Used Oil Analysis - Post Them Here
03-10-2011, 09:05 AM
#352
What I am trying to get at is are there any signs that engine is about give up or wearing at accelerated rate..which metals would shoot up?
03-10-2011, 06:51 PM
#353
Ok you got me, my UOA is post #267, posted by 9krpmrx8 because I'm too lazy to erase personal info.
I've seen pics of excess bearing wear during engine rebuild, and I've seen excess chrome on some UOA's that might be telling on this wear, but I've only heard of seal failure sometimes with excess carbon, and that problem is not related to oil flow system since it's once through oil.
Sometimes the water jacket seal can fail, and the UOA might tell you that (antifreeze in oil), but if you want to know health of engine, a compression check is best way.
I've blown two rotaries; the water seals on one where water would flood the chamber when cold and you'd have to heat the plugs to fire it, and I ran top end at 7k rpm until one apex seal blew, and still ran with loss of power.
You can run about any oil with any weight, and you're not gonna blow up in the sense that a engine throws a valve or piston and it seizes up on the spot.
UOA's are best to find oil change interval (condition of oil - not engine), fuel in the oil, silicon (dirt), and antifreeze. On the occasional high horse piston engine you can tell by lead, copper, and chrome that there's something wrong, but iron can be high (up to 150ppm), and not be having trouble.
I've seen pics of excess bearing wear during engine rebuild, and I've seen excess chrome on some UOA's that might be telling on this wear, but I've only heard of seal failure sometimes with excess carbon, and that problem is not related to oil flow system since it's once through oil.
Sometimes the water jacket seal can fail, and the UOA might tell you that (antifreeze in oil), but if you want to know health of engine, a compression check is best way.
I've blown two rotaries; the water seals on one where water would flood the chamber when cold and you'd have to heat the plugs to fire it, and I ran top end at 7k rpm until one apex seal blew, and still ran with loss of power.
You can run about any oil with any weight, and you're not gonna blow up in the sense that a engine throws a valve or piston and it seizes up on the spot.
UOA's are best to find oil change interval (condition of oil - not engine), fuel in the oil, silicon (dirt), and antifreeze. On the occasional high horse piston engine you can tell by lead, copper, and chrome that there's something wrong, but iron can be high (up to 150ppm), and not be having trouble.
04-26-2011, 12:56 AM
#358
New member here. Just got into my 2010 8, previously in a 07 Speed 6 and have been in the likes of Audi, BMW, Nissan, and an EVO. It has been great to be able to analyze so many UOAs from these engines. However, one thing that sticks out is the use of HDEO (diesel oil). This was great in a DI app like the Speed or in a stressed Otto app like the EVO or Nissan 3.5LVQ. However, in our app that is designed to consume oil HDEO is not advisable. The heavy use of Calcium will leave significant ash behind and lead to deposits. Hence the move in the diesel world to low SAPS oils or salphated ash. This ash will clog the particulate filters. Only stirring some thought and open to discussion.
04-26-2011, 06:57 AM
#359
My 8 only uses 1/2 quart at 2k miles which is not much consumption for any engine, but I agree that diesel oils are formulated for heavy diesel soot, and gasoline oils are a little more on the antiwear additive side.
I've sold both kinds of oils for years, and the oil companies would get you to use the diesel oil in your whole fleet of trucks and gas pickups so it'd be "Goof Proof".
I've known guys getting 500-600k miles on a Chevy 350 out of 15w40 diesel oil in hot dusty weather, but my 8 won't go that far, and I do run a gasoline oil Mobil 1 0w40.
I've sold both kinds of oils for years, and the oil companies would get you to use the diesel oil in your whole fleet of trucks and gas pickups so it'd be "Goof Proof".
I've known guys getting 500-600k miles on a Chevy 350 out of 15w40 diesel oil in hot dusty weather, but my 8 won't go that far, and I do run a gasoline oil Mobil 1 0w40.
04-26-2011, 09:12 AM
#360
1% evil, 99% hot gas.
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However, one thing that sticks out is the use of HDEO (diesel oil). This was great in a DI app like the Speed or in a stressed Otto app like the EVO or Nissan 3.5LVQ. However, in our app that is designed to consume oil HDEO is not advisable. The heavy use of Calcium will leave significant ash behind and lead to deposits.
My 8 only uses 1/2 quart at 2k miles which is not much consumption for any engine, but I agree that diesel oils are formulated for heavy diesel soot, and gasoline oils are a little more on the antiwear additive side.
I've sold both kinds of oils for years, and the oil companies would get you to use the diesel oil in your whole fleet of trucks and gas pickups so it'd be "Goof Proof".
I've known guys getting 500-600k miles on a Chevy 350 out of 15w40 diesel oil in hot dusty weather, but my 8 won't go that far, and I do run a gasoline oil Mobil 1 0w40.
I've sold both kinds of oils for years, and the oil companies would get you to use the diesel oil in your whole fleet of trucks and gas pickups so it'd be "Goof Proof".
