, hoping that the thin stuff will sneak into the bearing better. I have seen it go both ways though.

I am fully expecting this block to crankwalk again. I am just hoping it'll hold out a few tens of thousands of miles between doing it. If a rebuild like this is something that needs to be done every 2-3 years, I can live with that. If it walks again by next week, I will be severely pissed off.

bryanwheat · 06-04-2012, 11:14 AM

You don't have to machine the squirters out, they drive right out with a punch, and new ones go right in with a punch. I wouldn't even bother rebuilding the engine without either blocking the old ones off or installing new ones.

As for the moly lube, i've built too many engines to count using that lube without one single failure.

H@xtGSX · 06-04-2012, 11:33 AM

Damn... I wish I had thought of that before I put it all back together! This car is my DD, so I did the basics to get it going and tried to fix everything I could think of. I didn't even mess with the squirters. Are they something I could replace without yanking the whole motor again? I didn't look to see how they were removed, so I don't know what would be involved. Is there any disadvantage to blocking them off?

bryanwheat · 06-04-2012, 11:36 AM

You would have to remove the crank to replace the squirters.

H@xtGSX · 06-04-2012, 11:41 AM

edit:

Nevermind what this used to say... I figured it out. For some dumb reason my brain didn't recognize that as the bottom of the block and not the bearing girdle. Time for some coffee...

How would I go about blocking them off properly? Is there a plug made for the discharge side? Or would I need to tap it and put my own plug in? Or could I just remove the one's that are in there, weld them shut, and stick them back in? I didn't look at them close enough when I had it open to make that judgement...

Gamble97 · 06-04-2012, 11:47 AM

If your lucky you will get 10k miles out of that engine before it walks again. One the block walks it will always walk again.
Happened to me, mine walked and I did a full out race build and it lasted 10k miles and I could move the flywheel in/out 1/8".
Better start shopping for a 6bolt.

H@xtGSX · 06-04-2012, 12:24 PM

I know that the conditions for crankwalk are still in my block. I didn't have the knowledge or funds to correct everything this time around. What I don't get is if I were to correct the known issues and ensure the crank geometry is aligned and correct, why would my block be any more prone to crank walk than any other 95-96 7 bolt that hasn't walked? That adage of "if it does it once...." just doesn't stand to logic in my mind if the conditions are addressed.

H@xtGSX · 06-05-2012, 09:24 PM

I guess what I really want to hear is someone having a GOOD experience with a rebuild. I am holding out hope and doing everything I can think of to make that thrust bearing last as long as possible.

Purple_Demon · 06-05-2012, 09:35 PM

Im in the same boat you are in, I have the old style 7 bolt engine, I have the 6 bolt block as well. I just dont want to deal with doing a 6 bolt swap ATM. Id like to pick up a 97+ block but I cant find one. Ill be checking in with this thread to see if anyone has any good info or feedback on rebuilt crankwalked motors.

Good luck on yours though!

WES_393 · 06-05-2012, 09:46 PM

I rebuilt my 95 7-bolt. It had pretty excessive end play so I picked up a different non-walking crank and had it machined. It's been good to me so far, but it always sits in the back of your head. I disconnected the clutch switch, use a 2200lb pressure plate, keep it 100% on oil, and hope that I'm not forced to throw a 4g64 in there anytime soon.

But seriously, if everything is within spec upon assembly, there is no reason to worry about it.

Oh, and I have never seen Moly lube do that. I use that same brand sparingly and pull the pan after every break in. That looks gummed with silicone sealant to me, maybe someone went a bit crazy with the RTV?