Renault Engine-Best Synthetic Oil?

[My S1]

Quick question for you long term owners.  The average all year round temperature in my place is 50 to 60 degrees Fahrenheit and I only do street/hwy driving.  What is the best brand (US) and grade of synthetic oil to be used?

[jbcollier]

Oil is a subject even more controversial than most religious matters over which wars have been fought.  One opinion will get you twenty contrary ones.  Some general comments:

Our cars don't see the mileages they did when they were new.  If you do 3K miles/5K kilometres, or less, a year, then simply change your oil once a year and that's it.  Change it right before you put the car away for winter and it is ready to go in the spring.  With such frequent oil changes, you can use synthetic or conventional oil.  Both will be fine.

The Renault engine is a flat tappet engine and likes to have extra additives to deal with flat tappet associated wear issues.  The marker for this is zinc levels -- please note it's not the zinc but the accompanying phosphorus that does the actual good deed.  However, too much of this good thing can be harmful.  Look for zinc levels in the 1100 to 1600 range.  And look often as manufacturers change the formulas often.

Diesel oils are formulated for diesel engines which have different operating conditions than spark-ignition engines.  Diesel oils are not a good choice.

Mobil 1 20w50 V-Twin was a good choice last time I checked its specs.  Check before buying though.  There are others out there, just check the specs.

[My S1]

Thank you John for that education.

[Bryan Boyle]

Quick question for you long term owners.  The average all year round temperature in my place is 50 to 60 degrees Fahrenheit and I only do street/hwy driving.  What is the best brand (US) and grade of synthetic oil to be used?

Boy, this is another topic for which the popcorn can be deployed. 

As JB says, religious wars have been fought over less than what is the 'right' or 'best' oil. 

With the advent of closely controlled emissions, ZDDP (Zinc Dialkyl Dithiophosphate) which was the additive of choice to ensure boundary layer (such as on the flat tappets we have in both the R16 and TC engines) lubrication did not collapse under the stress of the metal-to-metal contact (in fact, the lube layer between rubbing parts in measured (depending on the pressure) in tens to hundreds of thousandths of an inch), which it did very well.  Its byproducts also poisoned catalytic converters (among other things, heavy metal contamination, etc contributed to the stress to remove it and replace with synthetic anti-wear products, roller cams (crank pins are suspended in a hydrodynamic fashion; they should never touch, but rotate in a 'sleeve' of lubricant), and other methods had to come into play.

That being said...you don't want the latest and greatest "Sx" (as in SG, SM, etc. ratings...I have no idea what Sx they're up to...my other car is a european diesel, so there is a completely different grading method) oil; you are going to be looking at formulations that you should not use in current engines due to the chance you'll mess with the emissions dictates.

That being said, two that I've found work well are (and I have NO financial interest, but is the result of my research):

PennGrade1 20w50 (which is the modern Kendall "green" oil with modern partial synthetics but plenty of Zn and K):
https://penngrade1.com/products/high-performance-oils/penngrade-1-partial-synthetic-high-performance-oil-sae-20w-50/

Valvoline VR-1 20w50
https://www.valvolineglobal.com/en/vr1-full-synthetic-racing-motor-oil/

Of course, believe or not, STP contains a pretty good dose of ZDDP (not that I'd consider using it...but it's there and an option if you can't find the above and have to refill your sump...)

Others will have different opinions...but these two (and not considering the boutique oils that are limited production or geographic dispersion).  If you're stuck on synthetic...I'd consider the VR1 20w50 to be what you're going to be using (unless you want to be using ZDDP additives to protect the flat tappet valvetrain.)

My suggestion and it's worth what you paid for it.

[My S1]

Sounds like my main concern should be protecting the tappets with the proper portion of zinc.  The Valvoline folks hawk the flat tappet protection.  Thank you for you most valuable (free) suggestion.

[GavinT]

This must be my cue to fill in the blanks from me mate, Rohan. 
Here's what he said re synthetic oils:

Hi Leslie

By now you should know I love a discussion over a beer or red wine about engine building :lol:

I have a nice glass of good Australian red here so lets go !

Why Synthetic versus Mineral oil?

