Everyone with oil temp issues

semtex · 07-17-2009, 03:02 PM

You guys really don't get it do you? The issue has nothing to do with the durability or flashpoint of the oil itself. The issue is with the bearings that Nissan now puts into engines as a result of trying to be more environmentally responsible. As has been thoroughly explained by Mike Kojima on his blog:

Quote:

Soft metals can be used as engine bearings because under normal conditions, the crankshafts journals never touch the bearings surface. Since the liquid oil layer is not compressible, the crank rides on a pressurized hydrodynamic film of oil a few thousands of an inch thick that is maintained on the bearings surface by the engines oil pump. The oil pump must maintain pressure (this varies for as low as 5 psi at hot idle to more than 60 psi at higher rpm) and continually replenish the oil because the oil leaks out at the edges of the bearing and is flung out by the centrifugal pumping action of the rotating rod journals. This circulation is necessary because the shearing action of the oil in the boundary layer between the rotating crank journal and the static bearing surface creates heat and this heat must be dissipated. Most of the heat is removed by the oil as it passes though the interface between the bearing and crank.

The bearings, although soft still have to bear a heavy load because the incompressible liquid oil film transfers the forces acting upon the engines reciprocating parts to the bearings, thus the bearings have to withstand thousands of pounds of force even though direct contact does not happen. The best engine bearing have high embedability with a high load bearing capacity.

Usually everything works fine until a couple of things happen. In the case of modern late model engines, the green movement is to blame for part of the problem. In the last few years, Nissan has worked hard to make their cars green and more recyclable. In an engine traditionally one of the most toxic areas was the bearings. A few years ago, many Nissan bearings were made of trimetal construction using layers of lead, zinc and tin alloys of different percentages. This tri metal construction has been a mainstay of heavy duty bearing construction and composition for decades. The old Nissan bearings were very strong, heat resistant and durable. It’s a little known secret that old L-Series Nissan bearings are so strong and durable that many race engine builders use them, adapting them to other engines. The Infiniti IRL engine used in Indy cars used off the shelf L-Series bearings for this reason.

Sometime in the last few years, in an effort to be greener, Nissan discontinued the use of lead in all engine bearings. We know of this through discussions of sources deep within Nissan which will have to remain unnamed. At this time the engineers at Nissan noticed that warranty claims for bearing failure in the RB26 GT-R engine, another Nissan engine noted for running high oil temps, spiked. Nissan launched an intensive study on the reasons of this bearing failure and discovered that the new environmentally friendly bearings started to loose their load bearing capacity at temperatures as low as 260 degrees. Although there was plenty of reserve strength for normal passenger cars, the turbo high output RB motor pushed many sets of bearings to the failure point. Although you think of lead as a very soft metal with a low melting point, it was still a major contributor to the bearings mechanical properties and resistance to heat.

So as the oil temperatures climb, the bearings soften and loose their load bearing capacity, if the temperature climbs past 300 degrees and the engine is being pushed hard the bearing material can start to flake and spall. This disrupts the hydrodynamic film allowing metal to metal contact, resulting in catastrophic failure of the bearings, the crank, rods and even the entire engine often within seconds. Oil also begins to deteriorate quickly at temperatures above 260 degrees. It starts to oxidize and thicken, loosing its lubricity while forming sludge and varnish. This further compounds the problem, generating more drag and heat in the bearing/crank interface area.

To bed with this already, huh? Whatever. I for one am installing an oil cooler just to play it safe. I don't think any of us need to worry about temps hitting 300, but as the article explains, the bearings start to lose their load-bearing capacity in temps as low as 260. That can't be good for the long-term reliability of the engine.

bluzman · 07-17-2009, 03:03 PM

Quote:

Originally Posted by Modshack

But watching the irrational speculation and panic is so much fun!

This is a non-issue that has been spun into something much more than it is.

TheWeatherman · 07-17-2009, 03:03 PM

Quote:

Originally Posted by wstar

I'm sorry, but that's faulty logic. The flashpoint on my first change of Nissan Ester 5W30, when it came out of the engine, was testing at 390F. Are you saying that if my oil temps were peaking at 350 I'd have nothing to worry about?

Are your temps peaking at that? Track=Cooler. Roads=Just Fine. Someone lock this thread already.

Oh, I noticed all of those 350Z on my way home broken down due to too many miles on the engine combined with warm oil. Semtex, I think you know the answer to all of this. What I just said above. Put on the cooler and get on with it.

You know, it's funny. I was at a Z meet, and this person with the only other 370 sat and bitched about his oil getting too hot. I said, "Are you having any problems yet?" He said, "No." I said, "Are you tracking your car?" He said, "I might." I said, "You bring it on the track, put on a cooler and stop bitching." You all have plenty of options. Use them. I repeat now for you Semtex, Track=Cooler.

The Midwest's quality control engineer said, "This engine is built to handle all oil temperatures right up to the limp limiter." He was involved in the 370Z's testing and traveled the world to make sure this thing was ready for the road. I have his cell number and he has mine. This is right from Nissan. Why would he make this up? He worked with the Japanese, and knew exactly what the engine can handle. He said the engine is just as reliable and you will have no oil-related problems if you keep the oil from prolonged stints over 300 on the guage. What more do we need? The other person on this board who talked to this guy is Spearfish. He gets it too. What more do you want? Track and cooler. He said that. The engineer also said any car that's taken on a racetrack for prolonged periods have to be prepped for racing. He happens to race a Porsche. He needed an aux. oil cooler but tries to keep is track temps from 240-260. Hmmm, an engineer. Those temps. He said I could meet him at the track by me and he'll show me. Come on, is this enough?

semtex · 07-17-2009, 03:08 PM

I repeat, from Mike Kojima's article on his blog: "the new environmentally friendly bearings started to loose their load bearing capacity at temperatures as low as 260 degrees." [sic]

semtex · 07-17-2009, 03:11 PM

Quote:

Originally Posted by TheWeatherman

Are your temps peaking at that? Track=Cooler. Roads=Just Fine. Someone lock this thread already.

