My son has 1985 12A that had low compression on the front rotor. We decided to try the MMO treating by pulling the leading plug and putting about 1 oz. in each plug hole. I let this sit and then turned the engine to get to the next stroke and the engine appears to be seized. I tried rocking it backwards, no luck.

I suspect that the MMO worked to well and loosened something up and now it is "locked".

Any suggestions?

Thanks,

John

 

That MMO is powerful stuff. Try it again tomorrow?

Ray

 

What about the Amsoil power foam. Does anyone have experience with this and carbon block?

Does it seem reasonable that the MMO could have loosened enough "crap" to cause this?

Regards,

John

 

When my motor was siezed from 4 years of carbon buildup, I used ATF. I don't advocate it's use for anything other than unsiezing engines, since alot of people say it can be not-so-nice to the engine under other conditions. In this case I see you have little choice.

I've never tried MMO but if it does the same things as ATF, you should probably proceed like this:

1. Pull all four plugs
2. Squirt liberal amounts into all four holes and let sit at least an hour. (up to a day if it's really buggered in there)
3. Turn the engine by hand, pushing the top of the main pulley away from you (if you're standing on the driver's side). You can turn back and forth to get it moving, but in the end you want to be turning it this way so that the rotor edge scoops excess MMO and forces it to dribble out the bottom spark plug holes
4. Repeat the process, rotating the motor so that you can soak all the apex seals in MMO.
5. At the end, make sure you do three or more full rotations of the main pulley away from you, so that as much excess MMO and carbon crap as you can get is pushed out the bottom spark plug holes (the more MMO left in the engine, the worse it is for cat-clogging smoke and other not-so-good things).

6. Replace the plugs (make sure they're good and clean and dry before they're reinstalled) and try to start the car.


You'll probably want to have another set of plugs handy because leftover MMO fouls spark plugs pretty bad. Or at least ATF does, I'm not sure about the famous Marvel Mystery Oil.

Good luck guys. Hopefully this will un-carbonize your engine, and get it running again. You might also have to consider the idea that perhaps the low compression leading to siezure is caused by a buggered apex seal. If this is the case, your engine might need a rebuild. I'll caution now that if you get the engine turning, but it's *really* hard to turn and MMO doesn't seem to make it better, *DO NOT* try to start it. A loose apex seal in a cranking engine will score up the sides of the chamber and make it un-rebuildable. I know, my friend Eric just went though this.

Good luck
Jon

 

Amsoil power foam works well for decarboning motors, the problem is that once they're locked, there's no way to hand crank the stuff in through the intake. Any time you put a chemical in the motor to dissolve carbon deposits, you run the risk of loosening carbon only to be redeposited in perhaps a worse location. That's why when I use power foam, I only let it sit for about an hour, then I start it up and take it for a drive on the freeway for at least 30 minutes to be sure that all the crud gets blown out and not redeposited in an apex seal slot. However, having no experience with MMO I can't really tell you how to proceed with your particular problem. Sorry.

 

I like step 5 viper. Makes good sense instead of turning motor it's normal rotation and pushing that sludge down the exhaust pipe.

But if you take the exhaust manifold off you can push all that ATF and carbon Yuk out the motor and it will only burn a puff of smoke during startup.

 

Yeah, but taking the manifold off is a PITA, and doing this way by hand does basically the same thing.. The only difference is that it gets the gunk running down the side of your engine by the spark plugs... not a problem for me since mine isn't painted or sandblasted or anything :P... Then again, if it was, it'd have been rebuild and thus wouldn't need this anyway!

Jon

 

Unfortunately the engine won't currently spin in reverse either, this is what really has me concerned. I guess I will try to pull the manifold and go from there.

Regards,

John