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Technical Engine oil synthetic VS conventional

Discussion in 'The Hokey Ass Message Board' started by andy198712, Jul 5, 2020.

  1. andy198712
    Joined: Jul 3, 2020
    Posts: 1


    I've been reading allot of articles and it seems like this is still a 50/50 mixed opinion issue.

    I've got a fresh oldsmobile 403 so oil leaks are not a concern for me as all of the seals are new. I'm wondering if i should use conventional or synthetic oil after the break in?

    If synthetic i planned to use MOBIL 1 full synthetic 10w-30, should i use the zinc additive with MOBIL 1 synthetic or does it have a sufficient amount of zinc in it already?

    I like synthetic oils because they claim to have higher levels of detergent, so in theory if ran from beginning to end of the engines life cycle it should run overall cleaner?
    31hotrodguy likes this.
  2. DdoubleD
    Joined: Nov 18, 2009
    Posts: 221

    from Michigan

  3. Mike VV
    Joined: Sep 28, 2010
    Posts: 1,917

    Mike VV
    from SoCal

    No...there's not any question whatsoever..! Why is there a question ?
    The only question is, maybe the cost.
    I've been using Mobile 1 in both my cars AND motorcycles for MANY years.
    And guess what, no oil related failures in either my bikes (engine AND transmission) or cars..!


    The web site noted above -
    There's about a year's worth of reading there to get it all.
    This guy (540 Rat) has done a lot of independent testing. Basically, synthetics are worth the money.
    I've also used Castrol, GTX (dyno oil) oil with excellent results. But will always go to Mobile 1 in any engine that...doesn't have rope seals and leaks all over..!
    Last edited: Jul 5, 2020
    Special Ed and BigDogSS like this.
  4. blazedogs
    Joined: Sep 22, 2014
    Posts: 443


    My opinion really doesn,t mean much .I ,m not a chemist,a college graduate ,just a old guy that has been playing around with old cars for years. I use what I,ve, been using for years ,don,t like change.. although I did go to oil with a higher zink content for my flat tappet engines. I use conventional oil Valvoline V1 with higher zink content 10/30. I saw on the shelf recently that Valvoline sells that same oil now in ( synthetic) also. Gene in Mn
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  5. I have been using Amsoil full synthetic in all my vehicles, boats, and aircraft, since 1980. I just purchased a 4x4 beater as a daily driver, and switched just the engine to 5W-30 full synthetic, and the combination city/highway mileage improved from 28.5 mpg to 32.5 mpg ( Imperial Gallon). I haven't switched the diffs, transmission, and transfer case, yet, but that will improve the mileage even more.
    Jet aircraft have been using full synthetic oils since the early sixties. These oils are formulated differently because of the different requirements, such as higher temperatures, cleaner environment, and different seals. The company I flew for, did a spectromatic test of the oils on a 100 hour interval, approximately once per week, and the tests could determine problem areas in an engine just by monitoring the levels of the metal determined from the tests. The oil was not changed, unless there was extensive maintenance. In one case, I am aware of the three engines on a DC 10-30, going over 25,000 hours. I retired in 2000, and I am reasonably certain that procedures and product have only improved over the years.

    BTW. Not driving much in the last 6 months, has reduced the operating cost considerably.

    norms30a and dirty old man like this.
  6. Arominus
    Joined: Feb 2, 2011
    Posts: 391


    M1 0-40 is a better choice, it’s 1100ppm of zinc already which is fine for a flat tappet motor.
    Joined: Aug 1, 2009
    Posts: 491

    from 94577

    And like assholes, everyone has one :p
    A fellow 403 Rocketeer. Great underrated torque engine.
    After the engine has been broken in, I would opt for any of the 5W-40 M1 oils. They have higher zinc additives than the 0W-40 or even some of the 15W- 50 oils, which I feel is too thick for a street car anyway. M1 has two or three 0w-40 but only one is 1100ppm of zinc. The other(s) are less.

    5W-40 M1 variants are fine. They vary from 1100-1300 ppm of zinc.
    Zinc additives are probably not going to work in any kind of off the shelf 'on road' oil as the detergents will wash the added zinc out of the oil and it won't mix.

