90% of engine wear occurs at startup

[Drstressor]

The amount of wear at startup vs operation is obviously determined by how a car is driven, so a statement that X amount of wear takes place at startup is nonsense. Most wear at startup is not direct abrasive wear, but something know as corrosive-abrasive wear. A well designed engine holds pooled oil close to all of the friction parts, so even a heavy oil will set up an initial film quickly. But as an engine sits between operation periods, the oxidation inhibitors in the thin film of oil coating the parts become depleted through exposure to air and moisture. This allows for re-activation of acids that were previously neutralized by the oil additives. Eventually, some metal surface corrosion occurs and a thin film of oxidized metal forms that is removed during startup. This is the source of most "normal" wear metal in a typical personal automotive application.

A strong anti-oxidant package (i.e. fresh oil) and metal bonding fluid components such as esters should reduce, but not eliminate, corrosive-abrasive wear upon startup. At low temperatures, a significant amount of time can pass before fresh oil reaches engine parts from the oil pump. Under those conditions, lower viscosity oils should provide better protection as everyone already knows.

 

[moribundman]

quote:

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At low temperatures, a significant amount of time can pass before fresh oil reaches engine parts from the oil pump. Under those conditions, lower viscosity oils should provide better protection as everyone already knows.

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How much time are we talking about? A few seconds?

[ August 02, 2003, 04:20 PM: Message edited by: moribundman ]

 

[Rexman]

quote:

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But as an engine sits between operation periods, the oxidation inhibitors in the thin film of oil coating the parts become depleted through exposure to air and moisture. This allows for re-activation of acids that were previously neutralized by the oil additives. Eventually, some metal surface corrosion occurs and a thin film of oxidized metal forms that is removed during startup. This is the source of most "normal" wear metal in a typical personal automotive application.

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Hmm . . . fascinating explanation. That would account for the low amount of wear in the CR taxi test--they were always doing stop-and-go city miles, but were constantly on the move--their engines were always warm and oil was circulating, so no chance for build-up of re-activated acids.

Definitely lends credence to the old saying that it's best to drive your car every day--and not let it sit for days on end, or allow it to become a pampered "garage queen".

Could also make for a convenient excuse to get out of the house. "Honey, have to take the car for a drive now--don't want to let those neutralized acids to get re-activated in the engine!"

[ August 02, 2003, 04:11 PM: Message edited by: Rexman ]

 

[Jerry]

***When I recently pulled a valve cover I was astonished by how little oil was on the cam lobes. They felt barely oily. The car had been sitting for maybe 12 hours, and the oil was M1 0W-40. ***
This is exact reason I will not run Mobile 1 in any vehicle that may sit around for a few days or weeks. I find the drain back is sever. I have had several folks mention to me that when they start a vehicle up that has been sitting around for a period of time with M1 in it, it sounds like a bucket of bolts. I have also suffering excessive camshaft wear on two infrequently used vehicles with M1 (both solid lifters). Once I switch back to dino, no problems. M1 is great for daily drivers only in my opinion.

 

[Shannow]

quote:

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Originally posted by BOBISTHEOILGUY:
......I do not agree that start up wear being that much. When is the highest wear. When an engine is completley warmed up driving in traffic. What most are forgetting is LOAD. At a start up, cold or warm, you have no load on the engine until you put it in gear to move. Starting an engine has no load thus do demand to shear the oil film.

At stop and go traffic, the wedge of oil is minimal and as someone commented, it's when you have a heavy foot from light to light that's when you create wear. The amount of scuffing due to load/shear of the wedge oil is dramitic.

You'll see many "little old lady's" drive their car local, start it, put it in gear, do the in town driving only and it never wears out, but take same car,with the same amount of startups, put a young person, they do jackrabbit starts from each light, and see the difference. The little old lady does easy starts off at lights, the other, putting heavy load and demand on the engine at start while the wedge between the parts is a mixed film at best.

So, imo, stop and go traffic with a heavy foot is where most wear is created, not startup.

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Bob,
your statements here could be interpreted as advocating a heavier oil, and thus gaining a greater film thickness at operating temperatures.

What are your thoughts on the thick/thin debate ?

 

[friendly_jacek]

This is to put a spin in the discussion.
I have read a technical paper on designing the new Toyota 1ZZ-FE engine.

The Japaneese engeneers used radioactive tracer in the piston rings. They measured radioactivity in oil to detect minimal wear.

The reasults were very clear. Very little ring wear with normal engine temp. Significant wear with warming up.

The most interesting thing:
The wear was strongly associated with the amount of sulfur in the fuel.
It supports the claim by Drdestressor above:
the engine wear is not so much mechanical as it is corrosive (H2SO3 and H2SO4 in case of sulfur), at least for cylinder/rings.

People here spend so much time discussing potential (again: only potential) minute differences between say 5W30 or 10W30 oils, while the facts with the greatest impact (IMHO) like fuel quality, combustion kinetics, ambient temp, warming up styles, and driving distances get relatively little attention.

 

[moribundman]

quote:

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The Japaneese engeneers used radioactive tracer in the piston rings. They measured radioactivity in oil to detect minimal wear.

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I guess VW does the same thing. I recently came across an article that was talking about wear being measured via isotopes. I forgot what exactly they called that procedure...

