Proper Oil For Classic Car

[AVS619]

I know oil use has been an issue for quite some time but I need to ask again. I have to change the oil on my wife's 1923 Rolls-Royce 20 and her 1925 Pierce-Arrow Series 80. The last time I changed the oil I used off the shelf 10W-30 but I may not be using the right oil. Other than the oil the Classic Car Club or Hemmings sells is there an off the shelf, store bought brand that would be suitable for these cars? I am in a more or less rural area with few stores for oil (other than Farm and Fleet up the road) but I would like to get an oil that I do not have to have shipped to me. Any suggestions?

[MCHinson]

You are going to probably get more opinions on this subject than you know what to do with. I recently switched to American XT 20w50 that is available at Family Dollar Store. The best research that I have done seems to indicate that the zinc levels are adequate for my 1937 Buick and it is reasonably priced and while I don't normally shop at Family Dollar Store, it is close by for me. Hopefully there will be one near you too.

[Grimy]

In all my vintage cars (see list) including my own Series 80, I use Shell Rotella-T 15W-40, a "crossover" oil primarily for diesels but also API-approved for gasoline engines.  HOWEVER, on all the cars, I have had the oil pans down and have cleaned the oil pump screens, and am reasonably satisfied that there is no significant accumulation of sludge or debris in those engines.  Diesel oils are allowed by law to have more ZDDP than oils certified for ONLY gasoline use.  As I recall, gasoline-only oils are limited to about 800 ppm, and the Rotella is about 1100.  The Rotella has slightly more zinc and phosphorus than the Chevron RPM Delo 15W-40 I have used in my Ford Powerstroke the last 18 years.  My cars don't demand high (or indeed, ANY) ZDDP, nor do your cited cars.

 

I buy all my oil at Walmart, which usually has convenient one gallon, two gallon, and 2.5 gallon jugs of Rotella and Delo--and their prices remain stable unlike "sale vs full-price" spikes at retail chain auto stores.

 

As Mr. Hinson said, you will undoubtedly get a number of impassioned responses that may differ.  This works FOR ME, and I put quite a few miles on my cars.  I change oil HOT (after a run) about every 12-15 months, preferably in the late fall, irrespective of mileage.  Additives in oils are depleted with time as well as with use.

[nzcarnerd]

I know you said you did not want anything that would have to be shipped but, to get an idea of want can be obtained, have a look at the catalogue from this company who have a specialised range of oils for old cars   -    http://www.penriteoil.com.au/

[poci1957]

Lots of opinions on this I am sure, I will also be interested in the responses.  My thought is a modern 10W30 detergent oil off the shelf is probably better than oil from the past and that is what I use too.  BUT there are a few factors out there.  The ZDDP is an ingredient that has been much discussed as a problem for older engines, primarily higher performance 1960s cars with flat tappet camshafts. Many are using Rotella diesel oil with these as mentioned by Grimy, I do not do that but I do add a can of STP which I am told also adds ZDDP.  I do not worry about this much with my stock 1950s car or anything older.   

 

Grimy also mentioned checking for sludge.  My understanding is that by it's very nature a detergent oil will dislodge and wash impurities into the oil flow if the engine is older and not freshly rebuilt or not previously running detergent oil, I.E if it contains sludge.  If your engine is fresh and clean I would go detergent, if not I would proceed with great care.  Good luck, Todd C     

 

 

[Spinneyhill]

Non-detergent oils are generally made with inferior stocks. They are superseded technology. The thinking of their proponents is that oil "back then" was non-detergent so we should use it to prevent entrainment of dirt etc. But that is misinformed because one of the problems back then was the generation of sludge which entrained dirt particles and continually circulated them. When the engine is shut down, those particles are deposited where they land, everywhere in the engine - in the oil ways, inside the cranckshaft oil ways, all over the timing gear, around the valve chamber and so on. They are not picked up again in many places because the oil does not move fast enough.

 

If you have a look at Richard Widman's paper on oil http://www.widman.biz/Corvair/English/Links/Oil.html, you might like to think about the points he raises. The first number is relevant on startup (i.e. 10W). Startup is when most wear occurs so a lower viscosity better enables the oil pump to get oil around the engine quickly. I am using a 5W-40 in my 1930 Dodge 8. The second number refers to the viscosity when the oil is hot. 30 or 40 is probably what would be right for your car.

