"The Society of Automotive Engineers (SAE) is on record in countless technical papers as having found that as high as 80% of any engine's life span is lost in the cumulative total of those few seconds the engine spends without lubrication on the initial start-up and on subsequent start-ups in normal use."
CIRCLE TRACK Magazine

"In fact, as high as 95% of engine wear occurs in the first 10 seconds after startup before oil has pressurized and coated bearings and other critical parts."
Fall '98 issue DIY BOAT OWNER

"Significant engine wear can occur at start-up, so it’s critical for engine parts to receive proper lubrication as soon as possible. Prior to start-up, most of the oil resides in the engine’s sump. When the engine is started, a short period of time elapses before the oil can be pumped from the sump and supplied throughout the engine. During this critical time, engine parts are not adequately lubricated."
Mobil 1 brochure

"There is clear evidence that most of the engine cylinder and ring wear occur when an engine is started up from a cold condition, and at the location on the stroke where the lubricant film is least well-established, at the hot end of the cylinder (top-dead-center)."
A Review of Sub-Scale Test Methods to Evaluate the Friction and Wear of Ring and Liner Materials for Spark- and Compression Ignition Engines November 2001

"More than 75 percent of engine wear occurs on startup and shutdown."
Fleet Management: Vehicle Rotation Criteria.(Law Enforcement Agencies) From: The FBI Law Enforcement Bulletin Date: 8/1/2002 Author: Exley, Curtis W.

 

"Engine wear occurs most swiftly not during high-speed driving but in the first moments after a car has been started, when the cylinders are starved for oil."
How to Make Your Car Last Twice as Long, David Solomon

"Most engine wear occurs immediately after a cold start, so it’s important to have oil that is thin enough to circulate easily -- especially at cold temperatures."
What type of motor oil is best for my engine? Yahoo Autos

"90% of all engine wear occurs on cold start because the oil gets thicker the colder it is - which causes engine wear."
Drivers Technology Ltd

"Because most engine wear occurs at start-up, the faster the oil can be pumped to all the moving parts, the better."
www.rislone.com

"Typically, it takes several crankshaft rotations to pressurize the oil galleries at start-up, and until then, the engine has minimal, if any, oil film protecting the surfaces. Independent studies attribute as much as 90 percent of engine wear to cold-start scuffing."
High Performance Pontiac

 

Kid,

I think they mean startup until the oil has thinned to an acceptable viscosity which would be around 150 degrees or so. That's the way i've always intrepreted it.

 

all engines are subject to the thermodinamic laws, one of them states that 'in a given sistem (the engine in this specific example) the temperatures of the different areas tend to stabilize toward one single figure', this means that if we cool the oil that will 'help' cooling the engine...the oil gets hot for two reasons: internal movement which speeds up its molecules and heat translated from the engine, at the same time its (oil) heat will rise or lower engine heat...

it's a group of related iussues and one push the other toward a single direction: to arrive to a single temp figure, of course this never happens because the 'sistem' is unstable in its temp (could go and down) along the time...and all the factors which determines it fluctuate quickly.

in a phisical 'perfect' sistem creating heat, the heat will be equal in all its parts, on the long run, if the variables keep constant through the time...

...and now i have to go to work

 

Best description yet.
Panic has a good understanding of basic physics

SAE has also many years ago established that roughly 60% of the gasoline engine is cooled by the oiling system and 40% by the coolant system. Oil cooling is important to say the least. It does more than just lubricate.
Adding an external cooler though, in most cases is not necessary. The sustained use thru higher rpm or increased workload can put the oil over it's design temperature, and lose it's film strength and cause the metal to metal contact that destroys moving parts. Generally oil in the pan and read by a sump sensor may only show a crude average of 200°, but the oil at the rod end bearing may be at 300° thus degrading that oil. Once the majority of oil has been "burnt" so to speak, then it quickly loses it's lubrication qualities and the engine will suffer quickly. Sensors thruout the critical areas of the engine are impractical so educated prevention is the only resource.

So understanding that a lot more than just engine cooling is a concern, keeping the oil itself in good shape would benefit by an additional oil cooler, although not mandatory. As with synthetics, you will be able to slightly increase oil change intervals.

The hot new type of cooler is a Laminova, a liquid to liquid cooler, with such a great novel design, that GM amongst, other leading makers are adapting them to engine use in their new product lines. They have long understood their importance, it is that just now it has become practical and economical.

 

[QUOTE=noonie;1559191641]Best description yet.
Panic has a good understanding of basic physics

well, ehem...it's the result of my studies in thermodinamic during my first biennal course at the university

 

 

Add the high wattage stereo that requires 260 amps of charging power to the wasted money & added weight category. A Corvette has a very small cockpit; there is no way you need that kind of power for good sound. . .unless your goal is to have enough "thumps" to impress all the adolescent boys in your neighborhood.

It takes a real engineer to determine what is truely required and beneficial. Anybody can come up with an "overkill" solution.

 

Larger oil pans help with cooling and longevity of an engine. All the more expensive cars run them. Porsche runs a huge oil pan compared to the size of their engines; and we all know how long they last. Initial start up is where the critical wear takes place, which is greater now that engine tolerances are much closer. That is why manufacturers are recommending 5/30 and 0/30 weight oils; to provide instant lubrication for the engine. The wear that can occur at start up is so critical that the larger earth moving machine manufacturers often install a prelube system that spins the oil pump to prelubricate all the internal moving parts before the engine is ever cranked. A larger oil pan is not going to cause a delay in engine warmup time, the thermostat controls warmup, but does provide for more stable oil temperatures. Yes, there are some very misinformed people on the forum.
Bernie

 

No need to bash me for how you feel about something I am doing and because you don't agree. It's all your opinion, and judging or bashing me based on that's a tad uncalled for. Very assuming and judgmental.

