JDM 7-bolt...from RVR...please advise..

[95TalonTsiAWDam]

Looking at a JDM 7-bolt to replace my crapped out 7-bolt in the 95 Talon Tsi AWD 5sp. I have been and was about to order a 6-bolt and do a conversion when the guy said have you considered a 7-bolt JDM? He said that they did not have CW problems as the JDM 7-bolts (evo ver 3 and RVRs) were different. It is out of an late 90s RVR Suv from Japan and has the 13g turbo on it..I wouldn't be keeping the turbo, but I just want to know for sure or not if they did have CW problems.
The JDM 7-bolt would be the easiest to install back into my 95 and the guy said he had personally been involved in 1 swap and it was a direct drop in pretty much.
If anyone has any info on this topic please post. I want to get an engine ordered asap. If you have any reason of why a 6-bolt would be better or not please let me know.
Thanks,
Michael M.

 

[evolvingGS-t]

If memory serves me right, this guy is correct. I'm certain that the only walking crank(s) come from the U.S. market DSM. And of course you'd be getting a JDM which is a different market for parts.

The 7-bolt wouldn't be a bad deal cause you wouldn't have to deal with the swap of parts and re-wiring of a couple things.

 

[GPTourer]

I've never seen any conclusive proof that says that is true, and would be interested in hearing more about it. People talk about the differences in an Evo engine in things like compression, injectors, turbos - but everything else is the same, right? So why would they be less prone to crankwalk? And of course this being from an RVR at that. I also don't understand why a "JDM" 7-bolt would be any better then a 2G engine. All 4G63's are "JDM", there were no 4G63's built in Normal - its an assembly plant. Your original sticker, like all Mitsus today - say engine origen: Japan.

 

[95TalonTsiAWDam]

Yes, I know all 4g63s are from Japan, and that is the reason I am asking this question, how are they different? Yes, I have heard Evos have 9.0:1 as we have 8.5:1 (2g), but I don't know if the "all" RVRs have the 9.0:1 or not. I have heard there are 2 different versions from the RVRs one with the "evo" engine higher compression and it was offered with a 5sp. and the other was just an RVR 4g63 (assuming 8.5:1 compression).
But as I stated above, how would they be different than our 2g 7-bolts...why wouldn't theirs CW like ours when some power is thrown to it? Did Mitsu revise the 7-bolt after a certain year for the RVR and not the Eclipse/Talon?

Thanks for the thoughts...keep em coming.
MM

 

[evolvingGS-t]

You mentioned that it was an early '90 RVR, right? If that's correct, then it is like having a 7 bolt from certain 1g DSM's.

Is the crank from a 2.0l, 1.8l, turbo/non turbo RVR??

I know for sure that the EVO 3 was of course a 1995, which is when walking crank dates back to. Personally, I think you'll be okay with that crank cause I have seen the cranks out of EVO3's put into a DSM (2g) with no pbroblems for the life of the car.

 

[95TalonTsiAWDam]

It is from a late 90's RVR...96~99.
I thought it was the bearing(not being wide enough) around crank and not the crank itself that cause CW?

 

[eclipsegst3131]

FYI---all motors have the possibility of a walking crankshaft. 2g's are just more prone to it. the mazda miata also, is very prone to crankwalk. just felt like i could add my 2 cents


(correct me if i'm wrong)

 

[95TalonTsiAWDam]

FYI---all motors have the possibility of a walking crankshaft. 2g's are just more prone to it. the mazda miata also, is very prone to crankwalk. just felt like i could add my 2 cents


(correct me if i'm wrong)

Yes i believe you are correct, but as we all know 6-bolts hardly every. But the question still remains, are the JDM 7-bolts different from the "US spected" 7-bolt?
Will it live with the 50trim I want to throw on it?

Someone with the knowledge, let us know...

 

[hks-gst]

Hey I was going to do the same thing and order a jdm 7 bolt but I just decided to start fresh, with a motor from www.overbore.com check it out


ps. japan hates the u.s thats why we got crankwalk motors and theres dont. JUST KIDDING I love japan

 

[95TalonTsiAWDam]

Hey I was going to do the same thing and order a jdm 7 bolt but I just decided to start fresh, with a motor from www.overbore.com check it out


ps. japan hates the u.s thats why we got crankwalk motors and theres dont. JUST KIDDING I love japan

Yeah I have read about his "fix" to the CW problem, but that is way out of my price range.
I have a limited budget of ~1300 for a motor. I would like to see some higher millage overbore engines though(in a few years), just to see if he had "fixed" the problem.
Thanks for the input though.

 

[GPTourer]

the mazda miata also, is very prone to crankwalk.

