Thicker oil for performance ?

[chrisri]

Hi CATERHAM.
I'm not sure OP is only thing to consider when we choose motor oil. Do you think that A1 oil with it's low HTHS is good enough when car is spec'd for A3 oils? 0w30 grade should be fine, just i'm not sure about A1 oil for this application.

 

[vintageant]

Originally Posted By: CATERHAM
I'm sure you mean 250F which is 121C.


Thanks, Caterham! I could be a smart Aleck and say something like I was waiting to see if anybody would notice, but truth is, yes, I goofed and it was 250 F / 121C.

Still a little warmer than we liked

 

[SwampSurvivor]

Originally Posted By: brandini
Use the thinnest oil you can that when fully hot still reaches that oil pressure target.


Agreed!

 

[CATERHAM]

Originally Posted By: chrisri
Hi CATERHAM.
I'm not sure OP is only thing to consider when we choose motor oil. Do you think that A1 oil with it's low HTHS is good enough when car is spec'd for A3 oils? 0w30 grade should be fine, just i'm not sure about A1 oil for this application.

A common misconception.
Yes an engine requires a minimum HTHSV (sometimes referred to as bearing viscosity which oil pressure correlates to) but it's not the HTHS rating of an oil that's measured at 150C that's important it's the maximum oil temp's in service that's the main limiting factor how high a HTHSV rating is necessary.

You saw the original recommended oil grades that were spec'd for this engine I posted on page one of this thread where even a 20 grade oil (HTHSV 2.6cP) is specified for ambient temp's generally not exceeding 70F? Now while ambient temp's do limit maximum oil temp's, oil pressure (an OP gauge is an viscosity meter) is an actual measure of operational viscosity and is therefore much more accurate.

We know 45 psi @ 2,000 represents a safe minimum OP for this engine. The lightest oil in terms of it's HTHSV rating that allows this minimum OP at normal hot operating temp's is the heaviest oil that's required. Anything more represents excess viscosity offering no additional protection just increased oil drag.

 

[Cristobal]

Originally Posted By: Dogan
thank you all for answers.
i'm living in Yalova which never see -10 in winter and never above than 37C in summer.

...

and 10w-40 is balanced it think.






I looked on the map and at Yalova you are fine using 10W-40 the year round, unless you travel a long way into the middle of Anatolia in winter. Even then, only a real cold snap would give you trouble starting your motor.

 

[Dogan]

i think 10w grade won't give me trouble because in my city last cold winter never see below than -7

caterham said check your oil pressure, good idea
but my car doesnt has OP gauge, it has a oil indicator, if something wrong it lights red. i never see it lighted while driving.
only red while starting up, after this nothing.

i have my car manual, you can see oil table picture and 50 grade oil, i think my oil pump is good enough pump 40grade oil if recommended 50grade.
i don't know how is it work but maybe its about oil pressure.

 

[Shannow]

Originally Posted By: CATERHAM
You saw the original recommended oil grades that were spec'd for this engine I posted on page one of this thread where even a 20 grade oil (HTHSV 2.6cP) is specified for ambient temp's generally not exceeding 70F?


Originally Posted By: CATERHAM
My first car as a kid was a Ford Capri with the same 2L engine.
All grades were recommended based on ambient temp's:
20W-20 up to 70F
10W-30 up to 70F
30 grade up to 90F
10W-40 up to 90F
40 grade 50F to 120F


Given that the 20W20 was/is Newtonian, and had an HTHS of 3 or greater, back in the day when such was specified (below) 70F, it's a bit disingenuous to claim that the Ford OHC was specified for a 2.6 HTHS oil.

As you well know (history lesson again), HTHS was not included in J300 until the late 80s, and included only as a result of poor performance of the early multigrades.

the 20W20 that you lay claim to proving the 2.6HTHS is in actuality an oil that you would label as "clearly a 30", and the straight 30 specified up to 90F is really representative of a modern A3/B3/B4, xW30 grade.

