Overactive imagination at work. Better to visualize the oil pump at work with the engine running squirting that oil all them moving parts.
90% of engine wear occurs at startup
- Thread starter moribundman
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I came to have strange habbit of starting the engine. I turn on the engine and wait a few minutes until rev goes down somewhat. And then I shut off the engine and wait for 15 seconds to a few minutes. Why? I imagine the scuffs and small particles accumulated around piston ring flow down during that period. Then I start again and drive car. In my imagination, I feel the car is quiter and smoother.
This is not based on any science or knowledge and may be silly, but at least to my gut feeling, i feel the difference.
I wonder what you gentlemen think about this practise. I hope any of you just try this and let us know if you too feel the difference.
Sei
This is not based on any science or knowledge and may be silly, but at least to my gut feeling, i feel the difference.
I wonder what you gentlemen think about this practise. I hope any of you just try this and let us know if you too feel the difference.
Sei
Quote:
Remember the "90% of your engine wear happens at startup" advertising campaign? This fact is absolutely true, but as it happens, it's less to to with "grinding engine parts" and more to do with combustion. When the combustion gases burn, they form acids which are highly corrosive when their vapours condense. These acids collect in the upper cylinder areas where their temperature is raised above their dew point. The acids condense and etch the cylinder walls and piston rings. In reality, this accounts for over 85% of engine wear, the other 15% being down to abrasion. So the adverts are nearly right - most of the engine wear does happen at startup, and it is because of a lack of oil, but it isn't because the oil isn't coating moving parts - it's because it's not transporting these acidic gases away. Having said that, if you start the engine and let it idle for 15 seconds or so before moving off, you can probably add another 100,000 miles to your engine's life without one bottle of additive. This warms the oil up a tad and makes sure it's in all the most vital areas before you start putting a strain on the engine. Most handbooks tell you not to let the engine warm up before driving off (they're referring to the acid corrosion mentioned above), but they mean don't let it reach working temperature. If, however, you insist on starting up and belting off down the road, think of this next time: it takes an average engine around 3 minutes of average driving for the exhaust manifold to reach 300°C. If you blast off and run around at full throttle, right from the word go, that process takes a little under a minute. Think about it - from outside air temperature to 300°C in a minute - what exactly is that doing to the metal in your manifold? Ask anyone who's ever owned an original Audi Quattro - they'll tell you exactly what happens.
Remember the "90% of your engine wear happens at startup" advertising campaign? This fact is absolutely true, but as it happens, it's less to to with "grinding engine parts" and more to do with combustion. When the combustion gases burn, they form acids which are highly corrosive when their vapours condense. These acids collect in the upper cylinder areas where their temperature is raised above their dew point. The acids condense and etch the cylinder walls and piston rings. In reality, this accounts for over 85% of engine wear, the other 15% being down to abrasion. So the adverts are nearly right - most of the engine wear does happen at startup, and it is because of a lack of oil, but it isn't because the oil isn't coating moving parts - it's because it's not transporting these acidic gases away. Having said that, if you start the engine and let it idle for 15 seconds or so before moving off, you can probably add another 100,000 miles to your engine's life without one bottle of additive. This warms the oil up a tad and makes sure it's in all the most vital areas before you start putting a strain on the engine. Most handbooks tell you not to let the engine warm up before driving off (they're referring to the acid corrosion mentioned above), but they mean don't let it reach working temperature. If, however, you insist on starting up and belting off down the road, think of this next time: it takes an average engine around 3 minutes of average driving for the exhaust manifold to reach 300°C. If you blast off and run around at full throttle, right from the word go, that process takes a little under a minute. Think about it - from outside air temperature to 300°C in a minute - what exactly is that doing to the metal in your manifold? Ask anyone who's ever owned an original Audi Quattro - they'll tell you exactly what happens.
