How does very short OCI's hurt an engine?

[CaspianM]

10k is far from being broken-in for oil test unless they had already established a trending with this engine.

One more point is that the incremental difference (iron for example) per 1k miles dosen't indicate that it peaked at 3k miles. I bit it peaked well into first 1k range. They did looked at the wear in overal average vs. incrementts.

Adding oil would also void the validity of the test as well.
Isn't that ironic that the car did not burn oil until 3k but then after. That itself is an indication of condition of the oil regardless of wear#'s.

 

[CaspianM]

Iron wear trend:
0~1k..8 ppm
1~2k..2ppm
2~3k..2ppm
3~4k..5ppm
4~5k..4ppm

This show that at 1000 miles iron had already peaked and on the way to level off. Where they got the 3k miles I have no idea.

 

[edhackett]

Was this data corrected for carry-over? Was carry over addressed in any way?

Say your oil has 100 ppm iron at the end of a an OCI. You change the oil, but ~10% of the old oil remains in the engine(not an unreasonable amount for a 5 qt sump). Your engine produces X ppm/1K mile. Your sample at 1K will be 10+X. The iron numbers will decrease on a per mile basis as mileage climbs as that initial 10ppm is spread over more miles. Some would conclude that new oil causes more wear. Those that think about it a minute see that it is likely just carry-over.

OldCowboy: You are right. A link to the paper with that graph needs to be posted so that the supporting text can be read. That graph does not show what he poster thinks it does. No SAE paper would refer to additive activation as "wear in".

Also, in the SAE paper where they saw more cam wear on the bench with new oil, they completely cleaned the anti-wear layer left from the previous oil/test off the cam between tests. Unless you completely clean the layer off of every wear surface of your engine at every OCI, this test doesn't apply to actual engine operation in an automobile.

Ed

 

[FZ1]

I don't buy the reasoning in the article. The rate of wear metals is less important than the total ppm. If I change the oil,I have dumped more aggregate ppm than I have just poured in with fresh oil. Whatever the case,the ppm is not enough to reduce the life of the engine.

 

[Gunner14]

I'm the guy who started this post... Sure has been many ideas, opinions, and data posted. Because of all the interest, I decided to directly ask a friend who is a chemical engineer and has worked in the petro industry for years. He contacted me today and said he would forward some abstracts/summaries of actual studies completed by some large manufacturers of automobiles and engine oils. If I get his permission, I'll provide access to those actual documents.

His take on oil changes:

Best indication for an oil change = analysis - as the actual ideal OCI will be particular to the engine and the oil and the conditions as used; oil detergents and "base(?)" additives stabilize during the first 250-500 miles of use in 99.9% of all commercially available engine oils due to the complexities caused by the engine heat cycles, and are specifically designed to do that by the manufacturers; changing engine oils all-the-time in intervals shorter than 500 miles can be quanitatively deterimental to the long-wear picture of an engine (i.e., the detergents compete with the wear additives higher during this period); 3000 mi oil changes are usually excessive given the current oils and the new engine designs and tolerances (rate is less for metals released in oils as today's engines wear); changing your oil at 3000 miles may waste $$$, but not harmful - as wear is only slightly higher during the initial 250-500 mile period post an oil change (he emphasized that in a few of the studies he has reviewed, the wear was not "meaningfully" or "measurablely" higher even during that first 250-500 miles with the new oil).

I have tried to summarize what he said as I remembered, but they are not exact quotes.

 

[ltslimjim]

^That sounds reasonable. Nice quote from your friend. I suppose that sticking with one oil may/may not impact this initial higher wear for the 250-500 miles or so into an oil change. If going from a conventional to say...Red Line, would it take 1,000 to have the wear trend down again, for instance; then each oil change with RL having the settle in effect happen closer to the 'norm'(the suggested 250-500 miles instead of 1,000 on initial swap) for any particular app.

 

[demarpaint]

Originally Posted By: Gunner14
I'm the guy who started this post... Sure has been many ideas, opinions, and data posted. Because of all the interest, I decided to directly ask a friend who is a chemical engineer and has worked in the petro industry for years. He contacted me today and said he would forward some abstracts/summaries of actual studies completed by some large manufacturers of automobiles and engine oils. If I get his permission, I'll provide access to those actual documents.

His take on oil changes:

Best indication for an oil change = analysis - as the actual ideal OCI will be particular to the engine and the oil and the conditions as used; oil detergents and "base(?)" additives stabilize during the first 250-500 miles of use in 99.9% of all commercially available engine oils due to the complexities caused by the engine heat cycles, and are specifically designed to do that by the manufacturers; changing engine oils all-the-time in intervals shorter than 500 miles can be quanitatively deterimental to the long-wear picture of an engine (i.e., the detergents compete with the wear additives higher during this period); 3000 mi oil changes are usually excessive given the current oils and the new engine designs and tolerances (rate is less for metals released in oils as today's engines wear); changing your oil at 3000 miles may waste $$$, but not harmful - as wear is only slightly higher during the initial 250-500 mile period post an oil change (he emphasized that in a few of the studies he has reviewed, the wear was not "meaningfully" or "measurablely" higher even during that first 250-500 miles with the new oil).