 

The STP is a viscosity index raiser. Adding that just increases the viscosity and is a waste of money. It will slow initiation of full oiling on cold startup. You are using a 10W30; in reality it is probably more like a 15 to 20W-40 or 50 with STP in it.

 

Much is said about ZDDP and whether older flat tappet engines benefit from it or not. Personally, I would use it because I want maximum benefit and modern technology is far better then 1922. At times my car is driven hard too. The maximum zinc content is available if you use a diesel oil of CI rating. CJ has slightly less zinc.

 

You should be able to find a SAE CI-rated 10W-30 oil at your local Farm shop.

[mercer09]

you will get 100 differing opinions, in the end, totally up to you.

 

consider that ALL oil today is superior to what was offered when your cars were built.

 

my preference is synthetic, but many hate it- to each his own.............................

[C Carl]

Tom : Type Widman into the search box above. Read Widman's superb 33 page paper. You will then know more about oil than 99.9%+ of the people who have not yet read it. From your bio , I think you would be in an appropriate position to inquire of Richard Widman as to his take on specific oil for our 'teens & '20s cars. PLEASE , AS AN EDITOR , DO SO , AND PROMINENTLY POST FOR GENERAL EDIFICATION. THANK YOU IN ADVANCE ! I use an Amsoil 20w/50 (plenty of zinc and phosphorus also) , in my mid '20s unrestored Cadillacs for reasons you will see. If the engines were new ,or recently overhauled , that would be too heavy. I drive the cars at full operating temps for hours on end , even on hot Summer days. If they were just short distance down to the park and back , or cold temp drivers , I would lighten up a bit. The reason for this also will be obvious , post Widman. 

 

As you note , Tom , this subject comes up frequently. Once or twice a month , or once every month or two. A number of us have repeated recommendations, and admonitions , and also relevant anecdotal tidbits. Here again , for you with perhaps naught but a rural feed store from which to procure lubricants : I have been using synthetic oil for several decades , and it was not universally available back in the '70s , or so. Traveling in Montana wheat country long ago , found myself in need. Directed to the feed store by the Mobil station who had not yet developed a sophisticated clientele for advanced lubricants. Purchasing Mobil 1 stimulated fertile conversation among agricultural professionals there assembled. They attested that upon availability of synthetic grease , wear in greased articulations in their heavy machinery ceased to be an issue. I took that to heart ; they neither had parts to replace that day , nor an axe to grind ! Do you remember the Hot Rod Magazine synthetic oil article of perhaps 35 years ago ? The Chevvy 350 1/4 million mile test ? An unsubstantiated rumor I harbor claims the military has been using synthetics since WW2. With your (or anyone else) , coinciding interests can you verify ?

 

I certainly hope this laborious (I primitively thumb tap my iPad mini postings with arthritic 72 year old hands) composition and informative reference is of some use to some of you dear treasured cyber forum friends. I again ask that one of you more able communicators , if not Tom , contact Richard Widman for relevant period specific advice. He will know , and may induce advantageous adjustments.

 

Also , Tom , give me a call regarding your search for an open early - mid '20s RR.  206-790-6912.   - Carl

 

N.B. : Todd C , be hesitant to add STP or any V.I. improver to engine oil unless that engine is a bit loose. These products flatten the temperature/viscosity curve , raising the viscosity , particularly at the high temp end of the scale. This may put your engine oil out of the optimal envelope , a counter productive modification. See Widman.

[poci1957]

28 minutes ago, C Carl said:

N.B. : Todd C , be hesitant to add STP or any V.I. improver to engine oil unless that engine is a bit loose. These products flatten the temperature/viscosity curve , raising the viscosity , particularly at the high temp end of the scale. This may put your engine oil out of the optimal envelope , a counter productive modification. See Widman.

