2.4 stroker - forged or cast crank

[peregrine]

That is so much better . I know it’s hard sometimes not to be confrontational when replying to a guy you believe is totally wrong, unfortunately been there and probably will again. It would be nice to always have the courtesy to ask why the other guy thinks is right before, and then try to present your evidence.
Would it be too much to ask who your machinist is and if he sold you the crank?
Also what kind of hardness numbers did he give you on the two cranks?

i got my 2.4 motor from a junkyard in sacramento so he didnt sell me the crank. the name of the machine shop is hewes performance located in reno nevada. i cant remember any of the data he showed me but i remember being satisfied with the results (its been a year ) this all resulted from me asking him if the crank needed to be turned and he said not if it didnt need it because of the nitride. i thought the same as you but he showed me different. ill see if i can get those numbers for you.

*edit* heres my machinist. he owns the shop. every result you see is him. he holds all sorts of drag racing records.
http://search.yahoo.com/search?ei=utf-8&fr=slv1-&p=tony hewes reno

 

[jtmcinder]

Nitriding hardens the surface of the crank, maybe to a depth of 0.03" at best. Differences between two cranks that are deeper than this will not only remain, but might not be detectable by a Rockwell test for surface hardness. In addition, different lengths of nitriding can change the depth of hardening while not changing what one would observe in a quick and dirty Rockwell test.

In short, equal Rockwells does not imply that the cranks are the same. It is consistent with such, of course, and might even be seen as one point in favor of the idea that the cranks are the same, but it is far from proof.

Glad to see the thread take a turn in this direction.

- Jtoby

 

[Suparata]

Hopefully you can get those hardness numbers soon. In the meantime take a look at these pictures that might explain why I believe that the two cranks are not the same.
http://www.engintecs.com/gallery2/main.php?g2_view=core.ShowItem&g2_itemId=2433
If the differences are obvious, the next step would be to analyze them and compare to the 2.0 Mitsu crank which can be considered as a standard.

 

[peregrine]

Hopefully you can get those hardness numbers soon. In the meantime take a look at these pictures that might explain why I believe that the two cranks are not the same.
http://www.engintecs.com/gallery2/main.php?g2_view=core.ShowItem&g2_itemId=2433
If the differences are obvious, the next step would be to analyze them and compare to the 2.0 Mitsu crank which can be considered as a standard.

thats really weird as my crank doesnt look like that. that crank in that pic is obviously not hardened. this makes me wonder if some were hardened and some were not. speculation?

 

[Suparata]

The one in the middle in this picture
http://www.engintecs.com/gallery2/main.php?g2_view=core.ShowItem&g2_itemId=2927&g2_imageViewsIndex=0 is a new Hyundai which looks similar to a Mitsu but it is still not the same. It does however have the same surface hardness as the used Hyundai crank.
Do we agree on the fact that they are not the same exact ones as the Mitsu?

 

[peregrine]

The one in the middle in this picture
http://www.engintecs.com/gallery2/main.php?g2_view=core.ShowItem&g2_itemId=2927&g2_imageViewsIndex=0 is a new Hyundai which looks similar to a Mitsu but it is still not the same. It does however have the same surface hardness as the used Hyundai crank.
Do we agree on the fact that they are not the same exact ones as the Mitsu?

yes you are right there. whats weird is that my crank looks *exactly* like the one on the right. see the coloring on mine? and yes im positive its a hyundai crank. this is weird.

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[Suparata]

The one on the right (yellowish, tan, whatever) IS a Hyundai crank.

 

[peregrine]

The one in the middle in this picture
http://www.engintecs.com/gallery2/main.php?g2_view=core.ShowItem&g2_itemId=2927&g2_imageViewsIndex=0 is a new Hyundai which looks similar to a Mitsu but it is still not the same. It does however have the same surface hardness as the used Hyundai crank.
Do we agree on the fact that they are not the same exact ones as the Mitsu?

The one on the right (yellowish, tan, whatever) IS a Hyundai crank.

your confusing me.

 

[peregrine]

heres a shot of a 2.0 crank in my garage. same coloring. the difference in color between my hyundai crank and any mitsu crank ive seen is non existant.

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[peregrine]

nevermind the above posts i was on like 2 hours sleep. this whole arguement is going nowhere. i saw the results of the test on my crank and was satisfied. i cant expect my machinist to have/remember stuff from a year ago. peace.

 

[Big Woo]

As Suparata stated earlier in this thread with regards to the title "billet vs cast" All of the cranks mentioned, and pictured in this thread are forged, none are machined from a billet, and none are cast. Having been through 75 plus Mitsubishi 4G63/64 series motors, I have yet to find one with a cast crankshaft. Please do not take this to mean that there are no Mitsubishi cast crankshafts, I am just saying that I have yet to find one in 4G series motors that I have been through.

