5w30? 5w40?

SonyAD

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silverbox said:
Sony, I take issue with your definitive statement "Only the very best 5w40 synthetics and the exceptional 0w40 synthetics provide a normal engine enough protection".
There are quite a few examples of Xw30 oil providing adequate protection on 1.9 and 2.0 TDI's. Check the Used Oil Analysis Database on this forum.
A good example is Total Ineo Mc3. Also Member Indego Blue Wagon Had great results going 20,000mi with Elf Full Tech.
These are both PAO Synthetic oils which may have had something to do with the good results.
You didn't include the qualifier:

Only the very best 5w40 synthetics and the exceptional 0w40 synthetics provide a normal engine enough protection (film strength and film thickness) in a HTHS environment. I don't think a 30 weight would cut it in my engine if I'm pushing 115 ~ 120°C oil temperature (at the sensor).

What is the HTHS viscosity of those w30 oils? Simply not enough. I remember reading somewhere that VW mandates a HTHS 3.5 or 3.6 (can't remember exactly) centipoise. That likely excludes any w30 oil from the get go.

Also, there are tolerances associated with any and all of an oil's specifications. Even if the Technical Data Sheet states a HTHS viscosity of 3.5 centipoise, it isn't necessarily exactly 3.5 in any and all jugs of that oil you might find at Walmart or wherever. There will be fluctuations. And 3.5 is already borderline or bellow, per what I've read.

I also use a PAO synthetic (supposedly fortified with group V polyol esters, at least that's what I read somewhere, either here or on BITOG - don't remember). Only it's a 5w40. And I'm not sure it would be enough to save the engine in the event of a HTHS situation.

I would love to see an 0w40 that leisurely ensures enough HTHS viscosity with shear down safety margins on top that don't get eaten through during the OCI. So far, only the John Deere Plus-50™, mentioned in another thread, fits the bill. But I'd like to see other people test on their own dime how well it stays in grade (doesn't shear down) before I bestow my "Sony's Oil of Choice" award on it.

Because anyone can just pour viscosity index improvers into a thin base stock. Not everyone can make an 0w40 oil with excellent VI / proper HTHS viscosity that neither shears down between oil changes.

No ACEA A1, A2, A5, B1, B2, B5 for me, thank you. I'll stick to oil that's thicker than cowpiss when push comes to shove.

T_D_I_POWER said:
It's a stress reliever. Radius and and chamfer corners have less stress than sharp ones.
Yes but the camfer makes it easier for oil to get out of the way of the advancing cam.
 
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T_D_I_POWER

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SonyAD said:
....
Yes but the chamfer makes it easier for oil to get out of the way of the advancing cam.
Then it will crack the cam right in the corners under high loading. Besides it'll not pass the stress analyses.

SonyAD said:
......unsupported camshaft bearings....
I am still not understanding with what you said. Can you clearify please
 

Dimitri16V

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T_D_I_POWER said:
I am still not understanding with what you said. Can you clearify please
you will find out when you pull the cam out ;)

Sony , you are in Romania , you can get M-1 5W-50. that should fit your description of robust oil.

BTW, why are there so many Americans in romania lately ? are you in the military ?
 
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T_D_I_POWER

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Dimitri16V said:
you will find out when you pull the cam out ;)
I don't need to. What he's saying doesn't make sense at all. Where and what part of the camshaft isn't supported?

A camshaft is very high loading component and has to be fully supported, end to end. Otherwise, there'll be large bending moment and it won't be able to open and close the valves properly.
Eah pair of cam lobes have a support bearing between them where the highest bending moment occurs.
 
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SonyAD

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silverbox said:
Sony what oil are you using?
3/4 Liqui Moly Diesel Synthoil 5w40 + 1/4 Liqui Moly MoS2 Leichtlauf 10w40.

T_D_I_POWER said:
Then it will crack the cam right in the corners under high loading. Besides it'll not pass the stress analyses.
Why would it crack on the edges? The cams are quite thin without the camfering.

