Just got my email Noria "Lube Tips." The following is in it:

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Today's Tip: Rule of Thumb for Selecting Oils

The pour point is the lowest temperature at which an oil will flow. This property is crucial for oils that must flow at low temperatures. A commonly used rule of thumb when selecting oils is to ensure that the pour point is at least 10 degrees C (20 degrees F) below the lowest anticipated ambient temperature.

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This is good in that pour point is the only cold property comparable across different "w" grades of oil. Cold cranking and cold pumping are both measured at different temperatures for different "w" numbers. However, I frequently have heard that pour point is not a good indicator of cold performance, nor is cold cranking the best, but to focus on cold pumping, specifically the mini rotary viscometer (MRV) parameter.

Also, I have heard that pour point is typically acheived by adding pour point depressants to prevent wax crystalization (which is why synthetic is so good--no waxes), but that cold tempertures cause a depletion of the pour point function. So then, does the pour point deteriorated with use and sitting in the crankcase in the cold? If so, should one rather look for an oil that is maybe 20C lower pour point than the lowest expected temperature?

Tallpaul

Is it good to go for too low?

M1 0W40 & 15W50 Motorsport are only products available in UK, so must cover UK oil requiements.

However I have wondered whether a say a 15W40 may give better protection over flow on start up in view of the following.
• 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.

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However I have wondered whether a say a 15W40 may give better protection over flow on start

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No.

Callisa

Any reason?

Information on BITOG suggests 10W30 oils have lower wear numbers than 0W30

NAPA 15w50 synthetic (probably gp III) has a pour point of -33C. So by this article, I could run it here in Detroit as we rarely get below zero F, although maybe this winter will prove that statement wrong as it is going into single digits (F) tomorrow night here! Howevere I think that 10C above pour point is an absolute minimum type of rule of thumb, not something to flirt with.

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Information on BITOG suggests 10W30 oils have lower wear numbers than 0W30

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I bet that in this test not the same additive packages were compared with each other, or that the conditions for both oils were different.
To compare "10W-30" against "0W-30" without exact knowledge of the oil formulations is a dead end.

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NAPA 15w50 synthetic (probably gp III) has a pour point of -33C. So by this article, I could run it here in Detroit as we rarely get below zero F

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Read SAE Paper 2004-01-1932 "In-Service Low Temperature Pumpability of Crankcase Lubricants- Effect of Viscosity Modifiers"
Pourpoint is not everything for cold start.

I have seen a reference to 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.
Engine wear is not so much mechanical as it is corrosive (H2SO3 and H2SO4 in case of sulfur), at least for cylinder/rings.

There are probably minute differences between say 0W30 or 10W30 oils, while the facts with the greatest impact like fuel quality, combustion kinetics, ambient temp, warming up styles, and driving distances get relatively little attention, but these facts we cannot control.

So the rule of thumb looks an easy way to pick the right oil, or is there a better way to make a choice.

In the UK I could use a 15W40 or 0W40, which is best choice to maximise protection.

MGBV8:
I'm trying to figure out where on BITOG you picked up an absolute rule about 10W30 showing less wear compared to 0W30 grades. Certainly 0W30 GC and Mobil's Saab turbo 0W30 have very good reputations there.

The question of whether a 15W40 or a 0W40 provides the greatest protection depends on the oils in question and the application. I'm very uncomfortable using 15W40 in gas applications below freezing, and certainly below 20 degrees F.

In reference to the orginal post, I agree that MRV and cranking numbers are far more useful than pout point. I suspect that most cold weather oil selection can be done simply by grade anyway, and the pour point numbers, when comparing group IV synthetics, are mostly marketing gimmicks.

http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=1;t=009001

Analysis from information
Viscosity Avg Wtd Fe Avg Wtd Al
10W-30 552 1842
5W-30 517 1836
0W-30 384 1707
5W-20 365 1626
0W-20 186* 848*


As I drive classic cars from 1970 era, the manual will state a 20W50 mineral and 3K or 3 month changes. My normal road car is a modified Rover V8 with 300bhp run with Holley carb. In addition other engines are 1275cc A Engine and 1.8 B engine, all set up for fast road use.

Oil choice can range from
Castrol GTX mineral 15W40
Castrol Magnatec 15W40
Motul 300V
5W40 4.51
15W50 5.33
Silkolene PRO S 5w-40 = 4.07cp
Silkolene PRO S 10w-50 = 5.11cp
Silkolene PRO R 15w-50 = 5.23cp
M1
0W40 3.6
15W50 5.11
Millers 10W60 being used on race car

Thanks for helping me understand where you got the 0w30 v. 10w30 thing. I would say that 0w30's were handicapped by a lower number of samples and no temperature correlation in that BITOG thread.