 

[CATERHAM]

You're the right HTHS viscosity measure hadn't been developed yet back in the 60s and early 70s but the SAE grades had a KV100 range just as they do today and there would have been 20W-20 oils at the lighter end of the spectrum.
You'll note that the 20W-20 had the same maximum temp limit as the 10W-30 of the day, the worst examples of which were very shear prone. I'm willing to bet that a modern PCMO 10W-30 (even a 5W-30) with a HTHSV in the 3.0-3.1cP range would have allowed a maximum ambient temp' on par with the lighter straight 30 grades of the day.
Once again you're interpreting things through your thick oil bias.

 

[CATERHAM]

Originally Posted By: Shannow
How would he get such a test done CATERHAM ?

As you've pointed out me before, simply pulling off the road/track changes the oil temperature markedly, so by the time he gets to a shop, has the gear installed, and engine restarted, he's running a completely different oil viscosity to that he'd see in normal service.

I'm flattered that you remember some of the practical points that I've made regarding operational viscosity.

Yes driving flat out for an extended period of time will of course maximize bulk sump oil temp's and the moment you lift (your foot of the gas) oil temp's will quickly start to fall back towards the hot end of normal.
But the thing to remember about the factory OP test spec's is that the low end of normal operating temp's is what they are generally provided at. In some cases they will actually give a specific oil temperature. With Porsche it's at a rather low 80C.
So for cars not equipped with their own OP gauge, having your OP checked at the shop (or borrowing a gauge and doing it yourself) will tell you how much viscosity reserve you have with the particular oil your using vs the test spec'.
At higher than normal oil temp's your OP will be lower, possibly lower than the test spec' but that doesn't mean the oil is too light.

In this case our friend says he doesn't use high rev's a lot so I suspect as with most drivers he won't be seeing oil temp's much higher than normal. Knowing what you're oil pressure is vs the test spec' is a very useful piece of information to use in deciding on what oil grade to use. He could also take the temperature of the oil at the tip of the dip stick with an IR temperature gun as a point of reference. Again the more info' one has the better.

 

[Shannow]

Originally Posted By: CATERHAM
I'm willing to bet that a modern PCMO 10W-30 (even a 5W-30) with a HTHSV in the 3.0-3.1cP range would have allowed a maximum ambient temp' on par with the lighter straight 30 grades of the day.


I'd tend to agree with you...

Originally Posted By: CATERHAM
Once again you're interpreting things through your thick oil bias.


Calls to mind something about pots and kettles...your reference to 20W20 being a 2.6 HTHS is clearly demonstrative of how you interpret the world through your choice of eyewear...

http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/2569050/Re:_Red_Line_5w20,_20K_miles,_#Post2569050

 

[Shannow]

Originally Posted By: CATERHAM
Originally Posted By: Shannow
Given that it's oval track...AND you get reasonably unpressured pitstops, I think you can ditch an instantaneous oil temperature reading, and with get/borrow an IR temperature guage, and check the sump temperature after a run...could drop the thermocouple from a cheap multimeter down the dipstick tube for a check. Sooner after the run the better.

You want a proper oil temp' gauge, that's the only way to know what maximum oil temp's you're seeing under full throttle conditions on the track. The moment you lift you can see the oil temp's drop start to drop immediately if the oil temp's are well above the normal base line. And after a cool down lap and finally pitting and getting around to measuring your oil temp's with an IR temp' reader, your oil temp's could easily have dropped to normal; not much use in that.


http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/3286196/Re:_Need_an_oil_recommendation#Post3286196

So which is it ?

Or was I wrong at the time because I don't agree implicitly with your "science" ?

 

[CATERHAM]

I appreciate you have no racing experience but yes you're obviously wrong and I'm surprised you'd want to bring it up again.

I also suggest with your interest in motor oil that you install oil gauges in your daily driver and then you may be able to explain to me (not to mention yourself) why you feel the need to run a grade or two heavier oil than specified.

 

[Shannow]

Originally Posted By: CATERHAM
why you feel the need to run a grade or two heavier oil than specified.


Where and in what vehicle ?