I did a search on this but didnt find too much....
I also googled it an didnt come up with a lot either.

Does anyone have any personal experience with cryo treating engine parts?

Also if anyone has any links to websites that explain the process and gives comparisons on how much integrity is added to the part?

I may cryo treat my stock crank, and rods and add ARP bolts to the main caps and rod bolts. I have forged pistons and plasmamoly rings that will probably get the treatment as well.... this will be used on an LE2 heads/cam 355 LT1.

im really curious to see how the strength of these treated parts and the personal experiences of those who have used them or are currently using them.....

 

I know this doesn't answer your question, but let me ask why you are considering doing this? If you only plan on building an LE2 355 then you are going overkill with the forged pistons in my opinion.

From what I understand about cryogenic treatments, the main advantage is the durability at a given power level. Cryogenic treatment hardens the metal, but should therefore also make it more brittle. So I would say that if your crank is good for 500hp now it might only be good for 485hp after cryo treatment, but it would last twice as long without have to be turned.

I could be completely wrong about all of this though, but I'll research it a little and post again if I can be of any more help.

 

Waste of time and money.

Rich

 

Interesting tidbit. Ferrari does something similar to a part of the heads on their engines (retainer maybe?) just to make it cold enough so the machine can set it in place and let it expand to normal size.
Another interesting tidbit is that they say all their engines are handbuilt.
*thinks about ls7*

 

That's just doing the opposite of a typical "shrink fit" procedure where the outer member is heated the inner member inserted and the outer member shrinks to produce an interference fit. Chilling the inner member is often easier, especially for a very light interference, and if the inner member is small, like a valve guide.

This assembly procedure isn't really cryo treating which usually involves soaking the parts at the low temp for hours.

If you REALLY wanted a tight fit, you could use this procedure to make a 2-piece rear end pinion into a "one piece" part: Machine splines on the (hollow) shaft and the pinion gear which interfere about .015, cool the shaft in dry ice and alcohol to ~-120°F, induction heat the gear to about 1000°F and use a 40 ton press to assemble the parts (spline-to-spline). You can hear the metal squeel during the assembly for 50 yards in a noisy gear plant. If you section the part, polish the section, etch it and look at it under a microscope no joint of any kind is visible. Only the grain flow direction changes indicate where it is.

This procedure was used because making the hollow stem out of tubing was easier than drilling 8 inches thru a forging. The shaft and the gear could also be different steel alloys. This was done more than 45 years ago, BTW.

LS7 engines are "hand built" but they use some very sophisticated assembly tools. Ferrari does also. The torque on every (critical) fastener in the engine may be recorder and keyed to the engine serial number. I think it would be cool to get a CD with your LS7 engine with the torque (or perhaps stretch)data on every fastener. I'd pay extra!

 

I know that a lot of Honda guys are heat treating their trans internals instead of Cryo treating them. The guys that are breaking transmissions have stated that they saw no or nearly no durability improvement over stock with cryo treating. Those same people have had great luck with their "heat treated" gearsets.

Thumbs down to cryo from me, too...

Ryan

 

It's a waste of money. Any further formation of martensite by cryogenic treatment would need to be engineered into an alloy from the beginning.

 

Both good points.

Unfortunately most folks including most gearheads don't have much knowledge of metallurgy, let alone heat ( or cold ) treatment of steels. Even Googleing (or is that 'Googling"?) "martensite" wouldn't make what 95 Z/28 LT1 posted have much meaning to most folks. That's what makes it easy for opportunists to sell high-priced processing like "cryotreating" as a magic metal enhancer. It isn't.