Oil - synthetic blend versus straight mineral oil in our oldies but goodies

Engines, Exhaust and Fuel Systems

  1. shadango

    shadango Well-Known Member

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    I have been running Valvoline 10w30 conventional in our slant 6s and my older (92 and 78) 318 engines for years.....

    Seems now that straight 10w30 in Valvoline at least is selling at $28 for 5 quarts but the "max life synthetic blend for high mileage engines" in the same weight can be had for $17 for 5 quarts.

    Any thoughts on using this? The 92 is high mileage at 125k miles....one slant 6 is in the 20k mile range (rebuilt several years back) and the other supposedly has less than 40k but has never been opened.....

    Worried that the synthetic will make any leaks we now have MORE prevalent....

    But to save $10 a jug (multiplied by 5 or 6 jugs) is attractive.....

    Thoughts?
     
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  2. volare 77

    volare 77 Well-Known Member

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    You can maybe check out the 10w30 Valvoline diesel oil. Usually diesel oil has more zinc. Looks like it can be bought for around $17. I don`t see where it says it is synthetic or conventional though. Maybe it is a blend ? I don`t know.
     
  3. toolmanmike

    toolmanmike Super Moderator Staff Member

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    I also use Valvoline 10/30 conventional and a half bottle of Rislone ZDDP additive. The zinc in the oil and the additive will give you 1500 ppm or so. More than enough to keep your Mopar running a long time.

    rislone-zinc-zddp-e1443532059691.png
     
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  4. Aspen500

    Aspen500 Well-Known Member

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    The diesel oil, like Shell Rotella, has had the zinc content reduced in the past few years. That said, I run Rotella 15W40 in my Aspen since it doesn't get many miles in the summer and none in cold weather. Dakota and Mustang are full synthetic only though.

    Synthetic won't CAUSE leaks in older engines but it does seem to make existing leaks leak more. Not sure why that is, other than maybe it just flows better?
     
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  5. LSM360

    LSM360 Well-Known Member

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    The 92 shouldn't need the zinc additive so if it isn't leaking now I'd run synthetic because as Aspen500 wrote, it won't cause a leak, it may just make an existing one more pronounced. Was the slant six a stock flat tappets rebuild? It will need the zinc then and I use Valvolines VR1 20W-50 in my 360. It seems to love it. Oil pressure is always good and it has the zinc.
     
  6. Mikes5thAve

    Mikes5thAve Well-Known Member

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    Like what's been said syntehtic won't cause leaks but it will make existing ones more noticable.
    I never use synthetic because it costed more but if this is a reversing trend I'd run it for sure especially at those savings. I usually bulk buy when oil goes on sale.
     
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  7. Aspen500

    Aspen500 Well-Known Member

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    Synthetic oil may cost a bit more BUT, it will save you money in the long run. At work I've seen engines in certain vehicles that were run on conventional and then need timing chain(s) at 80,000 miles, where one's run on synthetic are still fine at 200,000 and if you do need to open the engine up, it's spotless inside. I'm talking GM Ecotech and 3.6L. Of course, it still needs to be changed and not when the oil change reminder comes on. We recommend 3,000 miles for conventional and 5,000 for synthetic. That depends also on how, when, where the car is driven AND the make and model of the engine. Some are failure prone if not maintained religiously. Again, the GM Ecotech and 3.6L come to mind but there are others as well.
    Extra cost per oil change for (example) 2012 GMC Acadia 3.6L at our shop is approx $15 vs conventional. Cost of replacing the timing chains and guides on the same vehicle at 80,000 miles? About $1,600 and 80% of that is the 16 hours labor to do the job. Do the math, lol.:)
     
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  8. XfbodyX

    XfbodyX Well-Known Member

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    I try to never pay more then $2 a quart for regular oil on a stock motor. Just change every 3k miles. I do put a hint of additive in my truck oil because it gets used hard.

    Ace Hardware oil is bottled by Chevron
    Harvest King is bottled by Citgo
    Look for deals in 5 gallon jugs, name brand still $2 a qt in the end.

    Im always stocked up about 2 years ahead. You local ace hardware clears stock out every fall $2 a qt.

    If you look at the driven race oil web site it states this below the link. Simply because your never create the conditions to activate what zinc really does with low pressure/friction.

    The Truth About Zinc & Motor Oil – Driven Racing Oil

    "Are you ready for some good news? The key to how much and what type of Zinc your engine needs depends on your engine’s valve train. If you have a stock valve train and no other performance modifications, then an API licensed oil is all you need. Every API licensed oil will protect stock engines under normal street driving cycles."

    Opinions always vary on oil but for myself ive never had a oil related failure. Just change as needed.

    So here is a low buck option above to consider if your trying to provide proper protection and not overspend. Even if you buy a bottle of additive and use it in moderation which the Driven guys and others say is not needed your still money ahead.

