How oil affects LSPI

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This is a very recent SAE paper on effects of oil on low-speed preignition (LSPI). In summary:
  • Calcium (detergent) increases LSPI events dramatically
  • Magnesium (detergent) decreases LSPI events dramatically
  • Increasing oil viscosity increases LSPI events (because more oil is left in the combustion chamber after the piston ring scrapes the oil), especially at higher magnesium levels
  • Increasing ZDDP and moly decreases LSPI events, however effects only significant at higher calcium levels
  • NOACK volatility doesn't significantly affect LSPI events
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Note that lower-viscosity base oils (not the overall viscosity including the viscosity-index improvers in the finished oil) increase timing-chain wear. Therefore, 0W-xx oils should be avoided and 5W-xx or 10W-xx oils should be used instead if timing-chain wear is a concern.
 
Originally Posted By: Gokhan
Note that lower-viscosity base oils (not the overall viscosity including the viscosity-index improvers in the finished oil) increase timing-chain wear. Therefore, 0W-xx oils should be avoided and 5W-xx or 10W-xx oils should be used instead if timing-chain wear is a concern.

This whole thing was very interesting, but this last statement stood out the most. I can't imagine the timing chain wear is drastically increased with a 0W vs a 5W because of how many manufacturers now spec 0W-XX, but it is something to think about nonetheless.
 
I may have asked this before but can "lspi friendly" oil be not as suitable for non di (pfi) cars?

I mean lowering or increasing certain chemicals to combat lspi which may not be ideal for PFI engines ....
 
Last edited:
Originally Posted By: JustN89
Originally Posted By: Gokhan
Note that lower-viscosity base oils (not the overall viscosity including the viscosity-index improvers in the finished oil) increase timing-chain wear. Therefore, 0W-xx oils should be avoided and 5W-xx or 10W-xx oils should be used instead if timing-chain wear is a concern.

This whole thing was very interesting, but this last statement stood out the most. I can't imagine the timing chain wear is drastically increased with a 0W vs a 5W because of how many manufacturers now spec 0W-XX, but it is something to think about nonetheless.

Note that that last statement came not from this but a separate paper by Nissan, referenced in this thread. They mention that they can still achieve good protection against timing-chain wear with a 0W-xx oil if it's made from a sufficiently thick base oil. Therefore, this implies that if you're concerned about timing-chain wear, go with 5W-xx or 10W-xx instead of 0W-xx for even a thicker base oil.
 
Originally Posted By: OilUzer
I may have asked this before but can "lspi friendly" oil be not as suitable for non di (pfi) cars?

I mean lowering or increasing certain chemicals to combat lspi which may not be ideal for PFI engines ....

LSPI-certified oils are basically oils with less calcium detergent and sufficient magnesium detergent. So, your question translates into whether magnesium detergents are not as good as calcium detergents in protecting the engine.

The answer is in some ways magnesium is better and in other ways it's worse. The main disadvantage of magnesium is that, unlike calcium it fails to neutralize certain acids that harm your engine. This disadvantage is also an advantage because since magnesium doesn't react with certain acids, it lasts longer in your engine and you get better TBN retention, in other words longer protection against other acids. Therefore, it's best to have a detergent system that's both calcium and magnesium. This way you are still protected against all types of acids while having good TBN retention. You also get a certain degree of protection against LSPI events depending on how much you lowered calcium.

The Chevron Oronite paper referenced in this thread discusses calcium and magnesium.
 
Originally Posted By: OilUzer
I may have asked this before but can "lspi friendly" oil be not as suitable for non di (pfi) cars?

I mean lowering or increasing certain chemicals to combat lspi which may not be ideal for PFI engines ....


I read in this forum somewhere that indicated that Dexos 1 Gen 2 developed for DI/LSPI concerns also gave better wear protection for cam-chain driven engines - maybe because of the add pack used for LSPI concerns. Can't seem to find that thread right now, but that's what I recall reading and why I'm choosing a Dexos 1 Gen 2 full synthetic 5W-30 oil for my next oil changes.
 
So maybe Redline, despite it's high calcium, wouldn't dramatically increase LSPI event chances due to also having high ZDDP and moly.
 
The way I understand that is calcium does not necessarily have to be reduced... but the ratio of calcium to magnesium must be less than pre-T/GDI engines to combat LSPI.

If you add all of the factors together, I see no real reason why you couldn't still have an oil with say 2300ppm of calcium, 1500ppm of magnesium, and a good dose of ZDDP/moly. The higher magnesium and ZDDP/moly will offset the calcium. That's the way I read it, especially when combined with the fact that NOACK and viscosity are not significant factors.

Maybe SOJ will weigh in.
 