The pictures show some obvious differences between the crank forgings, enough to at least suggest that the forging dies used are different. I am no expert in forgings, but logic would at least suggest that if different dies are used, then they are being forged in different locations, on different presses, with a slightly different material composition.

Actual hardness numbers achieved depend greatly on the exact chemical make-up of the material used in the hardened part. Basicily differing amounts of iron, carbon, coke, nickle, chromium, and molybdenum (among others) determine the hardenability of a given part.

 

[AL92]

I am building a 2.4 6 bolt and have already bought pistons,rods,etc. Now another guy I just talked to has had a 2.4 crank go on him. I didn't get all the details yet on if he turned it,magnafluxed it or whatever. I am a bit paranoid and could maybe still sell the 2.4 block and crank and new wiseco pistons and build a 2.0 6 bolt for my 97 talon have a spare 2.0 6 bolt sitting here also or can buy a built one maybe for cheap locally.

But also heard a few things like leave the balancer shafts in the 2.4 and also wondering how much a super strong clutch as this guy runs a 2900 act might effect the crank.Have another buddy happily running a 2.4 for over a year with no problems yet and read of several guys happily running them and pretty sure magnus and jackson machine and several other shops are still selling these 2.4s with not much if any problems with the crank breaking. Now you guys are saying there is a alternative I can buy for this 2.4 and its like 1200 bucks? That is pricey but might consider it if really need too.

So how many guys have actually broke these 2.4 cranks and curious about if they were turned,balance shafts if any in motor,clutch ,etc.

 

[jpbrazill]

I have a 4G64 block and crank in my talon. I put in Eagle rods, wisecos, and removed the balance shafts. I have an ACT 2100 6 puck, and did NOT get it balanced. I have had no problems with it. Before the head work, put down 377whp with 9:1 A/F ratio. Didnt have enough time to finish tuning.

Other than that, even with the stock head and cams I got into boost REAL quick. Cant wait till shes all back together. Just waiting for the cams now... hope that helped.

 

[93AWDTalon1]

what kind of boost were you running?

 

[jpbrazill]

what kind of boost were you running?

18psi. Here are all the numbers:
377.70 whp
335.99 torque
61.98 * F
24.34 in-HG Humidity 31%
Mac Autosports Parker, CO
Dynojet

That was the last run of the day...didnt get to cool her down at all, we ran out of time

Anyway, hope this helps

J.P.

 

[Turbocharged]

Could you guys clarify something for me? I was under the impression that all 6 bolt cranks were out of hyundai's and all 7 bolt cranks were out of the mitsu's. From Suparata's pictures both the hyundai and mitsu appear to be 6 bolt's. Im sure I just got wrong information from another thread .

I am currently building a 4GCS. The crank that I purchased was polished but has nothing else done to it. I am not planning on any other machining because I do not want to compromise the nitride surface treatment. What suggestions do you guys have?

Also, my crank is hyundai and is gold/yellow like suparata's picture... From what I remember in my material science course, nitriding will turn exposed metal from a dull color to a more of a gold color. Are our cranks gas or liquid nitrided from the factor?

 

[Kevbo6204]

Having done Rockwell Hardness Testing is my metalurgy class I can tell you a few things I learned. Nitriding for one is a case hardening process which only effects the surface of the metal for around .02 inches into the surface of the part. Taking Rockwell Hardness Testing of a Nitrided surface says nothing in the sense of the internal strength of a crankshaft. A true test to see if these cranks are the same would be to take 2 cranks and cut into them for a sample of each. Then taking a Rockwell Hardness underneath the nitriding. As for the type of Nitriding used I would guess a process called Ion Nitriding. This if you really would like to know is where electrically charged low pressure nitrogen is released into a chamber where the part is. Ions from this gas are attracted to the part and begins to collide quickly with the surface of the part thus heating it up to the 950 degrees needed for the diffusion of the Nitrogen into the part. Thus you have Nitriding. The gold color you see is the coating. The reasons for not just coating the journals of the crank are becasue its just not cost effective in the automotive industry for the time spent masking it off the rest of the crank. The crank would have to be completey cut out and all machining done before this process were used. Also any heatreating would have to be preformed as well as stress relieveing the part do to internal stresses that would other wise warp the part. Trust me I have more to say about it but its toooo much typing Man I love college! HAHAHA By the way before you guys get in tooo many arguments about stuff you guys should really get a copy of Machinery's Handbook. SOOOOO many questions you have will be covered in there. Its honestly my Bible for being a Tool and Dye Maker!

Peace,
First Year Machine Tool Student!