Vintage Cars & Synthetic Oil

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I've been researching engine oil for an article I am writing for the ACCCC car club. Club members have cars dating back to the teens and many could use more information about the oil they use in their cars. I understand that non-detergent SA engine oils were used in cars up until 1930. Castor oil was/is a excellent lubricant for these engines. Starting in 1931, additives were introduced (SB oils) to combat sludge. An earlier post on BITOG provided a link to the following study: Slide show of SA oils in modern engines 2004 I believe cars of the 1930s had to contend with the same sort of problems with sludge. I'm not sure if they had the same sort of wear issues though. Exxon Mobil clearly believes that synthetics (including Group IV?) are suitable in older engines because they mention it being used exclusively in a 1955 Chevrolet pickup: Mobil 1 TV Ep 2: Debunking Myths About Synthetic Motor Oils However, in the 1931 Ford Model A thread, Johnny writes the following:
 Originally Posted By: "Johnny"
I would surely want him to use a modern oil, but I would not recommend a PAO/Ester based synthetic. Talk about seal incompatibility. I would recommend something like a Rotella, Delvac, or Delo straight 30W for that little jewel.
ExxonMobil and Johnny apparently disagree on the use of synthetics in older engines. Perhaps EM should have explained how old. What sort of seal incompatibility would someone expect to experience with the use of a PAO/Ester-based synthetic? Has anyone used synthetics in engines dating back to the 1930s and 1940s? If so, what oil did you use and did you experience any problems?
 
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I have nothing to add other than a couple of questions: Wasn't one of the first synthetic oils created by Standard Oil in the 1920s? Didn't the German Wehrmacht use synthetics in their panzers and aircraft (and discover the excellent cold-flow properties on the Eastern Front)?
 
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At some point some pointy headed know nothings, put nice high detergent ester filled synthetics in their woefully maintained sludgy engines and they started leaking when the worn seals and valve cover gaskets got all the sludge melted off... and now every hick-neck-billy with an opinion thinks that synthetic will run out of his engine like water through a spaghetti strainer... The whole Slick 50 teflon debacle didn't help things, the same people just ignorantly associate things like this together.
 
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That youtube video is pure junk. No evidence, just M1 people reading off a board saying "M1 is the best oil" over and over again. I want Evidence! ha.
 
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 Originally Posted By: fraso
Exxon Mobil clearly believes that synthetics (including Group IV?) are suitable in older engines because they mention it being used exclusively in a 1955 Chevrolet pickup: Mobil 1 TV Ep 2: Debunking Myths About Synthetic Motor Oils However, in the 1931 Ford Model A thread, Johnny writes the following:
 Originally Posted By: "Johnny"
I would surely want him to use a modern oil, but I would not recommend a PAO/Ester based synthetic. Talk about seal incompatibility. I would recommend something like a Rotella, Delvac, or Delo straight 30W for that little jewel.
ExxonMobil and Johnny apparently disagree on the use of synthetics in older engines. Perhaps EM should have explained how old. What sort of seal incompatibility would someone expect to experience with the use of a PAO/Ester-based synthetic? Has anyone used synthetics in engines dating back to the 1930s and 1940s? If so, what oil did you use and did you experience any problems?
The market for oils that are used in 1930's era cars is infinitesimally small, so I don't think EM would make any claims like that in order to sell more oil. However, as you noted, they only made statement about a 1955 Chevy pickup, not a 1931 Ford Model A. When synthetics first came into wide use, there was a problem with seals, but additives have been put into synthetics to resolve that problem, especially with High Mileage Synthetics. Someone posted a link not long ago about some research EM is doing with Ester stock that reduces the seal problem even more and does not require as much seal protection additives as is currently used. The impression I got was the problem was more with PAO than Ester stock. But the other problem is that in an older engine there may already be so much engine wear (not to mention that build tolerances were not like modern engines) that a synthetic is just too thin for these older engines (due to the inherent nature of synthetics to flow at cold temps) and synthetics may have too little friction compared to what the engine is used to (flame wars will start on this claim). One might actually consider a high viscosity synthetic racing oil, or a High Mileage Synthetic at a minimum. M1 has a racing oil that you can order via the Internet, and several companies sell High Mileage synthetics. But if I owned a 1931 Ford Model A, I am not sure why I would want to experiment with a synthetic. It might work, but what would the expected advantage be versus the risk? For a new car, I would always recommend synthetics, but not sure about something that old.
 
