SJ replacement?

[Drew1987]

Hey all I am aware that the current SN is insufficient for a flat tappet motor like my small block (1985) BUT what about “modern” cars? I may swap my 2002 ES300 (SL if I remember correctly) for a 2001 LS430. That’s SJ for sure, and a relatively high performance v8. Something feels funny about running sn blindly looking for some info. I change every 3k and usually use what’s API SAE certified and on sale. Currently working on a 7 gallon box of Partsmaster 5w30 full synthetic. I guess it’s made by valvoline? Anyway, would love to hear feedback on what’s best for 20 year old cars

 

[dparm]

By definition, the newer API spec is backward compatible for a vehicle requiring an older API spec. In other words: a car that was made 20 years ago calling for API SJ can use API SN without any ill-effects. SN meets/beats all SJ requirements.

 

[Linctex]

Originally Posted By: Drew1987

.... a 2001 LS430. That’s SJ for sure,.. and I usually use what’s API SAE certified and on sale.

Are you worried that new SN oils won't protect as well as a good API "SJ" would?

 

[danez_yoda]

Just add some stp to it so the old engine can have some nastalga. Lol!

 

[SonofJoe]

Just to be absolutely clear, the technical basis on which the API makes these all encompassing, 'backwards compatibility' claims are tenuous to the point of being non-existent! Are Group II/III SN oils more resistant to oxidation than a Group I SJ oil? Definitely yes, but is a Group II/III SN 5W20 better on tappet wear than a Group I SJ 10W30? I'm personally not so sure about that. It all revolves around the role of ZDDP in the respective oils. Back in the day, ZDDP was added to Group I primarily as an Antioxidant with its Anti-wear properties sort of coming as a freebie (albeit a necessary one). Again back in the day, supplementary Antioxidants (hindered phenols & phenylenediamines which are routinely used today) were viewed as overly expensive, which put 'extra' pressure on oil formulators to max out on ZDDP to carry the oil over the line in SJ's oxidation-related engine tests. One should also be aware that as we have moved from SJ to SN, changes in the specs have impacted on the chemical nature of ZDDPs used in oil. Today, you need to meet specified requirements for 'phosphorus volatility' which just didn't exist in the days of SJ. This has moved some companies to shift to 'heavier', less volatile ZDDPs. This is all fine and dandy until you factor in that the so-called 'activation temperature' of the ZDDP has increased and your low temperature wear protection has directionally been compromised. In direct answer to the OP's question, in a very old car, if I couldn't readily find SJ oil, I'd use an SL oil in preference to an SN one and I would definitely not 'go thinner'. If you are truly concerned about wear, then a splosh of extra ZDDP wouldn't go amiss either.

 

[KL31]

I'd listen to SonofJoe on this one. SN has reduced ZDDP limits. Some modern oils, for example my favorite to grab on special here in Australia is Castrol Edge 5W30 A3/B4. It has many great approvals like MB229.5, ACEA A3/B4 and LL01 but it's "only" SL rated. This is because they have have used more ZDDP than the API SN allows. They didn't use more to make the oil worse. So as suggested, a recent oil with recent euro approvals but only SL API rating is likely to have increased ZDDP levels and could very well be far superior to something that just has API SN approval only.

 

[Shannow]

And bear in mind, the phos driver has been applied to all cars to allow inordinate "normal" oil consumption on a handful of cars that should have been fixed under warranty/recall to meet mandated emissions systems longevity. As always, SoJ brings some great insights to the thread

 

[Drew1987]

Thanks all That’s what I was worried about I’m talking about a 2001 Lexus LS430 i may even trade for my 2002 Es300. Ls has 146,000 already so the “damage” would already be done. This is pure insanity that oil isn’t as protective as it was when 20 years ago. I wish someone would make a catalytic safe additive (not a fan of additives usually) that brings SN to a little better standard. For my flat tappet smallblock, I use $8.20 per quart Brad Penn Green Oil which is 2000ish ppm zink and great for antiques. I so badly wish there was something at Walmart or one of the candy stores (autozone) that was $20/5qt jug that would be ok, but other than maybe diesel 15w-40, I don’t think there is. Same with the Lexus (Lexi?) either of them will see 28,000 miles per year with me, $8/quart oil may not seem a lot of money but things add up when your a family of 4 conservatively living in one income. I know that’s personal but it sheds some light on why this maters to me. I use 89 octane in our Honda 3.5. 91+ in tne Lexus 3.0. Always seek out the original equipment but not from the dealer. Like Denso and Aisin. So I’m not cheap, but after I find whts best, I look for the best price on that

 

[Linctex]

Originally Posted By: Drew1987

For my flat tappet smallblock, I use $8.20 per quart Brad Penn Green Oil which is 2000ish ppm zink and great for antiques. I so badly wish there was something at Walmart or one of the candy stores (autozone) that was $20/5qt jug that would be ok, but other than maybe diesel 15w-40, I don’t think there is.