T_D_I_POWER said:
I am still not understanding with what you said. Can you clearify please
The net force on the camshaft (vertically speaking) is downward.

See pics in

http://forums.tdiclub.com/showthread.php?t=172713

and

http://forums.tdiclub.com/showthread.php?t=253137

and

http://forums.tdiclub.com/showthread.php?t=241279

For what the camshaft lower half-bearings sit, rather precariously, on.

Dimitri16V said:
you will find out when you pull the cam out ;)

Sony , you are in Romania , you can get M-1 5W-50. that should fit your description of robust oil.
I thought about Ravenol RRS 5w50 for this summer but I've yet to find a 5w50 carried anywhere at decent prices and the ideea of changing oil with the seasons doesn't appeal to me. It's overkill even for summer.

All I want is a 5w40 (or 0w40) with a HTHS viscosity around 4.0 cP guaranteed not (just) to stay in grade but maintain HTHS viscosity for a meagre 6500 miles of arduous and persistent abuse.

I thought I read that the John Deere Plus-50™ has a HTHS viscosity of around 4.0 in that other thread. I was quite excited.

Then I read the stats again and saw it only had 3.75 cP HTHV. So I'll just continue using my 5w40 (of unspecified HTHS viscosity) and hope for the best.

Dimitri16V said:
BTW, why are there so many Americans in romania lately ? are you in the military ?
No.

PS: If I drove a flat tappet engined car I would run nothing but 5w50 and friction modifier/dry lubricant additives for the startup wear. The real McCoy, not 2+2, Duralube, PTFE, whatever.
 
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Bob_Fout

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Sony, the only 5w40 or 0w40 with an HTHS of 4.0 I have seen are API oils.
 

T_D_I_POWER

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SonyAD said:
....
Why would it crack on the edges? The cams are quite thin without the chamfering......
You meant the bearing shell. W/o the chamfering, very likely it'll start to crack in the 4 corners, not on the sides
 
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SonyAD

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What corners? I meant the bevelling on the edges of the cam, not the half bearings.

About the camshaft bearings I was saying the lower half are unsupported. Well not completely, but under much of their surface. This would not be a big deal were these not PD engines, where the camshaft is pressed down into the lower half-bearings by the prevailing force of the unit injector rocker arms.

In most other OHC flat tappet/tappet under cam engines, the prevailing force on the camshaft would be upward, due to the valves' return springs so this wouldn't be an issue, I think. And the force would be lower than the resistance the unit injectors exert on the cam through the roller rockers.
 

Bob_Fout

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Bob_Fout said:
Sony, the only 5w40 or 0w40 with an HTHS of 4.0 I have seen are API oils.
I thought about this some more, and ACEA E-series 0w40 and 5w40 might have such HTHS too.
 

RalphVa

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The specs for 30w are 9.3-12.5 cS at 100 C and 2.9 cS min at 150 C. I could run the calculation to see if it'd be above 3.6 cS at 120 C, but think it's a safe bet that it is. These are the current SAE J300 specs. The min spec for 40w is 3.7 at 150 C.
 

Dimitri16V

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I don't think a 30 weight would cut it in my engine if I'm pushing 115 ~ 120°C oil temperature (at the sensor).
has anybody measured that ? if PDs run that that high oil temps , it is a cause of concern
 

SonyAD

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Gassers certainly do. I saw it on my friend's 407 1.8i this winter. Square at 115°C and it was well bellow freezing. Might have gone even higher but that's what I happenned to see. Pretty sure it goes higher than that in the summer. He doesn't know how high it's ever been, says he doesn't watch it.

I think all OBD2 engines have oil temperature and oil pressure sensors, it's just that few also have gauges on the dash. The 407 happens to have an oil temperature gauge.

It's only 11:1 compression but it's naturally aspirated whereas all ours are turbo. 16v, likewise bucket tappet under cam.

