<BR>I have 3 classics. Two of them were run on detergent oil when I bought them in '93 and '95. The 3rd is a 30,000 mile original that ran on non detergent all of it's life. I just changed to detergent 300 miles ago based on the fact that the previous owner dropped the oil pan about 2,500 before I bought it and cleaned out the pan but continued to use non detergent. I've been told, and I've heard this before, that detergent oil will loosen sludge left by non detergent but now I've been told by a well meaning friend that detergent will attack the babbitt in cars whose engines haven't been rebuilt. Non of the 3 classics I own, 2 Cads and a Pierce, have had their engines rebuilt. The Cads seem to run fine with 64,000 on each and I've been told by others that the detergent won't harm the babbitt. What's the new thinking on oil, babbitt and engines that haven't been rebuilt? Thanks everyone!

<A HREF="http://www.ahooga.com" TARGET=_blank>www.ahooga.com</A> has many a posting on oil for the Model A. Although not a classic to some, it is an older car with enough history to have had this question come up often. The archives area would be where most postings on the matter are located. This AACA board has the same discussions with the 600w lubricant posts located within it. I believe (relying only on a poor memory) that there may have been some discussion as to your particular question as well in that area.<P>Personally, I don't believe the babbit destruction theory. Not any supportive evidence I have ever known of or been shown to prove me wrong. Although people mention the theory, they just can't produce any evidence of it having ever actually happened. (Sort of makes it an old wive's tale). I recently saw where a chemist was saying that "all oils/lubricants" have a certain low percentage of detergents contained within them. The overall amount was the difference in the classification, but hardly seems that your "detergent oils attacking babbit" theory would hold water if the chemist was accurate in his statement.<P>I believe that once you remove standard oil and start replacing it with anything else, you will need to continue to use what you have changed to. You will likely even have to change the oil more frequently than recommended the first few times in removing all the old oil. The detergent oils may clean the antique engine over time so thoroughly that the rings lose some oil in blowby and such. A slight loss of power may even happen over time, due to sludge being removed in the cylinder walls and rings. As I said, though, it "MAY HAPPEN." No promises on that one, but it is my theory.<P>If I come across better sites for this discussion, I'll share. I just think the newer oils will work fine throughout the life expectancy of the owner of the antique vehicle. Those vintage cars of yours will be hummin' along long well after your gone and the next owner is looking at which oil to use; detergent or non-detergent.<P>Huey<p>[This message has been edited by coupe1942 (edited 10-17-2000).]

[Hal Davis (MODEL A HAL)]

What is the construction of a modern insert bearing? I'm sure a lot of us have seen worn ones where the copper colored material was showing through where the babbitt-like material was worn away. It may even be steel under that, but what is the gray colored "Babbitt" material that lines the insert? You know, the part that contacts the crankshaft. Is it babbitt? If so, high detergent oils don't adversly affect them.

[ply33]

If I recall correctly, as of the early 1970s when I was taking mechanical engineering classes, the only real difference between poured babbit and the thin shell inserts was the thickness not the material.<P>Basically the babbit material is there so that the expensive steel pieces are not damaged as much when the bearing fails. The babbit material, being softer than the steel, takes the damage.<P>I do not believe that any reasonable oil additive will damage engine bearings. (Early hypoid gear lube used chemicals that damaged bronze. But that is another story and, I believe, those additives are no longer used.)<P>Contrary to popular belief, detergent oil will not significantly clean an engine. All it does is help keep the new crud from settling out and forming more sludge.<P>Oil is pretty much oil until you add the additives. And todays additives make oil a lot better than what was available 20 years ago much less 50 or 70 years ago.<P>Go with a good grade of oil now and change it often (the lower operating temperatures and lack of positive crankcase ventilation on older cars means the oil gets dirty faster).<P>I use a multi-viscosity oil because I want to minimize the start up drag on the starter and get good fast coverage of the bearings and cylinders on start up, but my car is happiest with a 30 or 40 weight high temperature viscosity when moving along at 50 MPH. So, I have been running 10w-30. I might change to 20w-50 because it really does not get that cold here.<p>[This message has been edited by TodFitch (edited 10-17-2000).]

[novaman]

I do know of a Model A that a guy bought, changed the oil from the non-detergent to detergent muilt-weight, then took it on a 1,000 mile tour. 500 miles, knock knock. Who's there? Piston slap. It was nice to be able to tell the noise was from the top of the block and not from the bottom. He drove it home if I remember correctly. (this was about 18 yrs. ago)<BR>I personally would pull the valve cover or the oil pan and see how much sludge is in the engine. if very little I'd use the detergent oil. If a lot I'd use the non-detergent. <BR>I don't believe in the babbit wear theory either.

I remember reading an article by an automotive engineer a while back about this. His reasoning on not using detergent oil was that detergent oil suspends the dirt on its way to the filter for cleaning. Since older cars (if they have a filter) usually have a bypass filter design, the majority of oil simply gets recirculated with detergent oil carrying the dirt with it through the babbitts and causing needless wear. He did not quantify the wear. Also, according to his article, non-detergent allows the impurities to "drop out" in the pan. <P>Since it sort of made sense to me, I continue to use non-detergent 30 in my 48 Packard, but I also add 1 cup of kerosene (as recommended in the owners manual)to act as a sludge reducer and makes cold starts easier.

[ronbarn]

For what it's worth, I agree with Tod. I am bolstered in this opinion by the presentations made by Harold Sharon during the how-to-it sessions at the AACA Annual Meeting. His basic premise was that modern lubricants are far superior. Change oil more frequently if you are concerned about "floating" particles.

[ply33]

Chris NJ,<P>Your use of kerosenes "to act as a sludge reducer and makes cold starts easier", simply says to me that you are using 50 year old techniques to do a job that today's "off the shelf" multi-viscosity(easier start) detergent(sludge reducer) oils do better.<P>I believe that the kerosene will reduce the lubrication ability of the oil much more than the oil companies' standard set of additives.<P>Anyone out there want to do a bearing/engine wear analysis test? By running different possible detergent/non-detergent/non-detergent with kerosene options and sending samples from the changed out oil to a good analysis lab we could confirm or deny rumors about modern oil in old engines.<P>Me? I am firmly in the camp that says lubricants are lots better today than they ever were in the past. And I want to take advantage of the improvements in that technology.

I found this article from the UK on the web. Worthwhile reading.<BR> <A HREF="http://www.classicmotor.co.uk/oil.htm" TARGET=_blank>http://www.classicmotor.co.uk/oil.htm</A>

Ron is right on target. We've been by this subject about safe use of modern oils in antiques and classics in several threads over the past year. Most of the real experts have come up with the same answer - detergent oil suspends and carries particles.<BR>So use the much better modern oils and just change your oil more often if you don't have a filter.