Where do you think engine oil take the most abuse?

[KevGuy]

Let's consider a typical passenger car or truck operating normally. We can all agree that over time with use, the oil becomes ineffective and that is why we change it out every so often.

Where do you think oil takes the most abuse? Would it be:

1. The shear with lobes on the camshaft?
2. The shear in the crankshaft main bearings?
3. Piston under crown/oil control ring area?
4. The heat produced from combustion being transferred to the oil?
5. In the oil pan due to piston blow-by (air/fuel blow-by or combustion products blow-by)?
6. Any shear caused by the timing chain?
7. The shear of the oil going through the gears of the oil pump?
8. Others? (e.g. turbos if equipped)

Looking forward to seeing your opinions.

 

[ZeeOSix]

Combo of 3, 4 and 5 cause oil shearing, thermal breakdown and contamination. The rings shear oil pretty good too, especially at higher RPM. Rings typically wear out (loss if comprrssion, increased blow-by, increased oil use) way before journal bearings or cam shafts. There's a lot of oil abuse around the ring area.

 

[UncleDave]

The rod bearing shells.

The direct injection pump or diesel heui pump

UD

 

[Mad_Hatter]

I always thought it was where you have the tight(est) clearances?? MOFT
(bearings, journals, valve guides, piston-cylinder wall, cam lobes, crankshaft etc)

 

[LotI]

The oil does just fine. The "tween" temp between ambient and operational is what kills the additives.

 

[OilUzer]

In DI engines I think its fuel dilution ...

#4 is not that significant

 

[ZeeOSix]

Originally Posted by OilUzer
#4 is not that significant.


Oil temps in the ring pack are definately elevated due to combustion, piston crown temp and from the high shear rates. Rings are also the thermal "bridge" between the hot piston crown and the cylinder liner, so the rings and the oil around the rings most likely run hotter than in any journal bearing. Rings can "coke up" and stick in the ring grooves from oil thermal breakdown.

 

[OilUzer]

Originally Posted by ZeeOSix
Originally Posted by OilUzer
#4 is not that significant.


Oil temps in the ring pack are definately elevated due to combustion, piston crown temp and from the high shear rates. Rings are also the thermal "bridge" between the hot piston crown and the cylinder liner, so the rings and the oil around the rings most likely run hotter than in any journal bearing. Rings can "coke up" and stick in the ring grooves from oil thermal breakdown.


iirc, the combustion chamber can be in the 1500°F range and the cylinder walls & head can reach 300-400°F range ... It is a hostile environment

However, I was responding to the following general statement:

"The heat produced from combustion being transferred to the oil?"

Shannow had a fancy heat flow diagram showing that the heat transferred from combustion to the oil is not significant ... relative to the heat generated by the internal engine parts.

 

[Silk]

Pistons is where you see destroyed oil.

 

[Mad_Hatter]

Originally Posted by ZeeOSix
Originally Posted by OilUzer
#4 is not that significant.


Oil temps in the ring pack are definately elevated due to combustion, piston crown temp and from the high shear rates. Rings are also the thermal "bridge" between the hot piston crown and the cylinder liner, so the rings and the oil around the rings most likely run hotter than in any journal bearing. Rings can "coke up" and stick in the ring grooves from oil thermal breakdown.

Rings are one of the key areas the field test engineers at Oronite look at for wear.. along with the valve train, crankshaft, cam, piston, liners and rockers/rollers.

Oronite

 

[ARCOgraphite]

Rings and sitting on the head around the spring pockets after shutdown. Many New engines don't have external manifolds anymore rather they have cast in long exhaust runners in the head.

Then all the moisture in the pan condenses on the VC and drips in this area.
A recipe for sludge and varnish.

 

[littleant]

Shear caused by the timing chains especially engines with with more then 2 chains like the Ford 4.0 with 4 chains. Just my opinion

 

[alcyon]

IMHO, the turbo.

 

[SR5]

Where does engine oil take the most abuse?
In a BITOG Royal Purple thread

 

[wemay]

Originally Posted by SR5
Where does engine oil take the most abuse?
In a BITOG Royal Purple thread

You win!

 

[Snagglefoot]

Good post. It brings up how brutal operating conditions are for motor oil.

 

[ka9mnx]

In order:
cylinder liners
timing chain/gears
rocker arms
Honorable mention:
Flat tappet cam lobes/lifters

 

[Rand]

Originally Posted by wemay
Originally Posted by SR5
Where does engine oil take the most abuse?
In a BITOG Royal Purple thread

You win!


Winner.

Nothing against them personally I even bought some when it was clearanced at walmart making its price reasonable.

 

[Mitch Alsup]

It depends on what the engine is doing.

If the engine is running down the highway at 65 MPG and 20% of redline, there probably isn't any real wear going on in either the engine or in the oil.

on the other hand if the throttle is wide open, there is going to be sh!tloads of heat on the pistons, a lot of forces on the conrod bearings and main bearings.

 

[Mad_Hatter]

Originally Posted by SR5
Where does engine oil take the most abuse?
In a BITOG Royal Purple thread

...‚...‚...‚...‚... now that's funny!