1. The engine does not know the source of the oil or whats on the bottle all it sees is the physical and chemical properties
2. Synthetic oils have a much more uniform and stable molecular structure so their viscosity performance is more stable over a greater temperature range
3. The more stable structure also means they oxidise and evaporate less and maintain their properties longer and don't deposit gum and burnt oils sludge in the engine
4. Mineral oils use "viscosity improvers" to enhance their viscosity performance over the full temperature range due to their inferior molecular structure. These are typically chopped up polyethylene molecules which perform well when new but get destroyed rapidly when exposed to the high shear rate conditions in bearings. Thus the mineral oil looses its viscosity stability quickly.
5. A huge range of lubrication tests consistently demonstrate that synthetic oil is superior in every situation in every test. They also show that polyol ester synthetic oils ( eg Redline) are superior to Poly Alpha Olefin synthetic oils (e.g. Mobil One) which are superior to severe catalytic cracked mineral oils that are allowed to be labeled synthetic oils ( eg Valvoline Synthetic) which are superior to your classic straight mineral oil (e.g. you typical "classic oil")


One downside of poly alpha olefin synthetic oils is that the olefinic molecular structure can react with high olefinic fuel compounds and water to form a sludge foam in engines that do not get hot enough for long enough and build up fuel and water resides in the oil from blow by gases. I used to run a plant that made these high olefinic fuels as a by-product and these were blended in as a key component in high octane premium unleaded fuel typically used in high performance BMW and other similar European cars. These car also use synthetic oil as standard. These cars also get driven by wealthy people who have short but slow commutes because they can afford the car and the expensive houses near the city where they work so they never get hot enough. These were the cars that suffered from a grey sludge foam build up in their sumps causing lubrication problems ! The owners blamed the car company, the car company blamed the refinery fuel, the refinery blamed the high octane blend stock we made. The reality was if they just changed to a cheap mineral oil the problem went away :lol:

As for why your engines show such high oil pressure when the relief valve is designed to maintain the pressure at no more than 40 PSI is an interesting question. But without a lot more data on engine build and oil used and ambient temperature conditions I cant answer on why it is running at an unnecessarily high pressure for a road engine


As for using oil versus grease in trunnions I only discuss that now with lubrication engineers and even many of them don't understand the fundamental differences and why grease is far superior :roll:

cheers
Rohan

[GavinT]

And here's Rohan's take on ZDDP levels.
Bear in mind these are ~10 year old posts and that they're from the Elan forum, so the Twink is the main focus and products and/or formulations may have changed over time.

Perhaps worth noting in a general sense is his reference to engines "where the follower is upside down" which I'd take to include the Renault engine, though the Renault lifters aren't really narrow.
More grist for the mill.


I agree with Rob that ZDDP levels in oil is not really an issue in an Elan

Every now and again I get the urge to talk about all this ZDDP level in oil b****t one more time. I have had a couple of glasses of red wine so here i go again - turn off now if you dont want to read any further

All the data I read about problems with excessive cam or tappet wear happens in 1 of 3 circumstances and the failure mode of each is well understood.

1. New engines
2. High performance push rod engines flat tappet or overloaded overhead cam flat tappet engines
3. Engines with mismatched cam and tappet metallurgy

These have been problems for many years and they are not caused by the recent small reductions in ZDDP in modern oils. Though a poorly designed or built engine that was marginal to begin with may fail a little quicker with a low ZDDP oil than otherwise.

So now for why they fail

1. New enginess - all flat tappet engines require careful running in of the cam to follower surface - to high or to low engine speeds or oils with to low ZDDP can ruin the surface due to galling on break in. Galling is microscopic welding and then tearing out of particles on the two surfaces as they slide over each other. Always use a specific running in oil, these have very high ZDDP levels and other additives to ensure correct break in and to prevent galling. Phosphate coating of the cams and follower and use of a cam assembly lube which has high ZDDP levels all also help. Recently DLC ( diamond like coating) have been also been used to aid in break in especially with steel cams and followers ( see point 3 below) You need to use these running in oils also to ensure good ring bedding. None of the normal oils you can buy are really suitable as running in oil - which is why car builders change the oil after the first 1000km as its been filled with a running in oil. Once the cam to follower surface had been bedded in then the level of ZDDP is not critical in most circumstances and not critical for a road Elan.

2. Push rod engines where the follower is upside down and not as well lubricated,plus they have heavier valve trains and thus heavier loads on the interface and they typically have smaller diameter followers to fit them all in a row - especially on a american V8 or narrow bore long stroke 4 like a B series - suffer the most from low ZDDP levels once run in because the design is marginal in the first place especially for a hotted up engine with modern aggressive short duration high lift cam profiles. Fortunately this is not a Lotus problem. Most modern 4 valve engines have very light valve trains and spring loads and its not a problem in them either. A race elan with very high spring load to handle a 0.5 inch lift 9000 rpm cam may be a problem but even then I doubt it. A road elan with the correct springs is not a problem and the design is far from marginal.