So are MKIV Supras apparently. Maybe not nearly as bad as 2G's or Miatas. But when you think about the fact that there were only 5000 TT Supras (right?) ever made, compared to the tens of thousands of turbo 2G's and Miatas, it maybe be relative. Seems to hapen to guys with certain clutches and recent rebuilds. Sound familiar?

 

[94awdcoupe]

Early evos get crankwalk real bad. You have to search kinda hard cause there are virtually no early evos in america. Since the baords are based in america you wont find manny posts on the subject. I have seen posts from two overseas posters that have stated evo4 cars get crankwalk all the time.

I have a friend in the states that bought an extremely clean evo1 with 90k kilos on the clock. (57k miles). The engine had severe crankwalk. I have driven the car ands its badazz.

Crankwalk is a result of the crank in ALL 7-bolts not being nitrided like they are in 6 bolts. there is no comparison in surface hardness between the two style cranks.

 

[Batty200]

So are MKIV Supras apparently. Maybe not nearly as bad as 2G's or Miatas. But when you think about the fact that there were only 5000 TT Supras (right?) ever made, compared to the tens of thousands of turbo 2G's and Miatas, it maybe be relative. Seems to hapen to guys with certain clutches and recent rebuilds. Sound familiar?

Supras arent prone to crankwalk. Chris Bergeman crankwalked two from about 1000 starts with the clutch in in a few days to tune the AEM. Just disconnect the clutch switch if you are starting a car a couple hundred times a day.


Later

 

[95TalonTsiAWDam]

Early evos get crankwalk real bad. You have to search kinda hard cause there are virtually no early evos in america. Since the baords are based in america you wont find manny posts on the subject. I have seen posts from two overseas posters that have stated evo4 cars get crankwalk all the time.

I have a friend in the states that bought an extremely clean evo1 with 90k kilos on the clock. (57k miles). The engine had severe crankwalk. I have driven the car ands its badazz.

Crankwalk is a result of the crank in ALL 7-bolts not being nitrided like they are in 6 bolts. there is no comparison in surface hardness between the two style cranks.

So, should I just go with the proven 6-bolt and do the conversion(yeah i know not real hard, but why do it the hard way if there is no need)? I was told this engine from the RVR is identical to the evo 3 and the 2g american, as with the way it mounts. But where these cranks and bolts nitrided as you say? Would it be safe?

On a related note, I was under the impression that the width of the bearings was what cause CW (hence the suposed "fix" by overbore.com to widen the bearing journals). I thought Mitsu reduced the width try to free up power due to less friction between crank->oil film->bearing and that caused additional stress on the crank when perpendicular forces from the flywheel (during shifts) happened.
Now this was just what I was told, I have no proof (if anyone really does) so I didn't know if all 7-bolts where built that way or not.

Back to the question at hand though...are the 7-bolt JDM RVRs different than ours and will it live?

Ltr,
MM

 

[GPTourer]

Supras arent prone to crankwalk. Chris Bergeman crankwalked two from about 1000 starts with the clutch in in a few days to tune the AEM.

So your saying that one guy is the only one to have a CW'd Supra? That an auto MKIV has never walked? I spent 2 mins searching on Supraforums and found both of those statements to be false. The clutch pedal bypass helps out the 2G's too. And let me state again that I don't think Supras approach nearly the proliferation of CW as 2G's do (or Miatas, but I don't know much about them) but the shear number of cars on the road, plus the cost of ownership, might have something to do with it.

 

[eagle51]

Looking at a JDM 7-bolt to replace my crapped out 7-bolt in the 95 Talon Tsi AWD 5sp. I have been and was about to order a 6-bolt and do a conversion when the guy said have you considered a 7-bolt JDM? He said that they did not have CW problems as the JDM 7-bolts (evo ver 3 and RVRs) were different. It is out of an late 90s RVR Suv from Japan and has the 13g turbo on it..I wouldn't be keeping the turbo, but I just want to know for sure or not if they did have CW problems.
The JDM 7-bolt would be the easiest to install back into my 95 and the guy said he had personally been involved in 1 swap and it was a direct drop in pretty much.
If anyone has any info on this topic please post. I want to get an engine ordered asap. If you have any reason of why a 6-bolt would be better or not please let me know.
Thanks,
Michael M.

hey, can please tell me where you are geting a jdm 7bolt motor

 

[98spydert]

Crankwalk is a result of the crank in ALL 7-bolts not being nitrided like they are in 6 bolts. there is no comparison in surface hardness between the two style cranks.

This is one of many guesses. There isn't an answer or known cause for crankwalk! Remember that and don't spread bad information.