Rebuit 7bolt walked, odd? grinding on crank may have caused it? Need Help!

[95Eclipse]

Sorry it's so long but I couldn't make it any shorter!

Hi, well where can I start, I spun the #4 bearing after a mis shift, I decided to do the rebuild the 7bolt since the engine didn't stop because of crankwalk and the factory thrust bearings were in pretty good shape, even with 120k miles.

I took the crankshaft to the machine shop, it was bent and also needed to be turned, so they straightend it and turned it and ended up .10 - .10 (Don't know if that's how it's written) on both the mains and rods, I ordered the bearing kits from them, (ROCK bearings) they said those were the only kits they carried and were using for a long time without problems, and since they knew what to order I "kind of" had to get those.

When the new kits arrived, the thrust bearings didn't quite fit in the main journal, it was a bit wider and was a little tight trying to sit it in place, so the guy said they had to machine the sides of the crankshaft (where the thrust bearing walls are) just enough to accommodate for the size of the new bearing, so I had that done for "free" we put everything together and I checked the clearance in the thrust bearing sides and was .004 the most to slide in so I thought "it's all good".

After we started the engine and warmed it up to normal temp for a while I noticed something it didn't do before, the RPM's slowed down (500RPM) when the clutch was pressed, I didn't know then it was a very strong sign of crankwalk, so I took it for the brake in and drove it 250 miles then the very faint pinging from the Crank sensor appeared . I checked the crank pulley with belts and everything still on and could literally push and pull the whole crank.
I took the oil pan off and the thrust bearings are completely shredded on the thrust side, there are literally bearing slices all over the oil pan and to finish off it also f***ed the crank's thrust wall that they machined. I am very pissed Do you think that the machining on the thrust walls may have caused it to walk or just for being a 7bolt it was meant to happen? I did a search and couldn't find anybody machining the crank thrust walls for this matter....I'm so pissed, I mean it was crankwalked as soon as I turned the key.
I'm going to take this engine to the machine shop to show them what happened and if it was their fault make them do something about it, so I need you guys's help or opinion.
before I open my mouth! I'll try to post some pics later.


Thanks for reading the whole thing!!!!!!!

 

[Defiant]

I took the crankshaft to the machine shop, it was bent and also needed to be turned, so they straightend it and turned it and ended up .10 - .10 (Don't know if that's how it's written) on both the mains and rods, I ordered the bearing kits from them, (ROCK bearings) they said those were the only kits they carried and were using for a long time without problems, and since they knew what to order I "kind of" had to get those.

When the new kits arrived, the thrust bearings didn't quite fit in the main journal, it was a bit wider and was a little tight trying to sit it in place, so the guy said they had to machine the sides of the crankshaft (where the thrust bearing walls are) just enough to accommodate for the size of the new bearing, so I had that done for "free" we put everything together and I checked the clearance in the thrust bearing sides and was .004 the most to slide in so I thought "it's all good".

7-bolt cranks are not to be serviced, only replaced. The shop should have known this.

 

[DsMWookie]

Defiant is right they should've known better. Second I would get reimbursed but def. don't let people who ####ed up your first motor try and fix your second to make things right. I would want full refund and take it to a knowledgable machinist.

 

[bullettdsm]

Grind to fit thrust bearing?! No, no, no! That's should have been a sign that something was wrong. Do not go back there.

MB

 

[95Eclipse]

Defiant is right they should've known better. Second I would get reimbursed but def. don't let people who ####ed up your first motor try and fix your second to make things right. I would want full refund and take it to a knowledgable machinist.

I am going to take it to them so they can look at it and try and make them pay back at least the money I paid for the machining. I know already that they are going to try and blame it on the builder or oil starvation. I know everything was bolted down to factory specs.
My grandfather has being rebuilding engines (mostly V8's) since before I was born and said he never had a crank machined in that area. He said there's a coating on the crank that's supposed to be there and that by machining it it loses strength. so I guess I'm pretty much screwed.