    All newer oils have lots of detergents in them, even conventional.
    Synthetics are created from a better base stock of oil. This makes the oil more durable and less likely to break down from heat and wear. This gives synthetic oils a longer life in the engine.
    Unless you are running stupid high spring pressures, 5w-40 M1 will be fine for a street use.
  8. squirrel
    Joined: Sep 23, 2004
    Posts: 46,099


    If I were running a fleet and had to get the last mile out of a bunch of engines, I'd put some research into it.

    Most of us are just playing around with toys, and it doesn't really matter what oil we use, we won't wear out the engine in our hot rods.

    If you want to spend a little extra for a particular brand, or for synthetic, go for it. You probably won't hurt anything. I use it in the late models, but not the old cars.

    And the cost difference isn't very much any more, unless you go for an expensive brand.
  9. 6sally6
    Joined: Feb 16, 2014
    Posts: 1,107


    I have ALWAYS run what was 'on sale' and NEVER had an 'oil related' break down issue!!
    My opinion is...if you think "name-brand" synthetic oil is BETTER (just because you pay more for it!) you probably insist on Heinz Catsup and Green Giant peas etc.
    If it has the API (or whatever that stamp is!) then it probably came outta the same hole!
    Just my feelings. Not trying to be ugly.
  10. stanlow69
    Joined: Feb 21, 2010
    Posts: 4,321

    from red oak

    Dollar General got sued for selling oil in New York state compatible to water.
    fiftiescat and Boryca like this.
  11. I have been running Pennzoil 30W in everything for nigh-on 50 years with no problems. But then I am biased since I run a Pennzoil decal on my Willys. Colors are perfect!!
    CD picture.jpg
  12. Blues4U
    Joined: Oct 1, 2015
    Posts: 4,671

    from So Cal

    It's always interesting reading posts on these types of threads. Lot's of opinions expressed, most (all?) without any kind of backup. Synthetics have more detergent? Says who? Zinc additives? Detergents wash the zinc out of the oil and it won't mix? Really guys? Wow.

    There are several different kinds of synthetic oils, for engines they tend to be mostly what's known as Group III base oils (heavily refined mineral oil), PAO's (polyalpholefin) (assembled from the light ends pulled off the crude oil in the distillation tower), and maybe 1 or 2 are made with Ester's (result of mixing an alcohol with an acid). Actually, all PAO's use some esters as a carrier for the additives because PAO's don't solubolize additives very well at all. Each type of synthetic has it's own advantages and disadvantages.

    Engine oils are a blend of about 70% base oil & 30% additives. Those are rough numbers, each one will be different. The base oil (synthetic or mineral) supplies certain characteristics, the additives supply other characteristics. Some additives impart new characteristics not present in the base oil, and some additives are there to protect the base oil from deterioration and aging. An engine oil comprised of nothing but base oil would be a lousy oil, it wouldn't provide much protection to an engine at all. Think back to the 30's & 40's, that's how long ago we started additizing engine oils. So, which is most important to the performance of an engine oil, the base oil or the additives?

    I assure you, we can take a good mineral oil and blend up an engine oil that will easily outperform a decent synthetic oil with a poor additive package. However a good synthetic with a good additive package can definitely be best overall, but at what cost? What is your goal anyway?

    Wear protection? Cleanliness? Long service life? Extreme temperature range? Fuel mileage? Synthetic base oils provide increased film strength for wear protection, which is good; they have poor solvency so they are not great at keeping an engine clean, they require detergents to do that, but they will resist oxidation better than mineral, so they won't turn to varnish as easily, but what varnish does form will plate out on interior surfaces easier with a synthetic oil, which is bad. But that resistance to oxidation does provide good long service intervals, and they are more thermally stable, so they will withstand more extreme operating temperatures. If you operate in extreme hot or cold environments that could be a benefit for you. For most of us good quality mineral oils will survive just fine. What about fuel mileage? Synthetics have more stable viscometrics, and they are less volatile, which means you can get away with running a lower viscosity grade, which in turn results in less pumping losses and incrementally better fuel mileage. If you had a fleet of a few thousand vehicles every percentage point of better mileage can total up to some pretty impressive savings. For the individual with a few cars probably not so much. So what is your goal?

    For the average enthusiast who changes his oil once or twice a year, modern mineral oils are easily up to that, and more. Modern mineral oils are very good oils. But the peace of mind using a synthetic may give you may be worth the extra cost.