3. The final problem area is mismatch of cam and follower metallurgy and hardness. In the good old day with cast iron cams and cast iron tappet followers this was not a problem as cast iron is very forgiving. But with new lighter better stronger steel cams and followers the details such as alloy composition and hardness difference between the components have a big affect on galling resistance. Again tends to be a problem in modified engines where people are buying after market components that have not necessarily been properly specified tested or made.

If you have an engine with one of the base case problems then you have a problem whether you use low ZDDP oil in normal use or not and use of higher ZDDP may or may not help get you over the line. So before condemning the oils and the EPA for forcing a reduction in ZDDP levels understand all the issues which may affect your engine wear performance

If you're worried and want to be conservative with your twin cam then use the high ZDDP oils as we don't have catalytic converters to worry about. The oil companies now make these again in response to the somewhat overblown concerns that if they exist at all are really restricted to the American hot rod market and hot MGB's - it does not hurt . But if your serious about the best lubrication for your twink its more than just ZDDP levels so spend the $100 plus for 5 litres of Redline. it has high ZDDP levels plus a Polyol Ester base stock that is much better and more stable than other synthetics plus the rest of the additive package also is superior.

Sorry to be so boring

cheers
Rohan

[Bainford]

Interesting reading. Thanks Gavin.

[jbcollier]

My personal opinion is thatLotus TC engines do not require extra wear additives.  The cam and followers run in an oil bath and lubricationb is not an issue.  Renault engines, however, have "upside-down" followers and are not lubed directly.  They depend on oil mist/spray from the cam box.  It works but it is not ideal.  I use oils with extra wear additives in my Renault (and other upside-down lifter) engines.

[dakazman]

   Thanks for all this valuable information, JB, Gavin and Bryan.
       Build lube required in the start up of new engines. I will pressurize the oil system. from another thread , Thanks.
  I have two engines ready for a run-in and a third being built up as we speak, Thanks to Paul Z . I'll be happy to put 3k miles on my wedge and another 3k on the crossflow.
  It's just nice to be aware of the pitfalls.
   Thanks to all,
     Dakazman

[GavinT]

Yes JB, and we've seen a few instances where engine builders have installed oil flow restrictors in the galleries under the camshaft. The stated purpose is to limit the supposedly excessive flow of oil in this area.

This practice seems to be a solution looking for a problem and for the reasons you stated, I'd kinda prefer to have the oil splashing around.

[Clifton]

If you have time and want to read a good long oil comparison, this is it.
Quaker State 5-30 looked the best from his test but the full read is below. I'll post the Quaker State numbers too.

https://540ratblog.wordpress.com/

** 5W30 Quaker State “Full Synthetic” (abbreviated QSFS), dexos 1 Gen 2, ILSAC GF-6A, API SP = 152,674 psi
And that psi value sets a WHOPPING NEW ALL-TIME RECORD for motor oils that I have put through my Engineering Torture Test on motor oil. It was tested in Spring 2021

5W30 Quaker State Full Synthetic, API SP

Silicon = 10 ppm (anti-foaming agent in new oil, but in used oil, certain gasket materials and dirt can also add to this number)
Boron = 89 ppm (detergent/dispersant, anti-deposit buildup/anti-sludge, anti-wear)
Magnesium = 511 ppm (detergent/dispersant, anti-deposit buildup/anti-sludge)
Calcium = 1400 ppm (detergent/dispersant, anti-deposit buildup/anti-sludge)
Barium = <1 ppm (detergent/dispersant, anti-deposit buildup/anti-sludge)
Zinc = 905 ppm (anti-wear)
Phosphorus = 764 ppm (anti-wear)
Molybdenum = 176 ppm (anti-wear)
Potassium = <1 ppm (anti-freeze corrosion inhibitor)
Sodium = <1 ppm (anti-freeze corrosion inhibitor)
TBN = 6.1 (Total Base Number is an acid neutralizer to prevent corrosion. Nowadays, new gasoline engine motor oil TBN values can range anywhere from about 6.0 to 13.0).
Viscosity (cSt at 100*C or 212°F) = 11.6
Viscosity (cSt at 40*C or 104°F) = 67.2