Here's a very technical test I did some years ago on a non cryogenic Crank and one that was. both Cast cranks where from the same factory production year and the same part number , both Cranks lent there services to this test due to them being reground all they could. From a distance of 3 feet I tossed the non cryogenic treated Crank at a big rock and it broke in two , the other Crank survived with only some nicks, in fact I tossed that Crank 3 times over at that rock and that was all my arms could take, lol!
Wow very interesting, I would love to see more info on the testing... I regret not getting my 350 block cry treated.
You know, I was just tidying up my tool box and discovered my Quantimet was missing. Larry - did you borrow it again ?!?! o No:ou::grin:
I am pretty sure you cannot cry treat a complete engine because it will change slightly in dimensions. This is why with my billet crank for instance what they did is they CNC the crank to rough shape, cryo-treat it, do rough machine work to it, cry-treat it again, and then do the finish machine work and its done. If they did not re-machine the crank after the cryo-treatment it would be out of spec. The freezing aligns the molecules strengthening it however this also makes a minor change to the shape.
Make sure it's filled with deionized, purified water first. :laugh: That was a good question, I wasn't intending disrespect. Maybe drop a few Mentos tablets into it for a rapid thaw cycle
Makes sense for a newly machined billet crank but for a 37 to 49 year block that has been through that many season changes especially in Canada with the ultra cold, the block shouldn't move much at all beyond the molecular level being how it should be well "seasoned" before treating. I have heard of the General stacking blocks outside for a couple of years before machining so the blocks would be "seasoned" so they wouldn't move after machining.(not sure how true that rumor is though) When making precision angle plates and other precision tools the metal would be machined, heat treated and rough ground, then back in the day they use to bury that kind of stuff so its in the frost line for at least 2 years to "normalize" the metal before finish grinding. Doing it that way you were insured that the angle plate or other tool would not move after finish grinding. Fast forward and the same thing can be done with a -30 freezer and a programmable heat treat oven to slowly take the tool up to about 200* F IIRC and slowly bring it back down to room temp. Doing this a couple of times would mimic what burying the parts for 2 or 3 years would do but a lot faster, days instead of years! Then finish grind and the tool would stay true for the life of the tool if its not abused or overly used. But no big deal to re-grind something like that if you still work in the shop that you originally ground the tool in the first place. Anyway, it wouldn't hurt to ask if it is possible to treat an assembly. Derek
I see your point and you may be right... I would be interested to see this done to a complete engine it would be cool if it worked! Someone should call one of these places who do cryo treatment and find out if it's possible.
Derek, I think you realize with cryogenics the temperature goes way beyond what Canada can produce, right? From memory, the company we used went over (or under?) what is technology the start of cryo which is -238*F
No, you can't treat an assembly. Need to finish hone the cylinders after cryo treatment. I have done several. JW
I didn't suggest that the Canadian winters would cryo an engine! :laugh: I was simply pointing out that with 37 to 49 season changes the sbb engines have normalized enough that they won't move as much or at all as they would if they were only a year or two old. That's where the term "well seasoned block" came from that rebuild companies use with the insinuation that the block is done moving and the re-machine for their rebuild will be better than from the factory. And that's why I asked if an assembly could be treated. Thanks for answering JW. Derek
Great thread! Every time I come here I learn something. And I wouldn't mind a little cyro here. Its 100 F today. Thanks to all posters! Chris
