BRAND New motor walked!

[Richrx_tsi]

Just to start of this post i know this has beat beaten with a stick already. Now that thats cleared up, anyway i will give a little history to give you a better feel.
A few years ago i bought a 96 motor from a friend, he told me it had spun a bearing. So i decided to rebuild it. ( i will post part list plus machine shop bill when i get to a scanner) The motor had ross pistons, eagle rods, acl bearings. When i brought the motor to the machine shop i told them that it had spun a bearing. I also brought them all the new race parts, and had them assemble the shortblock. Now skipping a few years and a few thousand later. I get it all started up and running and when I pushed the clutch the rpm would drop. Right away i was scared of crankwalk. So I took it in to have endplay checked. Then guess what? Yep it actually was crankwalk. The trust bearing was down to the copper and it had filings in the pan.
So I'm really curious how this happened on a brand new motor? I mean it started these symtoms for start up. I dont know if it was a machine shop error that caused this to happen or what. Im mainly looking for some serious help here. Im unsure what to do now. The block is still good on the car, i caught it soon enough. I really would like to have the car up and running again but idk if i should start all over again or if i should get a new crank and new bearings.

Sry for the long post but someone could seriously help me i would appreciate it. Coming from the guy who just spent three grand on a motor to have this happen

 

[92AWDHX40]

New parts no quesiton why use over again? Your probably not going to know, but i would find another shop, to begin with and replace with new parts and start over again.

 

[DSMReviver]

Your friend probably didnt tell you the motor had walked before. Form what i have seen time and time again, if a motor had walked, it will always walks...

If you have the mains line bore on this fresh rebuild to begin with, it would have been different results. maybe the motor could have been save.

My advise would be to find 99 block with split thrust "revised" design. Then you can transfer your new parts to the new motor.

 

[turboglenn]

Yea, it was probably crankwalked in the past. Form my experiences of watching other people rebuild engines that walked it's something i wouldn't bother doing because it seems most of them walk again right away or withing very few miles. Since there's no deffinite answer as to why they walk, but instead many many theories, i would just get a 6 bolt. I know they can walk to and so can a 1g 7 bolt. But out of all the engines you can get the old 6 bolt is the only one i'd spend my hard earned and hard to come by money on.

I'm not dogging ya for building that engine so don't take it that way, i'm just saying i'd cut my losses with it, toss it in a dumpster and find yourself a good 6 bolt core (even the old NT blocks are fine to build without the oil squirters or you can have the block machined and tapped to use some squirters if you really want to)

You can find 4g63 6 bolt engines both turbo and non almost anywhere if you search craigslist and old junkyards your sure to pick one up for 100 bucks or less (tell the junkyard you want a core motor or they'll try and hit you for more money for something "running" and they are probably gonna give you the same engine either way since there's no real demand in the mainstream automotive repair shops for these engines)

 

[BogusSVO]

what do the thrust faces look like on the crank?

 

[Richrx_tsi]

Pictures by richrx_tsi - Photobucket THRUST BEARING

I dont have any pics of the crank i dont think but it just looked like the side of the thrust bearing it was all grooved up.

Thats what i was thinking, that he did not know it crankwalked. He might have just thought it spun a bearing. Does anyone know if the machine shop would have been able to tell that the motor crankwalked? Or would it look like just a spun bearing or something to someone who has never seen or heard of it.

The reason i wanted to re use the block was because i have ross pistons and eagle rods and a few other goodies in it. Looks like the best option would be to sell the internals and start over again though

 

[turboglenn]

or use those internals in a block that hasn't walked (that's if you feel like going 7 bolt again) but i'd say just for piece of mind go 6 bolt. Could be the bad luck associated with the number 7 causes CW, good of a theory as i can put together , or if could be that the DSM gods have OCD and don't like odd numbers on things

A machine shop would have been able to see the eaten away bearing if it was there.. Was the engine assembled (or at least have the crank and rods in it) when you got it and gave it to the machinist>?

kinda sucks that the internals are so proprietary between 6 and 7 bolt engines, because you have to make a big decision with those internals in mind as far as either ditching the whole thing or moving onto a 6 bolt platform

 

[TalonTsi_291]

From the looks of that bearing I'd say the crank bores arent correct (casting mistake, original line bore mistake) or something along those lines. Or the crank is bent. If it were me, Id go 6 bolt or revised 7 bolt. If you do a 97-99 block I think you can use all your parts from the first build. If you went 6 bolt you'd need new rods and have them bored out for the 2g wrist pin. Saves you from buying new pistons.

 

[JusMX141]

Someone didn't load the bearing properly upon installation, a damaged crankshaft was re-used, or the block was not align-honed....or a combination of the three. It's not like these engines are totally failure-prone or Mitsubishi would have undoubtedly done a revision much earlier than they actually did.

 

[donniekak]

That block/crank combo has other issues beside the thrust surface. The center main being chewed like that is usually from a bent crank.
While a line bore/hone can correct a main journal alignment issue, it does nothing to the thrust surface of the block/girdle, or crank. Every crankwalked block i've checked has a thrust surface that is not perpendicular to the crankshaft centerline. Even if this was corrected there are no oversized thrust bearingsfor a 4g63. However, in your case it looks as though the bearing material from the failing center main is what damaged the thrust in your engine, as the wear on the thrust is symmetrical.

 

[awddarrell]

At least they were still in one peice when I took mine apart they were in chunks.

