|
That's the problem--there's no way to identify any constants since one person would have to establish a purchase pattern or some such starting point.
I couldn't even prove that there would be a problem with the reformulated (MTBE/ethanol) blends of gas, but there were a lot of problems with it's first introduction.
With simple reasoning, we can say that it isn't happening very much, otherwise a lot more people would be broken down with valvetrain issues. (It isn't a cause for total alarm by any means, but certainly for multivalve owners it could be of some benefit. The new, hot running powerplants seem more resistant, and they're cleaner burning.
The one way that the fuel identifies itself is by fouling the entire combustion chamber with junk. A clean chamber is normal, with a little carbon buildup being totally normal for a city driven car. The filthy, coated combustion chambers are totally baffling, but indicate something related to combustion. Severe oil loss is another thing entirely. It shows up, of course, as oil fouling of the whole chamber, but doesn't turn to the same kind of cement as the fuel does.
I'd suspect, more than JUST the fuel, it would be a reaction of the fuel with either an additive, the plastic gas tank (as unlikely as that should be), a contaminant introduced in the ground tanks, or some other extraordinary fouling of the formulation that causes these problems.
I've even heard firsthand reports of having to take the sludge off of the bottom of the tank with a putty knife, which ultimately ended up just being a total tank replacement out of sheer frustration. It was almost a gluelike substance on the bottom of the tank, and exactly the same yellowish/brown color as what we found this time.
Again, this is purely theory. I could be totally wrong, but a bad valve stem seal on one or two valves, allowing oil into the combustion chamber, doesn't foul all the cylinders with gum and varnish.
One additional feature is that the lower end (the cylinder) is clean. That's even more mysterious.
I keep running into people who say it's sugar in the gas tank, etc. But come on; how many times is that going to happen without screwing up the injectors, fuel pump, or other parts of the fuel system?
I'm even thinking that perhaps it's some sort of feature of water being introduced into reformulated gas, and causing some sort of a chemical reaction.
But I'm not a chemist, so I come up short on that end of it. Merely a speculation. The worst thing is that we'd never get a good explanation from the fuel companies or the EPA, but there are several other people I know of who have had this problem.
The thing I'm sure of is, the B230 engine is one of the more resilient powerplants. To have the problem happen to that engine TWICE is beyond belief. It was simply a diluted fuel issue. First time, full junk concentration. second time, maybe half. The more the car idles, the less it burns off. The faster it runs, the more deposits it burns off of the intake and exhaust valve stems, and the more it cleans out the combustion chamber. These are all simple principles but applied to the problem it still is a tough question to answer. I'm hoping that someone can shed some light on it, whether simple or complex. ALL of us who have to buy that gas could stand to benefit from it.
One thing I'm sure of is that I've never personally had a problem with any car of my own using either MTBE or ethanol blend. But now, with the fuel blends aging and becoming more contaminated by old tanks, equipment, or just age itself, I'm starting to see this yellow/brown gas in old marine tanks too. The smell is immediately recognizable, and the sludge that it leaves after a period of sitting is unmistakeable.
Strangely, just now I realized that we had a tank of gas in a twin-engined Boston Whaler with brand new Evinrude FFI 90HP engines. This was at the middle of last season--the boat had been involved in an allision (non-vehicular COllision in marine vocabulary) in the first few weeks of the boating season, and was rebuilt by mid season last year. There was some 1 year old gas in the tank, but not much of it. Maybe 5 gallons. Unfortunately the boat was not winterized properly as I wasn't called to perform the maintenance last season. When I got there for the first start-up, I found that there was the same kind of corn-syrup sludge in the bottom of the throttle bodies, and it was unable to be removed by simple solvents like gasoline, kerosene, lacquer thinner, or whatnot. Carb & Choke cleaner did the trick, though. This is another thing that clued me into the non winterization of the boat. Of course, a 2-stroke outboard doesn't have a valvetrain to foul, but it DOES have compression rings and fuel injectors that can fall victim to that crap. In the days of "old" gas, these problems were hardly evident after that short of a time, and you'd find a less resistant varnish leftover from old fuel.
Whatever is causing this, it would seem to be directly related to the environmental gas blends. That's all that I can see from my exposure to this problem.
I do feel confident, though, that a well-maintained car with little valve stem leakdown and highway miles, won't suffer the same fate. The 960, however, with it's smorgasbord of valvetrain issues, might be more subject to problems than would be the vehicles with larger valves and more powerful valve springs.
Again, these things are just my estimation of the problem. The more information we can gather, the easier it'll be to keep the problem at bay--if there IS only one problem. There is theoretically the possibility of a coincidental issue causing it as well, but I have no idea what that could or would be.
--
Chris Herbst, near Chicago, IL. 93 940, 91 240, 90 240, 88 740, 87 240
|