    Synthetic blends can be a great alternative, giving the best characteristics of both mineral & synthetic, and costing less than full synthetic too. Our best performing diesel engine oils are synthetic blends; our blends easily outperform competitors full synthetics. But, there is no industry standard on what constitutes a blend, so you really don't know what you're getting. A blender could blend in 5% synthetic into 95% mineral and call it a synthetic blend. The consumer really doesn't know what he's getting. I guess you have to trust the brand.

    Re zinc in Mobil 1, here's a link to a pdf that Mobil puts out that lists the zinc levels:

    Note that it's the higher viscosity grades (40 & 50) that have the higher zinc levels, which is good, as those are the better viscosity grades for classic car engines; but there goes the fuel mileage....

    Note, I've been informed by the tech guys at Castrol that Castrol Edge 5W-50 contains ~1400 ppm of zinc. Edge is a PAO type full synthetic motor oil. You might consider that too.

    But let me ask, how much zinc do you need? Does anyone know? Consider that in the 50's to mid 60's when most of these classic V8 engines were designed and sold the zinc level was probably no higher than ~800 ppm, maybe up to 1200 at the highest. Unless you have a modern high lift cam with high pressure valve springs, what makes you think you need more zinc than that?
    Cosmo49, loudbang, G-son and 14 others like this.
  13. Tuesday already? Gee, oil day comes around fast.:rolleyes:
  14. Garpo
    Joined: Jul 16, 2016
    Posts: 183


    Probably best to chose a high spec oil from your favorite brand that ticks all the right boxes for you, rather than a lower spec plus a can of additive.
    The oil chemists spend a lot of time and money developing oils for each and every application.
    Unless you know more than the experts, there is a chance that the can of additive adds cost rather than quality.
    Someone told me it is a bit like adding something extra to mothers cake recipe - Sometimes it helps, but not always.
    Blues4U and Gman0046 like this.
  15. Elcohaulic
    Joined: Dec 27, 2017
    Posts: 912


    5-30 Mobil 1 full synthetic.. I've used it in everything for well over 10 years and never had any issues. I have had issues with Brad Penn, it would foam on me while climbing long hills and the roackers would start to tap like crazy. I drained it out and put Mobil 1 in and that issue went away.. This was on two different motors.
    That Brad Penn must have a lot of wax in it..
  16. Jmountainjr
    Joined: Dec 29, 2006
    Posts: 1,103


    I think your choice is a bit like your favorite drink preference. A number of good choices, but some better than others. I spent a number of years as the maintenance manager for large truck fleets, so spent a lot of time evaluating oils and associated performance and life cycle costs. But when it comes to my hotrods, most of that doesn't matter. I am not looking for maximum fuel mileage. If that mattered I would have assembled a different engine. I base oil choices on the application and environment. Living in a climate that puts a vehicle into storage for part of the year changes my approach. I don't rely on an oxidation additive to deal with condensation from storage, I drain the oil. So I run conventional engine oil because I won't get to the point of taking advantage of the properties of synthetic oil.
    Truckdoctor Andy likes this.
  17. birdman1
    Joined: Dec 6, 2012
    Posts: 902


    Just a point to consider, mobile 1 has a good guarantee on there oil.
    Elcohaulic and Truck64 like this.
  18. Tow Truck Tom
    Joined: Jul 3, 2018
    Posts: 15

    Tow Truck Tom
    from Clayton DE

    Three decades Mobil 1 for my personal rides. A lot of miles. All day and nite. My companies used Royal Purple in their International and Freightliners. They would extend change mileage with the proper filters. My preference for cars is regular mileage 4,000. I enjoy having a lead foot. Never a problem with high RPMs or hard off the line starts. Have run most near 200,000 mi when Mama wants new. I'd prefer to go for three hundred Gs.
    Elcohaulic likes this.
  19. Actually Heinz uses a K. But I also like Hormel Chili with shredded Kraft cheese on my fries as well.
  20. Gman0046
    Joined: Jul 24, 2005
    Posts: 6,217