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I have used mobil 1 HM 10W40 in a few of my survivor Muscle cars and it seems to work great. The engines seem to run a little cooler and smoother. I used the oil in a Dodge Coronet R/T(440 magnum) and also a 1963 Galaxie R code(427).
 
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fraso

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From what I have learned so far, cars of the 1930s (at least the Dodges) required an SAE 30 oil under normal operating conditions. (See Chrysler Oil Recommendations.) Only when ambient temperatures became high (~ 90°F daytime average) did the factory recommend an SAE 40 oil. SAE 20 oils were also recommended for normal operation at temperatures above 32°F. It would seem to me that a tight 1930s vintage engine (not all are worn out after all) could benefit from an oil with a high viscosity index because they start off cold just like modern engines and unnecessarily high start-up viscosity will not benefit them either. Engine wear during start-up should therefore be minimized with 5W-30 or 0W-30 oil. Because of the rarity of these engines, I believe that every effort should be made to protect them from wear. Rather using a racing oil, I thought a HDEO would be better choice, especially because of the rudimentary crankcase ventilation systems these engines were equipped with.
 

fraso

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Why not? The viscosity of Esso XD-3 Extra (for example) 0W-30 is 12.2 cSt @ 100°C. With a VI of 176, this oil should stay with the SAE 30 viscosity limits over a wider temperature range than many SAE 10W-30 conventional and synthetic oils. Am I mistaken with this reasoning?
 
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My Dad has a 1929 Model A, he uses Castrol GTX 20W50. Engine has been rebuilt approx 35 years ago, only drives 500 miles a year.
 

fraso

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 Originally Posted By: OVERK1LL
I ran M1 5w30 in a 1950's Ford 312, but that engine had been rebuilt and wasn't stock.
Was the engine rebuilt with original-style gaskets and bearings? If so, did you notice any seal deterioration or leakage?
 Originally Posted By: marshall25
My Dad has a 1929 Model A, he uses Castrol GTX 20W50. Engine has been rebuilt approx 35 years ago, only drives 500 miles a year.
Has your dad opened the engine up lately to check the condition of the bearings?
 
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 Originally Posted By: fraso
Why not? The viscosity of Esso XD-3 Extra (for example) 0W-30 is 12.2 cSt @ 100°C. With a VI of 176, this oil should stay with the SAE 30 viscosity limits over a wider temperature range than many SAE 10W-30 conventional and synthetic oils. Am I mistaken with this reasoning?
I dunno. I guess that old engines would have some crude, big clearances and they were designed with the straight weight oils of the day. There wouldn't be a problem at operating temp, but maybe you see plumes of smoke at start-up with a 0W-30 weight oil like Esso or GC?
 

fraso

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Even if they had big clearances, the factory only recommended a 30-weight oil for normal operation above 32°F. If you don't get plumes of oil smoke during normal operation with a hot 30-weight mineral oil, why would you expect to get smoke at start-up with a cold 0W-30 synthetic?
 
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because anything with an 0 at the begining must surely be as thin as water! ;\) Don't you know the older the engine the more it needs bearing starving 20w50? IMO the only reason to use 20W50 is if your engine makes less than 10 PSI per 1000RPM on 15W40, AND you can't get it rebuilt right away. But seriously I think the "loose factory tolerance" theory has some merit, but mostly due to the fact that quality control factors were poorer way back when... not because they wanted low oil pressure and commonly built with horrible bearing clearances and slack piston rings. Yes it was more common for oil to get past rings and be burned, "oil consumption" and topping off between changes was commonplace, whereas today even many older American engines don't "use oil" But is Synthetic REALLY going to get past rings and into the combustion chamber "better" than an identical weight Dino? I suspect maybe a few percent maybe with a decimal before the number... but I doubt you're going to use say an extra QUART over Dino.
 