Brad Penn has a lot of zinc (ZDDP) but is missing a LOT of other additives that a normal passenger car motor oil needs. It is most certainly NOT designed for long oil change intervals. Did you know too much ZDDP is actually a BAD thing?!?!?! Valvoline VR1 Racing oil has a lot of zinc. So does Pennzoil racing oil.

 

[SilverFusion2010]

Rotella t4 meets SM even though it doesn't claim it and has 1150ppm zinc iirc. M1 0w-40 also has high zinc. SN allows more zinc with the heavier grades so move up to a 5 or 10w-40

 

[Garak]

Originally Posted By: Drew1987

Thanks all That’s what I was worried about I’m talking about a 2001 Lexus LS430 i may even trade for my 2002 Es300. Ls has 146,000 already so the “damage” would already be done. This is pure insanity that oil isn’t as protective as it was when 20 years ago. I wish someone would make a catalytic safe additive (not a fan of additives usually) that brings SN to a little better standard.

Note, too, that it does depend on spring pressures, as well. A lot of older flat tappet engines are surviving out there, just that they don't have an aggressive profile. For those who want to pay, of course, there are ZDDP enhanced oils out there. Some are semi-affordable, others are nuts, and there are additives. Valvoline VR1 10w-30 might be one of the simplest options out there.

 

[SonofJoe]

Originally Posted By: Linctex

Originally Posted By: Drew1987

For my flat tappet smallblock, I use $8.20 per quart Brad Penn Green Oil which is 2000ish ppm zink and great for antiques. I so badly wish there was something at Walmart or one of the candy stores (autozone) that was $20/5qt jug that would be ok, but other than maybe diesel 15w-40, I don’t think there is.

Brad Penn has a lot of zinc (ZDDP) but is missing a LOT of other additives that a normal passenger car motor oil needs. It is most certainly NOT designed for long oil change intervals. Did you know too much ZDDP is actually a BAD thing?!?!?! Valvoline VR1 Racing oil has a lot of zinc. So does Pennzoil racing oil.

I'd dispute this argument that too much ZDDP is a bad thing. It's reputed that too much ZDDP causes corrosion. Maybe once upon a time, in the dim and distant past, when ZDDP was the ONLY additive in oil & when ZDDPs were 'under-based' it might have been true; but not now. When oil formulators set about putting together an oil, ZDDP is probably THE additive you want to use most of. It has both anti-wear & antioxidant properties. It's also fantastic at reducing TEOST deposits and has much overlooked load bearing properties. To cap it off, it's dirt cheap and relatively simple to manufacture. The only reason you don't use more of it is because the specs physically prevent you from doing so because of concerns about catalyst poisoning (personally I think the cat poisoning thing is overdone and reflects the fact that Americans have in the past been far too tolerant of engine oils with stupidly high Noack volatilities). Most of the oils I put together typically contained between 800 - 1000 ppm Phosphorus (around 0.9 to 1.1% ZDDP) but I would have had no qualms whatsoever in using double that amount. Of course there's a secondary argument to be had about whether high levels of ZDDP are economically sensible. Most additives tend to conform to the Law of Diminishing Returns and ZDDP is no exception. You get far more performance bang for the buck by going from zero to 0.1% ZDDP than you do from going from say 0.9% to 1.0% ZDDP. Going from 1.9% to 2.0% ZDDP might give you so little incremental performance that it becomes more sensible to consider adding another type of additive (like going from zero to 0.1% Moly).

 

[KL31]

Most oil formulations won't go too silly either with ZDDP, probably not in their best interests to murder engines. Even specialty oils here like Penrite racing have 2200ppm of zinc (combined total with boron included in stated amount). Nothing too drastic. It seems to pop up around here that too much ZDDP is bad. Never is an amount given when these discussions are running. SonOfJoe, can there be a harmful amount? And forget about cat poisoning, they're like $200 maybe $300 to replace with aftermarket, less if you DIY and fail less than things like starter motors, alternators, water pumps, which can cost far more. Just interested in actual engine related issues that can arise from ridiculous levels of zddp?

 

[Shannow]

KL31, the only stuff that I've ever been able to find is a kind of intergranular cracking/stress corrosion cracking process that lets cam material spall from the faces. I think that's the corrosion reference, but a bit misplaced. (for example, in the high temperature metals at work, we have to choose marking pens, NDT chemicals and antisiezes that are free of low melting point metals and chlorine...they get into the grain boundaries and upset the apple cart).

 

[SR5]

Originally Posted By: SonofJoe

I'd dispute this argument that too much ZDDP is a bad thing. It's reputed that too much ZDDP causes corrosion. Maybe once upon a time, in the dim and distant past, when ZDDP was the ONLY additive in oil & when ZDDPs were 'under-based' it might have been true; but not now.

