Recommendation for engine oil

PittsSpecialPittsSpecial Posts: 39Member

Can anyone recommend a brand and weight of engine oil for a 308 7x tune engine ?.



  • BigSkyBigSky Posts: 257Senior Contributor
    You are a brave man to ask car guys what oil to use, next you’ll want to know how often to change it.... Let the debates begin!

    Honestly you did the right thing asking the guys who own 308 7x engines.  I don’t but would recommend looking at the additives carefully.  Today’s oils are better in some ways but also could be damaging due to the changes or loss of certain additives in today’s oils.  The issue is that changes in oil formulation have reduced the amount of a Zinc additive (zinc dialkyldithiophosphate, ZDDP) and often increased the amount of detergent in modern oils.  ZDDP is not good for catalytic converters which is the primary reason for its removal.  

    I have never used Lucas Oils but they have a very good following & reputation and have classic car specific oils.   Someone with more knowledge will surely chime in soon. 
  • 50C8DAN50C8DAN Posts: 1,747Senior Contributor
    I use Shell Rotella 10W-40 in my C8
  • railknightrailknight Posts: 275Expert Adviser
    edited November 2018
    Yeah, asking what motor oil to use is like asking ten Chicagoans where's the best hot dog stand in the city. You'll likely get ten different answers they'll all swear is the best (my vote, Super Dawg). Anyway, if you're concerned about zinc content (ZDDP) there are a number of good sources. Valvoline Racing Oil, PennGrade (formerly Brad Penn) and as BigSky mentioned, Lucas Oils. I use PennGrade synthetic blend 15W-40 in my Super Wasp 262.
  • BrowniepetersenBrowniepetersen Posts: 3,038Senior Contributor
    edited November 2018
    I think this is a good question to ask. It is very important in that we are discussing High Performance 7X and beyond engines... You folks with stock 131,161 and 308's that are not modified might listen in as well. Engineering is changing and it is important to keep up on it. Most of the comments to this point have expressed the importance of Zink for use in our type of applications. Now, as a user of Rotella, the following information is important. When the "tree huggers" started cleaning up the environment automotive motor oil stopped putting metals such as Zink in their oil and they added detergents to compensate (you read this above). Diesel vehicles were exempt. A few "high mileage" oils started adding 1200 or 1400 zink to their oil. Rotella did one better and started the Old Cars Oil special formulations. Well folks, coming up in the next stage is the removal of zink from Diesel oils. What we are left is high grade racing oil or a brand like Rotella, (20000ppm Zink is the ehat is needed for protection for these engines.) and a few others. Problem is that these bargan basement oils will either have to increase in price or go out of business. The racing oils are special production and are exempt. There are several out there but here is my choice from review of products: Check it out and tell me what you think? I agree oil is better today than it has ever been, but for me and my beyond 7X engine only the best is good enough....
  • octoberhilloctoberhill Posts: 2Member
    Amsoil Z-Rod with ZDDP has always been great for the many, many, many old cars I've owned. Re-filling with Z-Rod is usually one of the first things I do.
  • maruefermaruefer Posts: 18Member
    Here is a side comment. What if you had three cases of Quaker state 20W from the 50's in metal cans, never opened. Could you still use?
  • keithfullmeryahoocomkeithfullmeryahoocom Posts: 367Expert Adviser
    Man! I'd save those puppies and have them on a shelf in the garage. Great old shop paraphernalia.
  • BrowniepetersenBrowniepetersen Posts: 3,038Senior Contributor
    Always ran QS in my cars as a kid. Pure Pennsylvania grade crude oil. However, I would not. The oil manufactured today is far superior to the stuff available in the 50's. Not all that good for your car. You should go with one of the recommended oils above. You read my choice.....
  • railknightrailknight Posts: 275Expert Adviser
    I have several cans of 10W-40 unopened motor oil (Wolf's Head, Pennzoil, Quaker State, and even a Phillips 66 Trop-Artic (40W) from the 1950's - orange and black logo). Thought about using the vintage oil in my Hudson, but from everything I've read on-line, motor oil does have a "shelf life." So, seeing that this oil is way too old and as Browniepetersen points out, isn't as good as today's motor oils, the cans instead have become "man cave" items displayed on a shelf in my garage.
  • PittsSpecialPittsSpecial Posts: 39Member
    I was not aware this was such a controversial subject ... I'll take a look at some of the recommendations and if still conflicted come back for more guidance.
  • PerPer Posts: 163Member
    What parts of stepdown 6 engines are vulnerable to damage? Will this damage occur if the engine is never run faster than 2400 revolutions per minute?