I have tried to summarize what he said as I remembered, but they are not exact quotes.


Nice info, thanks for posting! You mention this: " as used; oil detergents and "base(?)" additives stabilize during the first 250-500 miles of use in 99.9% of all commercially available engine oils due to the complexities caused by the engine heat cycles, and are specifically designed to do that by the manufacturers; changing engine oils all-the-time in intervals shorter than 500 miles can be quanitatively deterimental to the long-wear picture of an engine (i.e., the detergents compete with the wear additives higher during this period"

Would an extended drain have more of a negative impact during this initial period, and would the amount of miles needed for an extended drain oil to stabilize be more? Thanks

 

[armos]

Carry-over is a good point. Between carry-over and first-start I think both could account for some of the early wear that might show up on the first analysis.

Carry-over is a good reason not to be too aggressive with the change interval. Off the top of my head, I think I'd want the oil to be able to survive 3 intervals before whatever's left turns to sludge.

From everything I'm reading, my impression is that the oil might be a bit below peak performance for the first few hundred miles, but it sounds like it's probably not anything dramatic. But it is making me think it might be best practice to drive easy on the engine for the first few hundred.


Originally Posted By: meangreen01
Originally Posted By: crazyoildude
agree with you on the dry starts!


No joke! As happy as I am to have nice clean oil, I cringe to turn the [censored] key. Torture.


When I first started doing oil changes, this was something that really bugged me. For the first few seconds on the first startup, I noticed a distinct smell of magic smoke. It was especially bad on my car because GM programmed it to idle at 1500rpm when cold, or even 2000rpm when really freezing cold.
After a couple oil changes, I decided I couldn't stand the stupidity of it anymore.

I got in the habit of disconnecting the ignition on the first start. I always just crank the starter until the oil pressure comes up. Only then do I reconnect the ignition. I'm sure there's still some abrasion but the starter doesn't turn nearly as many RPM, and it makes me feel a lot better.

I should start trying to fill the filter. My old car didn't allow that at all, it had the filter sideways. The car I bought last winter has it at an angle so I guess that's an improvement.

 

[Patman]

I'm surprised no one mentioned this (unless I missed it?) but another factor to consider is that a brand new oil filter does not filter as efficiently as one with a few thousand miles on it. So for people who change their oil (and filter) every 1000 miles or 2000 miles, they are never getting to the "sweet spot" of their oil filter's life where it's doing it's job the best. (Although one could also argue the whole issue of filtration versus flow rates of an oil filter too, and which of those two is more important to engine life, but that's a whole new ball of wax!)

 

[charbaby]

There are so many replys that I couldn't read them all and I hope I am not duplicating a responce.

I'd like to add that I have read that each time we change our oil/filter and then restart the engine, we may experience start up rattle/dry start *even if we pre-fill the filter*. Changing the oil more often will cause more of this dry start up.

I currently have engines that experience this start up rattle after an OCI and others that do not...Even when pre-filling the filter!

 

[FZ1]

I don't think it's a dry start ,if you change the oil with a warmed engine. The oil is already on the parts.

 

[rg200amp]

Originally Posted By: meangreen01
Increased wear from dry starts. I've always gotten a pretty nasty sound for a couple seconds before oil pressure builds.


Prefill your filter.

After prefilling the filter, the minimal "dry" start would be the same if not less worse than starting your car after it sat off for two days. Needless to say nothing happens.

 

[bluesubie]

Originally Posted By: ARCOgraphite
It appears no one here is grapsing how the detergent package functions, would you jump in your neighbor's swimming pool just seconds after he "shocked" it? Same thing with a fresh detergent package in fresh oil when it highest in Base #. It dissallows the EP package from being as effective as it could be in time. I see the biggest problem here in casual street racers, drag racers and weekend warroirs who would use a high TBN oil say Mobil EP and go out and race with baby fresh oil. They are doing the most harm. They should be using a race specific oil with low detergency. Go to Joe Gibbs Racing and read up, its a Good read for the layperson.

I agree Arco!

While some of the spun bearing problems at nasioc are due to a lot of things (wrong oil for the application, neglect, abuse, etc.) a good number of them happen within a few hundred miles after an oil change.

-Dennis

 

[ltslimjim]

Originally Posted By: bluesubie
Originally Posted By: ARCOgraphite
It appears no one here is grapsing how the detergent package functions, would you jump in your neighbor's swimming pool just seconds after he "shocked" it? Same thing with a fresh detergent package in fresh oil when it highest in Base #. It dissallows the EP package from being as effective as it could be in time. I see the biggest problem here in casual street racers, drag racers and weekend warroirs who would use a high TBN oil say Mobil EP and go out and race with baby fresh oil. They are doing the most harm. They should be using a race specific oil with low detergency. Go to Joe Gibbs Racing and read up, its a Good read for the layperson.

I agree Arco!

While some of the spun bearing problems at nasioc are due to a lot of things (wrong oil for the application, neglect, abuse, etc.) a good number of them happen within a few hundred miles after an oil change.

-Dennis


Ironically, this may be what I'm experiencing right now. I could have a spun bearing, the problem is I can't remember if I heard this sound before I changed my oil last or after it.

+1, to ARCO's point. Though, I don't race my car.