Originally Posted By: buster
Quote:
Remember the "90% of your engine wear happens at startup" advertising campaign? This fact is absolutely true, but as it happens, it's less to to with "grinding engine parts" and more to do with combustion. When the combustion gases burn, they form acids which are highly corrosive when their vapours condense. These acids collect in the upper cylinder areas where their temperature is raised above their dew point. The acids condense and etch the cylinder walls and piston rings. In reality, this accounts for over 85% of engine wear, the other 15% being down to abrasion. So the adverts are nearly right - most of the engine wear does happen at startup, and it is because of a lack of oil, but it isn't because the oil isn't coating moving parts - it's because it's not transporting these acidic gases away. Having said that, if you start the engine and let it idle for 15 seconds or so before moving off, you can probably add another 100,000 miles to your engine's life without one bottle of additive. This warms the oil up a tad and makes sure it's in all the most vital areas before you start putting a strain on the engine. Most handbooks tell you not to let the engine warm up before driving off (they're referring to the acid corrosion mentioned above), but they mean don't let it reach working temperature. If, however, you insist on starting up and belting off down the road, think of this next time: it takes an average engine around 3 minutes of average driving for the exhaust manifold to reach 300°C. If you blast off and run around at full throttle, right from the word go, that process takes a little under a minute. Think about it - from outside air temperature to 300°C in a minute - what exactly is that doing to the metal in your manifold? Ask anyone who's ever owned an original Audi Quattro - they'll tell you exactly what happens.
Where is Mori, I would like his thoughts on the matter?
Quote:
Remember the "90% of your engine wear happens at startup" advertising campaign? This fact is absolutely true, but as it happens, it's less to to with "grinding engine parts" and more to do with combustion. When the combustion gases burn, they form acids which are highly corrosive when their vapours condense. These acids collect in the upper cylinder areas where their temperature is raised above their dew point. The acids condense and etch the cylinder walls and piston rings. In reality, this accounts for over 85% of engine wear, the other 15% being down to abrasion. So the adverts are nearly right - most of the engine wear does happen at startup, and it is because of a lack of oil, but it isn't because the oil isn't coating moving parts - it's because it's not transporting these acidic gases away. Having said that, if you start the engine and let it idle for 15 seconds or so before moving off, you can probably add another 100,000 miles to your engine's life without one bottle of additive. This warms the oil up a tad and makes sure it's in all the most vital areas before you start putting a strain on the engine. Most handbooks tell you not to let the engine warm up before driving off (they're referring to the acid corrosion mentioned above), but they mean don't let it reach working temperature. If, however, you insist on starting up and belting off down the road, think of this next time: it takes an average engine around 3 minutes of average driving for the exhaust manifold to reach 300°C. If you blast off and run around at full throttle, right from the word go, that process takes a little under a minute. Think about it - from outside air temperature to 300°C in a minute - what exactly is that doing to the metal in your manifold? Ask anyone who's ever owned an original Audi Quattro - they'll tell you exactly what happens.
Where is Mori, I would like his thoughts on the matter?
Quote:
0W-20 BENEFITS:
Fuel efficiency -- Viscosity is defined as “resistance of a fluid to flow". The lower the viscosity, the
lower the resistance, the less heat generated, the more power that gets to the wheels, the better the
fuel economy of that vehicle. Toyota says that the use of 0W-20 will save between 0.4 and 0.6 MPG.
Honda claims you will see a 1.5% fuel economy savings as compared to 5W-30.
Less wear -- Engine design, materials and manufacturing processes have changed.
• Engines are now designed with larger bearing surfaces, which spread the load and lowers PSI..
• The load bearing surfaces are smoother (mirror like) and less porous than in older engines.
Therefore, thinner oils can keep moving surfaces apart without excessive wear.
• Clearances have been reduced to the point that thicker oils can not get where needed. The
Honda Civic Hybrid and Insight have bearing clearances of just 0.0095 inches.
• At start up, thinner oils can get where needed faster thus reducing wear. A Ford study
concluded that 75% of wear occurs at start up.
• Hybrid cars that cycle between battery and gasoline engine are constantly starting, stopping and
jumping to high speed. 0W-20 is needed in this environment.
Cooler Engines -- Thin oil moving fast will remove more heat than thick oil moving slowly.
