Ash content corrolations to Pre-Ignition

[vex]

To which paper are you referring. I have two NSU lubrication papers (2nd and 3rd). Neither paper references a Fig16, however the 3rd NSU paper has a section 16... As for the Cat VOA I haven't looked too much into those yet. I'll look at them now, but I by no means, am an expert when it comes to figuring out which oils will be perfect for the rotary engine.

[vex]

Disclaimer: I'm still refining this list and doing research as best I can to give the most accurate representation of the data I can. Please check this post often (or at least until the disclaimer disappears as I'm constantly refining the oils listed).
Ash content is usually caused by impurities in the base oil. Which I believe is caused by Calcium being the biggest indicator. Looking solely at that these are the oils that contain calcium in <500 ppm.

Castrol 0w-30
Cenex AGME 4EP
Cenex AGME 7EP
Cenex Indol ISO 68
Cenex ISO 46
Cenex Mercon/Dexcon ATF
Cenex Turbine XL ISO 100
Cenex Turbine XL ISO 320
Chevron 80w-90
Exxon 60wt
Exxon 60wt
Hyde Dexron
Royal Purple 75w-90
Shell Omala 320
Unspec Unspec

Now you'll notice that a lot of the previously mentioned oils are not really suitable for use in an engine (gear oil, increased wear with ATF/dexron belnds, etc). So getting rid of those what we have left is:

Castrol 0w-30
Cenex Indol ISO 68(Really light oil it looks like)
Cenex ISO 46 (Really light oil it looks like)
Unspec Unspec (4/26/05)
Cenex Turbine XL ISO 100 (may be too thick for use; viscosity rating is the same as a 20w oil)
Turbine XL ISO 320 (may be too thick for use;viscosity rating is the same as a 20w oil)

Now looking at the additive package: High in zinc, low to medium in phosphorus, we have the following arranged low to high by such [Phosphorus|Zinc]

Unspec Unspec (4/26/05) [2|38]
Castrol 0w-30 [284|2]
Cenex Indol ISO 68 [383|517]
Cenex ISO 46 [963|1163]

Conclusion: Although a majority of the Oils listed can be used in a rotary engine, I would suggest using Cenex Indol ISO 68 based on the information I could see from the CAT VOAs. This is basing it off the findings of the NSU/SAE papers previously referenced. If the PPM on the Phosphorus is not high enough for your tastes Cenex ISO 46 will work slightly better. Please be aware though that the higher the Phosphorus the more likely foaming will occur. Please take steps to keep this from happening if and where possible.



So far I've only been able to find this product from Cenex that is even close to what we're looking for. Further investigation is needed as previously attested two stroke oil will wear parts faster than conventional oil.

http://www.realtruck.com/shared/pdf/...ineextreme.pdf
http://www.cenex.com/portal/server.p...ed=true&mode=2

Further break down of the previous Oils listed:
Cenex Indol ISO 68: https://www.cenex.com/portal/server....dol_010305.pdf
Cenex ISO 46: https://www.cenex.com/portal/server....nex_122104.pdf
Cenex Turbine XL ISO 100: https://www.cenex.com/portal/server....lXL_010305.pdf
Cenex Turbine XL ISO 320: https://www.cenex.com/portal/server....lXL_010305.pdf

[Heeley]

Originally Posted by vex

I'll have to double check what the cycle times were for the endurance run. But yes, that was comparing ATF to Two Stroke.

So if i'm interpreting things correctly, does this mean that using ATF in an oil injection system is better for apex seal lubrication over 2 stroke? Then what would be the comparison to engine oil? and at what point does the ash content come into play? Doesn't it just trade off one problem for another?

[vex]

Originally Posted by Heeley

So if i'm interpreting things correctly, does this mean that using ATF in an oil injection system is better for apex seal lubrication over 2 stroke?

No, Two stroke out performs ATF with slowing Apex seal wear

Then what would be the comparison to engine oil?

See later posts regarding that

and at what point does the ash content come into play?

Pre-Ignition events. The lower the ash content the less likely a pre-ignition event occurs

Doesn't it just trade off one problem for another?

Not really. We're looking for low ash content which is reflective in the base oil being excellently refined. We're also looking for an additive package that still cleans and protects. The protection comes from the oil and additives, not from the ash and impurities.

