Is 'most wear at startup' a myth?

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quote:
The viscosity IS too thick at start up. One of the mandates of the SM rated oil is to provide thinner oils for the start up period. This is not meaning for minus 30 degree weather but for normal everyday use at start up.
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Dr. Haas, you no doubt are the premier advocate of thinner weight oils at this site.
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How does the API SM service grade mandate thinner oils for the start-up period?

Low temperature (-30C to -40C) pumping viscosity is addressed by Sequence IIIGA with a ASTM D-4684 test run with the end-of-test sample from the Sequence IIIG test.

But the intent is to limit damage from oils that don't pump in very cold, subzero temperatures.

The SAE J300 viscosity chart remains the same for API SM.

Which Sequence or ASTM test are you referring to?
 
quote:
Wouldn't it make sense to make sure that ALL the oils are zero weight at low temperatures? That would prevent oil being TOO thick at startup?
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But then what do you do with cars that are actually taken to the track and get the snot run out of them? While simultaneously experience high oil temperatures (265dF)? Using oils with an HTHS number less than 3.6 would not lead to long life in these applications.

So, you can't make all oils that thin, but you can make a lot of oils thinner, decorate the shelves with these oils, and over time train owners that thinner oils are better for most uses.
 
SKUNKY: "AMEN...Like starter puck'en"

I've really enjoyed the seriousness of this discussion, but it reminds me a lot of similar theological discussions about how many angels can dance on the head of a pin.
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This is the API service sheet that states that one of the purposes of SM oils is better low temperature performance:

http://api-ep.api.org/filelibrary/API_MotorOilGuide_2004.pdf

Also, if I remember correctly the main study showed that a HTHS of 1.8 was sufficient using outdated oils not currently formulated. Thicker is not necessarily better. What is best is the appropriate thickness for the application.

aehaas

[ November 09, 2005, 08:02 AM: Message edited by: AEHaas ]
 
Since no apparent studies exist - what percentage of this "startup wear", specifically the wear from crank to full operating temperature is from actual cranking.

Question as it applies to installing a preoiler or not. No turbo. M1 Truck & SUV. Bypass filter. Parked outside. Offroading. Driven hard.

And - it depends on the tune.
 
Read this:
Effect of Break-In and Operating Conditions on Piston Ring and Cylinder Bore Wear in SI (Spark-Ignition) Engines, Schneider et al (from SAE):
The rate of wear is much higher within 15-20 minutes of start-up than after reaching normal operating temperature. The initial start-up time period (first 20 minutes) result is 100 nanometers of wear whereas the steady state wear rate was only 4 nanometers per hour thereafter.

Read the original article it may shock some people.

aehaas
 
That's why the high wear period is a lot more than cranking time. As for cranking, some Toyota's don't allow you to do anything except start the process. The brain runs the starter and turns it off when it determines the engine has started. The best way to get protection during the warmup period is through engine oil, and if the weather is really cold, then after synthetic oil, a garage and pan heater are the ticket. Driving habits help, too. In the end, the single best solution is, as Dr. Haas has said, thin is in.
 
Ya'll can discuss the physical and chemical technicalities forever, but boiled down to real life, isn't the best way to avoid undue startup wear is simply drive gently for the first 10-20 minutes (until temp comes up)? Limit RPM's to say, 3000, and not load the engine greatly. Old school says to warm up your engine in the driveway until the temp gauge comes up. New thinking says drive off right away, just take it easy until the temp comes up. We can make this complicated, but am I right in my asessement of what we can do as drivers to limit start up wear?
 
Here are the improvements as noted by API for the SM service grade:

Quote per API Shelf Card:

For all automotive engines currently in use. Introduced November 30, 2004, SM oils are designed to provide improved oxidation resistance, improved deposit protection, better wear protection, and better low-temperature performance over the life of the oil. Some SM oils may also meet the latest ILSAC specification and/or qualify as Energy Conserving.


I believe this statement is referencing the Sequence IIIGA MRV pumping requirement of 60,000 cP max for the appropriate -25C, -30C temp of the viscosity grade. This test is run with a end-of-test sample of oil from the Sequence IIIG test, 3600 rpm, and 150°C oil temperature for 100 hours.

If that’s the case, API is talking about the tendency of used, high mileage oil to thicken and it now cannot go beyond the 60,000 cP grade requirement during the life of the oil.

I think, from a practical standpoint, this requirement has little effect on oil viscosity at temps of 32F and higher.

In regard to reference links, here's a valuable one to bookmark:

SWRI Listing of GF-4 Test Sequences
 
drive gently for the first 10-20 minutes (until temp comes up)


That would be 70% of the motoring publics entire driving experience.

Most people only 'take it easy' until the coolant gets up to temp. That, due to emissions related modifications, has been shortened radically in the past 30 years (where you used to leave your car warming in the driveway). It still leaves a butt load of time in elevated wear.

Most people don't drive like that until they're middle aged or older ..sometimes not even then.
 
I would love to install a preoiler and bypass filtration system in my vehicles, but being honest about this, where the heck am I going to fit it under today's super crammed in there hoods?

My system is with a 1-2 minute warm up, then drive easy for the first 10 minutes, then drive as normal (or in my case, like a bat out of ....)!!!
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This is a great thread!
quote:
I just drive gently for 5 minutes, "normally" after that and avoid running the vehicle hard at all until ~20 minutes of operation. No extensive idling at start-up either. I start the vehicle and it idles just long enough for me to put on my safety belt, put everything in it's place and then I'm in gear driving away.
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I concur with Fastride:cheers:
"Dynamic warmups" save fuel and wear. The idea is to get the engine to operating temp ASAP. I figured this out when I got my first diesel. Diesels don't "warm up" much at idle, they just wash down the cylinder walls and contaminate the oil. Once you get oil pressure, off you go at a sedate pace. You had to be a little more careful in the olden days of motor oil. I remember some minus 45 degree startups (no block heater) where my old Land Rover's rocker arms were squeaking, even with a 10W-30 weight oil. It took a couple of minutes for that to stop and I couldn't bring myself to drive off until it did. I soon switched over to Amsoil, which was a young company then, at least while living in that winter wonderland. Gotta love synthetics in cold weather!
 
Jim Allen, that method might be OK for a naturally aspirated gasoline engine, but a turbocharged diesel is an engine of a different color. My Dodge has printed right on the driver's side sunvisor to let it idle for at least 30 seconds when it's below 68F!!! It also states longer is required as the temperature drops, to try to use the block heater at 40F to about 0F, and that it's a MUST at 0F and colder.

I'm not saying that you need to sit there for a full song on the radio, but a few extra seconds won't do that much more damage, but will help out the engine in the long run.
 
What would reduce wear more;

1. a block or oil pan heater.
2. Preoiler.

I vote for no. 1. Or option D, move to California.
 
I say #1. Pre-oiler has short-lived effect immediately upon startup while the heaters' effects last the whole way through the warmup phase. Better yet, move to the equator!
 
When it's cold out, the longest I let any of my engines idle after it's first start of the day is only a minute or two at the most. The exception to this is when I have to scrape ice, etc. I'll drive a "little lighter" than usual until the water temp hits 150 though. Letting a modern, fuel injected engine idle any longer than a couple of minutes is just wasting gas. They're designed to "start and go" compared to older carbureted engines. When the engine is hot or when it's warm outside, I'll wait until the fast idle comes down to normal, usually 10 seconds or so, then I put it in gear and go.
 
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