Thread: Mmo
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Old 12-12-2011, 10:45 PM   #18
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Join Date: Mar 2010
Location: Milwaukee
Posts: 2,164

1999 SL2
Default Re: Mmo

MMO or SeaFoam can also clean valves, and that is where miracles are worked, especially in the old carburetor days. Dirty valves make for a very poor running engine.

I rebuilt my 1951 Chevrolet 216.5 and put 100,000 miles on it. Somewhere early-on I installed an Ampco automatic oiler. The valves and intake on that engine were always extremely clean, and to this day it runs exceptionally smoothly. An automatic oiler might possibly gum up your catalytic, though.

Berryman's B12 Chemtool is an excellent sludge, carbon, and varnish remover. It has many very strong solvents--far stronger than MMO or SeaFoam. However, it has no lubricating qualities, and evaporates quickly. It will remain in a closed cylinder for quite some time (provided it doesn't leak past the rings), but is best left to shorter 2 hour soaks, or at least if longer soaks are performed, more should be added on occasion. It is also probably far more critical to change the oil after a soak with this product, as if a good quantity leaks past the rings, it will dilute the oil in a bad way.

On a side note, my '99 SL2 was run on regular oil all its life. The engine did not look pristine inside. It was coated with a thin layer of black soot and sludge, but nothing even remotely like the BMW engine above--just a very thin layer. On a positive note, however, the cylinder crosshatch was still present at 219,000 miles, with no trace of a ridge on the top. New rings are currently riding on that original crosshatch at about 227,000 miles. It seems to be rather common for Saturn cylinders to be virtually unworn, though. I've read many posts mentioning this, so it seems that regular oil does not adversely affect cylinder life. However, I have seen numerous posts in various forums showing how clean synthetic oil can keep an engine, so it does have benefits. I'm not sure if it is economically feasible, as according to the factory the oil is never supposed to be used past 3k miles due to dilution (or maybe it's thickening) and improper operation of the hydraulic chain tensioner. Not sure if synthetic oil might still protect properly past this usage period. If you could make use of it longer, as you typically can in other vehicles, then it might be economically feasible.

Synthetic oil might possibly keep the rings cleaner and free-er. It'd be interesting to see the pistons from that Saturn engine above that was run on synthetic.
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