0W-20 BENEFITS:
Fuel efficiency -- Viscosity is defined as “resistance of a fluid to flow". The lower the viscosity, the
lower the resistance, the less heat generated, the more power that gets to the wheels, the better the
fuel economy of that vehicle. Toyota says that the use of 0W-20 will save between 0.4 and 0.6 MPG.
Honda claims you will see a 1.5% fuel economy savings as compared to 5W-30.
Less wear -- Engine design, materials and manufacturing processes have changed.
• Engines are now designed with larger bearing surfaces, which spread the load and lowers PSI..
• The load bearing surfaces are smoother (mirror like) and less porous than in older engines.
Therefore, thinner oils can keep moving surfaces apart without excessive wear.
• Clearances have been reduced to the point that thicker oils can not get where needed. The
Honda Civic Hybrid and Insight have bearing clearances of just 0.0095 inches.
• At start up, thinner oils can get where needed faster thus reducing wear. A Ford study
concluded that 75% of wear occurs at start up.
• Hybrid cars that cycle between battery and gasoline engine are constantly starting, stopping and
jumping to high speed. 0W-20 is needed in this environment.
Cooler Engines -- Thin oil moving fast will remove more heat than thick oil moving slowly.
Originally Posted By: buster
Quote:
0W-20 BENEFITS:
• Engines are now designed with larger bearing surfaces, which spread the load and lowers PSI..
.
.
.
• Clearances have been reduced to the point that thicker oils can not get where needed. The
Honda Civic Hybrid and Insight have bearing clearances of just 0.0095 inches.
Funny thing is that both of those increase the drag of the bearing...so they are going to a thinner oil, predominantly for less drag, then having to reduce bearing effective pressures, and increase the shear rate to get protection back again.
Quote:
0W-20 BENEFITS:
• Engines are now designed with larger bearing surfaces, which spread the load and lowers PSI..
.
.
.
• Clearances have been reduced to the point that thicker oils can not get where needed. The
Honda Civic Hybrid and Insight have bearing clearances of just 0.0095 inches.
Funny thing is that both of those increase the drag of the bearing...so they are going to a thinner oil, predominantly for less drag, then having to reduce bearing effective pressures, and increase the shear rate to get protection back again.
0.0095 " bearing clearance is HUGE, not small.
.0095 is almost 10 thousandths of an inch. I believe the number is .00095. Even the older engines had bearing clearances between 1 and 2 thousandths of an inch.
This is the second resurection of this ancient thread.
Now, let's say that all of this is true.
What do we know now that we didn't know before?
We know that with reasonable drain intervals using an oil of suitable certs and grade, our engines will reach 200K without issue, in most cases.
We know that our engines wear, but we really don't care what causes that wear, since it is inevitable.
Would idling for fifteen seconds after start transform the engine into a machine virtually immune to wear?
I don't know, but I doubt it.
OTOH, there was a retired mechanic from California whom I haven't seen posting lately who was fond of saying that the car serves you, and you don't serve the car.
I don't think that you should start the beast and then floor it.
I do think that gentle driving provides a quicker warmup than idleing in the driveway.
I also think that the quoted material is long on theory and short on empirical evidence.
Now, let's say that all of this is true.
What do we know now that we didn't know before?
We know that with reasonable drain intervals using an oil of suitable certs and grade, our engines will reach 200K without issue, in most cases.
We know that our engines wear, but we really don't care what causes that wear, since it is inevitable.
Would idling for fifteen seconds after start transform the engine into a machine virtually immune to wear?
I don't know, but I doubt it.
OTOH, there was a retired mechanic from California whom I haven't seen posting lately who was fond of saying that the car serves you, and you don't serve the car.
I don't think that you should start the beast and then floor it.
I do think that gentle driving provides a quicker warmup than idleing in the driveway.
I also think that the quoted material is long on theory and short on empirical evidence.
Originally Posted By: JohnBrowning
I agree that more wear occurs at start up then any other time but do not belive in dry starts. First we have all of these fine AW additives that have been taken up by the metal. Then we have residual oil films on parts. Synthetics can cling to surfaces as long as a month compared to a few hours for non-synthetic.