Has anybody ever known of somebody machining the crank's "thrust walls" (where the thrust bearing goes) that survived, even on a 6bolt??

 

[1fast97gsx]

Has anybody ever known of somebody machining the crank's "thrust walls" (where the thrust bearing goes) that survived, even on a 6bolt??

I've heard of people with too much endplay welding onto the thrust walls and then remachining it. I believe slowboy were the ones I first heard of doing this. Just buy some bearings that will fit no problem and buy a good used crank from somewhere.

 

[95Eclipse]

I've heard of people with too much endplay welding onto the thrust walls and then remachining it. I believe slowboy were the ones I first heard of doing this. Just buy some bearings that will fit no problem and buy a good used crank from somewhere.

That's what my father said that can be done to it, but he is not very familiar with DSM's and doesn't know much about the crankwalk issue that surrounds 2g DSM's, but instead of buying a 6bolt and spend $800 or more for a used running engine Do you guys think I should give it a second try and have it welded, machined and re-hardened for much, much less? cause I can't find anybody locally that sells a 7bolt crank with reasonable price and in good shape. I'm kind of in a tight budget.

Putting the engine together and droping it in the car doesn't cost me a thing (except for the pain in the ass) since I do that my self, with some help.
By the way which brand of bearings do you all recommend for the next try on either the 7bolt or 6bolt should I decide on it? would Clevite or Federal Mogul be top quality??

 

[DsMWookie]

Go to a junk yard or check the board u can probably get a bottom end turbo or non and use the crank and clock from that.


I use clevites and so does Shepard if that makes you feel any better.

 

[Strm Trpr]

Machining cranks will remove the surface treatments, i.e., heat treatments, nitriding, carbonizing, and unless the surfaces are reprepared as original after machining, the freshly machined surfaces have no hardening and will grind themselves away as you unfortunately know.
Good luck and let us know your remedy.

 

[1fast97gsx]

Don't even waste your time with the crank you have anymore. After all the welding and machining costs you could have just bought a good used crank for the same amount of money. Not to mention the protective coating will have been removed then. I personally would swap a 6 bolt since you can get them for really cheap anyways.

 

[95Eclipse]

Go to a junk yard or check the board u can probably get a bottom end turbo or non and use the crank and clock from that.

I use clevites and so does Shepard if that makes you feel any better.

Would the 7bolt crank from a turbo and not turbo block be actually the same?
how about on a 6bolt? is it the same turbo and non turbo?

 

[95Eclipse]

There is this 1st gen 7bolt N/A complete engine I saw in a junk yard and need to know if in fact the crank would be the same from a turbo and a non-turbo,
I might be able to get just the crank from it, if it will work for me, I saw this engine some time ago so I need to go this Saturday and check it out....
If somebody that knows can tell me if the N/A crank will fit my turbo block.

Thanks!!

 

[bjones18]

- Welded thrust surfaces are common place in the engine world. So is re-nitriding.
- Crankwalk is not unique to 7bolts nor DSMs.
- Most engine wear is on start up (no oil supply).
- 7 bolts have a problem with crankwalk, ever so on rebuild.
- Axial alignment of girdle is important
- You will get crankwalk advise from people who have never rebuilt a 7 bolt.
- Disconnect your "depress clutch to start" switch forever & start in neutral.
- get full oil pressure upon rebuild with NO spark & NO plugs (spin engine no compression, disconnect sensor at head).
- break in with normal oil then switch to synthetic (heavy).
- consider an external oil cooler.
- make sure your oil pump works.
- wait for my crankwalk experiment results (2nd thrust surface)
- Use normal bearings (clevite or DSM)
- Reworked cranks are sensitive to low tide, planetary line ups and other nonsense.
- Screwed-up reworked cranks are by definition.... screwed up.
- A fresh untouched crank is worth $100 for your piece of mind.

From a guy who has build a 200 mile crankwalker and a 2500 mile non crankwalker, working on a third with 2 thrust surfaces.