What part of engine is generally hardest on oil?
- Thread starter zach1900
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There's some evidence that chains/gears can be hard on the VII additives, shearing them, and dropping viscosity in service...and also leaving pieces that can form sludge/gel.
But I agree, the ring belt is probably the chemical cracking zone where most everything bad happens.
But I agree, the ring belt is probably the chemical cracking zone where most everything bad happens.
Originally Posted By: zach1900
I was just thinking out loud to all my prior cars and it seemed the timing chained ones darkened the oil the fastest. ,Mostly on Nissans. Never seemed to shorten their longe though.
A lot of Nissan cars only have a 3 quart capacity.
I was just thinking out loud to all my prior cars and it seemed the timing chained ones darkened the oil the fastest. ,Mostly on Nissans. Never seemed to shorten their longe though.
A lot of Nissan cars only have a 3 quart capacity.
M
Originally Posted By: Miller88
Originally Posted By: zach1900
I was just thinking out loud to all my prior cars and it seemed the timing chained ones darkened the oil the fastest. ,Mostly on Nissans. Never seemed to shorten their longe though.
A lot of Nissan cars only have a 3 quart capacity.
My lowly although extremely durable 2001 Sentra 1. 8 had a 3qt sump +timing chain and was still running like a top at 250,000K abused miles with lax oil changes. Ditto for my 4tg gen 3.0 Maxima.
Originally Posted By: Miller88
Originally Posted By: zach1900
I was just thinking out loud to all my prior cars and it seemed the timing chained ones darkened the oil the fastest. ,Mostly on Nissans. Never seemed to shorten their longe though.
A lot of Nissan cars only have a 3 quart capacity.
My lowly although extremely durable 2001 Sentra 1. 8 had a 3qt sump +timing chain and was still running like a top at 250,000K abused miles with lax oil changes. Ditto for my 4tg gen 3.0 Maxima.
Camshaft to lifter rubbing area is very high pressure. Right-angle gear drives like most old V8s used to drive the distributor and oil pump have a wiping action.
Originally Posted By: zach1900
I was just thinking out loud to all my prior cars and it seemed the timing chained ones darkened the oil the fastest. ,Mostly on Nissans. Never seemed to shorten their longe though.
It all depends on the engine/manufacturer. My CR-V leaves the oil pretty golden for about 6k and then begins to darken (chain). My Pilot darkens much more quickly (belt).
I was just thinking out loud to all my prior cars and it seemed the timing chained ones darkened the oil the fastest. ,Mostly on Nissans. Never seemed to shorten their longe though.
It all depends on the engine/manufacturer. My CR-V leaves the oil pretty golden for about 6k and then begins to darken (chain). My Pilot darkens much more quickly (belt).
I think the timing chain, dohc has twice the valve springs for the timing gear to pull the cam through. Valve spring pressures may have some bearing( pun) on this.
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Micro-dieseling in the bearings?
Different parts are "hard" on oil in different ways.
-On all engines, the space in the ring pack is extremely hot and is where the oil is usually oxidized.
- The cam lobe/lifter interface on non-roller cams has by far the highest contact pressure anywhere in pretty much any type of engine, and oil that gets pinched between a lifter and a lobe is exposed to enormous shearing forces, and the ZDDP additive is activated there as well.
-Gears (timing gears, oil pump drive gears) and to a lesser degree chains shear oil. Oil pump drive gears are right-angle (helical) drive and like hypoid gears subject the oil to a lot of shearing force due to the sliding contact at high pressure. Not a factor on more modern engines with direct-drive pumps off the crank instead of gear-driven off the cam.
- Bearings are usually very easy on oil, except when they're under-designed like the BMW engines that need 10w60 oil just to survive.
-On all engines, the space in the ring pack is extremely hot and is where the oil is usually oxidized.
- The cam lobe/lifter interface on non-roller cams has by far the highest contact pressure anywhere in pretty much any type of engine, and oil that gets pinched between a lifter and a lobe is exposed to enormous shearing forces, and the ZDDP additive is activated there as well.
-Gears (timing gears, oil pump drive gears) and to a lesser degree chains shear oil. Oil pump drive gears are right-angle (helical) drive and like hypoid gears subject the oil to a lot of shearing force due to the sliding contact at high pressure. Not a factor on more modern engines with direct-drive pumps off the crank instead of gear-driven off the cam.
- Bearings are usually very easy on oil, except when they're under-designed like the BMW engines that need 10w60 oil just to survive.
On my Nissan Altima it changes color depending on the oil and gas run. My car has a 4 7/8 qt capacity. Castrol w titanium in the gold bottle and Pennzoil Ultra Platinum didn't change color quite as fast as the Sunoco Ultra I'm currently running. I've also been running Sunoco gas for awhile now and not my normal Shell 93. The Sunoco Ultra gasoline does run very well in my car. My oil color is turning darker earlier than I'm used to in my car. But its running very well and quiet as the Castrol w titanium gold bottle and the Pennzoil Ultra. So I'm hypothesizing its the gasoline that may well be the cause for it darkening sooner. Usually the oil isn't this dark until past 3500 miles. It's only 2200 so far.
It makes a lot of sense what Shannow and others that it's the ring belt that causes the most change in color, plus the timing chain could be a factor as well.
It makes a lot of sense what Shannow and others that it's the ring belt that causes the most change in color, plus the timing chain could be a factor as well.