Gone are the days of washing the cylinders with gas while trying to start the car. Gone are the days of haveing to run at a high RPM until the engine would idle. GOne are the days of haveing to rev the engine on cold start to keep it running. Most vechiles have full oil pressure in less then 15 seconds in the winter time with synthetics. They have possitve oil pressure almost imediatley.
I just do not buy all the drama about dry strarts!! It would be different if you had an unprimed pump and oil system and no AW additives!
My Hyundai's ECU revs the engine on startup to light the cats with fuel enrichment. [censored] greenies...
I agree that more wear occurs at start up then any other time but do not belive in dry starts. First we have all of these fine AW additives that have been taken up by the metal. Then we have residual oil films on parts. Synthetics can cling to surfaces as long as a month compared to a few hours for non-synthetic.
Gone are the days of washing the cylinders with gas while trying to start the car. Gone are the days of haveing to run at a high RPM until the engine would idle. GOne are the days of haveing to rev the engine on cold start to keep it running. Most vechiles have full oil pressure in less then 15 seconds in the winter time with synthetics. They have possitve oil pressure almost imediatley.
I just do not buy all the drama about dry strarts!! It would be different if you had an unprimed pump and oil system and no AW additives!
My Hyundai's ECU revs the engine on startup to light the cats with fuel enrichment. [censored] greenies...
Last edited:
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Startup wear=marketing propaganda
Originally Posted By: mechtech2
0.0095 " bearing clearance is HUGE, not small.
hahaha, I'm glad someone noticed! That was great for a laugh.
0.0095 " bearing clearance is HUGE, not small.
hahaha, I'm glad someone noticed! That was great for a laugh.
Originally Posted By: Shannow
Nope,
there's plenty of papers in the SAE that demonstrate a pre-warmed, pre-oiled engine will have a life extension of 2-4 times.
Agreed.
I've been taught (and believe) that a engine will benefit from easy driving/slight warm up until they get to operating temp.
Would love to read those though...
Nope,
there's plenty of papers in the SAE that demonstrate a pre-warmed, pre-oiled engine will have a life extension of 2-4 times.
Agreed.
I've been taught (and believe) that a engine will benefit from easy driving/slight warm up until they get to operating temp.
Would love to read those though...
FWIW, my Evo saw infrequent starts (usually sat for a few days, sometimes a few weeks) and relatively short trips, often 2 miles or less. Also, I didn't change the oil for over 2 years, due to the small number of miles put on it. Did a UOA after 2 years and 3000 miles; 2 Al, 6 Fe, 1 Pb. Averages were 3/9/2, also for 3000 miles intervals. So clearly just infrequent starts and short trips doesn't do it.
I do live in SoCal though, and I do let the car warm for 30 seconds or so before going. I also typically take it very gently until the needle hits halfway or so. So, from the data I have, I can only conclude that starts, even on an engine that's been sitting for days, does not cause too much wear by itself. I hypothesize that hard driving when the engine is cold does cause more wear. It always makes me cringe when people hammer their cars just after turning the key. Just because FI lets you do this, doesn't mean you should.
I do live in SoCal though, and I do let the car warm for 30 seconds or so before going. I also typically take it very gently until the needle hits halfway or so. So, from the data I have, I can only conclude that starts, even on an engine that's been sitting for days, does not cause too much wear by itself. I hypothesize that hard driving when the engine is cold does cause more wear. It always makes me cringe when people hammer their cars just after turning the key. Just because FI lets you do this, doesn't mean you should.
Some have said keep to around 1500rpm until the engine warms up before you tramp the accelerator.
Any way I let it warm for around 20secs before driving off to get the other fluids in the diff and auto-trans up and flowing as well.
Any way I let it warm for around 20secs before driving off to get the other fluids in the diff and auto-trans up and flowing as well.
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Keep it in a heated garage?
I guess if you have a transaxle it will warm a bit from shared heat?
I guess if you have a transaxle it will warm a bit from shared heat?
Originally Posted By: Shannow
How do you warm the diff ?
You know what I mean.
How do you warm the diff ?
You know what I mean.
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