Resurfacing a crankshaft - Subaru WRX Forum
 
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post #1 of 15 Old 01-07-2008, 11:30 PM Thread Starter
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Resurfacing a crankshaft

Can an ej207 crank be resurfaced, or any crank for that matter? If so, what is the procedure, how to get it done?

The crank is forged, nitrated, factory balanced, you know, the best... But the motor spun a rod bearing and there are these very bad (screaching fork on the glass bad) scratches.

help please,
thanks

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post #2 of 15 Old 01-08-2008, 01:03 AM
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no clue but you should be aware that the EJ207 is a JDM motor which never hit the USDM market. Your 2.0L is a bastardized version of the EJ205...

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post #3 of 15 Old 01-08-2008, 02:05 AM Thread Starter
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I know, i have the motor appart right now. I swapped the motor for an ej205, so the car is driveable. The thing is, i am not sure on what to do with the parts from a blown motor. It is a spec c 2.0 with a spun rod bearing.
Few options that are out there for me to put the jdm 2.0 back together are replace a crank with a used one, or get a sti 2.5 crank and build a 2.2 lt motor, or resurface. I am not familiar with resurfacing, hence for the question.

At this point it only a matter of time coupled with style of driving before the 205 goes. It is fed by vf39 at 22psi tapering to 18 on the short ration 6 speed, so more stress on the motor. I am trying to make a decision on wether to detune the current 205 set up so it would last or just push it and rebuild the 207.

Just wanted to add that i did the swap by myself and am planning to rebuild by myself; learning while saving money.

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post #4 of 15 Old 01-08-2008, 11:25 AM
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kk, sounds like you know more about it than me than. Hopefully somebody can help you. Good luck!

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post #5 of 15 Old 01-08-2008, 03:38 PM Thread Starter
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kk, sounds like you know more about it than me than. Hopefully somebody can help you. Good luck!
thanks MOSC... I always appriciate your comments.

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post #6 of 15 Old 01-08-2008, 04:01 PM
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Well from my experience you'd be better off buying a new crank. The crank is reground, retreated and rebalanced, but the cost of having everything done to the crank will probably cost more than a new one.
You know what why not just give me the whole motor and your problem will be solves... I say go for the stroker motor anyway.

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post #7 of 15 Old 01-08-2008, 05:14 PM Thread Starter
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Thanks, that is what i was thinking.
I won't give you the motor although that idea might come up if i fail or get tired of the build--when one's pissed anything can happen. I can get a USDM sti crank for about 300-400 dollars used and hopefully not abused, a set of used or new forged rods, some new crank and rod bearings--around $1000 for a beautiful stroker. Plus all my labor and a good tune. Maybe by the end of Summer this will be complete... If not i'll just give it to psinuse...

Cheers!

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post #8 of 15 Old 01-08-2008, 07:04 PM
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ProjectWRX -A Subaru WRX enthusiast site - Content Here is a link that can get you started on your stroker, of course you already have some of the parts so it won't cost as much. Good luck man.
p.s. As far as getting mad yeah, my tool set and old laptop could tell you stories... :P

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post #9 of 15 Old 01-08-2008, 09:48 PM
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do you have a JDM ECU laying around? You're going to need one if you go that route. Or maybe a Hydra if you're smart like that (I'm not).

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post #10 of 15 Old 01-08-2008, 11:29 PM Thread Starter
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do you have a JDM ECU laying around? You're going to need one if you go that route. Or maybe a Hydra if you're smart like that (I'm not).
Yes, i have a jdm sti ecu. As far as Hydra, i have no idea about it right now. I am reading a book by Hartman on tuning and engine managment systems, so maybe later i'll be able to use sophisticated stand-alone's. But, first i would like to learn how to use opensource safely.

But You bring up a good point indirectly: whether or not a 2.5 crank will be able to rev to 8500 rpm in this planned stroker since i will be using it with jdm heads. I guess, some more research.

Cheers!

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post #11 of 15 Old 01-09-2008, 06:13 AM
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It can be made to rev that high with the correct internal balancing, but I don't know if I would do that. Of course the type of stroker your wanting to build does have a smaller piston just a longer stroke so it might be okay, just ask the guy at the machine shop what he thinks. As far as tuning with opensource

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post #12 of 15 Old 01-09-2008, 12:24 PM
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I wouldn't run a stroker kit at the old redline on basically any motor. You're multiplying the stress. I would caution more like a 7500 RPM redline for that. Maybe even less mattering on where the power line ends up being.

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post #13 of 15 Old 01-09-2008, 04:24 PM
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Originally Posted by mosc
I wouldn't run a stroker kit at the old redline on basically any motor. You're multiplying the stress. I would caution more like a 7500 RPM redline for that. Maybe even less mattering on where the power line ends up being.
Well just using the stroker kit I will agree with you, but if you build the motor to rev that high it will be able to go higher in the RPM range without problems. This of course means that the valvetrain, heads, cams and various other parts need to be able to handle the added revs as well as the added engine size. I also will stress the fact that a good internal balance will make the engine rev easier and higher than just slapping it together, but I digress.

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post #14 of 15 Old 01-09-2008, 07:55 PM Thread Starter
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Originally Posted by psinuse View Post
Well just using the stroker kit I will agree with you, but if you build the motor to rev that high it will be able to go higher in the RPM range without problems. This of course means that the valvetrain, heads, cams and various other parts need to be able to handle the added revs as well as the added engine size. I also will stress the fact that a good internal balance will make the engine rev easier and higher than just slapping it together, but I digress.
I have read that the limit of the ej257 is the valvetrain, since the plan is to use the ej207 heads redlining at 8250 might be fine. But yes, to dyno after the build and set the rev limiter accordingly to the powerband.

Thanks!

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post #15 of 15 Old 01-09-2008, 08:39 PM
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Originally Posted by b7g
I have read that the limit of the ej257 is the valvetrain, since the plan is to use the ej207 heads redlining at 8250 might be fine. But yes, to dyno after the build and set the rev limiter accordingly to the powerband.

Thanks!
If you plan on reving it that high it is going to cost more than $1000 . The machine work alone will probably cost upwards of $500-$600. Please if you do decided to build a high reving stroker talk to a machinist the knows what he is doing to make sure that the internals are balanced correctly, for that matter give Pauter a call and talk to them about it. The more knowledge you have going into this the better, but i'm sure I don't have to tell you that.

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