Recent Topics
Pennzoil Platinum at Walmart
by TheLawnRanger
Yesterday at 11:21 PM
Mopar OEM and Fram Ultra Oil filters, '18 Jeep JL
by IndyFan
Yesterday at 10:45 PM
What’s the odds..
by Eric Smith
Yesterday at 09:51 PM
Who can relate?
by Reddy45
Yesterday at 09:43 PM
No more oil changes
by goodtimes
Yesterday at 09:19 PM
Separating toddlers from their parents?
by fdcg27
Yesterday at 08:50 PM
gm 8.6 truetrac
by Spitter
Yesterday at 08:45 PM
New addition to my garage: 2000 Corvette FRC
by MrHorspwer
Yesterday at 08:34 PM
Rockauto 5% off
by Spitter
Yesterday at 08:32 PM
fumoto oil valve
by Santo
Yesterday at 08:19 PM
Grand solar minimum...
by ridgerunner
Yesterday at 07:57 PM
Pentofrost coolant $10 Autozone
by PD001
Yesterday at 07:49 PM
The things you find cleaning Garage 30+ btls slob
by digger327
Yesterday at 07:20 PM
Castrol GTX Magantec 0w20 - 6 pack $21.99 - Amazon
by 04SE
Yesterday at 07:07 PM
Havoline Pro DS 5w20 $3.15/quart - Amazon
by 04SE
Yesterday at 07:06 PM
Needing New Dipstick
by Geauxtiger
Yesterday at 05:11 PM
'98 Mercedes E300TD Rotella T5 10W-30 5k miles
by KenO
Yesterday at 04:35 PM
Premium guard oil filters
by Jaha24k
Yesterday at 04:09 PM
76 super motor oil- synthetic blend 5w-30
by Jaha24k
Yesterday at 04:07 PM
Who makes the Mopar 5038041AA filter?
by Quattro Pete
Yesterday at 03:55 PM
Newest Members
Shassis, Santo, aligoodn, memyself, MichiganKid419
65274 Registered Users
Who's Online
15 registered (boom10ful, Brad_C, BusyLittleShop, ctechbob, Astro14, Black, 1 invisible), 787 Guests and 35 Spiders online.
Key: Admin, Global Mod, Mod
Forum Stats
65274 Members
67 Forums
285629 Topics
4766665 Posts

Max Online: 3590 @ 01/24/17 08:07 PM
Donate to BITOG
Page 1 of 3 1 2 3 >
Topic Options
#4472692 - 07/28/17 06:34 AM Oil shear ?
Camprunner Offline


Registered: 02/19/08
Posts: 1034
Loc: MA.
If an oil inside a motor shears down a grade is it still protecting at that level or is the oil and add pack compromised to a point where the oil is not lubracating properly?

Top
#4472697 - 07/28/17 06:40 AM Re: Oil shear ? [Re: Camprunner]
dlundblad Offline


Registered: 09/30/13
Posts: 10012
Loc: Indiana
It's still protecting to an extent, but how much is it being ran AFTER it sheared down?

One would need a UOA to know for sure. I personally like oils with higher starting TBN's for this reason.
_________________________
03 Jeep WJ 4.0 199k Castrol Edge 10w40 HM Fram XG16
02 Volvo S60 2.4T 177k M1 0w40 Mahle OX149D
97 Chevy Blazer 4.3 145k Rotella T5 10w30 Fram TG3980


Top
#4472704 - 07/28/17 06:53 AM Re: Oil shear ? [Re: Camprunner]
SonofJoe Offline


Registered: 07/23/16
Posts: 1052
Loc: Europe
When an oil shears, only the VII polymer shears. The other stuff in the oil (ZDDP, dispersants, detergents, AOs, FMs etc) absolutely doesn't shear. So other than for a drop in viscosity, the oil continues to do what it's supposed to do.

Top
#4472712 - 07/28/17 07:01 AM Re: Oil shear ? [Re: Camprunner]
NGRhodes Offline


Registered: 01/06/13
Posts: 326
Loc: West Yorkshire, UK
popcorn

Top
#4472716 - 07/28/17 07:10 AM Re: Oil shear ? [Re: Camprunner]
zeng Online   content


Registered: 09/01/15
Posts: 2188
Loc: Malaysia
A sheared oil (and by extension, a fuel-diluted oil) is still offering protection, albeit at reduced protection level as a result of reduced oil film thickness consequential upon reduced operating viscosity.
However main bearings and con-rod bearings might predominantly still stays in hydro-dynamic lubrication regimes offering complete protection from abrasion/adhesion wear mechanisms.
Having said this, in the valve train systems and cylinder liner/piston ring tribo-pairs, there is increased levels of unfavourable boundary lubrication and mixed lubrication regimes ...... which are mitigated by essentially functioning anti- wear additive package.
The same cannot be said of gear-train systems, however.

