Why no mainstream ashless oils?

[69 Riv GS]

If wear reduction and desposit control are main priorities, wouldn't an ashless formulation be superior? In air compressor and natural gas engine applications ashless oils are the norm, why not in gasoline engines?

[ May 08, 2004, 03:53 AM: Message edited by: 69 Riv GS ]

 

[TC]

If I'm not mistaken, I believe it's primarily the detergents/dispersants which lead to ash deposits (someone please verify). In a non-combustion system, such as an air compressor, or a clean-burning engine (such as natural gas), there's less contaminants to deal with, and therefore less need for a strong det/disp package. Diesel engines, on the other hand, thoroughly contaminate their oils with soot over time, so higher levels of det/disp are required, tending to push up the ash levels in the process. There's "low ash" detergents/dispersants, and perhaps someone else can enlighten us on those particular additives (perhaps they're more expensive..?). But I suspect that the "dirtier" the combustion or lubrication process, the more det/disp are required, which inevitably tends to result in more ash when we're talking about the common additive packages components. Chevron Delo 400 diesel oil touts its "low ash" formulation at 1.34% ash, yet Chevron Supreme passenger car oil has only 0.9%. I believe the lesson is that, if you need high det/disp, it's tough to avoid a correspondingly higher ash content.

 

[69 Riv GS]

TC: Thanks for the reply. What you're saying makes alot of sense. Valvoline says their VR1 racing contains "new ashless anti-wear additives(I guess they're referring to calcium or boron) combined with ZDDP", I wonder if this is the start of a new trend; maybe in specialty oils?

 

[Shannow]

TC,
there's a Mobil synthetic for diesel marine that touts zero ash as an environmental selling point.

(I'll post a link when I find it again).

I'm, still confused about dispersents, detergents and ash, following trying to find a suitable oil for my Nissan turbodiesel.

edit
http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=4;t=000201#000023

[ May 09, 2004, 04:37 AM: Message edited by: Shannow ]

 

[widman]

Most of the sulfated ash does end up coming from the Detergent/Dispersant package, but some also come from other additives. Here are some of the values used in formulating:
Barium = 1.70
Boron = 3.22
Calcium = 3.40
Copper = 1.252
Lead = 1.464
Lithium = 7.82
Magnesium = 4.95
Manganese = 1.291
Molybdenum = 1.50
Potassium = 2.33
Sodium = 3.09
Zinc = 1.50

Natural gas engines require special, expensive, no-ash additives when they are 2-cycle engines to avoid filling the ports with ash - builds up in the corners - reducing the flow.
4-cycle natural gas engines normally require some ash residual to cushion the valves. The amount depends on the presures and sizes of the valves. Without enough residual ash, the valves wear at the seats - called "resesion".
Diesel engines require more detergency and a certain amount of ash to protect the valves. 2-cycle diesels often are limited to 0.90 ash or so to give enough detergency and still not fill the ports. 4 cylinder diesels, and gasoline engines don't suffer from excess ash deposits unless you get the ash residual over 1.50 or so, but the bigger ones can take more. The gasoline only oils are lower in ash content because they are lower in addtive content. This because in certain oils (not all) the additives vaporize or burn off early, addting to catalizer degradation, and the theory is you don't need as much protection in a gasoline engine as a diesel engine since the compresion normally ranges from 8:1 to 12:1, while diesel engines run between 13:1 and 20:1. Also claimed is that Diesel engines are run at 100% load much of the time, while nobody (except those who use this site) uses close to 100% of their available power in a gasoline engine.
The issue with compressors is detergency. You do not want detergents in compressor oils as they absorb moisture instead of separating it. It gets worse if you use a detergent oil in a compressor used for different gases, as the detergents might cause chemical reactions with the gas being compressed.

 

[69 Riv GS]

Shannow : I feel your pain brother, the technical aspects do get confusing. It sounds like the safe bet might be a regular(containing ash & zinc) heavy duty diesel oil.


widman : Thanks, very informative. It's interesting that ash actually cushions the valves. Makes me think a high quality diesel oil would be best for my hi-performance V-8s; especially without hardened exhaust valve seats. It also sounds like the higher quality(diesel and gas) oils might be less likely to suffer from early additive burn off. I wonder if there's any way to tell by looking at the spec sheet, maybe NOACK % or flash point?

