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Modern Motor Oil Question?


Guest jimstulga

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Guest jimstulga

I have been using Delo 400 and (or) Rotella 15 W 40 motor oil for some time, but today I noticed the word "Diesel" added to the wording of the label. I couldn't find any other 15W40 oil without "diesel" wording. Would this be a problem for my antique cars, '61 Imperial, '41 Cadillac? Also, I read a very convincing article years ago saying not to be concerned about adding zinc to modern oil as it wasn't there originally and was added to oils during the muscle car era for motors unlike what most of us have in our antique cars. True? Thanks,

Jim

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The first use of zinc in motor oil was about 1951. It was added after a spate of cam and lifter failures in new Chrysler and Studebaker V8s. It continued to be added until a few years ago, when it was removed for fear it would poison the catalytic converters on new cars.

The old flatheads don't need it and neither do new overhead cam models because their cams are lightly loaded. It is the old OHV pushrod models, especially the hot jobs with high lift cams and stiff valve springs that are at risk.

For the last few years some people have been using "Diesel" rated oil specifically because it still has the zinc additive.

By the way, the first use of zinc in oil I heard of, was in a handbook or formula book published in the 1870s called The Circle of Useful Knowledge. It gave the formula for watchmaker's oil as follows. Put a piece of zinc in a bottle of olive oil and leave it in the sun. A friend of mine tried it, with a little medicine bottle and a piece of zinc off a Mason jar ring. The oil gradually turned dark over the next week or 2 as the zinc dissolved in the oil. He used the oil on pocket watches and clocks he repaired.

I thought it was interesting.

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In the UK we struggle with oil on occassions. It is my understanding that older engines (those with plain (roller or ball bearing) or white metal bearings or bronze plain bearings) dont like the modern additives added to protect modern (fast reving) engines. We tend to buy stright grade oil (30W or 40W) which we are told contains no additives.

I have seem evidance of modern multigrade oils causing plain bearings (roller and ball) to skid rather than turn and then fail.

I further understand that oil (pre war) in the UK was as thick as grease when added and as thin as kerosine when it came out a few hundred miles later.

Motor Oil technoligy has moved on in great leaps and bounds so a stright grade oil, is likely much better now, than anything made when the car in question was new

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I believe you have been misinformed. I don't know what oil they had in England in the thirties but doubt it was as bad as all that.

I do have a collection of The Motor and Autocar magazines from the fifties. Many ads for detergent oil and articles about oil. One was a very interesting experiment in the correspondence column. The writer had a prewar car with a well worn engine. It burned a lot of oil. He decided to experiment with different oils to see if he could reduce the oil consumption.

His best results were with 20W20 or summer oil. If he used thinner oil, or thicker oil, the consumption went up.

A straight grade oil is more or less what they had in the thirties. There is no reason to believe today's is any better, and it may well be worse. There was more high grade crude oil available back then for one thing. Today we are scraping the bottom of the barrel for any oil we can get, and the quality is not as good. It is possible to improve the base stock with additives, but of course if you have no additives you have to take what you can get.

I don't know what additives you mean but the new oil can't be as bad for your engine as single grade non detergent oil. Modern engines use bronze, white metal and ball bearings. If you are really pernickity, there are specialists like Penrite that make oil specially formulated for old engines.

You are aware that multigrade oil was first sold in 1951? And detergent oil a few years earlier? If you have a post war car, and the original owner cared about it, or trusted his dealer or garage, chances are it used nothing else.

Edited by Rusty_OToole (see edit history)
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You are simply wrong, the oil available back then (1930's and 1940's and likely 1920's to 1950's) in the UK was that bad. Dealers sold replacement engines (just after the 2nd world war) for around £10 (held as stock items) - you could drop your car off on the way to work and drive home with a replacement engine fitted. This was (in the UK) as standard as having new brakes fitted today. I have first hand experiance of this.

Oil was very poor quality back then and simply did not stay in grade, it was very thick when you poured it in (in cold weather you had to heat the can to get it out) a few 1000 miles later the oil was like water.

Of course all oil available today is much better for your engine today than it was back then (assuming you put in the correct grade of oil), BUT some MODERN ADDITIVES eat phospher bronze bearings and will cause roller bearings to slide and damage the bearings

As you say, you know little about England, I am really interested to hear if things were different in the USA

I believe you have been misinformed. I don't know what oil they had in England in the thirties but doubt it was as bad as all that.

I do have a collection of The Motor and Autocar magazines from the fifties. Many ads for detergent oil and articles about oil. One was a very interesting experiment in the correspondence column. The writer had a prewar car with a well worn engine. It burned a lot of oil. He decided to experiment with different oils to see if he could reduce the oil consumption.

His best results were with 20W20 or summer oil. If he used thinner oil, or thicker oil, the consumption went up.

A straight grade oil is more or less what they had in the thirties. There is no reason to believe today's is any better, and it may well be worse. There was more high grade crude oil available back then for one thing. Today we are scraping the bottom of the barrel for any oil we can get, and the quality is not as good. It is possible to improve the base stock with additives, but of course if you have no additives you have to take what you can get.

I don't know what additives you mean but the new oil can't be as bad for your engine as single grade non detergent oil. Modern engines use bronze, white metal and ball bearings. If you are really pernickity, there are specialists like Penrite that make oil specially formulated for old engines.

You are aware that multigrade oil was first sold in 1951? And detergent oil a few years earlier? If you have a post war car, and the original owner cared about it, or trusted his dealer or garage, chances are it used nothing else.

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You might be surprise how much I know about the English motor industry and English cars and motorcycles of the fifties and sixties. I have probably owned more of them than you have.

The oil wasn't that bad. It came from the same wells as the oil used in North America, and it was refined and sold by the same oil companies.

