Cryotempering Happy Time 2 stroke engine

[chrisnbush]

I am considering trying this, there is a link on SpookyTooth for cryotempering these motors.

Cryotempering is supposed to improve the quality of metal - it is used in a lot of industries for automotive stuff, brake parts, etc. According to the link, you can get an engine to last up to 4x as long by bringing it down to -300 deg F for "a couple of hours".

I have a motor coming. My idea is to remove the magneto, wrap the motor in wet newspaper, and first place it in the freezer until -20. Then, after overnight, place it in dry ice at -70 in a cooler. Then, after a couple of hours, put it in another cooler and add a gallon or so of liquid nitrogen at -320 deg. F.

I was wondering if anyone ever tried the service that SpookyTooth advertises, I think it costs $75, but that does not include shipping. I assume that they can control the rate of cooling to make it much slower (!) than my rough steps above.

I am just toying with the idea at this point, as there is a pretty good chance I would just trash a new motor with my "treatment". But I don't know, I might just do it anyway. If it works, and I could get more than 2500 miles on an HT (my personal best at this point) it would be worth the $40 or so it is going to cost me in materials.

Any interest ?

Chris Bush

 

[spad4me]

Sounds interesting ,
The motors are so cheap. you could buy a thats dax longtblock for that price.
Post results .

I think they do that for their deathrace motors.

 

[give me vtec]

I think it would be worth it... I have a cryotreated 4g63 that I am putting into a 91 Galant vr4... when I get the money have the car painted.

Cryotreating is good for a lot of reasons... SimpleSimon would probably know more than me (so maybe you should contact him and see what he says) but I say go for it.

 

[arceeguy]

Honestly, I wouldn't waste my time.
Cryotempering, porting, polishing, etc. are just trying to make the HT into something it isn't.

High performance isn't in the DNA of the HT bicycle engine. It was meant to be inexpensive basic, motorized transport and it accomplishes those goals.

If you have a 50cc engine, I'd buy a cylinder with cast iron liner and a slant head. Better performance and durability.

 

[motorbikemike45]

If I were going to experiment with this I'd remove the crank, con rod, and any other steel parts and chill the engine in pieces, rather than assembled. Steel and aluminum contract and expand at different rates, cooling to this extreme will cause serious contraction and dissimilar metals might break under the stress. I'm guessing that crystallization occurs at these low temps and hardens the metal. I'm unclear if that same hardening wouldn't also make the metal brittle. I would bring the engine parts back to room temp very slowly and without shocks. Good luck.

 

[give me vtec]

Honestly, I wouldn't waste my time.
Cryotempering, porting, polishing, etc. are just trying to make the HT into something it isn't.

High performance isn't in the DNA of the HT bicycle engine. It was meant to be inexpensive basic, motorized transport and it accomplishes those goals.

...
yeah thats pretty much the truth... if you want reliability you gotta go with the eho35 GEBE.

 

[GearNut]

I have studied this technique and will share what I know to the best of my knowledge.
Each part would have to be done individually for it to work right.
Every part that is steel or iron can be frozen in liquid nirogen with excellent results. Auminum, brass, or pot metal can be frozen as well, it just won't have as great of an improvement.
It strengthens the metal (any kind) by causing it to freeze and contract at the molecular level to the point where it induces alignment of the individual atoms. Sorta like how a magnet works, but without mangetisim (no positive to negative electron charge specification).
In typical metals, even hardened ones, the atoms are arranged in a haphazard way. Aligning them greatly strengthens the part as a whole.
It will not harden metals like tempering will.
No, you will not end up with a "super" metal with cartoon like strength, just a metal with extrodinary strength compaired to the way it was before.
Here's some links on the subject to clear up whatever I may have gotten wrong:
http://www.metal-wear.com/
http://en.wikipedia.org/wiki/Deep_Cryogenic_Treatment

 

[chrisnbush]

Thanks guys, I will update this with results

 

[chrisnbush]

Well, here is a status report.

Liquid nitrogen equipment is expensive, you need a Dewars thermos (these cost 100s of dollars) to get a reputable welder supply place to give it to you, and they charge 7 bucks a liter for it. I probably could have borrowered the Dewars, but it can only be used for transport, it is either flask or canister shaped, you can't put a motor in them.
I don't think putting liquid N2 (-196C, -321F) in a 6 pack cooler is going to cut it somehow...

So I checked into dry ice (-79C, -109F), not as expensive, but I am in the sticks and the only supplier convenient (AirGas) wanted 5 bucks a 1 lb brick. I probably would need 4 pounds at least, and it was more than I wanted to spend. I also would have to buy a small 6 pack cooler as it would be best to fill the container as much as possible to slow the evaporation of the dry ice to treat as long as possible.

I work at a college, and as luck would have it, the biology department let me use their "so-low" freezer, which is -80 degC. So ->

1. I got my motor from DAX, removed the mounting studs + clamps. The motor comes without a plug, and I left the magneto in it, because, well I am lazy.
2. I packed the motor in a plastic bag, and covered with several layers of newspaper to "bundle" it.
3. I put it in a normal freezer for about 2 hours
4. I walked it across campus and put it in the "so low" I went as quickly as possible so the motor wouldn't warm up too much

I will leave it in the so low for 48 hours, then pick it up in a cooler, and reverse the process (put it back in a regular freezer for 2 hours, then bring it to room temperature).

Probably out a hundred bucks (!), but I have plenty of good magneto's and if worse comes to worse I will have "partially cryotempered" parts.

I know the temperature isn't low enough, but from what I understand about the process the higher temperature might have some effect, if you leave it in the freezer longer. The true cryotemper process, at least what is described in the link off spookytooth, is implied to be "a couple of hours".

Probably get it on the bike by the weekend to see what happened. I am pretty sure this voids the DAX warranty, dont' tell Duane ha ha

cb

 

[GearNut]

From what I understand, the true cryo treatment temperatures are soo cold that the electrons actually slow down in the individual atoms that make up an object. We are talking as close to absolutely frozen solid as you can get, where the atoms do not even move.
Normally on the atomic level, all the atoms that make up an object are constantly moving, vibrating at a resonate frequency, bouncing into each other. Glass, steel, rubber, rocks, water, trees, cows, elephants, lions, tigers, and bears, oh my, ect. everything on earth.