I've known guys getting 500-600k miles on a Chevy 350 out of 15w40 diesel oil in hot dusty weather, but my 8 won't go that far, and I do run a gasoline oil Mobil 1 0w40.
You say diesel oils are formulated for soot, but gasoline oil is formulated for less wear, then you say guys with gasoline 350's get half a million miles using diesel oil and you expect to get less using gasoline oil? Whoa. My head is spinning. 
What are you trying to say? 
04-26-2011, 09:18 AM
#361
Nature vs. Nurture
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This is timely, cause I have diesel oil about to go into my engine before a track day. Are there some references on any issues with diesel in a gas engine or a rotary? (I still have the omp pumping crap into my engine - funny not doing what is best (sohn) just for the sake of a warranty.)
04-26-2011, 09:36 AM
#364
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1/2 a quart consumption is not good, how many miles on your car?
Read this thread of mine:
https://www.rx8club.com/showthread.p...ghlight=theory
An yeah, I wonder where that thread is with the UOA's on Diesel oil
Read this thread of mine:
https://www.rx8club.com/showthread.p...ghlight=theory
An yeah, I wonder where that thread is with the UOA's on Diesel oil
04-26-2011, 09:45 AM
#366
Nature vs. Nurture
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Yep, mine is one of those UOAs with Rotella. Besides the proof you provided on Calcium, I was wondering if there are some good documents to read or other reliable source of info.
04-26-2011, 03:31 PM
#367
Ok so here are my 2UOA's:
First one is a mix of Shell Rotella 5w-40 and whatever was in there when I bought the car. That fill has 2 track days on it.
Latest one is 50/50 mix of Castrol Edge 5w-30 and Redline 5w-30/30wt racing oil. It also has 2 track days on it. I left the oil in the car. Should be good for another event or two.
I am not to concerned with lead since readline oil in known to produce spike in lead readings. I have a another track day this weekend.
One thing I did notice is that engine did run much smother once I poured redline oil in. I guess all that moly and zinc are doing it's job :-)
From now on I will run 50/50 mix of regular redline 5w-30 and redline 30wt racing oil.
First one is a mix of Shell Rotella 5w-40 and whatever was in there when I bought the car. That fill has 2 track days on it.
Latest one is 50/50 mix of Castrol Edge 5w-30 and Redline 5w-30/30wt racing oil. It also has 2 track days on it. I left the oil in the car. Should be good for another event or two.
I am not to concerned with lead since readline oil in known to produce spike in lead readings. I have a another track day this weekend.
One thing I did notice is that engine did run much smother once I poured redline oil in. I guess all that moly and zinc are doing it's job :-)
From now on I will run 50/50 mix of regular redline 5w-30 and redline 30wt racing oil.
04-26-2011, 04:38 PM
#368
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Thread Starter
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Not bad, but very low mileage OIC's. I'd be curious to see what it looks like fresh. When I tried German Castrol 0W-30 it broke down quite a bit in 1500 miles so I stopped using it.
04-26-2011, 05:03 PM
#369
Rotella T is very high in Zinc which is wonderful for your motor, and provides an anti-carbon coating. But if you have a cat its very bad causing catalytic converters to burn out faster.
Wonderful oil though, It has kept my 1958 motor running. Original engine btw.
Wonderful oil though, It has kept my 1958 motor running. Original engine btw.
04-26-2011, 05:10 PM
#370
I just wanted to flush whatever oil was in there when I bought the car.
5w-30 http://www.redlineoil.com/product.aspx?pid=2&pcid=21
30wt http://www.redlineoil.com/product.aspx?pid=14&pcid=1
5w-30 http://www.redlineoil.com/product.aspx?pid=2&pcid=21
30wt http://www.redlineoil.com/product.aspx?pid=14&pcid=1
04-26-2011, 06:36 PM
#371
Congrats on the new 8 and welcome to the forum.
With due respect, baloney. What heavy use of calcium? Look at the UOAs on here: With 10W-30 Castrol GTX my calcium was 2292, 2199, 2275. With Rotella T 15W-40 the calcium is 2229. So there appears to be no difference. This is why I love UOAs; they debunk speculation and hearsay.
I'm confused. You say diesel oils are formulated for soot, but gasoline oil is formulated for less wear, then you say guys with gasoline 350's get half a million miles using diesel oil and you expect to get less using gasoline oil? Whoa. My head is spinning. What are you trying to say?
With due respect, baloney. What heavy use of calcium? Look at the UOAs on here: With 10W-30 Castrol GTX my calcium was 2292, 2199, 2275. With Rotella T 15W-40 the calcium is 2229. So there appears to be no difference. This is why I love UOAs; they debunk speculation and hearsay.
I'm confused.
You say diesel oils are formulated for soot, but gasoline oil is formulated for less wear, then you say guys with gasoline 350's get half a million miles using diesel oil and you expect to get less using gasoline oil? Whoa. My head is spinning. What are you trying to say? Also, before quickly dismissing what I’m adding here is some of my background. I have been doing UOAs for 13 years for personal and racing apps. Additionally, I have personally been able to partake of Terry Dyson's vast wealth of knowledge and experience in addition to engineers at some of the major oil companies. Certainly nothing exclusive that couldn’t be had by others, but the experience and education did come at a cost.