Top
#4472724 - 07/28/17 07:22 AM Re: Oil shear ? [Re: zeng]
ArcticDriver Offline


Registered: 01/27/17
Posts: 1139
Loc: USA
Originally Posted By: zeng
A sheared oil (and by extension, a fuel-diluted oil) is still offering protection, albeit at reduced protection level as a result of reduced oil film thickness consequential upon reduced operating viscosity.
However main bearings and con-rod bearings might predominantly still stays in hydro-dynamic lubrication regimes offering complete protection from abrasion/adhesion wear mechanisms.
Having said this, in the valve train systems and cylinder liner/piston ring tribo-pairs, there is increased levels of unfavourable boundary lubrication and mixed lubrication regimes ...... which are mitigated by essentially functioning anti- wear additive package.
The same cannot be said of gear-train systems, however.


So I understand better.

If I am using a 5w40 and it shears to a 30w, then isn't it still offering the same level of protection as a 30w?

If my vehicle manufacturer suggests I should use a Xw40, then aren't they factoring in that Xw40 oils are going to shear?
_________________________
Multiple Diesel and Gasoline vehicles

Top
#4472743 - 07/28/17 07:57 AM Re: Oil shear ? [Re: Camprunner]
DdDd Offline


Registered: 06/08/17
Posts: 189
Loc: NY
An engineer with a half brain would spec a weight that is acceptable including shear for the duration. Then again a lot of hokey decisions get made by marketing too!

Oil film strength is a function of pressure and viscosity. If you can provide either in sufficient quantities you're doing good. My personal opinion is people who go up a weight to "stay in spec" are over thinking things. Modern engines have tighter tolerances and better oil pumps compared to yore.

I have yet to see an engine wiped out by 20weight oil. You'd think every 2017 model would be stranded on the side of the road.

Top
#4472749 - 07/28/17 08:04 AM Re: Oil shear ? [Re: DdDd]
ArcticDriver Offline


Registered: 01/27/17
Posts: 1139
Loc: USA
Originally Posted By: DdDd

Oil film strength is a function of pressure and viscosity. If you can provide either in sufficient quantities you're doing good. My personal opinion is people who go up a weight to "stay in spec" are over thinking things. Modern engines have tighter tolerances and better oil pumps compared to yore.



Or more like a "resistance to pressure", right?
_________________________
Multiple Diesel and Gasoline vehicles

Top
#4472762 - 07/28/17 08:23 AM Re: Oil shear ? [Re: Camprunner]
FordCapriDriver Offline


Registered: 10/22/15
Posts: 2378
Loc: Balearic Islands , Spain
Shearing is the destruction of the viscosity index improvers in an oil, it will cause the oil to get thinner, and it can increase the solid deposits in an engine.
_________________________
1975 Ford Capri II Ghia 3000 V6, - Valvoline VR1 20W-50
1988 Ford Escort MkIV 1.6 Xr3i Cabrio, - Shell Rimula R4X 15W-40 HDEO.

Top
#4472769 - 07/28/17 08:33 AM Re: Oil shear ? [Re: Camprunner]
tig1 Offline


Registered: 01/03/09
Posts: 13657
Loc: Illinois
Isn't it better for an oil to shear a tad than to oxidize?
_________________________
2007 Ford Fusion 227,000 miles
M1 0-20 EP
2017 Ford Fusion 49K
M1 0-20 EP
10,000 mile OCIs on both engines
M1 ATF and MC LV
M1 10-30 in all OPE
MC filters


Top
#4472774 - 07/28/17 08:35 AM Re: Oil shear ? [Re: FordCapriDriver]
tig1 Offline


Registered: 01/03/09
Posts: 13657
Loc: Illinois
Originally Posted By: FordCapriDriver
Shearing is the destruction of the viscosity index improvers in an oil, it will cause the oil to get thinner, and it can increase the solid deposits in an engine.


Isn't solid deposits caused more from oil thickening(oxidizing) than shearing?