If I were you...in "summer" weather...I would think the M1 and Motul 15w50 would be awesome choices. I have too little experence with Silkolene to reccomend it....but I've heard only good about it. In cold weather...the M1 0W40 seems to be the standout from your choices.

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Engine wear is not so much mechanical as it is corrosive (H2SO3 and H2SO4 in case of sulfur), at least for cylinder/rings.

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That's only partly true. Wear at cylinder wall / piston rings may also rise with high load / insufficient oil quality.
Extreme changing load conditions high load / idling / high load provokes a lot of wear, too.
Steady state high rev high load is not that severe.

How long should a person warm up their vehicle before moving it in my environment?

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MGBV8wear was strongly associated with the amount of sulfur in the fuel.
Engine wear is not so much mechanical as it is corrosive (H2SO3 and H2SO4 in case of sulfur), at least for cylinder/rings.

There are probably minute differences between say 0W30 or 10W30 oils, while the facts with the greatest impact like fuel quality, combustion kinetics, ambient temp, warming up styles, and driving distances get relatively little attention, but these facts we cannot control.

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Winter here now and many days are -20C [-4F]

I crank my car over and by the time it starts im already letting out the clutch to back out of the driveway. i don't like to wake the little woman. he he
To warm up I just poke down the street for about 400m[1/4m] at low rpm "just above idle" until I get on the main drag then drive at normal.

Engine block heater...
05-40 Shell syn.
Run PetroCanada 87 octane gas.
I drive 100kms to work one way.

In UK I let idle until full oil pressure then move off.

This is Shell Canada view with temperatures well below any I am used to in UK

http://www.shell.ca/code/motoring/tips/engines.html

Driving distance
If 90% of wear is on start up then there would be approx same wear for a journey of 10miles as one of 500miles.

Callisa

Hard acceleration may produce wear but its fun
Callisa

insufficient oil quality.
Can you expand on this comment

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Hard acceleration may produce wear but its fun

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My thoughts exactly. So now I am wondering how start up wear compares to hard acceleration wear. Maybe this startup wear is not so big an issue except for the person who babys their car.

I like to drive it hard (within reason) and I think that helps keep it running right. For example, wife's '92 Aerostar 3.0 was doing a lot of short trips (only 2400 miles in 6 months) and idling. Had developed a pretty nasty knock that even 93 octane would not eliminate. Then I did an Italian Tuneup. Took it out for an 80 mph 3rd gear drive, turning 4000 rpm for 20 miles with numerous 5000 rpm bursts (much fun). Wow! now just a little occasional knocking on the 87 octane.

The question is what kills an engine, for example, VW injectors could be worn by 80k miles killing bores by 150k, not an oil related problem.
However "dirty oil" can kill an engine but is this not deposits from mineral or a semi on longer OCI. Synthetics avoid these problems and with M1 could add an extra 5% peak bhp and thats without esters.

Ok lets see what we got here...

Shell Point 1]...I don't rev the engine, I usually drive at lowest rpms in highest gear but I don't let engine lug.

Shell Point 2]...I don't rev the engine before shutting off. I have a bad habit of shutting engine off before the car is stopped. old habit from sneaking into my ex girlfriend's parents backlane to pick her up....he he

Shell Point 3]...I timed it this morning as I was going to work. Start, drive down street to drive thru coffee shop, drive to highway....9 minutes before I reached 120km/h. The temp needle is near operating range.

As far as babying car, I think im in "slight abuse" category, in the am there are no cops on the highway except for monday so I run at 120~140 km/h. he he 3400~4100 rpms. he he he

I only measure speed from Rev counter, for V8 at 3k 84mph at 4k 112mph, rev limiter 6.5k

I would imagine wear is not an issue cruising at 3-4k. However above that then fuel could be an issue as potentially either running rich or leaning out.

Most wear is likely to be at start up, then 1st gear burn up from standing start, cruising minimal, flat out possible wear.

For most road cars start up must produce highest wear.

Is Castrol Start Up worth the money without changing to a Synthetic?

Also, harsh speed changes (and especially with a manual transmission) cause the crankshaft to shift longitudnally in the block. This may be why one main bearing has a side thrust bearing surface.