Another additive that may help seal the combustion chamber is Magnesium. However, I believe like calcium it also leaves ash. FWIW, the UOAs you are getting here do not include sulphated byproduct contents or reliable insoluble counts. For this to be reliable one would need to spend upward of 60 to 130$US for the UOA.
This may be a good, quick read for some further damning HDEO in our apps. http://www.synforce.com.au/sulphated_ash.html. There are others.
I may have isolated calcium errantly. It would be the healthier add packs in general from HDEOs that would create long term deposit issues, all the while likely providing superior wear protection.
FYI I cannot directly release information I have gained from Terry from my UOAs for confidentiality reasons, but can certainly share in my own observations.
Last edited by Iluvrevs; 04-26-2011 at 07:25 PM.
04-26-2011, 09:04 PM
#372
I'm confused.
You say diesel oils are formulated for soot, but gasoline oil is formulated for less wear, then you say guys with gasoline 350's get half a million miles using diesel oil and you expect to get less using gasoline oil? Whoa. My head is spinning. What are you trying to say? The rotary won't go the distance anyway with seals blowing, but it's not the oil quality.
I think the German oil specs define very several tests on engines considering the cost of those cars, so if you notice that gasoline Mercedes has only one oil that meets their spec: Mobil 1 0w40, and some of the cheaper German cars are known sludge monsters in which a diesel additive package might be just the thing.
I'll never run less than a 12 cst oil at operating temp on anything that I floorboard the gas, and that weight is Mobil 1 0w40.
Last edited by 40w8; 04-26-2011 at 09:50 PM.
04-26-2011, 09:58 PM
#373
You should know; you saw it last month! 
I'm blogging from an alternate universe.
I like that the oil spray is turned down so I can burn my own 2t premix at 3 times that rate. 1/2 oz per gallon (6-8 0z per fillup), and as you know I got the high vacuum reading.
I'm blogging from an alternate universe.
I like that the oil spray is turned down so I can burn my own 2t premix at 3 times that rate. 1/2 oz per gallon (6-8 0z per fillup), and as you know I got the high vacuum reading.
04-26-2011, 11:34 PM
#374
I'm debunking the guys theory that calcium or other additives in diesel engine oil won't allow gasoline engines to survive.
The rotary won't go the distance anyway with seals blowing, but it's not the oil quality.
I think the German oil specs define very several tests on engines considering the cost of those cars, so if you notice that gasoline Mercedes has only one oil that meets their spec: Mobil 1 0w40, and some of the cheaper German cars are known sludge monsters in which a diesel additive package might be just the thing.
I'll never run less than a 12 cst oil at operating temp on anything that I floorboard the gas, and that weight is Mobil 1 0w40.
The rotary won't go the distance anyway with seals blowing, but it's not the oil quality.
I think the German oil specs define very several tests on engines considering the cost of those cars, so if you notice that gasoline Mercedes has only one oil that meets their spec: Mobil 1 0w40, and some of the cheaper German cars are known sludge monsters in which a diesel additive package might be just the thing.
I'll never run less than a 12 cst oil at operating temp on anything that I floorboard the gas, and that weight is Mobil 1 0w40.
Not implying theory, my apology if I implied so.
For those pondering at this point I see Valvoline 5w30 as the better option in our apps. RLI may be another option though I cant speak for their add pacs or the clean burn of their base stock.
HDEO may work well if used with a cleaning premix.
Last edited by Iluvrevs; 04-26-2011 at 11:40 PM.
04-27-2011, 12:50 AM
#375
I've studied oil lit from Exxon since being a kid, and went to Exxon's distributor oil training school, and I've seen other's real world success.
In the 70's, some 240z guys working in some lab in Austin would come buy 10 cases of XD-3 40 diesel oil for their cars saying it was the best oil they found for holding up viscosity.
One guy ran the same oil in his 1980 Olds diesel for nearly 250k miles until the thermo stuck, and those diesels usually didn't last long (gas engine conversion GM experiment).
My opinion is that the 5w30 oils were early experiments into thinner gas saving oils, and back then were known to shear a lot.
That's why I'm a fan of the new ow oils, and I'd run 0w30 before 5w30 anyday, but 0w40 fror me.
So does anyone have oil test specs for Mazda rotaries like the German cars?
Tell me where so I can get new info, please.
In the 70's, some 240z guys working in some lab in Austin would come buy 10 cases of XD-3 40 diesel oil for their cars saying it was the best oil they found for holding up viscosity.
One guy ran the same oil in his 1980 Olds diesel for nearly 250k miles until the thermo stuck, and those diesels usually didn't last long (gas engine conversion GM experiment).
My opinion is that the 5w30 oils were early experiments into thinner gas saving oils, and back then were known to shear a lot.
That's why I'm a fan of the new ow oils, and I'd run 0w30 before 5w30 anyday, but 0w40 fror me.
So does anyone have oil test specs for Mazda rotaries like the German cars?
Tell me where so I can get new info, please.