After having one of our old crank shafts magna fluxed to check for cracks, we discovered 3 cracks in the rod journals. We recently had a new crank Cryo'd, knife edged and polished..
For those of you who do not know, Chryo is is a prosess of freezing the crank to super cool sub zero temepratures, where the molecular compound of the metal changes. This is supposed to make the part about 30% stronger..We shall see about that.
We also decided to have the crank knife edged while we were getting it balanced and polished. The knife edge may increase the efficiency of the cranks ability to cut through the oil in the upper oil pan, thus eleviating some reciprocating mass and freeing up some power and enabeling for higher revs. This process is used in lots of pro stock cars as well as Nascar.. We wanted to be different, so what the heck..Were always trying new things..

 

looks awesome!!

 

i saw this in person and yes it truly is awesome

 

Looks really nice. I will definatly keep posted on any updates and cant wait to see what if any differences it will make. Nice job.

 

I had looked into cryo treating components on my build, but decided against it. I was fearful of making the crank more brittle. Any thoughts?

 

I'm pretty sure it doesn't make it stronger unless the cryotreatment is done during the annealing of the original cast

 

I'm very curious about this also

 

there is always a trade off when heat treatments or, in this case, cryo treatments. Finding the right balance of strength to toughness is the key.

Please keep us informed on how this crank ends up performing!!! It's always great to see people trying new things!

 

Looks awesome, can I have one for free?

 

If you have a 19 year old hot girlfriend to donate to us, then YES..Yes you can.. Or cake..I can has cake?

 

Well, Cryo Treating has been done with great results for some time on alot of race applications. We will see if the crank shatters into a million pieces at 8000 rpms. although that would be pretty cool to see the aftermath of that..
What alot of poeple dont understand is that the atoms in materials are contantly at motion and moving around bouncing off of one another. The Cryo treatment slows down the atoms and rearranges them, which solidifies the material. At least, thats what I got from the long winded explenation...I could be wrong

 

30% stronger is a little far-fetched. It varies from material to material because all it is doing is changing the metal's crystalline structure from austenite into martensite which is a more refined grain structure. It increases wear resistance and actually reduces brittleness and reduces the residual stress from the original process. The increase in strength is marginal at best, probably less than 10%.
That being said I still believe in it and have done it on several engine parts with good results so far.

 

Julian, what would you say the mean operating temperature of the engine would be...specifically around the crank shaft?


http://www.finishing.com/340/78.shtml Stuff about cyrogenics...the first really long post is good from a materials engineering perspective.

 

No clue.

Coolant temp varies from 180F to 210F average, and Oil temp from 180-230F also..I would assume gigher than those numbers, since the fluids are being circulated through coolers to keep them at that temperature.

 

Im just going by what I have read and been told on Cryo. This will be my first experience with it.
I also dont know how they come up with the 30% numbers, do they test the breaking point of materials prior to and after the cryo? I would guess..

 

NASA uses that process on some of their parts.... so i am a believer

 

Looks awesome.

Flying out to east Europe shortly.

 

Julian,

Looks great - just wondering if you considered the GTM crank? (Or is this an incorrect application for that part - forgive my ignorance; have not read too much about replacing the crank).

Thanks.

 

(subscribing for results)

looks good J

 

GTM crank is big money and I think the lead time to get one is a little bit excessive. Maybe GTM can chime in with specifics