The reason English engines wore out so fast was that they were lousy engines. The piston rings were especially bad. Typical engine life for a forties or early fifties English car, 20,000 to 30,000 miles. This was for English cars driven in Canada, using American oil and gasoline, and maintained according to the maker's instructions.

Twenties and thirties American cars also had a typical life of 20 to 30 thousand between overhauls but during the war years they developed improved chrome piston rings, high nickel block castings yes and improved detergent oil and filters too. These were quickly adopted by American makers after the war, not so quickly in England.

I liked the English cars and wish I could still buy a Standard Vanguard, Austin or Rover. Standard Vanguard could have had the reputation and the market Volvo has today, Austin had the transverse engine, front wheel drive market cornered before Honda made a single car, and Rover had the best 2 liter 4 cylinder and 3.5 V8 executive cars, when BMW was trying to forget the Isetta.

But, they refused to progress and did not move with the times. Sic transit gloria mundi. We mourn our loss.

Edited by Rusty_OToole (see edit history)
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What kind of petunia oil were they using that went in like molasses and turned to water? Petroleum oil does not do that. Petroleum oil never wears out. The only way oil could change viscosity like that, is if it were diluted with gasoline. I suppose it would be possible if you did a lot of short trips with the choke pulled out. This would account for the rapid engine wear as well.

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Let's see how much you know about postwar British cars. Can you tell me who made the Black Prince, and what was unusual about the transmission? Who made the Jackall and what did it do? What parts did the Jaguar have in common with an American Ford ?

If you can answer those questions without a web search I will be impressed.

Edited by Rusty_OToole (see edit history)
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To get back to the original question. I don't think you will have any problems running the Rotella 15W40 oil, I'm not familiar with the Delo 400. I run Rotella in my 1950 Ford F1 flathead V8 on the recommendation of the fellow that rebuilt the engine and several others. It is my understanding that the diesel oil has anti foaming agents that gas engine oils don't have and exceeds any oil that was available at least throw the 60s maybe 70s. It also has some zinc or zinc substitutes that may or may not be needed in some of the earlier cars but will not hurt as long as you don't have something new enough to have a catalytic converter, which is why I was told the zinc was removed.

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I have been using Delo 400 and (or) Rotella 15 W 40 motor oil for some time, but today I noticed the word "Diesel" added to the wording of the label. I couldn't find any other 15W40 oil without "diesel" wording. Would this be a problem for my antique cars, '61 Imperial, '41 Cadillac? Also, I read a very convincing article years ago saying not to be concerned about adding zinc to modern oil as it wasn't there originally and was added to oils during the muscle car era for motors unlike what most of us have in our antique cars. True? Thanks,

Jim

Delo and Rotella are Diesel engine oil, whether labeled "Diesel" or not.

Oils made for Diesel are refined for the Diesel engines that lack positive crankcase ventilation and high compression with increased blow by in the crankcase as compared to gasoline engines.

In addition, Rotella and Delo have the ZDDP (zinc) that our old ohv engines need.

IMHO

All of these features make Rotella and Delo a good choice for our old cars.

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I've been using Rotella 15W-40 in our vintage cars for quite some time, as well as in our 7.3 Diesel tow vehicle.

It seems to provide the protection and additives which could help preserve our toys.

Overkill cannot hurt, and in my opinion, it has done well for the many long-distance drivers we enjoy.

Other than the 310K++ mile tow vehicle, in the old cars - the oil comes out just about as clean as it went in !!

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Just back to the engines of the past for a moment... the Morris/Austin/Wolseley/Riley 1100 engine was designed to have new rings at 30,000 miles. I found this in a book about its development. They would last a lot longer with proper care. Mine got to 70,000 miles before I sold it and it would not burn any oil. It did foam the oil in the rocker cover though and deposit a white foam in the cap (moisture in the oil). A change from Caltex (Texaco?) to Shell oil fixed that problem.

I found it very difficult to get oil formulated for flat tappets for my 5 year old small diesel tractor. In the end I bought one that said "diesel" on the packet and was one standard (C?/S?) behind the current one. For the old cars, both side valve, I use Penrite, because it says on the packet that it is good for flat tappet engines.

It is my understanding that detergents were added to oils to clean the inside of the engine (dissolve or solubulise combustion contaminants etc). They also added dispersants at about the same time, to disperse the crud in the oil (prevent precipitation and deposition) and carry it to the filter for removal, rather than have it precipitate in the sump and in crevices around the engine.

So our colleague using non-detergent oil had better clean out his sump(s) from time to time, coz the crud will be building up there. It will also be deposited anywhere the oil flow slows - in the camshaft openings for pushrods or valve stems, or in overhead valve gear for example. His engine will then wear faster coz this stuff gets onto wearing surfaces.

Remember also that low octane fuel burns dirty. Some engines required frequent valve grinds to cope - Austin 7 for example.

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The first use of zinc in motor oil was about 1951. It was added after a spate of cam and lifter failures in new Chrysler and Studebaker V8s. It continued to be added until a few years ago, when it was removed for fear it would poison the catalytic converters on new cars.

Zinc was never "removed" from motor oils, the content was simply reduced (by less than 50%). There is still more ZDDP (zinc) in modern SN motor oil today than there was in the SC rated oils of the mid-1960s. It's function in so far as a friction additive is now handled by other compounds, largely by proprietary friction modifiers. Those friction modifiers have been shown (with notable anecdotal exceptions) to be acceptable for use in previously broken-in flat tappet engines. Freshly rebuilt flat tappet motors with high tension valve springs need zddp additives at first. Otherwise this is a non-issue.

http://www.motorweek.org/features/goss_garage/too_much_zinc_in_your_oil

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