SF@Rx7

ok i had did the search saying ATF and MMO will take care of that
and i had done that
before i put the engine in the car i had noticed some rust on one side of the rear rotor surface. my friend told me that ATF will take care of the rust and seems like it did not. the compression reading is low in two side and indication of stuck apex seal.
can anyone know if ATF will free the rust lock for sure or maybe? i do not want to waste any of my time if it's not going to help freeing that seal
any input will be welcome thx

Naegleria_Fowleri

How bad is the rust on the housing? How long had the engine been sitting before you put it in the car?

I would probably try running seafoam through it. I thought the ATF and MMO treatments were to make the seals "swell" and creating more sealing, and in return, more compression. Seafoam will clean out the engine of carbon build up, so perhaps rust as well. That is just my suggestion, and if I am wrong please, someone let me know. lol.

rOtAryIsbEttEr

ATF and MMO arent likely to make metal seals 'swell', i think it works by softening up the carbon buildup so that it will break free and burn up during combusiton.

SF@Rx7

i believe the seal is rust lock not carbon lock will MMO or ATF still work?

diabolical1

iTrader: (3)

what is the history of this motor? how long was it sitting, obviously without proper measures to maintain seal lubricity? do you know how it ran before it sat? did it smoke, etc.?

get your grain of salt because what will follow is only my opinionit's totally up to you if you want to listen of not. understood?

if that apex seal is truly frozen by rust as you suspect, i seriously doubt that there is any soaking in anything that's going to take the rust away - at least, not without creating some other undesirable condition.
if it were mine, i would probably opt to bite the pillow and pull it apart, but i understand that my way of thinking may not mesh with many, if not most, others. i feel that that much rust is bound to lead to trouble - in one form or another.

so, my only other offering is for you to soak it for few days in MMO or the Seafoam - whichever you choose, i would suggest adding some 2-stroke oil to it. make sure to turn it by hand throughout the day, as many sessions as you can. if it turns freely, then you may even want to turn it with the starter a few times - no fuel though. if you can, try to see if the fluid turns completely to the color of rust - finger (without turning engine) or paper towel in the exhaust. then ... after your few days are up ... fire it. DON'T DRIVE IT! just let it idle until warm. let it cool and check your compression again the day after. see if your results are any better. if they are, great! if they are not, what have you lost? either way, i'd probably soak it once more after that overnight and then drive the next time i got it warm.

drive it. don't race it - you may already be on borrowed time. premix is your friend!

Kentetsu

Go with Seafoam rather than ATF... If carbon is your issue, then this will probably take care of it. Rust on the other hand may require a teardown of the engine...

Midwest 7's

iTrader: (4)

sometimes it will just take high rpm, centrifical force to free up stuck seals.

aussiesmg

iTrader: (1)

Have you visually inspected the spark plug and inside the housing via the plug hole

trochoid

iTrader: (6)

From what I see, you have 2 choices, install it, run it and hope for the best, or, tear it down for a rebuild. If you have more time and labor than cash, try option 1. Be prepared for a rebuild though.

SF@Rx7

i am going to let that seal soak in MMO for about couple days and i will try to start it again and will let you guys know about the result

full-cruise

iTrader: (5)

so how did you make out with this?