Bruce381 writes:
quote:
It is a mineral oil it is crap do not use . . . Do not use MMO it is junk. Seafoam see above oil and solvent same deal."
Hey, that is a an overly broad and sweeping statement which could be misleading. If you are saying that MMO and SeaFoam are not miracle instant cures for emissions problems, that dumping a bottle in your tank while waiting in the emissions inspection line won't win you a pass -- then I agree.
However, you are flat out wrong if you think MMO, SeaFoam and GM T.E.C. don't have a role in solving emissions problems.
Clean combustion chambers and valve train are critical to keeping a vehicle within its design specs so that it can meet its emissions target. This is especially important on late model vehicles.
With the increasing emphasis on reducing NOX emissions, a clean combustion chamber is a must. Brute force methods of NOX reduction like EGR systems are used less and less. Extensive use of computer simulations have led to more elegant solutions such as precise control of valve overlap and exacting attention to combustion chamber geometries. Carbon buildup and valve deposits can upset the engine designer's applecart.
Combustion chamber deposits raise compression ratios and increase combustion chamber temperatures causing more NOX emissions. Sticking valves and valves which don't seal properly, can skew the valve overlap. HC emissions are affected as well by dirty exhaust valves which don't seal properly, causing fuel vapor to leak into the exhaust during the compression stroke. Carbon in the combustion chamber is a culprit in raising HC levels, as it absorbs raw fuel vapor and releases it into the
exhaust stream without burning.
The engine designers calculate combustion chamber geometries into their emissions equations. That is why the wedge shaped combustion chamber is becoming a thing of the past, with pent-roof and hemi designs coming into increasing favor. Contrary to what some may think, it is
not marketing which is responsible for the deign changes. Combustion chambers with good cross-flow and clean designs which won't favor carbon buildup are the preferred way to go. Low surface to volume ratios keep raw fuel from clinging to the the walls and allow for more complete combustion. And one of the motivating factors behind interference design overhead cam engines is so that the valve cutouts on the pistons can be reduced or eliminated, which means one less place for carbon and raw HC to collect.
Short of a tear-down and rebuild, chemical tools like SeaFoam, GM T.E.C. and MMO can help maintain an engine in its original design territory. SeaFoam and GM T.E.C. fed through a vacuum hose can blast away years of combustion chamber deposits in a few minutes. MMO in the tank has been proven and demonstrated here by BITOG participants (with photographic documentation) to clean the inside of old dirty heads to sparkling condition. Techron in the tank is also known to work quite well, but at a more gentle pace.
And for the record, if SeaFoam and its cousins are described as merely "oil", one might as well refer to gasoline as "oil". SeaFoam, T.E.C., and MMO are volatile
light oils with a flash point about halfway between gasoline and engine oil. It is more accurate to think of these additives as Naphtha-like solvents. Putting these in your gas tank will not raise HC emissions. Your gas tank is already full of HC, and the combustion process is under closed loop computer control which easily compensates for any slight change in chemistry. A pint of MMO or SeaFoam in a full tank of gas is
no cause for concern.
Sorry to be somewhat long winded in covering these points. But the discussion of emissions on public forums is loaded with folklore and and misleading advice. Part of the problem is that much of the emissions test equipment is too expensive and impractical for the average driveway mechanic. Also there is a lack of popular literature which truly explains the working of emissions systems. So much wrong advice leads to unnecessary parts swapping in an attempt to shotgun the problem. The real key to keeping a vehicle emissions compliant is to maintain the system as close to the original design specs as possible.
In the case of teambeechstreet's 1986 Colt, he did the right thing by restoring his emissions subsystems to their original design specs as best he could. The use of chemical cleaning aids was one part of his many pronged approach. He used these products the way they were intended, and wasn't looking for some instant miracle fix. His efforts payed off nicely. Now he has an emissions clean, fuel efficient daily driver without any car payments in sight.
