It seems the ATF and MMO are nearly identical in their carbon softening ability. I was able to chip all the way through the carbon on the spring side of both apex seals with my thumbnail, all the way down to the metal. It took similar amounts of effort on both.



Then again, the carbon could have come off just as easily before the seals were soaked. I'm going to check out the remaining two (unsoaked) 13B seals in a few minutes.



In my opinion, ATF may be substituted for MMO for soaking parts to try to soften carbon, but it may not be necessary at all. I've personally never needed to soak carbonized parts to try to loosen carbon before, and probably never will. I see no need to.

The other 13B apex seals were actually already clean. I must have already ran a razorblade across the spring side. The 12A apex seals had a hefty amount of carbon on them though, and I was still able to cut into it with a fingernail. A razorblade would work ten times better. Besides, dry apex seals let the carbon chip off without sticking to it.



My conclusion is that soaking parts in ATF and MMO is unnecessary. If you need to pour something into your engine to try to unstick an apex or side seal, MMO is best because it is thin enough to get into tight spaces, and has some solvent action. If your engine is carbon locked, MMO will most likely save you from having to tear it down. If your engine doesn't like to start because of a slow starter, Castrol GTX poured into the intake in a small quantity will work wonders. If your engine is flooded, simply pull the plugs, dry them, maybe crank the engine with the fuel pump disconnected to blow all the excess gas out of the plug holes, reinstall the plugs and try again.



No need for ATF at all.



Oh, and another thing. To get carbon off of rotors, I've gotten great results from soaking the rotors in gas to eliminate the oil film. Then I let them fully dry (for obvious reasons). Then I wirewheel all the carbon off of the rotor faces. It works great because the carbon gets whisked away without redepositing itself onto the rotors. The apex and side seal slots, as well as the heat dams, can be cleaned with small scrapers or the seals themselves (the heat dams aren't that hard to clean with a walnut or dental tool).

I've since been adding MMO to my oil and fuel tank ever since this thread started. I've noticed an increase in my gas milage and I swear I have a bit more get up when my ports open up. I hope to get the most out of my orignal engine (137,000) before it is time to rebuilt and have the money to do it.





https://www.nopistons.com/forums/pub...1047683894.gif MMO

Would you have any pictures?

I made both pie plates dirty from scraping the carbon off the seals. They're still cherry-red, for the most part. I guess I could set up the camera and take a two-color shot (red and cyan). It's an experiement with a black and white CCD camera...

Here's one. Not much detail, but at least it's not black and white. https://www.nopistons.com/forums/pub...DIR#>/wink.png

great info! nice job. NOW you should see if the atf eats seals. if you have measuring tools see if there is a difference on the before and after now that they are clean,,,again nice job...

Thanks! I doubt ATF will eat apex seals. I'm more worried about it eating the soft seals. I don't have any handy to test right now.



Here's a closeup.

Now for some greater detail. The convergance is a bit off. See if you can notice it.

You can actually see some of the smaller details now.