Originally Posted By: AZjeff
Enough validation to go to D1G2 5W-20 from 0W-20 in the Toyota for that bit more protection and maybe even the super thick 5W-30.
I've had the same inclination (for other reasons), but some brands of oil aren't claiming D1G2 for their synthetic 5W-20 oils, when their 0W-20 and 5W-30 both do. Whether that's because their 5W-20 hasn't been reformulated to qualify, or only because they're simply declining to pay the licensing fee on it, who knows? Castrol tells you to use 0W-20 in GM cars that originally specified 5W-20.
 
Originally Posted By: CR94
I've had the same inclination (for other reasons), but some brands of oil aren't claiming D1G2 for their synthetic 5W-20 oils, when their 0W-20 and 5W-30 both do.


Mobil and Valvoline have 5W-20 D1G2 ... but Castrol and Pennzoil don't.
 
Originally Posted By: Gokhan
Originally Posted By: OilUzer
I may have asked this before but can "lspi friendly" oil be not as suitable for non di (pfi) cars?

I mean lowering or increasing certain chemicals to combat lspi which may not be ideal for PFI engines ....

LSPI-certified oils are basically oils with less calcium detergent and sufficient magnesium detergent. So, your question translates into whether magnesium detergents are not as good as calcium detergents in protecting the engine.

The answer is in some ways magnesium is better and in other ways it's worse. The main disadvantage of magnesium is that, unlike calcium it fails to neutralize certain acids that harm your engine. This disadvantage is also an advantage because since magnesium doesn't react with certain acids, it lasts longer in your engine and you get better TBN retention, in other words longer protection against other acids. Therefore, it's best to have a detergent system that's both calcium and magnesium. This way you are still protected against all types of acids while having good TBN retention. You also get a certain degree of protection against LSPI events depending on how much you lowered calcium.

The Chevron Oronite paper referenced in this thread discusses calcium and magnesium.


If I understand this correctly, you are saying an oil requires both magnesium and calcium to ensure it it neutralizes all acids and not just some?

Good TBN retention means nothing if it is not doing it's job neutralizing acids.
 
Very interesting, particularly the last sentence. Why should calcium be involved in promoting LSPI? What causes this?
Anyway, it appears that the problem of LSPI can be largely eliminated with no more than motor oil formulation changes, which is good news.
I do wonder why some TGDI engines seem not to have a problem with destructive LSPI regardless of oil used.
I'm thinking of Ford engines here, since Ford was a leader in introducing these engines on a large scale and has produced them for some years now.
 
Originally Posted By: CR94
Originally Posted By: AZjeff
Enough validation to go to D1G2 5W-20 from 0W-20 in the Toyota for that bit more protection and maybe even the super thick 5W-30.
I've had the same inclination (for other reasons), but some brands of oil aren't claiming D1G2 for their synthetic 5W-20 oils, when their 0W-20 and 5W-30 both do. Whether that's because their 5W-20 hasn't been reformulated to qualify, or only because they're simply declining to pay the licensing fee on it, who knows? Castrol tells you to use 0W-20 in GM cars that originally specified 5W-20.


Here's a list of D1G2 oil, seems current: D1G2 list
 
Originally Posted By: ZeeOSix
... Mobil and Valvoline have 5W-20 D1G2 ... but Castrol and Pennzoil don't.
I thought Pennzoil did, the last time I looked in Walmart. Castrol and Supertech did not.
 
Originally Posted By: Gokhan
Originally Posted By: JustN89
Originally Posted By: Gokhan
Note that lower-viscosity base oils (not the overall viscosity including the viscosity-index improvers in the finished oil) increase timing-chain wear. Therefore, 0W-xx oils should be avoided and 5W-xx or 10W-xx oils should be used instead if timing-chain wear is a concern.

This whole thing was very interesting, but this last statement stood out the most. I can't imagine the timing chain wear is drastically increased with a 0W vs a 5W because of how many manufacturers now spec 0W-XX, but it is something to think about nonetheless.

Note that that last statement came not from this but a separate paper by Nissan, referenced in this thread. They mention that they can still achieve good protection against timing-chain wear with a 0W-xx oil if it's made from a sufficiently thick base oil. Therefore, this implies that if you're concerned about timing-chain wear, go with 5W-xx or 10W-xx instead of 0W-xx for even a thicker base oil.




This is interesting. I am thinking of using 5w20 VAS on the next change based not only for the grade but the Noack of VAS 5w20 is 7.6 compared to 11.1 with the 0w20. The viscosity difference is very small though.

Good discussion.
 
I am wondering if Castrol is ever going to release an EP (gold bottle) D1G2 version of their titanium Edge, since Mobil 1 thought it was worth formulating their EPs to D1G2, despite it running contrary to using any long drain intervals in LSPI/deposit prone, TDI engines.
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Originally Posted By: AZjeff
Did anyone ever not use a PCMO because the NOACK was too low? Is there any downside to 7.6 vs 11.1?


The lower the better when it comes to NOACK from what I've read. NOACK is a measure of how volatile the oil is, and how much will "burn off" just from heat.
 
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