 

[Pablo]

To make an even lower ash oil, will cost dollars, so that should answer part general use.

As for today's oils, they are actually quite low in "ash" and leave practically zero deposits. Most "deposits" come from some engine issue, not the oil, IMHO.

 

[Jimbo]

Aviation motor oils come to mind when you say "ashless". Since clearances are so large on 4-cycle gasoline aircraft engines, the oil must burn off cleanly to avoid fouling spark plugs, filling ring groves with deposits, etc. Valve lubrication is not an issue due to the fact that they still burn leaded gasoline.

The downside for road vehicles is the low additive levels. There is no ZDDP, little or no detergents and no TBN buffering. 25 to 50 hour change intervals are the norm, a fraction of the Ford (gasoline) truck 200 hour recommendation. I tried running Areoshell in a motorcycle with the result of excessive varnish and other deposits.

One of the sponsors of this site sells Exxon aviation motor oil if you want to try it.

 

[MolaKule]

I would normally put this into the Interesting Articles thread, but since the topic was brought up here goes:

Detergent additives or agents contribute most of the ash deposits in IC engines. The heavier metals contribute mostly to ash deposits.

The perecent sulfated ash is the ash produced when the detegent is treated with sulfuric acid and burned. All organic material in the detergent burns leaving behind the metal sulfated ash. Sulfate ash results from the reaction of metal compounds with sulfuric acid directly, as with metal hydroxides and metal carbonates, or through the oxidative degradation of the metal sulfonate.

While detergents have the greatest contribution to ash, other compounds also contribute to ash, such as AW agents (ZDDP) and FM's such as MoDTC.

Since the metal compounds can lead to the formation of inorganic metal ashes on combustion, the formulator has to know the metal content of any additive in order to offset the effects of ash (metal) containing additives.

Having said that, there are a number of ashless detergents, and anti-wear and extreme pressure agents being developed as we speak. Many of these ashless additives are based on various phosphor compounds, esters of phosphors, and specialty esters. As others have stated, these compounds will be more expensive, at least initially.

 

[69 Riv GS]

MolaKule: Thanks for the info. It looks as though we'll be seeing more and more ashless additives in the future.

 

[buster]

Quote:

---

Having said that, there are a number of ashless detergents, and anti-wear and extreme pressure agents being developed as we speak. Many of these ashless additives are based on various phosphor compounds, esters of phosphors, and specialty esters. As others have stated, these compounds will be more expensive, at least initially.

---

This is what makes the SSO oil unique I suppose. It's proprietary ashless anti-wear system.

 

[buster]

Quote:
I would normally put this into the Interesting Articles thread, but since the topic was brought up here goes:

Detergent additives or agents contribute most of the ash deposits in IC engines. The heavier metals contribute mostly to ash deposits.

The perecent sulfated ash is the ash produced when the detegent is treated with sulfuric acid and burned. All organic material in the detergent burns leaving behind the metal sulfated ash. Sulfate ash results from the reaction of metal compounds with sulfuric acid directly, as with metal hydroxides and metal carbonates, or through the oxidative degradation of the metal sulfonate.

While detergents have the greatest contribution to ash, other compounds also contribute to ash, such as AW agents (ZDDP) and FM's such as MoDTC.

Since the metal compounds can lead to the formation of inorganic metal ashes on combustion, the formulator has to know the metal content of any additive in order to offset the effects of ash (metal) containing additives.

Having said that, there are a number of ashless detergents, and anti-wear and extreme pressure agents being developed as we speak. Many of these ashless additives are based on various phosphor compounds, esters of phosphors, and specialty esters. As others have stated, these compounds will be more expensive, at least initially.


Thanks MK

 

[Steve S]

When ashless oil is recommended for 4 cycle engines it is due to the engines used in steady state operation like a generator. Nat gas and propane engines used in automotive operation, automotive oils are used." note Widemans 2 cycle engine notes"

 

[Steve S]

Originally Posted By: buster
Quote:
Having said that, there are a number of ashless detergents, and anti-wear and extreme pressure agents being developed as we speak. Many of these ashless additives are based on various phosphor compounds, esters of phosphors, and specialty esters. As others have stated, these compounds will be more expensive, at least initially.


This is what makes the SSO oil unique I suppose. It's proprietary ashless anti-wear system.
Buster please. You have been on this site and used Amsoil enough to know that Amsoil is a fine oil but should know better.