pratch

For those considering it who are fortunate enough to have a running engine, my dad (systems engineer) and I had an interesting discourse. I tend to be on the camp of ATF needs to soak forever (2 weeks or so) to be worthwhile and accordingly isn't a cure-all. However, the realizations below (paraphrased ephiphanies during the conversation) show that if your engine runs, you might still get speedy benefits.

We all know ATF contains lubricant and detergents, right? We all know that we can basically say that either the detergents are volatile (ready to brust into flames) or non-volatile (they'll heat up and then boil or vaporize and then be carried away). With me so far?

Good.

We're moving forward on the belief that the detergents are non-volatile. During the starting up and burning off of the ATF, everything is heated up hundreds of degrees. The effectiveness of the detergents is a function of chemical reaction rates. Reaction rates double for every 8-10 degrees Celcius/Kelvin of temperature increase. It's conceivable that much of the value of the ATF treatment comes from the startup where everything is subjected to said high temperatures, rather than the weeks of soaking. If that is true (which it seems reasonable so far), then introducing the ATF to a hot engine and allowing it to soak then, the effectiveness may be increased considerably.

So let's run the rotary for 10-20 minutes to allow as much heat saturation as is possible. We should have a Kelvin temperature in excess of 400 degrees (300 F). Using Florida as an example, where we can say the mean temp would be about 85 degrees F (30 C/300K) were we to merely ATF a cold engine.

Here's where the faint of heart might want to move away...

Internal core temperature of the Rotary Engine after shutdown must be near 300 F (150 C), or 420 K
420 - 300 = 120 degrees
120 / 10 = 12 octaves (doubling of the reaction rate)
2^12 = 4096 The attained reaction speedup ratio.
Assume the engine cools down such that the effective time at the high reaction
rate is only 15 minutes.
4096 * 15 min / 60min/hr = 1024 hours

So... ATF soaking a hot engine for only 15 minutes, utilizes the detergents in such a fashion that... the effective reaction time of an ATF treatment done to a hot engine would be the same as 1000 hours of soaking at Florida summer temperatures, or nearly six weeks! Since the engine has a lot of aluminum mass and the coolant is near the boiling point of water when you shut down, the core temperature will actually rise for a while and the effective time at elevated temperature is probably beyond 15 minutes.

Even using internal temperatures nearer the boiling point of Water or Water/glycol results in seeing an effective reaction speedup of well over 100 so a hot engine treatment is well worth several days of soaking.


So now you have a wonderful peek into my family dynamics and the kinds of things my dad and I will talk about at odd times. We both drive rotaries, and definitely enjoy the uniqueness of that.

So, thoughts, comments, critiques? Should I post the email exchange in full? Oh yeah, Sterling - this one's for you - I can't let you have all the good theory posts

Metallic_rock

interesting... won't worry about letting it sit overnight or a week again...

inittab

you and your Dad must some goooood stuff

pratch

LOL, maybe many years ago, but the kind bud has not entered my lungs in over a decade

I'm just what would be called a "smart guy" My dad definitely falls in the category of what we would call a genius.

vipernicus42

iTrader: (4)

<----- loves these kinds of chem discussions, but thinks this certain one is slightly irrelevant.. despite how interesting it was.

Why is it irrelevant to me? Because ATF (in my mind at least) is *only* for people whose engines are siezed... It's a "Last-resort-only" kinda thing... I used ATF on mine, becuase I couldn't turn it at all. My choice was to try atf, or to rebuild the engine. I don't advocate using ATF on working engines...

But great chem theory there I've always loved Chem.

pratch

Well, for those having oil leaks due to stuck seals/springs, carbon build-up - all of these a relavent to the ATF matter. If you have a side seal leaking because the spring is stuck - voila - this instantly becomes germane

Tom

Very interesting- So if what your saying is true-I should superheat the water going into my washing machine, say to 300F, add my detergent and clothes, run for say a standard 15 minute cycle, and it would be the equiviliant of washing my clothes in Florida on warm for 1,000 hours??!! It would definately make my whites not only whiter but ULTRA-WHITE and super clean??!!

Dude- YOU are on to something here..

jk- sounds interesting to me. I'll remember this if the need arises. My father in law and I have similar conversations concerning mathmatics and economics (he is a mathematician//genius) Unfortunately i'm semi- smart and certainly above a dumb ***..
(I guess i'm just a smart-*** )

pratch

Until I read the last part of your sentence, I thought I was going to have to go off on you like you were some sort of plebian ****-bite

Now if you were washing your clothes in ATF on the other hand...

vipernicus42

iTrader: (4)

Someone once told me that the rotor's side seals would swell because they're rubber.. Not sure about that, and it's one of the things that has made me wary about using ATF....

Jon

Tom

Damn chemical / engineers are all the same.. Can't spell worth a damn. Thats plebeian ****-bite to you!

Actually I never heard of using ATF before. We've soaked seized tractors with Kero and some stuff called Kroil (i think) to break them free. ( I don't think I would try it on a Rotary engine though- the last time we used this combo on tractor looks like a flame thrower for a few moments after start-up!)

Wankelguy

So much mental rumination, I hate to say it, but...
ATF is bad for your exhaust system, at the very least.
You know how I clean my engine internals? I warm up the car and spray Amsoil power foam in the carb while I keep it running, then shut it down, fill the carb with more foam, hand-crank it into the motor, let it sit in the heated motor for about 30 minutes, then start it up and blow it out followed by a 30 minute drive at highway speeds to make sure that the carbon doesn't redeposit itself in an apex seal slot. I've been doing it this way for years, to hell with ATF.

inittab

You mean THIS STUFF? :

mwpayne

"The GOD-D*#@ Germans got nothin' to do with this!!!"
*Quote from sheriff Buford T. Justice, Smoky and the Bandit.

Couldn't help myself...

Jeff20B

iTrader: (13)

Interesting thread. I'd still steer clear of ATF though. I also like what I've read about this Amsoil power foam.

purple82

Pratch-

Chemical reaction is not only dependant on rate of reaction but also on concentration and rate of diffusion. So if you pre-soak parts before heating them, you've got a head start on diffusionand the time for the total reaction is reduced.

White84SE

My 2 cents on this matter... as was stated before, I will NEVER use ATF on an unseized engine again. My '82 flooded once and I pulled the plugs and ATF'd it. Let it sit for a bit and "cook" out... about three days later my engine went ka-put... my theory is that the ATF did hat it was supposed to do, and loosened some carbon. However it didn't destroy it. The next time the car ran, the chunk came loose and took out a seal.. could be speculation, but I won't know until I tear the engine down and check for total carbon buildup, but it's my opinion...

--Danny

Wankelguy

That's precisely why it's important to take the car out and drive it at highway speeds for at least a half-hour, to insure that all the crud gets blown out, rather than redepositing itself somewhere BAD.

White84SE

Well, I would have done that, but I was late for class and I had the car's battery on a charger, so I couldn't exactly hop in it and nail it...

--Danny