    I buy decent oil filters 5-10 at a time off ebay and pay 1/3 the parts store prices per filter for the exact same in qty.

    Im still learning the ropes on Synthetic Oils, kinda like needing to toss all conventional thoughts out the window while doing it.

    DSC01236.JPG

    DSC01235.JPG

    DSC01237.JPG
     
  9. kkritsilas

    kkritsilas Well-Known Member

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    I read the article, and it does present a number of interesting points, specifically the "fast burn" zinc additives and the zinc additive vs. detergent balance.

    I think the key point of all of this is the following paragraph:

    "A perfect example of proper balance can be seen is an API SN motor oil. While this spec oil is limited to 800 ppm of a catalytic converter friendly ZDDP, an API SN oil can break in a flat tappet camshaft. The flat tappet cam in question has less than .400 valve lift and no more than 215 psi valve spring pressure. So an API SN oil will protect a flat tappet cam, but you won’t see success trying to break in a Big Block Chevy cam with over .500 valve lift and over 300 psi valve spring pressure with an API SN oil. It is the different demands of the valve train loads that dictate what balance is required to protect."

    I took the following from this:

    1. The valvetrain specifications are very important to know the specifications of your valvetrain, as the article seems to make a point of illustrating the specifications of two different engines, the stock engine, and the hot-rodded big block Chevy. They spec out the .400" valve lift and 215 lb. spring pressure for the stock engine. I don't know what the stock specs for our small blocks is, but I am fairly certain that we exceed .400" valve lift. I have no idea what the spring pressure is. So does all of this still apply.

    2. The article seems to be oriented towards engine break in. Shadango was asking about engines that are way beyond break in. In the article itself, it says:

    "The bottom line is that bigger lift, longer duration cams with more spring pressure need a proper break-in oil to establish that critical anti-wear film. After break-in, a hot rod-style oil for street/strip should be used to maintain that protective Zinc film. Race applications meanwhile need a proper racing oil to deliver race-specific performance."

    Driven themselves are calling for a "hot rod-style oil for street-strip should be used to maintain that protective Zinc film" post-break in. I think Shadango's engines are at the post break-in stage of their lives. Driven are saying that in order to preserve the zinc film, that a hot rod-style oil should be used, or the detergents in newer engine oils will gradually strip away the zinc.

    None of this may answer the conventional, semi-synthetic, or full synthetic oil question, but it does bring up some interesting points.

    BTW, the lastest SAE API spec. is SP, not SN. I have no idea what all the changes are, but the move was geared towards reducing the carbon (for want of a better word) build up on the back of the valves in direct injected engines. I have not read anything more specific that that.
     
  10. XfbodyX

    XfbodyX Well-Known Member

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    I thought one concern was money spent thus the idea of using the cheaper synthetic oil. I just pointed out reg. oil can easily be found for $2 a quart. Id never use synthetic in our older motors for several reasons just like youd never use conventional oil in some of the new HP motors designed to use synthetic.

    The most easy way to sum up the zinc deal on a stock motor is to compare it to starting a fire by rubbing two pieces of wood together and trying to start a fire. Zinc is a friction fighter but it needs a certain amount of friction to become active and effective just like the wood would need a certain amount of friction to start a fire however a /6 or 318 if they were wood parts would never reach that critical point. And with most /6s and 318-s ect, what they may see 4-4500 rpm

    But people will do and spend what makes them feel better about things but as I posted I do know ive never had a cam fail at break in and never had a cam/lifter issue on a stock motor. After break in on a stocker the main cause of problems is simply not changing oil as often as specked. No amount of zinc will restore any wear on a 125k motor its a preventive product when called into play.
     
  11. XfbodyX

    XfbodyX Well-Known Member

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    Here is something funny, most everyone telling you you need an additive is trying to sell an additive.

    So I was searching for a non sales type discussion.

    In this link oil and whats proper and whats not is like religion and politics, is anyone ever really right or wrong? Nope, people do what seems to work for them.

    Dodge A-108 - 318 5.2LWhich Oil w/ Zinc? Rotella??
     
  12. kkritsilas

    kkritsilas Well-Known Member

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    i have participted in this discussion many, many times. I don't tell people what to do, nor do I pretend to be an oil "expert".