 

[Richrx_tsi]

The motor was completely intact when i brought it to the machine shop. I had them disassemble it and they should have inspected it. I had told them that the motor had spun a bearing or thats what i thought.
I keep having this feeling like more and more that it was a machine shop error. from what im hearing or im i wrong? I still need to post the bill i got from them but i will go ahead and post what the bill says they did.

boil passenger car block
bore passenger block
install soft plugs
gring passenger cars small block, vw, etc
passenger car heads 4 & 6
grind valve eclipse 16 valve
wet magnaflux crank
fit pins & align rods-up to !"
balance engine
mill flywheel step
mill 4 cylinder passenger car block
deck block
ill head 2, 3,4 cylinder, assenger head
assemble engine short block only no head file fit rings


Thats word for word what the bill says. Now say this was a machine shop error, I mean if.....?......well just thinking. How would i prove that it was there fault? I mean i feel like they just stole my money and messed my motor up.

On a side note if i was to do the 6 bolt swap. would i need a new trans to? just curious i know the clutch is specific to 6 or 7 bolt also.

Oh! hey also is there any other pics or info anyone would want to further diagnose?

 

[phunny]

Someone didn't load the bearing properly upon installation, a damaged crankshaft was re-used, or the block was not align-honed....or a combination of the three. It's not like these engines are totally failure-prone or Mitsubishi would have undoubtedly done a revision much earlier than they actually did.

I firmly believe in the preloading theory, I'd like to know if the op did or did not do this.

 

[92AWDHX40]

http://www.dsmtuners.com/forums/articles-engine-fuel/152329-how-do-6-bolt-swap-what-you-need.html


Damn i love the internet. Google

 

[romeen]

You don't need a new transmission or clutch if you decide to go with a 6 bolt. Your existing parts (minus the flywheel obviously ) will bolt up just fine.

 

[H4G64T]

I see indications of improper lubrication, possibly no lube used during assembly, even if it was sitting for years, lube shouldn't dissolve.

 

[MichaelSuch]

I firmly believe in the preloading theory, I'd like to know if the op did or did not do this.

Agreed. I have a 6 bolt that I had walked after 2,000 miles on a new crank. Crank was fine, but I never set the thrust properly after building it. After 1500 miles rpms dropped when clutched pushed in, not much longer it would die when pushing in the clutch.

Fast forward to today, I have since then rebuilt the motor, with yet another crank (this time a 6 bolt 4g64 crank), same rods, new stroker pistons. Same block. At first I did not set the thrust bearing. Checked endplay. It was .009", which I believe is the service limit. I pryed forward on the crank then, and it was .005". I loosened it back up. Pryed harder and had someone torque the thrust at the same time and got it to .003" endplay. Since then I've put 5,000 miles on my newly built motor. No issues so far. I have yet to check endplay again, but I believe that I won't see any problems from it in the near future, and this is with a block that has walked. When it previously walked the only damage that was done was to the crank, and the bearings. It never ate into the block itself.

Did you check endplay when you first built the motor? And did you pry forward on the crank while torquing the main bolts down?

 

[Richrx_tsi]

I firmly believe in the preloading theory, I'd like to know if the op did or did not do this.

op? I realy dont know what the machine shop did during assembly i picked up the short block that they assembled and the head. A friend and I put the head and short block together and dropped in the motor

 

[MichaelSuch]

Original poster.

I would ask the machine shop if they pried foward on the crank, I definitely think it's an issue with the thrust not being properly preloaded or set. Most machine shops in my area would not do this because they do mostly domestic/v8 engines, and I don't think it's necessary on those, but I may be wrong, I've never built one. I have only built 4g63's. I honestly believe that if the crank did not eat into the block you should be fine with a new crank and new bearings. That's exactly what I did when mine did this and 5,000 miles later still running strong with a Fidanza 4.3 2300lb pp clutch. Keep the same pistons/rings/rods intact.

 

[dsm03]

I purchased my current 2G with a walked engine once I got it home and pulled everything apart to do the timing and checked for end play to find the infamous crankwalking.. So, far since my rebuild, 1yr later with now about 8,xxx miles on the new rebuild it has been holding up fine. Possible the shop did a poor job rebuilding the engine for you. I am not doubting repeats of crankwalk again and again on the same engine though..

 

[chasedardis]

Check craigslist I got I 6bolt with head fresh rebuild for a 1000 bux which is cheaper that I could build. I did take it apart when I got it and everything was fine.

 

[2slow4now]

It looks like in the picture the op posted the bearing may have wiped out first which restricted flow to the thrust area causing the excessive end play. Or in this case ground up thrust bearing. I wonder if the shop even checked bearing clearances? Did they reuse the crank from the original build?

 

[Richrx_tsi]

It looks like in the picture the op posted the bearing may have wiped out first which restricted flow to the thrust area causing the excessive end play. Or in this case ground up thrust bearing. I wonder if the shop even checked bearing clearances? Did they reuse the crank from the original build?

it was a stock 7 bolt and yes the used that crank. there clearnces are written on the build sheet. which are
top.021
dec or lec(cant read his writting).024
main.0015
thrust 005
rods .0015
grind crank.01
bore block.02

 

[BogusSVO]

top.021<<<<<<<< your top ring end gap

dec or lec(cant read his writting).024<<<<<<< SEC ring end gap

main.0015<<<<<<<<< Main bearing clearance
thrust 005<<<<<<<< clearance between crank and thurst bearing

rods .0015<<<<<<<<< rod bearing clearance

grind crank.01<<<<<<<< crank was ground down .010/.25mm (both rods/mains?)

bore block.02 <<<<<< Cylinder bores are now +.020

 

[Richrx_tsi]

I finally uploaded the build sheets and part sheets. If someone could look them over and insure that corret specs were used along with parts. They did not use the main bearings i brought in, they said they were the wrong size or something just fyi.


http://s599.photobucket.com/albums/tt79/richrx_tsi/