First, thats anecdotal evidence, take it for what it is, second you'll excuse me if I highly doubt the validity of the story. If the oil was changed religiously every 2500 miles, there never would have been any sludge or carbon build up.
So this was the late 1980's with bulk oil from the late 70's, that would have made the oil an API SE rating. SF rated oils started in 1980, thus every vehicle 5-10 years old was using too old of a oil not designed to be used in those engines. Sounds like a bad maintenance program to me. Hey wait a second, some of those cars you said were 25 years old, that makes them well into the 1960's models (when oils had an SD service rating)and the "good batch" of oil was bought in the late '70's. Hmmm why didn't those older engines have problems with the late '70's oil?
I'll tell you why, your highly mistaken on the cause of the problems, again, wax in the oil does not cook into carbon, if something was getting the oil hot enough to turn to hard carbon deposites there were other major problems. Again, all crude based oils have wax in them and since the 1930's the refining process leaves roughly 15% waxes in the oil, which BTW to a degree is beneficial and there by design. This type of refining is still used today and the vast majority of the oil on the shelves is refined this way, these are called group II oils. In 1959 a new refining process was discovered which among other things still leaves about 3% wax behind, again by design since this 'hydrocracking' refining leaves creates a better quality oil that doesn't require as much wax. These oils are called group III and almost every on the shelf so called "synthetics" are of this type. So unless your using these group III's your using oils with the same amount of wax they have had since the 1930's, sorry!
First commercial detergent oil was introduced in the mid 1930s and after WW2 most oils were using it, since 1960 or '61 "high detergency" oils have been in use, about the only ones that didn't were some straight weight oils.
Facts, not anecdotal stories.
Quote:
Originally Posted by TheBobsHere  Back in the late 80's the theater I was working for had a ton of at the time 25 to 4 year old monsters they gave the actors to drive (so they had no excuses if they missed call). I was put in charge of the entire fleet of 60's and 70'sLincoln's and Caddy's as well as some early 80's Buick's. The records that were kept from before I was put in charge of the beastly fleet stated oil changes were done every 2500 miles for at least 20 years. The problems came when the bulk oil purchase they made in the late 70's ran outdeposits and they bought another 10 years of oil, only they changed brands (switched from Quaker State to ironically, Chevron). When they did this the modern (compered to 1977) oil started cleaning that crap off. I had to pull around 10 oil pans in one month just to keep from loosing the classic cars (and my job). So, regardless of where the carbon fritters inside of the engines came from, those deposits were more of a problem than the little bit of sludge that was present during oil changes. I flushed all of the engines and cleaned out the oil pans, which did have some tar like sludge but mostly a crapload of rock hard carbon chunks sitting them. We only lost a 77 Caddy, which since that car was possessed, was fine by me lol. So you see, today's oil is even better than the oil from 87 and will cause any buildup to just get cleaned off even faster than it did then and do the same thing it did then, clog the oil pickup and starve the engine for oil.
If you can look through the oil filler and see fried chicken like carbon buildup, you need to flush the system and clean the oil pan. Or you'll wish you did. |