 

Thank you Spinneyhill and Carl, what you are saying about thicker viscosity makes sense as my previous use of STP was in a hot-running "loose" engine.  I am about to change the oil in my freshly rebuilt 1957 Pontiac with just 120 testing miles--8.6:1 compression, hydraulic lifters, light irregular use like most old cars.  My oil of choice is Valvoline 10W30, Pontiac originally called for straight 30W but I do not think that is necessary, any thoughts? Todd C 

[C Carl]

Yes , hi , Todd and Tom & all. The above referenced Hot Rod Magazine article advised at the time to wear in a newly rebuilt engine on conventional oil. Declared synthetic lubricated so well (high shear strength and much higher flashpoint) , that cyl walls would retain hone marks , and never properly seat rings ( !! ) if synthetic were used from the get-go , if memory still serves. Been a while , and younger more able minds are encouraged to set me straight , if I am confused. Seems Widman corroborates this. They dismantled a Chevvy 350 , carefully measured every potential wear surface , assembled , and drove 250,000 miles. Changed synthetic oil 10 times. Took it apart again , and could not measure any wear ! So maybe run your new engine for perhaps 5000 miles on frequently changed conventional , and then go synthetic. Some aspects of your engine will then be a 5000 mile mill forever ! I have a magnificent 2007 Mercedes - Benz E550. It has always been maintained by M-B. Just had the periodic done , and they changed from 10W/30 synthetic to 5W/40 synthetic. Sounds like an evolution in thought regarding the superior lubricating properties of synthetics. Seems to correspond well with the extremely sound advice given by the other kind contributors on this thread.

 

By the way , I have stated before , and repeat : an '07 and '08 E550 is one of the greatest medium - high performance sedan bargains in all of automotivedom. I think new , they carried a premium over the much lesser 6 cyl E350 of something like $10,000. Well worth it then , now you can get the whole car for only half again that cash. Fifteen grand , or so ! Originally about $65,000 , find a low mileage , say 50 - 70 thou , with a COMPLETLY known service record at M-B. Mine has been an absolute jewel of a car. Highly regarded by Consumers Reports , a real drivers car. If God limited me to drive but one of my varied fleet for eternity , E550 hands down. And if almost 400 ponys is not enough ,and you have the bucks , try to find an E63 ! But really , that E550 has a superb ability to be exactly where you want it to be , exactly when you want it to be there ! Particularly in "S" mode. Some day , they will be "antique".  Safe driving fun , my friends.  - Carl

[captndan]

Rosella T 15-40 available at Farm and Fleet.  Period.

[60FlatTop]

You should check with the person who talked your wife into buying those cars. They must have been pretty slick to talk her into them, oily slick.

 

On the 20 HP, call 585-325-7393. You'll get help. Drop my name.

Bernie

[padgett]

Along with tires, the greatest improvements in the last century have been metallurgy and oils. Years ago I used to change oil when I saw a 3-5 psi drop at hot idle (usu 3000 milesish) as the additives broke down (long chain polymers became short and a 10w30 became straight 20 wt). Do not see that any more particularly with synthetics. 10W30 is fine for a good engine, 15W40 if a bit worn. Additives such as CD-2 or Stabil is more a matter of choice and probably won't hurt anything. Was once told that STP could save an oil-starved racing engine for 2 seconds but that or any motor honey (viscosity improver) was of little use in a street engine (and an accumulator was better).

 

So agree there are probably more opinions than cars and most will do no damage.

[Guest]

For all you scientist or chemist out there. Why does every manufacturer of new cars or old, foreign or domestic always say to always stick to the same brand of oil?   

[Mark Shaw]

On 7/12/2016 at 1:36 PM, Spinneyhill said:

"Non-detergent oils are generally made with inferior stocks. They are superseded technology. The thinking of their proponents is that oil "back then" was non-detergent so we should use it to prevent entrainment of dirt etc. But that is misinformed because one of the problems back then was the generation of sludge which entrained dirt particles and continually circulated them. When the engine is shut down, those particles are deposited where they land, everywhere in the engine - in the oil ways, inside the cranckshaft oil ways, all over the timing gear, around the valve chamber and so on. They are not picked up again in many places because the oil does not move fast enough."

 

OK Spinney hill, I need to throw my opinion into the fray to clarify how non-detergent oil works in older engines:

IMO, If your engine has not been rebuilt and does not have an aftermarket oil filter, you should not use detergent oils.

When it comes to older engines without oil filters (in the days before detergent oils) oil pans were quite large to slow the flow & settle out solids.  If you find sludge in your oil pan, it means that it has done it's job to remove the solids.  Detergent oils are designed to suspend solids so they can be removed by the oil filter.  If you have no oil filter, you should use non-detergent oils because detergent oils will keep the solids suspended and continue to circulate them throughout your engine. 

 

Edited July 14, 2016 by Mark Shaw (see edit history)

[padgett]

Interesting. Have never had a car that did not have an oil filter (though the XK Jags never were very good) so is a very good point and sounds like dropping/cleaning the pan should be part of every oil change.

