80% Wear Startup Shouldn't MRV Be Most Important?

[Fallguy]

How much can oils with better MRV numbers reduce startup wear vs oils in the same with higher MRV.

Say a one with 10,000 vs 15,000 MRV in the same grade.

Understand there would be better wear numbers or some advantage at low temps
but would there be any significant advantage or wear reductions on say startups at 40f+

 

[1JZ_E46]

Unfortunately many companies don’t list MRV, or if they do they just list the SAE max. I’ve always looked at pour point and KV40 for startup performance within a given grade.

 

[Shannow]

Not really...at 40F, the "W" rating has nothing to do with gallery filling.

And Gallery filling has nothing to do with startup wear at 40F and above.

 

[SonofJoe]

Agree with Shannow. Wear advantage for lower MRV is zip. Also didn't this 'x% of wear occurs in the first few minutes of start-up' come from some dodgy Greek scientist whose work has been discredited?

 

[Shannow]

Joe,
not sure of the greek guy...but the "80% occurs at startup" is incorrect for sure.
It's really

"As much wear occurs in the first 20 minutes of operation as the next number of hours" is more appropriate.

Cold, oil fully circulating, with components in their cold shapes, additives below activation temperatures, and the blowby gasses condensing leading to more "wear" as well as corrosion

 

[Patman]

^^^ I agree, I have always felt that the entire warm up process is where most of the wear is taking place. That's why I try to be very gentle with the throttle in my cars until the oil reaches normal operating temperature.

 

[ragtoplvr]

I want the warmup process to be as short as possible. I drive normally never open the throttle more than one third, and leave the heater off if possible until the water reaches 190F. Makes a difference in fuel consumed also. I have electric seats, big help. On a typical 20 degree morning not running the heater I reach 190 f in 3 to 4 miles. Running the heater it takes 5 to 10 miles depending on outside temp. Another experiment in winter on a trip, I leave the motel and get on the interstate, with heater off reached normal temp in 5 miles at 70 for a 5 or 6 minute warmup. With heater on it was 15 miles before the water reached 190. This is motels beside the interstate, minimal running to reach the on ramp. I was lucky the windows were frost free.

Rod

 

[4WD]

Originally Posted By: 1JZ_E46
Unfortunately many companies don’t list MRV, or if they do they just list the SAE max. I’ve always looked at pour point and KV40 for startup performance within a given grade.


Or like Mobil they tend to list it only for the 0W formulas … most 15W50 clients are not very conversant in rotational tests at temperatures some of us chose not to live in …

(Then the OEM hands me 0W20 anyway

)

 

[bumpasmerc]

Originally Posted By: Shannow
Joe,
not sure of the greek guy...but the "80% occurs at startup" is incorrect for sure.
It's really

"As much wear occurs in the first 20 minutes of operation as the next number of hours" is more appropriate.

Cold, oil fully circulating, with components in their cold shapes, additives below activation temperatures, and the blowby gasses condensing leading to more "wear" as well as corrosion



I would like to learn about two subjects you mention:

- could you give an example of an engine component in it's cold shape, that is particularly vulnerable to wear when the engine oil is cold.

- could you elaborate on activation temperatures for additives. I was not aware that additives needed heat to be activated.

Several owners manuals that I have had advise not allowing the engine to warm up at idle before driving off. They advise just start and go with light throttle. I am wondering if this advise is prompted by mandated fuel mileage targets and environmental concerns rather than what's best for the engine as far as wear is concerned.

 

[4WD]

Bet pistons are near the TDC of the list

 

[Ducked]

Originally Posted By: bumpasmerc

Several owners manuals that I have had advise not allowing the engine to warm up at idle before driving off. They advise just start and go with light throttle. I am wondering if this advise is prompted by mandated fuel mileage targets and environmental concerns rather than what's best for the engine as far as wear is concerned.


I'd speculate that this advice might be partly motivated by them telling you what they think you want to hear. A happy customer is a repeat customer.

 

[kschachn]

Originally Posted By: Ducked
Originally Posted By: bumpasmerc
Several owners manuals that I have had advise not allowing the engine to warm up at idle before driving off. They advise just start and go with light throttle. I am wondering if this advise is prompted by mandated fuel mileage targets and environmental concerns rather than what's best for the engine as far as wear is concerned.

I'd speculate that this advice might be partly motivated by them telling you what they think you want to hear. A happy customer is a repeat customer.

Or that's the quickest way to get your oil warmed up and is most beneficial for the engine in the long run, and will result in maximum longevity.