    I'm anal about my engines. If you ever read the brochures about Royal Purple products they are the greatest thing since sliced bread. I use their full synthetic High Performance Street oil 10W-40 and a Napa gold filter (made byWix).
    ekimneirbo likes this.
  21. Blues4U
    Joined: Oct 1, 2015
    Posts: 4,671

    from So Cal

    And you would expect their brochures about their products to be anything less than complimentary? :D
    lippy, Elcohaulic, Roothawg and 6 others like this.
  22. FityFive
    Joined: Aug 9, 2010
    Posts: 297


    I would like to read Blues4U’s opinion on this topic as he is one of our resident oil experts.
    6-bangertim and Truckdoctor Andy like this.
  23. squirrel
    Joined: Sep 23, 2004
    Posts: 46,099


    scroll up to post 12....
    warbird1 and Desoto291Hemi like this.
  24. squirrel
    Joined: Sep 23, 2004
    Posts: 46,099


    I try not to be a butt about my engines....I just build them right, and take reasonably good care of them, and the seem to last all right. I also use cheap oil, because it works pretty damn well. Even without the fancy brochures. But, you can do whatever you please!
  25. Truck64
    Joined: Oct 18, 2015
    Posts: 4,056

    from Ioway

    "We Guarantee - it's Oil!" ?
  26. Atta boy, Jim.

    jimmy six likes this.
  27. Gman0046
    Joined: Jul 24, 2005
    Posts: 6,217


    One of the great things about America is nobody forces anyone to buy one particular brand of anything. Most folks could care less about what someone else buys. I only shared what my choice of engine oil is. It wasn't meant to offend anyone.

    Obviously I was wrong.

    Evidently some people do care what engine oil others choose to use. Incredible but true. I wish all I had to worry about was what engine oil others choose to use.
    Last edited: Jul 7, 2020
  28. Gman,,,,,,dont think anything about it,,,,,,I would surmise it was the anal analogy that triggered the response,,,LoL .
    I never have understood why anyone would use that to describe their actions .
    I’ll bet some college kids got together years ago and had a contest to see how hard it would be to make regular guys start using the phrase .
    Just like years ago when the young adults started playing a new game called Cornhole ,,,,,,now churches have Cornhole tournaments,,,,LoL .
    Go figure .

    Oh yeah,,,,,,,like the man said,,,,,,whatever oil you want to use,,,,make yourself happy .

    Also,,,,,,Heinz Ketchup is great,,,,,,and I always remember the best jingle from when I was a kid,,,,,,,,”From the freshness of the valley,,,,,,,Ho,Ho,Ho,,,,,,Green Giant !
    I don’t like peas though !

    Last edited: Jul 7, 2020
  29. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 5,034


    While some folks could care less, I couldn't care less. I never could figure out why folks used the phrase "could care less", when it implies that they do care a bit. Maybe they do, I don't.
    Baumi and Desoto291Hemi like this.
  30. ekimneirbo
    Joined: Apr 29, 2017
    Posts: 1,098

    from Brooks Ky

    There will never be a concensus as to what oil choice is best. I'm glad you stated your opinion. Personally I choose to use Mobil 1 synthetic. Always had good luck with it, but there are many good choices that work well. It helps that I can get a 5 qt jug at Walmart for about $25. I usually pick up a couple and keep them on the shelf. Then a Wix from Napa and good to go.

    About 50 years ago before all the synthetics became popular, I purchased a 327 Chevy shortblock from a guy who was "anal" about his oil. He bought the engine new from GM and put it in his 56 Chevy. He hung out at a local gas station and he changed the oil in it religiously every 1,000 miles. I think he had little stickers listing the changes.
    Anyway, he told me before the purchase that when he removed the oil pan.........if I could find a spoonful of sludge he would just give me the engine. I think it had maybe 50k on it but don't remember for sure. Anyway, I ended up paying him for it.

    Now the point here is that even with the lesser quality oil available 50 years ago, regular maintainance goes a long way in the condition of an engine. Today many of the oils advertise that they last for extended periods before needing to be changed. Obviously if you are using oil in an engine that sees severe duty, its probably best to change more often. If its a family cruizer that never gets strained, then its your choice on how often to change oil. Both ways work well if the owner uses a little common sense. Today there are many good oils out there. I do think its best to choose a brand and stick with it just for compatibility when changing.;)
    6-bangertim likes this.

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