 

Back in the day it was common to drop in a quart of ATF (super high detergent, makes a good hand cleaner) 100 miles before an oil change.

[Guest]

VW's 1937-8 into the 70's never had a oil filter. They used a oil screen that worked very well. As a VW line, and later engine and transaxle mechanic in my youth in the VW dealership we never used non detergent oil.

!933-1954 Pontiac flathead straight eight and six never had a oil filter. They like VW had a oil filtration system. Unlike the VW whose filtration reverse flow screen was removed and cleaned every oil change at 1500 miles, the Pontiac system called the precipitation type oil cleaner. Pontiac engineers determined that tis devise effectively removed all particulate matter large enough to cause engine damage. I believe there was no service to be done on the system, only to be cleaned at engine rebuild time which was calculated to be over 100,000 miles.

 

 

 

VW's;

[Spinneyhill]

It is a myth that detergent oils circulate damaging particles. The physics of sediment transport come in here. The larger bits need faster, higher energy (or more viscous) flow to move them. The finer bits stay suspended in much lower speed flows. Clay sized particles only settle out very slowly, over a period of days or weeks. This is one of the reasons your oil stays black: the finest particles stay suspended.

It was recognised early on that there were three problems with oils in use at the time, with five significant symptoms (source: Service Station and Motor Mechanics Manual, George George A.M.I.A.E., M.S.A.E., M.I.A.M., F.I.C., 1940, p. 87). They were exercising the minds of motor lubricant makers:

1. Corrosion by the organic acid compounds produced by the combustion of the fuel, upon the upper part of the cylinder walls and upon the piston rings.

2. Sludge formation in the oil itself.

3. Rate of viscosity reduction with temperature.

4. Extreme pressure lubricants needed for gearboxes and differentials.

5. Corrosion of the new alloys being used for bearing metal.

 

Detergent packages include anti-oxidants that retard corrosion. They also prevent sludge build-up. And the additive packages provide for a flattening of the viscosity-temperature curve, hence multigrade oils. The base oil is probably still S.A.E. 30, but the additives make it behave like the numbers in the multigrade designation: easier to pump at startup (e.g. 5W or 10W) leading to far less wear, and holding their viscosity at operating temperature.

 

Remember that back in the day, engines were full of SLUDGE (a consequence of the oil, not a design feature). It held in suspension and circulated the larger particles. With modern detergent oils, there is NO SLUDGE so the larger particles (the ones that do the damage) settle out in the sump. If you have damaging particles, your engine is already in trouble anyway. The particles that are entrained are very very small - clay sized. With non-detergent sludgy oil, there are larger bits in circulation that may be bad for the engine and they settle out when the oil slows - everywhere on stopping the engine, such as in the oil galleries in the block and crankshaft, in the dipper troughs in splash engines, in the tappet chamber, in the oil pump, in the piston ring lands and so on. Once settled, it doesn't readily get picked up again by non-detergent oil. The oil ways are narrowed.

 

I don't for one moment think they would have continued to use old fashioned non-detergent oil once detergent oil became available. Non-detergent oil would not have been readily available. Reverting to it is a retrograde step.

 

When you next buy your bottle of non-detergent oil, look into the oil stocks used to make it. There is a pretty good chance it is low grade oil (see Widman's paper about this). If you want cheap low grade non-detergent oil, they will make it for you.

 

Note also that oil changes were very frequent. My 1930 Dodge is recommended at 1500 miles in summer and 500 miles in winter. That was how they dealt with the sludge, corrosion and oil breakdown problems: new oil, frequently. The large sumps were also to handle a lot of oil: more oil should last longer before it is all sludge. And I don't for a moment believe the mechanics would remove the sump every oil change (or second or third even) - the customer wouldn't want to wait or pay for it and it is not a fun job.

 

With a new engine I would never go near "old technology" oil. Your engine will last a lot longer on modern oil. Without a filter I would change frequently but still use a multigrade (i.e. detergent) oil. My Dodge has a bypass canister filter, but they are impossible to buy so I change the oil at 1000 mile intervals.

 

 

 

[Spinneyhill]

19 hours ago, helfen said:

For all you scientist or chemist out there. Why does every manufacturer of new cars or old, foreign or domestic always say to always stick to the same brand of oil?   