I always thought timing chain equipped cars were hardest on oil, especially DOHC, If you've seen inside the timing chain cover of a VQ35 or similar engine, there is like a mile of chain.
Originally Posted By: Chris Meutsch
Originally Posted By: zach1900
I was just thinking out loud to all my prior cars and it seemed the timing chained ones darkened the oil the fastest. ,Mostly on Nissans. Never seemed to shorten their longe though.
It all depends on the engine/manufacturer. My CR-V leaves the oil pretty golden for about 6k and then begins to darken (chain). My Pilot darkens much more quickly (belt).
Wouldn't that be a product of heat, not contact pressures, sliding frictions, etc?
Originally Posted By: zach1900
I was just thinking out loud to all my prior cars and it seemed the timing chained ones darkened the oil the fastest. ,Mostly on Nissans. Never seemed to shorten their longe though.
It all depends on the engine/manufacturer. My CR-V leaves the oil pretty golden for about 6k and then begins to darken (chain). My Pilot darkens much more quickly (belt).
Wouldn't that be a product of heat, not contact pressures, sliding frictions, etc?
Depends on the engine. Detroit Diesels (the old 2-stroke sort) had to run single weight oil. 30wt was mandatory. They would tear up any multi-weight oil and the engines would die early ... It was the oil scraper rings that really tore up the oil.
On some modern OC engines, it's the timing system.
Older designed push-rod motors mostly suffer lube failure in the valve train. But the oil is either fuel diluted, or the blow-by chemically alters the oils. The ring packs can suffer coking and the rings can get stuck such that they don't seal well and it all goes down hill from there. Hence the call for OCI at 3K miles for many of these engines.
On some modern OC engines, it's the timing system.
Older designed push-rod motors mostly suffer lube failure in the valve train. But the oil is either fuel diluted, or the blow-by chemically alters the oils. The ring packs can suffer coking and the rings can get stuck such that they don't seal well and it all goes down hill from there. Hence the call for OCI at 3K miles for many of these engines.
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MolaKule
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Wouldn't that be a product of heat, not contact pressures, sliding frictions, etc?
The pressures at the point of contact creates a temperature rise with higher loading forces (pressures). Pressure = Force/Area.
The contact area stays the same so higher loading forces creates higher pressures.
Temperature is proportional to pressure, so as pressures rises, so do temperatures.
To me, "hard on oil" implies, "Where is the oil stressed the most?"
And are we talking about shear stress, heat stress, fractionization....?
Wouldn't that be a product of heat, not contact pressures, sliding frictions, etc?
The pressures at the point of contact creates a temperature rise with higher loading forces (pressures). Pressure = Force/Area.
The contact area stays the same so higher loading forces creates higher pressures.
Temperature is proportional to pressure, so as pressures rises, so do temperatures.
To me, "hard on oil" implies, "Where is the oil stressed the most?"
And are we talking about shear stress, heat stress, fractionization....?
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Originally Posted By: Shannow
But I agree, the ring belt is probably the chemical cracking zone where most everything bad happens.
Right next to the raging fire
But I agree, the ring belt is probably the chemical cracking zone where most everything bad happens.
Right next to the raging fire
Originally Posted By: BrocLuno
Depends on the engine. Detroit Diesels (the old 2-stroke sort) had to run single weight oil. 30wt was mandatory. They would tear up any multi-weight oil and the engines would die early ... It was the oil scraper rings that really tore up the oil.
...Or was it because they burned and slobbered out so dang much that nobody could afford to feed them multi-grade oil?
Did a trip on a research ship once that had 8-V-71 generator engines, of course running 24/7. About 3-4 gallons of oil per 24 hours per engine. (!)
I always believed that the problem with DD 2-strokes and multi=-grade was the gumming within the ring pack from burning the VIIs in the oddball ring system on DD's (due to the intake ports at the bottom of the cylinder) which lets so much oil get into the ring pack and then into the combustion chambers. Could be wrong on that, but the engines themselves don't put a whole lot of stress... well... anywhere. Slow turning, relatively low BMEP, and a roller valvetrain decades before it was common in car engines. They do have a pretty complex gear drive in some applications, though.
Old DD's are interesting, for sure- they just keep going and going and start remarkably willingly (although 2 of the times I've been on a ship that went dead-in-water briefly, it was due to a Detroit problem... but to be fair they were *old* by then.)
Depends on the engine. Detroit Diesels (the old 2-stroke sort) had to run single weight oil. 30wt was mandatory. They would tear up any multi-weight oil and the engines would die early ... It was the oil scraper rings that really tore up the oil.
...Or was it because they burned and slobbered out so dang much that nobody could afford to feed them multi-grade oil?
Did a trip on a research ship once that had 8-V-71 generator engines, of course running 24/7. About 3-4 gallons of oil per 24 hours per engine. (!)I always believed that the problem with DD 2-strokes and multi=-grade was the gumming within the ring pack from burning the VIIs in the oddball ring system on DD's (due to the intake ports at the bottom of the cylinder) which lets so much oil get into the ring pack and then into the combustion chambers. Could be wrong on that, but the engines themselves don't put a whole lot of stress... well... anywhere. Slow turning, relatively low BMEP, and a roller valvetrain decades before it was common in car engines. They do have a pretty complex gear drive in some applications, though.
Old DD's are interesting, for sure- they just keep going and going and start remarkably willingly (although 2 of the times I've been on a ship that went dead-in-water briefly, it was due to a Detroit problem... but to be fair they were *old* by then.)
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