RalphVa said:
The specs for 30w are 9.3-12.5 cS at 100 C and 2.9 cS min at 150 C. I could run the calculation to see if it'd be above 3.6 cS at 120 C, but think it's a safe bet that it is. These are the current SAE J300 specs. The min spec for 40w is 3.7 at 150 C.
Not to plug LM in or anything but here is a low SAPS, slightly thinner oil than what I use, from the same manufacturer:

Top Tec 4100 5w40

They don't state the HTHS viscosity for my particular oil so I can only assume, from higher 40°C & 100°C viscosities and same VI, that it's more than the oil above's.

"High temperature/High shear viscosity : 3.5 m.Pa.s CEC CL-23." So above 4 cS.

I thought I remembered the Porsche minimum recommended HTHS viscosity as being 3.5 or 3.6 cP whereas it seems it's actually 3.5 cS.

However, my outdated CR turbodiesel develops 205 Nm (151 lb-ft) at 1750 ~ 2000 rpm whereas my mate's 1.8i develops 170 Nm (129 lb-ft) at 3750 rpm. It's the film strength that has to pick up the slack.
 
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Dimitri16V

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my Scirocco in stock form used to hit 120-130C in summer. Swapped a twin fan from a 16V Passat , a lower temp fan switch and I have not seen anything above 100C even in 100F days.
Constant 120C oil temps will create too much varnish in the enine , seen it on VR6s and 1.8Ts
 

RalphVa

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Those SAE J300 specs for 150 C I mentioned are cP. You divide by the s.g. to get cS. This would make them a bit higher, since the s.g. is probably about 0.8-0.9.
 

tdijerry

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donDavide said:
Since when did WAL-MART stop carrying M1-TDT? 2 near me and both have it. It is 21 inch michelin wiper blade i \have a hard time gettiing , I had to go 3 differnt ones
walmart here doesn'e even carry the mobil 1 0w40 or the mobil 1 5w40. :(
 

TornadoRed

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tdijerry said:
walmart here doesn'e even carry the mobil 1 0w40 or the mobil 1 5w40. :(
Many of them don't. Only the largest Walmarts with the full auto service departments, and then not even all of them. Then again, some smaller ones randomly have it.
 

Dimitri16V

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tdijerry said:
walmart here doesn'e even carry the mobil 1 0w40 or the mobil 1 5w40. :(
the ones here in DE and MD had a lot during the holidays , now it's all TSUV 5W-30 . They still have 0W-40 in qts , never seen it in jugs.
 

eddif

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T_D_I_POWER said:
I don't need to. What he's saying doesn't make sense at all. Where and what part of the camshaft isn't supported?

A camshaft is very high loading component and has to be fully supported, end to end. Otherwise, there'll be large bending moment and it won't be able to open and close the valves properly.
Eah pair of cam lobes have a support bearing between them where the highest bending moment occurs.
This is a great lube thread.

There may have been more hints as to physically what we are trying to overcome. Dimitri16V hinted at the design. NowT D I POWER is talking about operation. Oil formulation can solve a lot of problems and you guys have done an excellent job on lubrication. I do not wish to try and turn this into a cam bearing thread.

It is my opinion, that we can identify the forces that cause the cam not settle down into the bearings. The cantilever forces plus the friction climbing on #! cam bearing cause the cam to not sit down in the bearings as much as possible. No oil, other than a super low viscosity oil can reduce the cantilever forces on the bearings. No oil but a high viscosity oil can overcome the lack of supported bearing area at 4,500 RPM WOT making 26,000 psi injection pressure. These two situations are in conflict. How do you find a oil that will address both those issues at the same time?

You have covered the normal engine needs very well. How do you address the mechanical needs of our special PD engine? It takes both an engine designer and a lubrication formulator to overcome some problems. A broken bone needs to be set before correct healing can begin. All the foods in the world, that lead to bone growth, can not set the bone.

Many tears have been shed over this design.

eddif
 
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