 

Marketing. They have an agreement with the owner of brand of the oil they recommend.

 

George George (see ref. above) said in 1940 this was "another fallacious idea, as many lubricating oils when they reach the consumer are already blends of several types of oils, often from quite different types of crudes." He does say that in those days E.P. oils should not be mixed and that Castor oil will not mix with mineral oils.

[Guest]

1 hour ago, Spinneyhill said:

 

Marketing. They have an agreement with the owner of brand of the oil they recommend.

 

George George (see ref. above) said in 1940 this was "another fallacious idea, as many lubricating oils when they reach the consumer are already blends of several types of oils, often from quite different types of crudes." He does say that in those days E.P. oils should not be mixed and that Castor oil will not mix with mineral oils.

Then why does it say in my owners manuals 1962-2012 and all my cars in between (9)  that it does not matter which brand you choose of a reputable oil but stick to the brand of your choice once you have decided on a brand.

[Spinneyhill]

I would expect they are covering their backs in case there are incompatibilities. Every company has different additives and they probably do but there is a small chance they may not get on together.

[padgett]

"If you have to ask..."

I use synthetics in almost everything any more. 5 qt jug doesn't cost much more than dino.

Castrol R sure used to smell good.

[Guest]

1 hour ago, Spinneyhill said:

I would expect they are covering their backs in case there are incompatibilities. Every company has different additives and they probably do but there is a small chance they may not get on together.

Their statements has nothing to do with covering anything. They have no skin in the game in their statements, they are non committal on brand, just make sure it meets requirements and to stick to the same brand.  

[Stude Light]

My two cents: My 1923 splash lubricated engine much prefers a straight weight oil - SAE 30 or 40. As do the air-cooled Lycoming aircraft engines that I've owned or used over the years.  But none of these engines starts in a cold environment (car only runs in the summer and aircraft engines get preheated), otherwise I would use a multi-viscosity for cold starts (starts <40 deg F). I've already commented in the past about ZDDP and oil additives.... got my info directly from the oils technical expert at GM (now retired) and by reading the SAE papers written on the subject, some of which he co-authored, when the levels of zinc where being reduced. Based on that knowledge, I just use off the shelf mineral oil in my 1923 and change it often as I have no filter. If I had a filter and didn't do changes as frequently, I might use today's synthetics.  They are a superior oil.  If you don't know the "sludge" condition of the engine, I would definitely remove the pan and clean it out, run some fresh oil and change that after a couple of hundred miles then just go to a routine oil change regiment.

Scott

[C Carl]

Scott , could you please reference your ZDDP and additives comments ? Or perhaps a few sentences here and now giving the bottom line of your well qualified research ? For obvious reasons , all other things being equal , pilots and flight engineers generally have extra insight into matters regarding internal combustion engines. Thank you , - Carl

[Guest]

2 hours ago, Stude Light said:

My two cents: My 1923 splash lubricated engine much prefers a straight weight oil - SAE 30 or 40. As do the air-cooled Lycoming aircraft engines that I've owned or used over the years.  But none of these engines starts in a cold environment (car only runs in the summer and aircraft engines get preheated), otherwise I would use a multi-viscosity for cold starts (starts <40 deg F). I've already commented in the past about ZDDP and oil additives.... got my info directly from the oils technical expert at GM (now retired) and by reading the SAE papers written on the subject, some of which he co-authored, when the levels of zinc where being reduced. Based on that knowledge, I just use off the shelf mineral oil in my 1923 and change it often as I have no filter. If I had a filter and didn't do changes as frequently, I might use today's synthetics.  They are a superior oil.  If you don't know the "sludge" condition of the engine, I would definitely remove the pan and clean it out, run some fresh oil and change that after a couple of hundred miles then just go to a routine oil change regiment.

Scott

Scott you are quite right about air cooled engines liking straight weight oil from VW and Porsche air cooled flat fours and sixes, to six cylinder Continentals and 1820 and 3350's I worked on in the Navy. All those engines like to warm up slowly and evenly to expand to their operating temperature and internal dimensions  /  tolerances before work is applied to them. My VW's don't get driven until 115 degrees oil temp is indicated , it seems after all these years I'm still in the cockpit.