[Barry Bordes]

Originally Posted by vex

To which paper are you referring. I have two NSU lubrication papers (2nd and 3rd). Neither paper references a Fig16, however the 3rd NSU paper has a section 16... As for the Cat VOA I haven't looked too much into those yet. I'll look at them now, but I by no means, am an expert when it comes to figuring out which oils will be perfect for the rotary engine.

VEX,

Third Paper
LUBRICANT DEVELOPMENT FOR THE
WANKEL-TYPE ROTARY ENGINE
page 4, top and bottom, Figs. 16 & 17.
their "prime candidate" oil Fig 17, has half the wear, and the "Typical Marine Cylinder Lubricant" in fig. 16 also shows extremely low wear data.

Unfortunately the CAT VOR info doesn't include sulfur in their testing!

Which Castrol 0w-30 are you referencing? There are a few listed. It would be great to find an oil that was stocked locally in stores.

Barry

[vex]

Originally Posted by Barry Bordes

VEX,

Third Paper
LUBRICANT DEVELOPMENT FOR THE
WANKEL-TYPE ROTARY ENGINE
page 4, top and bottom, Figs. 16 & 17.
their "prime candidate" oil Fig 17, has half the wear, and the "Typical Marine Cylinder Lubricant" in fig. 16 also shows extremely low wear data.

Unfortunately the CAT VOR info doesn't include sulfur in their testing!

Which Castrol 0w-30 are you referencing? There are a few listed. It would be great to find an oil that was stocked locally in stores.

Barry

I see. I don't know why I didn't see that before. From my reading of it, the oil to which they are referring appears to be "...the oil formulation which satisfies the preignition test (explained later) and at the same time gives
the best cold-wear performance contains magnesium at a total sulphated-ash level of 0.4 per cent by weight." My best guess for that would be an oil based off of magnesium rather than calcium. The calcium and magnesium when burned produce a portion of the sulphated ash (see above figure for more understanding regarding that; basically, the more calcium the higher the ash content--that is my understanding at least). So we'd need to find an oil that has a magnesium 400ppm rating. That should give similar if not the same results for which they were relating.

As for the Castrol 0w-30, that is all the distinguishing markings of the oil they tested. There's no further classification of it. On the CAT charts look for Castrol [Blank] 0w-30. That is the one I'm referencing. You can verify that by looking at the calcium readings.

[Barry Bordes]

Vex, I read a few more articles about preignition on high performance outboard and air cooled aircraft engines. They only promote Ashless Oils.

It seems like Valvoline makes an ashless oil that may be a good rotary oil.

VR1 Racing Formula SAE 20W-50 (Turbo Approved) Motor Oil (other weights also).

Key features Valvoline VV211
High public presentation and shelter in spite of today's engines that go at high-pitched RPM
New ashless anti-wear additives combined by the side of ZDDP bring home the bacon most remote endure shelter
Enhanced anti-foam scheme helps secure the instrument regular for the time of uttermost emphasise
Enhanced additives preserve fronting high-temperature deposits with regard to a dry cleaner weapon
Friction modifiers facilitate gain h.p. yield

Barry

[joff]

Very interesting thread.

Any speculation as to why oil ash content causes higher preignition? Is it because of the ash in the exhaust->intake carry-over volume due to the burning oil in the expansion/exhuast strokes?

Compare that to oils that have relatively high ash contents (1.2, 0.9) which experienced their first pre-ignition event within 8 cycles.

Preignition within 8 cycles??!! I doubt many people have paid that much attention to oil ash content in the past -- how can there not be more blown motors because of this?

[vex]

Originally Posted by Barry Bordes

Vex, I read a few more articles about preignition on high performance outboard and air cooled aircraft engines. They only promote Ashless Oils.

It seems like Valvoline makes an ashless oil that may be a good rotary oil.

VR1 Racing Formula SAE 20W-50 (Turbo Approved) Motor Oil (other weights also).

Key features Valvoline VV211
High public presentation and shelter in spite of today's engines that go at high-pitched RPM
New ashless anti-wear additives combined by the side of ZDDP bring home the bacon most remote endure shelter
Enhanced anti-foam scheme helps secure the instrument regular for the time of uttermost emphasise
Enhanced additives preserve fronting high-temperature deposits with regard to a dry cleaner weapon
Friction modifiers facilitate gain h.p. yield

Barry

Sweet! I'm game for testing it out. Do we have a distributor (online or IRL)?

[vex]

Originally Posted by joff

Very interesting thread.

Any speculation as to why oil ash content causes higher preignition? Is it because of the ash in the exhaust->intake carry-over volume due to the burning oil in the expansion/exhuast strokes?




