TBN retention

[Joe90_guy]

Far be it for me to question the mighty Mobil, but I do wonder if they are misdiagnosing the cause of GDI pre-ignition by blaming it on ash.

In my 'umble opinion, a more likely cause, would be oil vapour recycled through the PCV system. I don't know what the RON or MON of light base oil is, but if I were to hazard a guess, I'd say it was close to zero! Not only would that make pre-ignition more likely, but any accumulated sooty deposits, cause by trying to burn oil, would serve as point ignition sources, again increasing the chance of pre-ignition.

 

[buster]

Good question Joe. I don't think the industry has quite figured it out yet, have they? I've seen papers suggesting ash level was not the reason behind it.

 

[buster]

http://www.infineuminsight.com/insight/may-2015/investigating-low-speed-pre-ignition

 

[Joe90_guy]

When I saw it was an Infineum article, I instictively thought, oh yeah, here we go again, Low SAPs is the solution, aren't salicylates great, blah, blah, blah.

Actually it was quite a reasonably written piece. Interesting that they too think oil combustion is implicated although they seem to be saying it's oil 'fling-off' rather than oil recycling around the system. I've also seen photographs of similar bashed up pistons on the internet where lands have mechanically failed and the cause has been ascribed to severe knocking. As I recall some of these knackered pistons were from VAG 1.4 TFSI engines which of course are GDI.

It will be interesting to see how this pans out in the future...

 

[camrydriver111]

Jet, does your shop carry just one oil type or two types (A3/B4 and C3)? I don't think there is a A3/B4/C3 oil.

Originally Posted By: SR5
Also that ACEA A3/B4/C3 spec., really annoys me, as it's not possible. Valvoline do it here, and it sounds like Castrol do it there. The two specs A3/B4 and C3 have a lot in common, like HTHS of 3.5 or more. But C3 needs a sulphated ash of 0.8 or less, while A3/B4 needs a sulphated ash between 1.0 and 1.6, so it not possible to be both. In Oz, Castrol is pretty good with this, and clearly mark two different Edge products 0W-40 A3/B4 for petrol and 0W-40 C3 for diesel.


Valvoline doesn't make a ACEA A3/B4/C3 product.

SynPower MST 5W40 is C3, SynPower HST 5W40 is A3/B4, SynPower 0W40 is also A3/B4.

I doubt Castrol makes one spec oil either, like you said they are mutually exclusive.

 

[Jetronic]

search for Shell Helix Diesel Ultra Extra 5w30 pdf and you'll see an oil that claims to meet ACEA A3/B3/B4 and C2/C3

and castrol magnatec professional B4 is claiming similar (not C2 though)

 

[camrydriver111]

It must be the old ACEA A3/B4-04 sequence and not the current one.

For example just like this Valvoline MST bottle from 4 years ago which specifically states C3-08 and A3/B4-04.

https://bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2197956

It looks like Magnatec B4 is also the low SAP version and doesn't meet BMW LL-01 spec. They must be citing an old ACEA sequence and must be why your customers are getting sludge and varnish.

 

[Jetronic]

even worse, with TBN of 7.6 it can't even meet the older A3/B4 spec requirement of tbn above 8...

 

[camrydriver111]

That is really confusing for customers.

There is no ACEA police but it sounds like there should be!

 

[Joe90_guy]

If you go back to 2008, there was no TBN spec on A3/B3 or A3/B4. The TBN specs of 8.0 and 10.0 min came out in ACEA 2010. As I recall, the introduction of the TBN specs was controversial because the whole point of API and ACEA is that specs are driven by actual performance rather than by arbitrary chemical limits. I dare say the change was justified on the 'need for clarity' and 'not wanting to confuse customers' but there were plenty of vested interests in play back then and everyone knew it was really a political decision to drive through Low SAP oils.

Also regarding Shell, the old monikers of Helix Super, Plus & Extra were ditched a few years back. I think it's something like Helix HX5, HX7 and HX8 now (although one doesn't equate to the other as Shell blurred the boundaries somewhat). The PDF you saw might be superceded now.

 

[SR5]

Originally Posted By: camrydriver111
Jet, does your shop carry just one oil type or two types (A3/B4 and C3)? I don't think there is a A3/B4/C3 oil.

Originally Posted By: SR5
Also that ACEA A3/B4/C3 spec., really annoys me, as it's not possible. Valvoline do it here, and it sounds like Castrol do it there. The two specs A3/B4 and C3 have a lot in common, like HTHS of 3.5 or more. But C3 needs a sulphated ash of 0.8 or less, while A3/B4 needs a sulphated ash between 1.0 and 1.6, so it not possible to be both. In Oz, Castrol is pretty good with this, and clearly mark two different Edge products 0W-40 A3/B4 for petrol and 0W-40 C3 for diesel.


Valvoline doesn't make a ACEA A3/B4/C3 product.

SynPower MST 5W40 is C3, SynPower HST 5W40 is A3/B4, SynPower 0W40 is also A3/B4.

I doubt Castrol makes one spec oil either, like you said they are mutually exclusive.


In Australia the valvoline SynPower MST is labelled "ACEA A3/B4/C3" on the bottle and also in their product catalog. No dates to suggest it's an old spec. When I rang valvoline australia up, they said they only use up to date specs, the bottle label was correct. The person from valvoline on the phone said they had no idea of ACEA TBN and SAPS level and therefore neither could I and that I was a bit of a trouble maker. I politely thanked them for their time, and joined BITOG.

 

[zeng]

Originally Posted By: SR5
In Australia the valvoline SynPower MST is labelled "ACEA A3/B4/C3" on the bottle and also in their product catalog. No dates to suggest it's an old spec. When I rang valvoline australia up, they said they only use up to date specs, the bottle label was correct. The person from valvoline on the phone said they had no idea of ACEA TBN and SAPS level and therefore neither could I and that I was a bit of a trouble maker. I politely thanked them for their time, and joined BITOG.



Hahaha ..... that's a nice one from a Valvoline pseudo-expert.