[Rusty_OToole]

On the question of when synthetic lubricants became available.Some time ago I read some reminiscences of an old hot rodder who ran at the dry lakes in the fifties. He had an aircraft designer for a neighbor, who took an interest in his amateur efforts at streamlining and building a speed record car. One of his contributions was some special grease made for jet or turbine engines. When he used it to pack his wheel bearings it practically eliminated friction. He could give the car a gentle push with one hand and it would roll 20 feet.

 

I think synthetics were first developed for the extreme high temps of gas turbine and jet engines in airplanes and helicopters and may date back to the forties. For a long time these lubricants were very expensive and only used in aircraft. I think the first synthetics for cars and trucks were introduced in the seventies.

[C Carl]

Thanks , Rusty , for the very interesting second source on this info. I had heard this from an old carrier-based airborn navigator , one of my greatest friends. Jim made his "final flight" over 35 years ago , and so availability for cross examination is currently on hold. Like the rest of us oldsters , the worst thing about longevity is the loss of friends. I am so incredibly grateful for this  modern technology which gives us the privilege to share real friendship on a screen !  - Carl

[padgett]

I heard that synthetics were developed for arctic conditions in the 30's and were relatively common during WWII.

[Guest]

Some might recall that  Germany during World War 2 ran it's war machine on synthetic gas and oil because of the lack of natural resources within it's sphere of control.

[Sweet64rivi]

PennGrade http://www.penngrade.com/

[Stude Light]

21 hours ago, C Carl said:

Scott , could you please reference your ZDDP and additives comments ? Or perhaps a few sentences here and now giving the bottom line of your well qualified research ? For obvious reasons , all other things being equal , pilots and flight engineers generally have extra insight into matters regarding internal combustion engines. Thank you , - Carl

Carl,

The ZDDP comments were put in a post back in 2011 and I found that post is no longer available since the site upgrade but, like other long winded posts of mine, I usually write them in Word then paste into the forum so I don't lose my work.  After a little searching I found what I was referring to and pasted it below.  One thing I would like to make clear is that my conclusions are my own, based on published works. Although I work for GM, I am not representing the company in my comments.  If you search SAE, you will find each of the publications listed below and can purchase those.

Scott

 

Okay, so I knew better than to comment on the ZDDP issue!  But now that I dug my hole and will get the wrath of others, I will have to comment further.

 

I think one thing we can all agree upon is that for a reciprocating engine and particularly our old engines without oil and air filters, the best thing you can do is to change your oil very often.  I have practiced this in every engine I own or operate and have had exceptional results with regards to longevity.  Cars, trucks, lawnmowers, tractors, aircraft (many of which still do not have engine oil filters) – frequent oil changes = good practice.  And today, oils are usually recycled so you can't feel bad about using a bit more than the average guy. 

 

My problem, like many others, is that I have limited resources.  Constant oil changes with expensive "specialty blends" or additives can get costly so I wanted to make sure I really needed these.  I started reading about ZDDP but found much of the information was put out by companies wanting to sell additives and specialty oils and had nothing more than a good story.  This information is then repeated in many forums.

 

I'm a test engineer at GM and am constantly bombarded by opinions and anecdotal stories to which I request the data to back them up.  So with the ZDDP issue I decided to dig deeper to get the data.  I was able to obtain copies of the Society of Automotive Engineers (SAE) publications that have the history of engine oil development, the need for additives, the introduction of ZDDP in the 1940's, continued work to balance oil performance with fuel economy /emissions and test results to back up the conclusions.  In addition to the paper listed earlier there are many related SAE publications dealing with ZDDP and tappet wear (821570, 560017, 852133, 861516 to name a few).  These are written by the industry experts that have no ties to selling product, but determine what is appropriate for proper oil performance to ensure that the consumer is protected by the standards set.  I have read the papers listed and would gladly post them so people could come to their own conclusions, but the papers are copyrighted by the SAE (you have to purchase them).  The oil additive issue is actually rather complex as it is not just about lifter wear but also related to bearing wear, antioxidant (corrosion protection), etc. and ZDDP specifically has traits related to both zinc and phosphorus levels that have a level of interaction with the other oil additives which are also improving with time.