Preignition within 8 cycles??!! I doubt many people have paid that much attention to oil ash content in the past -- how can there not be more blown motors because of this?

8 cycles on a single rotor test bed. Just because you have a pre-ignition event does not mean you'd have a catastrophic pre-ignition event.

As for speculation on why the ash causes pre-ignition events it's nothing more than a few ideas being passed around. As it stands right now the Pre-ignition is a direct result of ash because of carbon build up on the combustion surfaces. The carbon build up carries over heat causing the pre-ignition event where the gas reaches its flash point with contact to the surface. But that's just a theory.

[Barry Bordes]

Originally Posted by vex

8 cycles on a single rotor test bed. Just because you have a pre-ignition event does not mean you'd have a catastrophic pre-ignition event.

As for speculation on why the ash causes pre-ignition events it's nothing more than a few ideas being passed around. As it stands right now the Pre-ignition is a direct result of ash because of carbon build up on the combustion surfaces. The carbon build up carries over heat causing the pre-ignition event where the gas reaches its flash point with contact to the surface. But that's just a theory.

Vex and Joff,

In the NSU paper linked above, the engineers were finding engines being destroyed after high speed runs on the Autobahn. Their conclusion was preignition for metal ash deposits on the rotors.

The good news on the Valvoline VR1 is that I found it a O'Reilly's so it may be a other automotive stores also. They only had it in 50W and 20W50. It comes in 10W30 and 10W40 also.

Barry

[vex]

Originally Posted by Barry Bordes

Vex and Joff,

In the NSU paper linked above, the engineers were finding engines being destroyed after high speed runs on the Autobahn. Their conclusion was preignition for metal ash deposits on the rotors.

It's been a while since I've looked at the NSU papers, do you have a page to the conclusion that declares the ash deposits on the rotors as being the cause? I was thinking it would have been a combined effect of the plugs and combustion surface.

The good news on the Valvoline VR1 is that I found it a O'Reilly's so it may be a other automotive stores also. They only had it in 50W and 20W50. It comes in 10W30 and 10W40 also.

Barry

Is it classified as fully synthetic, or is it a highly refined conventional?

[joff]

Originally Posted by vex

8 cycles on a single rotor test bed. Just because you have a pre-ignition event does not mean you'd have a catastrophic pre-ignition event.

Yeah, I missed the part where 1 cycle = 2.5 hours and thought it was meant 8 rotations of the rotor which sounded absurd.

Originally Posted by vex

As for speculation on why the ash causes pre-ignition events it's nothing more than a few ideas being passed around. As it stands right now the Pre-ignition is a direct result of ash because of carbon build up on the combustion surfaces. The carbon build up carries over heat causing the pre-ignition event where the gas reaches its flash point with contact to the surface. But that's just a theory.

This theory could be tested by replacing oil with ashless oil and seeing if a high preignition rate continued. I presume carbon build-up accumulated would not instantly vanish?

[vex]

Originally Posted by joff

Yeah, I missed the part where 1 cycle = 2.5 hours and thought it was meant 8 rotations of the rotor which sounded absurd.



This theory could be tested by replacing oil with ashless oil and seeing if a high preignition rate continued. I presume carbon build-up accumulated would not instantly vanish?

That presumption would be correct (however the carbon instantly vanishing is not necessarily true. It will still need to be burned off, or dieseled to remove the built up carbon, which in and of itself may cause issues with the cars setup). NSU papers did multiple tests. The problem comes with the oil not containing ash, but impurities that produce ash when burned. Hence the high PPM of Calcium causing more sulphated ash, and the respected correlations. VOA and UOA are helpful in narrowing it down to oils that would work stellar in our engines. The problem comes in that a majority of "high end" oils contain low calcium numbers, but those numbers are still too high for our engines (remember the lower the sulphated ash the better; <500ppm of Calcium). Running a pure base, or synthetic that has <<<500ppm of Calcium is the better.

On that note; I did not find VR1 oils at Pepboys in Alexandria, VA. Next time I go to an autoparts store I'll check for it.

[Signal 2]

All interesting reading...thanks to VEX and all contributors. My head's spinning since I'm just a dumb goverment employee.

My question is that in the F I models, how well or poor the oil burns is only half the equation. How it performs in the high heat and extreme rpm turbo enviroment is the other. For that, it seems synthetic is superior. Is there something to look for in the analysis/content charts that would help a chemistry challenged lay-person balance those needs?