Edited by tig1 (07/28/17 08:36 AM)
_________________________
2007 Ford Fusion 227,000 miles
M1 0-20 EP
2017 Ford Fusion 49K
M1 0-20 EP
10,000 mile OCIs on both engines
M1 ATF and MC LV
M1 10-30 in all OPE
MC filters


Top
#4472802 - 07/28/17 08:54 AM Re: Oil shear ? [Re: tig1]
MotoTribologist Offline


Registered: 02/03/16
Posts: 562
Loc: NJ, USA
Originally Posted By: tig1
Originally Posted By: FordCapriDriver
Shearing is the destruction of the viscosity index improvers in an oil, it will cause the oil to get thinner, and it can increase the solid deposits in an engine.


Isn't solid deposits caused more from oil thickening(oxidizing) than shearing?

I'm also a bit confused at how shearing increases deposits....I'll await the explanation before further comment.

Top
#4472914 - 07/28/17 10:14 AM Re: Oil shear ? [Re: DdDd]
69GTX Offline


Registered: 09/23/15
Posts: 3815
Loc: Connecticut
Originally Posted By: DdDd
I have yet to see an engine wiped out by 20weight oil. You'd think every 2017 model would be stranded on the side of the road.


Wiped out vs. just simply excessive wear?

Real world experience seems to back up the advice of these experts too. Some of the best data from the modular community has come from Nick McKinney:

Quote:
"I have said it a few times now, heavier oil has better protection especially in the cam bores. ---I get 2-3 sets of modular heads a week through here, and any lay person just from looking would pick the 500,000 mile cores run on 15W-40 diesel spec all their lives over the typical Mustang head run 50,000 miles on the light stuff"


Fleets typically run their vehicles 250,000 to 500,000 miles! I've heard Nicks experience echoed several times by fleet managers. They wouldn’t run a 5w-20 oil for one minute.
_________________________
----------------

2001 Lincoln Cont 4.6L DOHC/ 39K mi / QS HM 5w30 / FUG XG2
1999 Camaro SS M6 /19K /Mobil 1 0w40 /Fram UG /GM MTL-ATF
1969 Ply GTX/RRs

Top
#4472918 - 07/28/17 10:17 AM Re: Oil shear ? [Re: MotoTribologist]
FordCapriDriver Offline


Registered: 10/22/15
Posts: 2378
Loc: Balearic Islands , Spain
Originally Posted By: MotoTribologist
Originally Posted By: tig1
Originally Posted By: FordCapriDriver
Shearing is the destruction of the viscosity index improvers in an oil, it will cause the oil to get thinner, and it can increase the solid deposits in an engine.


Isn't solid deposits caused more from oil thickening(oxidizing) than shearing?

I'm also a bit confused at how shearing increases deposits....I'll await the explanation before further comment.

Well, nowadays it isn't such a problem as modern oils contain less VIIs, and higher quality, more resistant VIIs, but back in the 70s when VII technology was still rudimentary and a lot of multigrade oils were absolutely packed full of them suchas some 10W-40 and 10W-50 mineral oils, when they were destroyed they did form sticky deposits inside engines and caused rings to stick etc etc etc..... or that is atleast what i've read!
_________________________
1975 Ford Capri II Ghia 3000 V6, - Valvoline VR1 20W-50
1988 Ford Escort MkIV 1.6 Xr3i Cabrio, - Shell Rimula R4X 15W-40 HDEO.

Top
#4473011 - 07/28/17 12:14 PM Re: Oil shear ? [Re: 69GTX]
tig1 Offline


Registered: 01/03/09
Posts: 13657
Loc: Illinois
Originally Posted By: 69GTX
Originally Posted By: DdDd
I have yet to see an engine wiped out by 20weight oil. You'd think every 2017 model would be stranded on the side of the road.


Wiped out vs. just simply excessive wear?

Real world experience seems to back up the advice of these experts too. Some of the best data from the modular community has come from Nick McKinney:

Quote:
"I have said it a few times now, heavier oil has better protection especially in the cam bores. ---I get 2-3 sets of modular heads a week through here, and any lay person just from looking would pick the 500,000 mile cores run on 15W-40 diesel spec all their lives over the typical Mustang head run 50,000 miles on the light stuff"


Fleets typically run their vehicles 250,000 to 500,000 miles! I've heard Nicks experience echoed several times by fleet managers. They wouldn’t run a 5w-20 oil for one minute.


Third party hear-say doesn't count. smile


Edited by tig1 (07/28/17 12:24 PM)
_________________________
2007 Ford Fusion 227,000 miles
M1 0-20 EP
2017 Ford Fusion 49K
M1 0-20 EP
10,000 mile OCIs on both engines
M1 ATF and MC LV
M1 10-30 in all OPE
MC filters


Top
Page 1 of 3 1 2 3 >