 

[Patman]

Originally Posted By: ragtoplvr
I want the warmup process to be as short as possible. I drive normally never open the throttle more than one third, and leave the heater off if possible until the water reaches 190F. Makes a difference in fuel consumed also. I have electric seats, big help. On a typical 20 degree morning not running the heater I reach 190 f in 3 to 4 miles.


I took the Corvette to work this morning and it was only 26F. I noticed that in less than 5 miles the coolant got up to 90C (194F) and less than a minute later the oil temperature caught up to it. So even though it's a bigger engine with a bigger cooling system and more oil in the sump, it still warms up much quicker than my Civic does. I actually didn't turn the heater off though, I left the auto setting to 22C. I did help it along a little bit by using the paddle shifters and holding the rpm closer to 2000 (compared to if I left it in drive it would choose a higher gear and the rpms would be under 1500)

 

[bullwinkle]

Originally Posted By: 4WD
Bet pistons are near the TDC of the list

And wrist pins would be right there too (unless piston expansion takes care of that too), along with valvetrain components (lifters/followers). That's where most of my cold racket comes from-nurse it until it quiets down, then off to the races!

 

[paulri]

Not too sure what ethnicity AEHaas was, but he reviewed one of those $28 SAE papers that showed that most wear does occur at startup: https://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=923479

This particular study had some 95% of the wear occur in the first 15-20 minutes, compared to one hour of wear after that initial warmup period. Roughly, 20 times the amount of wear in that initial startup, compared to an hour of driving at operating temperatures.


Originally Posted By: SonofJoe
Agree with Shannow. Wear advantage for lower MRV is zip. Also didn't this 'x% of wear occurs in the first few minutes of start-up' come from some dodgy Greek scientist whose work has been discredited?

 

[1JZ_E46]

Originally Posted By: ragtoplvr
I want the warmup process to be as short as possible. I drive normally never open the throttle more than one third, and leave the heater off if possible until the water reaches 190F. Makes a difference in fuel consumed also. I have electric seats, big help. On a typical 20 degree morning not running the heater I reach 190 f in 3 to 4 miles. Running the heater it takes 5 to 10 miles depending on outside temp. Another experiment in winter on a trip, I leave the motel and get on the interstate, with heater off reached normal temp in 5 miles at 70 for a 5 or 6 minute warmup. With heater on it was 15 miles before the water reached 190. This is motels beside the interstate, minimal running to reach the on ramp. I was lucky the windows were frost free.

Rod


I let my V8 idle for 5 minutes every morning. I hate driving in a cold car. It’s recent UOA test showed wear metals were extremely low.

 

[BrocLuno]

The start-up wear occurs because of residual oil film strength and people going slow so the crank can't sling enough oil to lube the cylinder walls (they are never, ever lubed by pumped oil ...). MRV means almost nothing to pistons, rings and cylinder walls. Residual film means the most

I've changed computers, so do not have access to my SAE 30 vs multi-grade chart/image, but it clearly shows a solid single grade having by far the lowest wear at start-up. It's all oil and no exotic chemistries to "help" flow. Of course it does not work well for many in the rust belt. But for aviation, marine and temperate climate users, it's the norm and way to go for reduced wear

 

[4WD]

Taxi drivers and LEO’s idle for hours … must mean 800 RPM at idle can sling … and engines with piston jets (no longer limited to exotic or fast cars, my Tahoe has them) get a little bonus that way …

So, thicker = cling and thinner = sling ? … can 0w40 do that ?
My driver did 745k on Mobil 1 0w40 plus spending untold hours at idle as well …

 

[kschachn]

Originally Posted By: BrocLuno
I've changed computers, so do not have access to my SAE 30 vs multi-grade chart/image, but it clearly shows a solid single grade having by far the lowest wear at start-up. It's all oil and no exotic chemistries to "help" flow. Of course it does not work well for many in the rust belt. But for aviation, marine and temperate climate users, it's the norm and way to go for reduced wear

I have no idea about marine users, but that's not the reason general aviation uses monograde oils.

 

[4WD]

Originally Posted By: kschachn
Originally Posted By: BrocLuno
I've changed computers, so do not have access to my SAE 30 vs multi-grade chart/image, but it clearly shows a solid single grade having by far the lowest wear at start-up. It's all oil and no exotic chemistries to "help" flow. Of course it does not work well for many in the rust belt. But for aviation, marine and temperate climate users, it's the norm and way to go for reduced wear

I have no idea about marine users, but that's not the reason general aviation uses monograde oils.


We run 7000 -12000 HP marine engines on 15w40 with a 15 TBN … the modern engines run clean and all the fuel is going low sulfur even for the big consumption motors …