Always good to have you around Joe. Like many Australians I've been raised on Penrite oil, and their HPR-30, which has been very popular for decades here, contains 1450 ppm Phos and 1570 ppm Zinc. If this was causing an engine problem you would have thought somebody would have noticed in the last 30 or 40 years. I think this is close to double the ILSAC limit. To add to your list above of what ZDDP brings to an oil, not only is it an antioxidant to protect the oil and an anti-wear to protect the metal, it's also strongly quenches LSPI events in modern TDI engines. It's effect is exponential, so a little bit more has a big effect in stopping Low speed preignition.

 

[zeng]

Good job, SoJ. Very enlightening indeed.

 

[SonofJoe]

All this stuff about 'too much ZDDP being bad' all sort of occurred 'before my time'. However this is what I think might have happened... To make any ZDDP, you first react Phosphorus Pentasulphide (P2S5) with Alcohol to get what's commonly referred to as 'thioacid'. In a way, thioacid is what you really want to add to your oil as it's where all the Phosphorus & Sulphur (the big traditional contributors to EP performance) reside and it's probably very reactive with metal surfaces. However you then neutralise two moles of thioacid with one mole of Zinc Oxide to make ZDDP (I'm no chemist but I think ZnO is one of the few basic oxide salts that can do this). This does three things. First it creates the right kind of molecular weight to be lube-like (thioacid would be too volatile otherwise). Secondly it reduces the reactivity of the thioacid. You now only get 'free' thioacid where temperatures are locally high enough to breakdown the ZDDP (any point of high friction eg the tip of a cam of the top of a lifter bucket). Thirdly, it stops the thioacid reacting with other basic (as in alkaline) stuff you might want to add to the oil (like Detergent & Ashless Dispersant). Now although the thioacid/ZnO reaction looks like it has a neat 2:1 stoichiometry, in practice, it doesn't. You can 'under-base' which leaves the ZDDP still slightly acidic (ie it will have a small but measurable TAN) or 'over-base' it with a small excess of Zinc Oxide (such that it will have a small TBN). Over-based ZDDPs tend to be more stable and find use in a lot of industrial oils. Under-based ZDDPs on the other hand are a bit cheaper to make, a bit more reactive to metal and in overall terms, more cost-effective. I don't know but suspect that decades ago, when ZDDP was the only additive in oil (with no Detergents & Dispersants to worry about), that the tendency was to 'under-base' the ZDDP. It might have been that using high concentrations of ZDDP, in high friction engines, resulted in too much free thioacid sloshing around the engine. This might have reacted at granular boundaries and been interpreted as 'corrosion' (although you could equally argue that it was simply doing what it was supposed to!). I'm not 100% sure if this is correct but it makes sense to me...

 

[SR5]

Originally Posted By: Shannow

KL31, the only stuff that I've ever been able to find is a kind of intergranular cracking/stress corrosion cracking process that lets cam material spall from the faces. I think that's the corrosion reference, but a bit misplaced. (for example, in the high temperature metals at work, we have to choose marking pens, NDT chemicals and antisiezes that are free of low melting point metals and chlorine...they get into the grain boundaries and upset the apple cart).

I'm not convinced. I've worked closely with corrosion metallurgists for many years. SCC (stress corrosion cracking) requires tensile stress and usually the presence of a Halogen (Chlorine, Fluorine, etc ) and is mostly a problem in stainless steel. IGC (intergranular corrosion) is mostly due to poor heat treatment on corrosion resistant alloys such that the elements inhibiting corrosion (eg Cr) are depleted from the grain boundary. The most likely place to see this is in welding of stainless steels, where the weld heat allows chromium carbide to precipitate and deplete the available chromium used in surface passivation, which is what protects the metal. Low melting point metals (eg Hg or Ga), Mercury can form amalgam with metals like Aluminium, but not iron. Gallium can diffuse along the grain boundaries of Aluminum and Steel, but zinc and phosphorous / phosphate are not know for this. I honestly can't see how P or Zn atoms can just diffuse into a grain boundary on normal engineering steels from mere surface exposure. And I do spend a lot of my time looking at grain boundaries in rocks and steels with electron microscopes.

 

[SR5]

Originally Posted By: SR5

I honestly can't see how P or Zn atoms can just diffuse into a grain boundary on normal engineering steels from mere surface exposure.

Or sulphur. Sure a thioacid may cause surface corrosion, but penetrate along a metal grain boundary ? It doesn't sit right with me. To me most grain boundary issues are cause by the metal being manufactured wrong in the first place, and it's a problem that penetrates deep into the steel. It's not just a surface effect. It usually requires elevated temperatures too, 100's of degrees C and deep into the core of the metal. There are some particular examples where this reacts badly with that in a catastrophic manner at lower temperatures. But when these are discovered, they are well documented, and become the stuff of metallurgical legend. And with gallium and aluminIum - YouTube legend too.

 

[Drew1987]

This has been educational, thanks all! So all of the aforementioned considered, perhaps rosella diesel oil is a good compromise for my 90,000 mile 1985 smallblock? It’s srock with performance exhaust carb and intake and is driven rather hard and only 4,000 miles per year. As for the Lexus(Lexi plural?) the “partamaster” valvoline made full synthetic 5w30 SN is sufficient?