I noticed the tech page calls for our Durants to run 30 wt. oil in the crankcase. this is what I used until I tore down my engine to replace rings. First, the smell of the oil pan reminded me of crude oil straight from the oil well. Of course, I don't know if this engine was ever apart since the car only has 26,ooo miles on it. Anyway, I noticed every oil ring on the pistons was plugged solid with crud/burnt oil. When these cars were first built there was no detergent oil available. Now there is better oil being produced. Now my question is: is anyone using a good detergent oil in there Durants? say mobil 10 W 30 or other? If not, why not? Does the motor know the difference between detergent and non det? I have doubts. Or is it just a preference? I want to run the best oil I can get to eliminate any future plugging of the rings and generally fouling up anything else. Thanks in advance for your input. Jim

Jim I just read an article in a magazine that said that the difference in the detergent and non detergent is that the non detergent does not suspend any of the impurities in the oil. It allows all the impurities such as carbon particles, dirt, etc to drop to the bottom of the pan. This was used originally for cars without oil filters so the crud would be flushed each time the oil was changed. The new detergent oils suspends the impurities in the oil until the oil filter can pick it up and clean it. Without a filter these impurities could get deposited in the bearings and cause problems. It sounds like the original owner of your car did not change the oil enough and by doing so let the sludge build up. It's my thought that once you rebuild your engine and change the oil regularly, you should not have the sludge problem again.

Hi Jim.....

This may be an Urban ledgend or in my case a farm country ledgend. I was told a long time ago that the reason not to use a detergent oil in a motor that had been using non-detergent oil is because it would loosen up all the accumulated crud . Thus clogging up everything.

If you totaly rebuild an engine and do a very thoruogh clean up of all passages then going to a detergent oil will keep it clean.

Probably some of our other members are more familiar with why or if this is true?

Hope this helps........

Frank ---

I found an interesting site on the web, "Motor Oil Myths and Facts" http://www.nordicgroup.us/oil.htm#Sludge
What I found particularly interesting was How Sludge is prevented and How sludge is formed...Additive in the detergant oils wash any contaminant particles off of internal engine parts and hold these particles in suspension until the oil is changed. It is important to understand that these particles are too small to cause engine wear but they do turn the oil a darker color. The key thing is to change the oil before the oil becomes too saturated with contaminents too hold any more...
Our older engines did have a suction screen for some protection, later engines had a screen and a "by-pass filter" but keep in mind that just a portion of the oil flowed through the filter and the oil flowing to the bearings is not pre-filted as in a modern "full flow system"... Interesting subject, More later, Bill

Thanks for the input so far, I will check the website you suggest Bill. seems to make sense what you describe. My oil pump does have a screen, and I have a bypass filter. Eventually, all the oil would have to make its way thru the filter. I know its not as good as todays full flow system, but its better than no filter. I will watch for more posts on this subject. Jim

Fellows:
I first rebuilt the 22AA engine in the 1932 Frontenac in 1970 and have been running 10 W 30 Quaker State oil ever since. This car has a by pass filter and I change it about every 3 years ( I have driven the car 50,000 mile since 1970) I change the oil at least every year. It doesn't get real dirty, but I like to change the oil in the fall just before the car is put away for the cold cold winter.
I agree with Frank. The country legend I have always abided by is that unless an engine is cleaned, keep on using the standard oil. Once you have had it cleaned, then the detergent oil or synthetic oil (whichever you prefer) is OK to use.
Gord.

Based upon my experience of running detergent oil in engines that have rebuilt and not rebuilt i have never encountered a case where the oil cleaned the engine. If you change your oil to remove the suspended particles you will be ok running detergent oil in non-rebuilt engines. If you do not change the oil it doesn't make any difference what you run you are in trouble.

You can even run it in a Model T.

Do not run synthetic oil and it tends to leak everywhere and will not work in a model T. (Too slippery)

So far I have heard some good common sense advice. I will have a clean engine to start out with and probably will use a good multi grade det. oil. I change oil frequently in all my other vehicles, so this is not a problem. My oil will never get extremely dirty. I think one area that needs attention will be to get a mesh screen of some sort on the air intake vortex of the carburator. Just to keep potentially dirty air from entering the engine. I have seen some of the ideas posted on our website, still looking for a simpler fix, as I want to retain as near original looking as possible. Thanks to all who answered this post. Jim

Just thought I'd post a recent reply I received from a tech man from Red Line Oil. I've used the oil and transmission fluid in my TR6 and was inquiring from them the chemists and technical people about using it in the Durant/Continental motors. Here's his reply:

Thank you for contacting Red Line Oil, I am very familiar with the Model A and the Durant is likely similar in a number of respects. Originally a 30W oil was used for summer use, a lower viscosity 10W or 20W for winter months.

With todays oils a 10W40 is similar viscosity to a straight 30W at moderate temperatures, a little lower at low temperatures and higher at higher temperatures. This seems to be a very good all around viscosity for these engines and the product I use it in our various Model A engines.

The engine in the Victoria uses a full pressurized crank and full flow oil filter. The other engines use splash lubrication and both are fitted with bypass oil filters.

For any engine, either with a filter or without, I would recommend a detergent oil. Originally non detergent oils were the only thing available, that has changed, today very few non detergent oils are available, those that are available generally are not high quality products and don't contain a complete additive package or a high quality base stock. A detergent oil will offer substantial benefits and advantages over a non detergent product. A detergent oil can be used in an engine without a filter, the detergent is still beneficial keeping the engine clean, holding contaminates in suspension and neutralizing acids, without a filter the oil should be just changed a little more frequently. If an engine has been operated for a years with a non detergent oil if a thick layer, a jell has build up in the pan and valve chamber, I would remove this before switching to a detergent oil.

With your rebuilt engine I would recommend seating the rings with a petroleum oil before switching over to our synthetic oil. Some of the currently available oils don't contain sufficient anti-wear additives for flat tappet camshafts, to be certain I would seat the rings and break in the engine with a good quality diesel engine oil, these will typically contain a good robust additive package with good anti-wear protection. Once the rings have seated, allowing 1500 to 2000 miles, I would recommend using our 10W40. A synthetic oil can and is being used very successfully in these older type engines.

Regards, Dave
Red Line Oil