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New oils for old cars?

Mark Golding

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Hi all I'm not sure this is the right forum for this but I felt it was important to everyone with a old car. it is written by the VP of the Wayne/Pike chapter Henry Antoniolli

I felt it very important that you all read this.

Mark Golding


"New oils no good for old cars"

I am an old car enthusiast like every one reading this article. I am not an engineer or a master mechanic, nor do I claim to be. I have a few old cars and I like to work on them as well as drive them. When I first heard of this oil problem I spent some time trying to understand it without all the technical terms.

If you are involved in the old car hobby I am sure that you have heard of the detrimental effects of new oils. Up until now modern detergent oils were the best way to go with re-built engines, as they drastically reduced sludge and kept everything inside clean. Detergent oils contain friction modifiers, anti-corrosion, anti wear and foaming additives. Many re-built engines would last two to three times longer than the originals with the vintage oil. Oil companies have been cutting back on the use of zinc (Zn) and phosphorus (P) as anti wear additives. Recent research has shown that an additive ZDDP which is zink dialkyl dithiosphosporus was harmful to catalytic converters which are in most modern cars. The answer was to use a Series Three or Diesel Motor Oil, as they had all the additives and then some, as diesel engines need high quality oil.

Within the last year with strict emission control standards, large road tractors are now equipped with catalytic converters and this is causing a drop in the ZDDP levels in diesel motor oils. In the workings of the engine the main and rod bearings ride on a cushion of oil to avoid the metal to metal contact. So what is the problem? The answer as I determined is that the camshaft lobes and lifter rotation is more of a friction contact. This is different and this is where the ZDDP comes into play, as it coats the metal itself. Most modern engines have some type of roller on the cam-lifter assembly and the new oils don't affect it. Many rebuilt engines were having camshaft wear problems at 1500 to 3000 miles and in was determined that the oils were the culprit.

There was a write up about this most recent ally in "Vintage Truck" magazine whereby many inline GM 6 cylinder engines mostly fifties and sixties vintage were prematurely wearing down the camshaft lobes. After much testing it was determined that the new oils were the culprit. I am sure in the future there will be old car specialty motor oil. Until then you should use an additive to raise the ZDDP and P levels. Many mechanics are recommending the addition of an oil additive made by General Motor’s called EOS (Engine Oil Supplement) or GM Cam Lifter Prelube at every oil change. This is an excellent choice. STP is also a good choice Note: the blue bottle does not have as much additive as the STP four cylinder treatments and the red bottle has no oil thickeners in it. Either one would be sufficient. An ideal target of 0.12% is ideal for Zn and P levels as documented by the 1977 SAE journal titled “Cam and Lifter Wear as Affected by Engine Oil ZDP Concentration and Type,” which evaluated the performance of these oils in various fleets around the country over the span of many years.

If you would like to research this further there is a good article printed by LNE engineers (web site address New oil in old cars ) which has a lot of the technical expertise on the oils and formulations, it is very informative if you take the time to digest it. Looking forward to seeing all of you at the next show

Hank Antoniolli

Honesdale PA

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I've been running diesel oil in the old cars for some time now and am pleased with their performance. I have actually noticed rocker areas cleaning up after starting to use it. I knew the catalyst diesel oils were coming and stocked up on CH-4 rated Rotella, but me stash is getting low- I have enough for two more oil changes for each car. Guess I need to run by Tractor Supply.

I'm a little leery of STP because I've heard it's best suited for engines that never completely cool down. Then again, I have to remember it was originally developed for Studebaker, and Studebaker's engineering department was at least the equal of Chrysler and Olds.

I could go buy a case of EOS. Some GM dealers don't stock it.

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yes - the deletion of the anti extreme-friction additive IS going to increase the possibility of rapid cam failure in SOME old cars.

Before anyone gets too excited about this, ask yourself what KIND of motor is in that old car. If yours is one of the higher priced cars built during or after the FIRST World War, it probably has roller tappets. At the moment, I cant think of a high-priced super luxury car that did NOT have roller tappetsm up until they started cheapening even the luxury cars in the late 1930's.

"Slider" type tappets and cams are a cheap method of building a motor. You can get away with it IF you dont need a "hot" cam profile, and/or you can get additives in or added to the engine oil to reduce the extreme friction that occurs on "slider" tappets, and no-where else in the engine.

So - if yours is not a super-luxury car and/or was built after 1939, you need to get some anti friction additive in your oil. It will say right on the label if it has the zinc anti friction stuff SOME of you need. I just bought some the other day for my airplane motor ( Lycoming motors now have roller tappets, but mine was built before the change-over)

If your motor does have roller cams, forget about it - it isnt your problem.

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I've been using Red Line synthetic oil in my 1971 TR6 for sometime and like their oils. Last year I wrote them in regards to using their oil in my 1928 Durant with a Continental 6 cylinder engine. Their technical advisor responded with the following letter to me:

"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

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  • 5 weeks later...

For those who are counting on using GM EOS oil additive in SM grade oils until some better solution comes along, I have bad news. I was just told by my local Chevy dealer that it has been discontinued. Some existing stock may remain on the shelves at dealerships for a short time. I had to go to two dealerships to find any.

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Mobil 10W30 5000 mile (conventional) oil, as of last week at Walmart, still listed it meeting back to SG standards if I remember correctly. Perhaps Mobil is selling to the old car hobby a little. I also investigated Exxon oil and it was up to the SM standard only. Since the oils are both owned by the same company now, I found that interesting. At least, it appears that they are different oils and not the same marketed under different name, at least for now.

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How about some forum discusssion about using <span style="text-decoration: underline">molybdenum disulphide</span> (MoS2) as an additive to reduce engine and gear wear?

This would be useful, as the claim is that MoS2 bonds molecularly to metal parts, preventing metal-o metal contact, withstanding pressure up to 200,000 psi. The claim further states that, after the oil has drained away, the wear and scuffing from starting a "dry" engine is greatly reduced because the MoS2 has bonded to the metal.

Similar claims are also applied to the transmission and differential as well (Product example: <http://www.mrmoly.com>)

How about some feedback?


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