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 Originally Posted By: fraso
Even if they had big clearances, the factory only recommended a 30-weight oil for normal operation above 32°F. If you don't get plumes of oil smoke during normal operation with a hot 30-weight mineral oil, why would you expect to get smoke at start-up with a cold 0W-30 synthetic?
There's a big difference between any multi-weight oil relying on additives to replicate the "30-weight" when hot and straight weight motor oils. I have heard anecdotal stuff from old heavy equipment mechanics saying that they had seen synthetic burn and leak at increased rates in older vehicles. That is not to say that if synthetic had been used from day one it wouldn't have been different. But a syn using a thicker base oil might minimize this no? I suspect it certainly would have as I've pointed out that synthetic oil is nothing new as was used extensively by the Germans after we blasted, and the Soviets overran, their refineries. But as pointed out, and older engine that may have had a steady diet of minimal detergent oils may have a synthetic do some "cleaning" causing leaks and burning...
 
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 Originally Posted By: 1bolt
because anything with an 0 at the begining must surely be as thin as water! ;\) Don't you know the older the engine the more it needs bearing starving 20w50?
Oh my! Surely you jest! or provide some evidence of 20W-50 being "bearing starving." I'm pretty sure many used these oils in cars that called for them such as MG's, and those vehicles ran a long time with happily lubricated bearings -even if their electrical systems fell apart ... I never said 0W-30 was "thin as water" as I have used 'German Castrol' SYNTEC 0W-30 --ironically here-- to control burning in a Saturn SL2 precisely because I was aware of its thicker properties when at operating temp coupled with its cold flow start-up in a DOHC. Both of which would be almost identical to Esso 0W-30 in those respects. And it worked well to an extent. However, my engine was designed in the late 1980s or very early 1990s. Not in 1936...
 Quote:
IMO the only reason to use 20W50 is if your engine makes less than 10 PSI per 1000RPM on 15W40, AND you can't get it rebuilt right away.
Or if the manual calls for it as the (older 60s or 70s vintage) engine runs hotter? Or if your car consumes a lot of oil and might require a thicker oil to maintain compression levels? Or it's an air-cooled Beetle or Mini?
 Quote:
But seriously I think the "loose factory tolerance" theory has some merit, but mostly due to the fact that quality control factors were poorer way back when... not because they wanted low oil pressure and commonly built with horrible bearing clearances and slack piston rings. Yes it was more common for oil to get past rings and be burned, "oil consumption" and topping off between changes was commonplace, whereas today even many older American engines don't "use oil" But is Synthetic REALLY going to get past rings and into the combustion chamber "better" than an identical weight Dino? I suspect maybe a few percent maybe with a decimal before the number... but I doubt you're going to use say an extra QUART over Dino.
I agree with most of your above statements. But I do take issue with your statement regarding synthetics and usage. I think that yes, synthetic will burn more readily in some engines that have been abused. Even Mobil1 qualifies its performance statements to the affect that no oil will fix mechanical defects. In any case, I've owned a couple junkers, or at least cars that had had abused engines or were simply older. In at least one instance, using both M1 and SYNTEC resulted in at least two or three times the burning than did using a conventional. The M1 also turned jet-black after only 500 miles whereas a conventional or semi-syn took 2000 miles to do so. I do also think that in some instances --maybe cars that use oil because of deposits on the ring packs like my Saturn did-- thicker synthetics can reduce and control burning via cleaning properties, or a more consistent viscosity at temperature... Secondly, thinner 5 and "0" weight oils were largely engineered in response to the increasing sophistication of engines using overhead cams and valves as lubrication needs changed. As did the technology for producing better base oils... Personally, if I had an older classic vehicle, I'd use a heavier synthetic such as M1 10W-30 or 40 High Mileage in it, and go from there. If no evidence of burning or low compression surfaced, then yes I'd consider GC or Esso 0W-30 which are essentially almost 5W-35 weights. If such a weight existed. But probably only in winter and I'm not even sure there would be much benefit to it as the oil doesn't really need to pump very far... Cheers:
 
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