 

[Drstressor]

I once read a technical paper by the Mobil folks on the development of Delvac 1. If I remember correctly, it took almonst 1 min for conventional 15W-40 to reach the bearings at -20 in a Cummins test engine. I doubt it would take anything close to that long for a 0-10W conventional oil to reach the internal parts.

 

[Jimbo]

That is what I dislike about Mobil and others with synthetic marketing hype. Of course 15W-40 won't pump at -20F, it is not intended to. This does not prove that you need synthetics at startup, only that you need a 5W-XX at that temperature.

 

[Jimbo]

Yes, I would use synthetics in arctic conditions. But that is not my point. My point is that they used the wrong dino grade for the application to somehow show that synthetics are better.

 

[friendly_jacek]

Correction:
The paper was on 2ZZ-GE engine, not 1ZZ-FE:
SAE TECHNICAL
PAPER SERIES
2000-01-1231
MMC All Aluminum Cylinder Block for High
Power SI Engines

See quotation below:

"Fig. 19 shows the results of the ring wear measurements
of using the DBDS-additive fuel with different sulfur
concentrations. It was clear that the higher the sulfur
concentration, the greater the ring wear at low cooling
temperature."
"Influence of Cooling Water Temperature
Fig.20 shows the results of ring wear measurements by
varying the inlet cooling temperature. The lower the
coolant temperature, the greater the wear. This tendency
become more pronounced when the coolant temperature
is 40 degree celsius and below. Furthermore, even in the
case of high-sulfur fuel, ring wear is small when the water
temperature is 80 degree celsius and above. As can be
seen in Fig.17, change in coolant temperature manifests
the change in wear rather quickly.
This mechanism is as follows:
• Acids in the bore increase when coolant temperature
is low.
• The acids eliminate oil film between the bore and
piston rings.
• Abrasive wear between the bore and piston rings
increase."

Moribundman,
It is called RI tracer analysis.

 

[moribundman]

quote:

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Moribundman,
It is called RI tracer analysis.

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I just came across something like that again. They called it an RNT (Radio-Nuclide Test).

[ August 05, 2003, 11:34 PM: Message edited by: moribundman ]

 

[MikeW]

Okay. But if you want a 5wXX, especially if XX>=30, your better of with synthetic. It can do 5w30-40 with little or no VII, dead dino can't (I don't know about group III).

For -20F, I think I'd go to 0wXX. That's pretty seriously cold.

quote:

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Originally posted by Jimbo:
That is what I dislike about Mobil and others with synthetic marketing hype. Of course 15W-40 won't pump at -20F, it is not intended to. This does not prove that you need synthetics at startup, only that you need a 5W-XX at that temperature.

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[Matt89]

quote:

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So, imo, stop and go traffic with a heavy foot is where most wear is created, not startup.

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I think there is a lot of truth to this, and not just with respect to engine wear. Having a heavy foot on the gas and brake is what turns a tight car into a swaying, rattling, smoking junkbox (obviously some cars are built to better withstand this than others).

For you racefans...back when racecars, engines and tires were not as durable as they are today, the drivers with a light touch and the ability to go fast while taking care of their equipment were the ones who were up front at the end of 500 miles.

Moral of the story...if you want your car to last a long time, drive like Terry (the Iceman) Labonte. If that's not as important to you, drive like Kurt Busch

.

[ August 06, 2003, 10:22 AM: Message edited by: Matt89 ]

 

[Whimsey]

I think you'll get more wear at start-up if you have an oil filter that has a poor anti drain back valve design. Especially with an engine that really needs to get the oil circulating fast, as in my previous 4.9L inline Ford truck engine.I would think that the longer it takes for the oil to circulate upon start-up the more wear is occuring. However, once you are up and running I agree with Bob that jack rabbit starts will put a strain on the oils ability to keep things safely lubed.

Whimsey

 

[friendly_jacek]

Mike,
If so, how do you explain the ring wear pattern in the Toyota radioactive tracer experiments I described above?

Matt,
You are exactly right. Because those big engines run almost continously, thay last for 5000 hrs or longer. Try to achieve it with your car.

This site is great and I learnt a lot. However, sometimes I wish more facts and less speculation was posted here.

 

[mikemc]

"Mike,
If so, how do you explain the ring wear pattern in the Toyota radioactive tracer experiments I described above?" I cannot explain an article I have not read. I did not state that start up wear does not exist, just that its not much of a concern when using the right oil and I think several UOA here does support this. The theories on fuel and operation are interesting.

 

[Matt89]

Looking at this a different way, if startup wear really is the dominant factor, then why do big diesels (like the Cats on ships or in power plants) ever need to be rebuilt? They have pre-lube pumps, lube oil heaters and purifiers etc. No really cold or dry starts, virtually clean oil all the time, etc...yet they are rebuilt on a regular schedule.

In that light, startup wear seems to me like something that's not worth worrying about (i.e. we have reached decreasing marginal utility of worrying), unless you are using the wrong oil viscosity or it's so cold that your oil is giving up on you. I think the "startup wear" issue really got fueled by the Slick50 marketing.

 

[isaac004]

So which do you think is better for decreasing cold engine wear and tear - let the car idle for a few minutes before you head for the highway (in my case a 4 minute drive to the highway), or just drive really easy to the highway.

My Dad always seemed to say just drive easy, because if you idle, thats just more hours your engine will be running in the long run, which makes sense to me.

 

[Whimsey]

Listen to your father.

Whimsey