 

I contacted Mr. Robert Olree, who published several of these SAE papers and served as Chairman of the International Lubricants Standardization and Approval Committee (ILSAC).  ILSAC is the governing body which has been empowered with the task of establishing minimum performance standards for the lubricants used in today’s gas engine passenger cars and light duty trucks.  I asked him about the ZDDP issue and he gave me some information and sent me a summary he had put together which I can post.  Mr. Olree worked for GM as a technical expert in the oils group.  He was co-author of publication 2004-01-2986 which dealt specifically with understanding how much ZDDP is required to prevent wear in modern and older engines.  The conclusion in this report, based on extensive research and testing, is that 0.08% phosphorus (in the form of zinc dithiophosphate) was more than enough to protect engines old and new.  It also suggested levels of 0.05% phosphorus and even as low as 0.03%, when used with other additives and phosphated cams (for initial break-in) could be acceptable. Keep in mind that these tests are based on the high contact loading of the newer flat tappet engines beginning in the 1950s and particularly from the1960s-1980s.  The pre-war engines had much weaker valve springs, lower lifts and much lower contact stresses at the cam/tappet interface and ran with no ZDDP oil additives in their day. The current ILSAC GF-5 API SN spec is 0.08% phosphorus maximum.  The sequence wear tests were specified to pass at 0.06% phosphorus.

 

In conclusion - I'm really not buying or selling that you should or shouldn’t use higher levels of ZDDP in your cars - just offering information.  The amount of data I reviewed convinced me to spend my money on more frequent oil changes and not worry about ZDDP levels causing any damage.  If you think it is wise to add ZDDP or buy specialty oils with ZDDP, I'm fine with that.  Just don't add too much ZDDP as the testing reported in SAE publication 2004-01-2986 indicates that phosphorus levels of 0.14% increased long term wear and at 0.20% phosphorus, camshaft spalling begins to occur.

 

Respectfully submitted,

Scott

[AVS619]

As usual, called out of town just after I posted my oil question. Thank you all for responding. Lots of good information. I found that Farm and Fleet, not too far from here, has the Shell Rotella.I think I will give it a try. I was supposed to take Joyce's Pierce to a CCCA regional picnic but I don't think I'll have time to get it ready. Joyce loves her '20's Pirece and Rolls. She also owns a '36 Cord. Joyce likes cars with starter motors. My collection is all brass era and with these I have been using off the shelf 10W-30. They are all crank start which has made using them this year a bit of an issue as I need a new hip. Had to be my right hip and if you have driven a brass-era car you also now the effort needed to work a cone clutch. Anyway, thank you all again for the information. Very interesting discussion.

[Mpgp1999]

As a fun experiment I did a few years ago with my 1926 Dodge was use antique oil. I had found several cans of green quakerstate motor oil. I used them in my car for about 500 miles. I sent a sample to Blackstone labs. The oil tested around sae 30 and api rating sb. The car performed perfectly normal and very well in warmer weather. Oil pressure was good etc. the only down sides were harder to start in cooler weather. The car needed longer to warm up before I could move it. That 500 mile mark was about the maximum. The lab said the oil had very little life after 500 miles. If I continued to use this I would expect to remove the oil pan yearly or so to remove sludge and buildup. Currently I use non detergent oil rated sb and I use Lucus additive and a zddp additive. The antique can of oil contained about 600ppm of zinc and about 500ppm of phosphorus. 
 

food for thought. 

[plymouthcranbrook]

All I can add to this is I have run all my vehicles since time immemorial on Blains Farm and Fleet house oil and have never had any oil related issues. I use synthetic on my wife and daughters cars(Kia Souls) and regular on everything else. My 1952 Plymouth, 1980 Plymouth, and 2001 Chevy Astro with 196,000 miles on it. Good oil pressure on all and almost no loss not leak related. I firmly believe that the key to long engine life is regular oil changes with a good quality oil.

[Matt Harwood]

This is a 4-year-old thread. Surely we've had more recent debates about motor oil...

[Steve_Mack_CT]

6 minutes ago, Matt Harwood said:

This is a 4-year-old thread. Surely we've had more recent debates about motor oil...

My gosh I hope not... 🤔😉😁

[padgett]

Any more I just use the recommended weight in Mobil 1 High Mileage (more additives). May be paying a bit for nothing but does not hurt. Just use the old racer's adage of 10 psi per 1000 rpm. Most cars of this century have more. Only thing I miss were the days of 5qts filled nearly everythiing. Now I have one DD that takes 8, another 7. Just buy 5qt jugs at the mart at the wall.

 

ps if it says 5w-30 I generally use 10W-30. Hot climate.

[bryankazmer]

PSI?