I am currently experimenting with the various metalurgical advantages of cryogenic treatment of engine componenets, namely crankshafts, and was curious as to whether any other members had any knowledge or information on this subject.
I am in the process of cryogenically treating an EJ207 crankshaft using liquid Oxygen however I was contemplating substituting the cryogenic medium for liquid helium allowing me to drop to 4K or -268 Celsius. My concern is that lowering the temperature this close to absolute zero may result in a breakdown of the molecular structure of the crankshaft. The only material that I know that has benefited from this level of cryogenic treatment is A06 Nitride Steel which saw and incredible 280% increase in sheer and torsional strength.

Any ideas? Unfortunately the only means I have of testing a cryogenically treated crankshaft is in an engine which I would rather not do if it will fail prematurely.

To tell you the truth, theres probably no need to cryo treat an EJ207 crank. How many EJ207 cranks have you seen broken or bent before?

I know cryo treatment can reduce wear, but in a situation where wear is accelerated i.e. race use, engines are replaced often enough to negate the need to spend money treating crankshafts.

I know of people over east running Mazda/Ford AWDs with weak gearboxes who swear by cryo treating the gear sets to make them stronger, but have not read/heard of anyone doing anything similar over here

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MY93 Impreza GX 1.8L, 0hp, 0nm

Thanks for the feedback guys,
yeah I'm sure an EJ207 crank could go without but I'm fortunate enough to have access to the facilities and thought I'd try 'dipping' some parts. I am working with my brother and luckily for me he has access to the Physics Department at the University of Western Australia. Could be an interesting thesis!

Yeah hows the dipping process all work anyway... is it just an in out thing once or is it done slowly like annealing? But yeah physics dept resources ftw! i wish theyd give me processing time on the supercomputer lol... guess ill have to make do using an entire lab of ee machines distributed processing

Wanna hook a subaru brother up? I wouldnt mind cryo treating my Legacy box. Its gotta come out soon to do a clutch change. And your brother can borrow it if he wants to use it for research for a thesis.

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RS Liberty - Because WRX's are only good for parts...

The process is very simple and is literally a 'dip' however the retention time depends on the mass of the item and the amount of cryogenic medium. Basically we measure the change in temperature of the medium as we add the item (say a crankshaft). We then seal and pressurise the item in the medium to bring the whole lot back down to the original temp which for liquid oxygen is around -185 celsius. We can go colder with more pressure but liquid oxygen is really only good for about -196 celsius.
(After that you take a huge step up (or down) to liquid helium but that is a whole other level as it is pushing on absolute zero. That is where we haven't been yet and was seeking information on before I sacrifice a good crankshaft).
Once the medium and the item are cooled to the desired level it is left for about 1 minute (it doesn't take long to freeze through)and then depressurized and removed from the medium. It is left to warm up by itself in a controlled environment of 2 percent humidity and 20 celsius until it reaches that point. For the EJ207 crank it took about 4 hours. The whole process for the EJ207 crank took about 6 hours. Unfortunaelty for you Mister Two we are only using about 200L of liquid medium and due to constraints on the size of the container we would not be able to fit the gearbox through the top port (it looks like a big milk bottle about 1200mm high with a 200mm round opening), I will ceratinly keep you all updated on our progress and as soon as we start doing some physical property testing I will let you know the results.
I can tell you that the piston rings from a an EJ205 (04 model) didn't work. The little bastards became so hard we couldn't get them around the piston again without deforming them.

Cheers.

You wouldnt want to cryo treat piston rings anyways as you need them soft enough to wear into the bore when running the engine in. Treating the piston itself is probably more important as you want the ring lands to be as strong as possible. But I dare say that nothing is going protect them from major detonation that can already kill a standard forged piston found in the ej207 short block.

As for my gearbox. If I get someone to break the gearbox down and pull the gearset out. Each gear or shaft shouldnt be any more than 200mm wide. I think.

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RS Liberty - Because WRX's are only good for parts...

I'll keep you posted Mister Two. At the moment my access to the facilities is dictated by my brother and his 'research' time. We did most of the testing over the summer but know that classes are back in full swing it may be a little harder to get regular access. To be updated!

any updates?

Yes I've been thread mining