    My basic stance is that the Mopar engineers knew what they were doing, when not being interfered wth by the cost accountants. In the early 1980s, the Mopar engineers determined what the oil requirements for the LA and /6 engines were. They made that determination on the basis of what was available at the time. In those days, longevity was a major consideration, and the oils of the time had a particular level of zinc. They spec'd out the oil, and even more importantly, built the engines (including the valve train) with those zinc levels in mind. Any oil, regardless of brand or type (conventional or synthetic) that has approximately the same level of zinc should be fine. If that oil is a standard API type oil, fine. If that oil needs to be a "Hot-Rod" type oil, that too, is fine. Let price be your guide. However, supposing that an API SM, SN, or SP oil will have the required zinc levels is playing with fire, because we know that the zinc levels after SH were reduced to help keep the catalytic converters from being "poisoned". In addition, to help with that, the lifters, even on "stock" engines, were changed from flat to rollers for this exact reason. If the flat tappet cams were fine with the reduced zinc levels, they would still be in use. I will grant that there may be some fuel economy improvements with the roller lifters vs. the flat tappet lifters, but I don't see it as a significant improvement in fuel economy. The reduction in zinc was not done due to the zinc not being necessary, it was done to help preserve the catalytic converters, and is the only reason that the zinc level was reduced.

    Also, it isn't the friction that activates the zinc, it is heat. That is why the article describes the newer zinc additives as "fast burn" and not "fast friction".
     
  13. Mikes5thAve

    Mikes5thAve Well-Known Member

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    It wasn't changes in oil that pushed the change to roller cams it was change in technology and better reliability. Well the large number of complaints of lifter failure on Hemis might be an argument against that last bit.

    I'm still in the fence with the zinc thing. To this day the only people talking about it is mainly online. Most people don't have a clue and there's never been sudden surge in wiped cams in older vehicles.
     
  14. Lightning II

    Lightning II Active Member

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    The "Hemi lifter failure" thing has appeared to be down to a couple things 1) dirt in the oil that seizes up the MDS function, or 2) the MDS Lifters just don't flow the amount of oil needed to the roller bearings on the lifter itself.

    I've been doing some research, might not be enough though.
     
  15. kkritsilas

    kkritsilas Well-Known Member

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    Please define "change in technology". Roller lifters, in the mechanical form, existed in the 1960s. So did hydraulic lifters. Roller cams were not used in the 1960s, 1970s or early 1980s on any factory engines. Roller hydraulic cams began to be used in the mid to late 1980s, more than likely after receiving a heads up from the API that the newer oil grades would be having their zinc (and phosphorus) content reduced going forward. I can't see any of the car companies increasing the build cost of their engines, without any direct increase in revenue due to this "feature", out of the goodness of their hearts. It is interesting that all of the car companies went to hydraulic roller lifters, without fail, over time. By the time the 1994 API SH specification came out, which was the first oil specification to reduce zinc (and phosphorus) content, all the engines had changed over. See this as a data point:



    you won't get much useful information until about the 7:00 mark. He does say that you will wipe out the cam lobes on a Ford 289 if the oil doesn't have enough zinc. Also of interest is that API SN oil has an 800 PPM oil limit. It is a LIMIT, and he does flat out say that many oils do not even contain 800PPM, as it is an expensive additive. I also found the statements about diesel oil pretty interesting with regards CI 4+ oil vs. CJ 4 oil.
     
  16. XfbodyX

    XfbodyX Well-Known Member

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    Like beating a dead horse. Good Luck.
     
    Last edited: Oct 17, 2020
  17. Mikes5thAve

    Mikes5thAve Well-Known Member

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    Yup.
     
  18. shadango

    shadango Well-Known Member

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    Thanks, all, for the copious amount of knowledge and info shared in regards to my original post.

    I, too, have participated in oil discussions over the years...cars, bikes, ATVs......many many opinions and "facts" and experiences.

    Seems like every now and then the discussion is warranted again....in this case my finding that "conventional oil" in the brand and weight I have been using for a long time is $25 for 5 quarts but the same weight and brand in a synthetic/conv blend is $16.95.

    I decided to go for the blend.

    I have always added ZDDP to the Cuda (hydraulic, but very angry cam) and the 80 Volare /6 (flat tappets) and the 81 Dippy /6 (hydraulic). Just to be safe. I also use Rotella T-6 "diesel" oil in my Honda motorcycle......had gone out of my way to use Honda oil in one of my bikes for years and it STILL died internally at one point....so I decided to go for another tact in my current bike, a Honda VTX1800.....Rotella. Works fine and is less expensive. Will not truly know unless the engine breaks. LOL

    The statement that "engineers back in the day knew what they were doing and spec'd the products based on what was available" is key and that is what makes it hard I think. So many new products and new claims.

    Even the "conventional" 10w30 spec'd for these engines 40 years ago is different from oil produced NOW, I am sure.

    I remember back in the early 80s...my old man put the then "new" Arco graphite oil into his 79 Trailduster 360.....the oil pressure gauge quit working in short time......he always blamed that on the oil....oil pressure was fine, just the gauge quit. AT the time others had a similar complaint......but he never repaired the gauge to find out for sure...LOL

    So for this oil change at least I guess I am good.....10w30 Valvoline Semi-sythentic blend, with ZDDP additive.