Non detergent 40W

[ford1]

Frank you made a lot of good points, now i will answer some of them ,detergent oil does not attack babbit, as you said modern bearings use a coating of babbit as the wear surface against the crank, and they run 200,000 miles or more using detergent oil, that myth started with some model a guys ever since detergent oil was put on the market, and like it or not particals are pumped thru the engine with or with out detergent oil, they can not all settle out over night, if they did the oil would show clean on the dip stick every morning, so they are still suspended and are circulated thru the system, and detergent oil does not flake off large chunks of oil, alto it does wash down the sludge stuck on the sides and bottom of engine , thus removing the sludge slowly, not in big chunks, but arguing that is like aruging religion and politics, you will never change the mind of a zealot or true beliver, best to just let it lie lol

 

[Steve Ciccalone]

In answer to the question, 40wt NDT is no longer carried at parts places or so it seems but is still available in 5 gal pails from Valvoline/Drydene, etc. One has to look on the internet. I don't think this is a continuation of the oil arguement. I will continue to use what I have had success with. NDT in old engines of unknown history and modern oil in clean rebuilt engines. I have never in over 40 years had a failure due to the oil. It boils down to the KISS principal. CHANGE THE OiL REGULARLY in accordance with prescribed original interval unless you have a filter. Oil is cheap vs. a rebuild.

 

[JEC]

You might want to try your local airport fixed base operator. We use straight mineral oil (Non detergent) for break in on light aircraft engines. After break in we switch to compounded oil (detergent).
We use Aero Shell 100 which is 50 weight But 40 weight could probably be ordered.

 

[mrtexas]

Non-detergent oil proponents. Have you ever seen the amount of sludge build-up when non-detergent oil is used? I found a half inch of sludge in the valve chamber in the 28 RPU I bought 2 years ago. Does that sound good? I cleaned out the pan and valve chamber with carburetor cleaner and put on an oil filter. No more non-detergent oil for me. I personally think detergent oil without a filter and changed every 500 miles would be better than non-detergent oil in the long run. The old VW opposed 4 didn't have an oil filter and had a frequent oil change interval, not that the air cooled engine was long lived.

 

[Uncle Bob]

Third, Model A and flathead V8 engines were clocking up many miles before zddp started being added to oil, which I believe was after WWII (someone may want to correct me on that?)

Mostly correct. It was developed/introduced in the mid '30s, but didn't come into common useage until after WWII with the beginning of widespread OHV, higher compression, and horsepower race.

Other items to think of for the thoughtful. What we loosely describe as detergent is actually referred to more correctly as detergent/dispersant. I suspect most people have a vision in their mind of something like that toilet bowl cleaner commercial that sends the little "scrubbing bubbles" around the bowl. Doesn't work like that. The dispersant word is more accurate. It's intent is to keep particles formed as byproducts of combustion in suspension as they get into the crankcase, not wait til sludge is formed then "disolve" it. It's second purpose is to neutralize acids that might be formed. (detergents are basic on the PH scale) Believe it or not that's probably less of an issue today than a few decades ago. Today sulphur levels in gasoline are more tightly controlled. Also, when lead was removed from gasoline the chemicals that scavenged out the excess lead freed up during combustion were removed. Those scavenger chemicals also formed acids when mixed with the water vapor resulting from combustion. A significant reason why engine internals and exhaust systems typically last much longer today than years gone bye.

 

[Old182]

Great information! Adding to the mess... ZDDP's (there are several) were added to oils in the mid 30s (as Uncle Bob said) as antioxidants, not antiwear agents. It turned out that over the years as engines became more powerful with increased compression ratios (thanks to octane improvement from tetraethyl lead), and higher engine speeds, antiwear became an issue, and zinc/phosphorous compounds were cheap, available, and already being used. Unc is right on the money regarding detergents/dispersants also: According to a research report from a major oil company, detergents were first used in motor oils to prevent valve sticking, and the first detergents were similar to - you guessed it - household cleaners! Modern detergents are largely "overbased" molecules with many compounds available that deliver varying characteristics, but none are like Lux Liquid. They help to neutralize the acids produced from combustion and oxidation as well as remove deposits and prevent rust. If you think about it, why would anyone design an oil with an additive that washes off oil? It doesn't make sense (and it doesn't happen). Unc's right again regarding sulfur: There's not much left in motor oils and it's virtually non-existent in gasolines today, but oxidation still takes place and that produces acids that need to be neutralized to protect bearings and other surfaces. Interestingly, base oils (non-detergents) are quite stable to oxidation, but many dispersants and detergents are pro-oxidative and, while they serve a useful purpose, must be considered. I'm still baffled as to how many of us take advantage of the improvements in bearings (inserts), crankshaft balancing, pressurized oil systems, lightened flywheels, overdrives, juice brakes, electronic ignition, yada-yada, but somehow can't come to grips with the improvements in engine oils during the last 80 years. Giving up detergent/dispersants, antifoam, antiwear, antirust, oxidation inhibitors, and friction modifiers in favor of base oil (great for compressors, gear boxes and electrical gadgets)....well, we are a diversified bunch aren't we? Since I'm sure I've worn out my welcome anyway, just a short comment about aviation oils: Piston aviation engines operate at or above 50% power for a lot of their lives and experience almost no stop and go conditions (student pilots excepted). And aircraft engines tend to run hotter than automotive engines, particularly during take off and climb. Although you might get away with using Aeroshell in you automotive engine, the additive package differs measurably from automotive oils. IMHO, it would be a good idea to know what you're putting into your baby's crankcase so as to possibly not regret it later. Sorry for all the wind....