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1992 Mitsubishi 3000GT VR4
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Discussion Starter · #1 ·
Hello,

I’ve attached some pictures of my crankshaft with scoring on 3 of the journals. Would a machine shop be able to repair this or is this non reparable damage? You can definitely feel these with a nail.


 

· Science, bitch!
1992 VR4
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It is my understanding that this type of damage is repairable but may require grinding the crankshaft (not just polishing), which would necessitate oversized bearings. Are you planning on building a high HP car, like 600+ HP?


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1992 Mitsubishi 3000GT VR4
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Discussion Starter · #3 ·
I’m planning to be in the 450-550hp range, why do you ask? And thanks for the quick response! I’ll definitely see what my machine shop can do and I’ve been looking at 3sx for bearing sets and I’m not sure which ones I’ll need if I have the crank ground.
 

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I’m planning to be in the 450-550hp range, why do you ask? And thanks for the quick response! I’ll definitely see what my machine shop can do and I’ve been looking at 3sx for bearing sets and I’m not sure which ones I’ll need if I have the crank ground.
Your machine shop will be able to supply bearings to suit the amount of material being removed.

Why is your bottom end in such bad shape, I thought it had just been rebuilt?
 

· Science, bitch!
1992 VR4
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I’m planning to be in the 450-550hp range, why do you ask? And thanks for the quick response! I’ll definitely see what my machine shop can do and I’ve been looking at 3sx for bearing sets and I’m not sure which ones I’ll need if I have the crank ground.
I was curious to see how hard you’d be pushing the reground crank. I think if the tolerances are correct and you get decent bearings, the crank should be fine at that power level.


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1992 Mitsubishi 3000GT VR4
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Discussion Starter · #6 ·
Your machine shop will be able to supply bearings to suit the amount of material being removed.

Why is your bottom end in such bad shape, I thought it had just been rebuilt?
Well I had finally got everything put together in the car and I didn’t wanna start the car yet because the fuel was rusty and had flakes in it but my friend who was with me that day convinced me it was fine. It wasn’t. So I basically ruined a brand new engine because of my own excitement to finally start the car and my friend convincing me it was okay to run the 15 year old fuel.
 

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1992 Mitsubishi 3000GT VR4
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Discussion Starter · #7 ·
I was curious to see how hard you’d be pushing the reground crank. I think if the tolerances are correct and you get decent bearings, the crank should be fine at that power level.


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Thanks for the advice, but do you think it would be better to just get a new forged crank? I know you said it should be fine but I do want to do this correctly with as little risk as possible of me screwing things up again lol
 

· Science, bitch!
1992 VR4
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Thanks for the advice, but do you think it would be better to just get a new forged crank? I know you said it should be fine but I do want to do this correctly with as little risk as possible of me screwing things up again lol
It all depends on the competency of the people doing the machine work, engine build, and installation. If you have a machine shop that you trust, know the engine will be assembled correctly, and do everything else correct, a reground crank shouldn’t be a problem at that power level. And a brand new crank won’t survive if there are issues with the rest of the build.


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old fuel didn’t hurt your crank unless you were doing WOT runs on it.

I was going to say ignore the few grooves in the journals but the journal in that last pic looks so scored, I’ve gotta ask… was the bearing spun? Like, what made you take this apart after it idled on old gas?
 

· Science, bitch!
1992 VR4
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old fuel didn’t hurt your crank unless you were doing WOT runs on it.

I was going to say ignore the few grooves in the journals but the journal in that last pic looks so scored, I’ve gotta ask… was the bearing spun? Like, what made you take this apart after it idled on old gas?
I was thinking to ask the same thing. If you spun a bearing you would need to be very careful reusing anything the oil system touches.


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