 

This is one of those occasions where the universal IT answer applies. It depends.

 

 

It wasn't a bash. As you said, it's my opinion. Somebody disagreeing with you is not bashing you.

 

 

It's never a black and white will/will not situation. If I had to go for a poll choice that's "most" right, then yes an oil cooler WILL affect engine temp. BUT it's probably by such a small degree as to go practically un-noticed.

Think of the engine, running at a certain condition, as a fixed heat source with a variety of interconnected and parallel heat sinks/outflows to ambient - By adding an oil cooler you are changing the balance, connection and even the direction of those flows.

If your oil cooler is oil-to-air, then you are rejecting a certain amount of that combustion and friction heat to ambient - this is the case where you might argue the OC has the most potential to influence running temp.

If you have an oil-to-coolant type cooler, then some of the oil heat is being re-directed back into the coolant flow, to be dumped out in the radiator. Since the coolant flow is thermostat controlled, this setup is unlikely to influence the engine temp (if by "engine temp" you mean coolant temp, which I guess you do)

Which medium, oil or coolant is the most influential in setting engine temp? Well, which medium picks up the most heat? An earlier poster said
"SAE has also many years ago established that roughly 60% of the gasoline engine is cooled by the oiling system and 40% by the coolant system. Oil cooling is important to say the least. It does more than just lubricate."

which I'm assuming is talking about the surface areas that the oil and coolant respectively see. That DOESN'T mean that 60% of the HEAT goes to the coolant though - it's a much higher percentage than that. I don't have any actual rig numbers in front of me now but off the top of my head I'll say 90% or more of the engine's total wasted heat (combustion and friction) comes out in the coolant.

The oil's just not influential enough in the overall picture to permit an oil cooler to have a major influence on engine temp.

I agree with the general consensus that it's probably not useful to install an OC unless you're seeing high rpm and low speed ( = low radiator air flows) ie racing.

I'm dyno testing a turbo diesel engine at the moment, which uses oil jets to cool the underside of the piston. This is a case where an oil cooler DOES have a use, because it's there to pull out all that heat from the oil which it picks up from the pistons.

And since we seem to have opened up a debate on whether it's warmup or startup that causes most wear, well, it's mostly startup. Once you've built pressure, the bearings should be seperated by a film of oil. The piston sees the same film effect at midstroke, but will always see a degree of metal-to-metal contact at either end of the stroke, because its speed isn't sufficient to build up the wedge of oil into a film.

Durango, if I were you I'd take some oil temp measurements first before fitting a cooler.. then it's as simple as:
Oil too hot = fit a cooler
Oil ok = don't fit a cooler

Cheers

Theo

 

That depends entirely on how that disagreement is stated.

 

Consider that almost all of the heat generated by the engine is from the combustion process in the cylinders. Yes, there is some frictional heating (hopefully, not much, because of the oil condition and temp) and some additional heat from loading (PS, water pump, accessories). The accessories heat is mostly from working the engine harder which again goes to combustion. The combustion heat is MOSTLY removed by the coolant/radiator system. There is no oil cooling system, save for the oil pan radiating some heat to airflow over it. Sooooo...an oil cooler will help, but as said above, depending on what type of system you use, you may add some of that back to the coolant system. My belief is that, unless you are really working your engine hard [drag racing, road racing, long time runs at high RPM] you really don't need an oil cooling system....you just need to make you water cooling system more effective. IMO, the best way to do THAT is with a larger, more efficient radiator and fan system. The pump needs to be sized to match with the radiator/fan capacity. But for a "street" car, the factory water pump is more than adequate for any radiator that will fit in the stock shroud.

 

About oil in V8!
cooling oil isn't the true problem! but volume of oil yes!
because with 5L (quantity of oil in a V8), in europe we use 5L of oil for a 2L engine (2L=122ci)
more rpm, more oil you need (no true for dry oil pan lubrification).
2L engine in europe rev more than a V8.

so as long as you have "few" oil you need to check oil temp!

hopes this help !



Durango--> i'm intresting to swap my clock to a oil temp, how do you do this?

 

BMW motorcicles dont need to be water cooled, their cilinders position gives them plenty of fresh air...same as ducatis V twins, they have only a small oil cooler and then they cool with the air going around...

 

7T1vette
Yep, you and I seem to agree! Again, I wish I had some easily accessible heat numbers to share (can't really be bothered to trawl through my data!) but the amount of heat moved by the coolant is many times greater than that removed by the oil, therefore any system which provides an extra heat sink FROM the oil (ie Oil-to-air OC) will only have a minimal effect on the engine temperature.

In the diesel I mentioned above, the OC's mainly there because we're using piston cooling oil jets, and you therefore NEED to provide a means of getting that extra oil heat input OUT. Now that heat goes off to the coolant, via the oilcooler, so you could actually think of it as having water cooled pistons, but with an oil "buffer" transporting the heat from piston to coolant. Which is good because I don't think water jets inside the engine are a very good idea
Come to think of it, I think big old ship diesels sometimes had water cooled pistons - imagine that!

Anyway, the point I'm trying to make is only fit an EOC if your oil temps tell you that you NEED one.