    Also, what parts of Terraplane engines are at risk? Assuming the engines are not run faster than 2200 rpm.
  • GeoffGeoff Posts: 3,538Senior Contributor
    Stepdown engines are fairly bullet-proof, but the Achilles heel is the bronze oil pump/ distributor drive gear. I'm not aware of any oil that will minimise this gear wearing. Perhaps full synthetic oil would be advantageous? On the 1934 to '47 6's and to '52 8's the main problem is the valve lifters and cam lobes, and these would definitely benefit from a high Zinc oil. I have not satisfied myself about using synthetic oils in these motors. Would probably be advantageous for the cams, but not sure how it would flow into the small holes that feed the main bearings.
  • BrowniepetersenBrowniepetersen Posts: 3,038Senior Contributor
    Lets keep in mind that this post question was about 7X engines and the engines that we build today that go beyond the engineering specifications that were for the 7X. These high performance engines run hotter, have closer tolerances and as such require additional lubrication. Geoff, my studies show that the multi weight oils of today are much better for the small holes than the 20 or 30 weight we used when we were kids....
  • GeoffGeoff Posts: 3,538Senior Contributor
    edited November 2018
    I agree about modern oils, but not sure about the ability of synthetic to fling around like the mineral oils. for all I know it could be much better, but somebody has to conduct the experiment!
  • PittsSpecialPittsSpecial Posts: 39Member
    Thanks for the input. Whatever i do, i plan to use a conventional oil and not go the synthetic route.
  • BigSkyBigSky Posts: 257Senior Contributor
    Pitts, I would suggest doing some research for yourself but synthetic oils are far superior to conventional oil.  Thus if your concerned about protecting your performance 308-7X here are some reasons why you may want to choose Synthetic Oil.

    Synthetic oils are superior due to the refinement processes and ingredients used, which result in better scientific control over molecular size and purity.  More uniform molecular size means less friction.  In your car “used motor oil” is a lot thicker and sludgier with conventional oil than synthetic oil given the same amount of oil wear.  Synthetic oil is by far better for performance because it protects the engine from wear due to lower levels of friction and reduced engine drag from greater resistance to thickening.  Additives help keep the engine clean of deposits and fewer impurities mean it burns cleaner, thickens far more slowly. 

    Be sure you don’t forget to look at the weight of the oil you use as well.  Full pressure systems like your 308 can handle heavier weight oils due to the pressure system.  This is contrary to older splasher engines have much tighter tolerances and need thinner oil to “sling” & “flow” better into the tight tolerances as there is no pressure to force it in. 

    Probably above everything said, is to change your oil often, because of how infrequent most of our classic cars are used.  If the car doesn't spend enough time on the road to reach its optimal engine temperature, the engine may not get hot enough to burn off the water vapour that's produced during combustion.  The water vapour tends to mix with your oil and forms a milky sludge.  On top of that you can get fuel carbons in the oil, which makes it acidic.  This is the reason you will hear people tell owners of classic cars to change oil in spring & fall, even if not driven over winter. 

    Hope this helps, but do your own research!
  • PittsSpecialPittsSpecial Posts: 39Member
    All, After a lot of research i went with Royal Purple HPS synthetic oil. Cheers Andrew
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