Oh, I noticed all of those 350Z on my way home broken down due to too many miles on the engine combined with warm oil. Semtex, I think you know the answer to all of this. What I just said above. Put on the cooler and get on with it.

You don't need to track this car to hit 260 degrees. That's the problem with your little Track=Cooler Roads=Just Fine dichotomy. If you never hit 260 on regular roads, more power to you, and congrats on saving ~$400 on an oil cooler kit. But there are some who do hit 260 on regular roads.

Robert_Nash · 07-17-2009, 03:13 PM

Quote:

Originally Posted by wstar

I'm sorry, but that's faulty logic. The flashpoint on my first change of Nissan Ester 5W30, when it came out of the engine, was testing at 390F. Are you saying that if my oil temps were peaking at 350 I'd have nothing to worry about?

I don't think that's what is being implied. This is what I've gathered from all this discussion and looking into it myslef...

From sources I've read and people I've talked with (and there has been quite a variety at this point), the flashpoint of an oil is a measure of how readily the oil actually breaks down from heat...the higher the flashpoint the more heat the oil can take before it starts to breakdown (Synthetics have a higher and in some cases a much, much higher flashpoint than non-synthetics).

All oils break down and heat is a major factor in that but the higher the flashpoint, the longer the oil life and the higher the temperatures it can tollerate before it breaks down. Or another way you can look at is that flashpoint indicates how long the oil can do the job of protecting the engine before it becomes unable to do so and the higher the heat; the more frequently you should change your oil.

However, it is also true that the viscosity of the oil changes (thins) as oil increases in temperature so, all other things being equal (and they rarely ever are); the higher your engine oil temperature is, the less "protection" the oiled engine parts have because the viscosity gives a thinner and thinner layer of protection as the heat increases. This would be different from how long the oil can do its job but rather how well it can do its job at any given temperature.

What I've yet to see anybody translate is how much or how little all this actually affects the life of an engine. If the 3.7 engine oil consistently runs at 240 degrees; how much sooner, on average will the engine fail than if it was consistently running at 220 or 200 or 180?

I think we can all agree that, 180 or 200 is "better" for engine life than 240 but that doesn't tell us how much better...at the consistent 220 mark, will the engine die at 210,000 miles instead of 220,000 or will it die at 155,000 instead of 220,000?

The bearings may well break down and fail "sooner" with high temps than not but how soon and will anyone own their 370 long enough to even find out??? I don't know the answer; if anyone actually does they should speak up!!!

Modshack · 07-17-2009, 03:19 PM

Quote:

Originally Posted by Robert_Nash

I think we can all agree that, 180 or 200 is "better" for engine life than 240 but that doesn't tell us how much better...at the consistent 220 mark, will the engine die at 210,000 miles instead of 220,000 or will it die at 155,000 instead of 220,000?

The bearings may well break down and fail "sooner" with high temps than not but how soon and will anyone own their 370 long enough to even find out??? I don't know the answer; if anyone actually does they should speak up!!!

And chances are 98% of the folks here will not own these cars when they achieve those miles...

semtex · 07-17-2009, 03:19 PM

Quote:

Originally Posted by Robert_Nash

I don't think that's what is being implied. This is what I've gathered from all this discussion and looking into it myslef...

From sources I've read and people I've talked with (and there has been quite a variety at this point), the flashpoint of an oil is a measure of how readily the oil actually breaks down from heat...the higher the flashpoint the more heat the oil can take before it starts to breakdown (Synthetics have a higher and in some cases a much, much higher flashpoint than non-synthetics).

All oils break down and heat is a major factor in that but the higher the flashpoint, the longer the oil life and the higher the temperatures it can tollerate before it breaks down. Or another way you can look at is that flashpoint indicates how long the oil can do the job of protecting the engine before it becomes unable to do so and the higher the heat; the more frequently you should change your oil.

However, it is also true that the viscosity of the oil changes (thins) as oil increases in temperature so, all other things being equal (and they rarely ever are); the higher your engine oil temperature is, the less "protection" the oiled engine parts have because the viscosity gives a thinner and thinner layer of protection as the heat increases. This would be different from how long the oil can do its job but rather how well it can do its job at any given temperature.

What I've yet to see anybody translate is how much or how little all this actually affects the life of an engine. If the 3.7 engine oil consistently runs at 240 degrees; how much sooner, on average will the engine fail than if it was consistently running at 220 or 200 or 180?

I think we can all agree that, 180 or 200 is "better" for engine life than 240 but that doesn't tell us how much better...at the consistent 220 mark, will the engine die at 210,000 miles instead of 220,000 or will it die at 155,000 instead of 220,000?

I don't know the answer to that and I doubt anyone else here does either (or if they do they should speak up!!!

)

That's a good point, Robert. We have no hard mileage numbers. I just don't like the idea of soft engine bearings with deteriorating load-bearing capacity is all. It doesn't sit well with me. Might be much ado about nothing though. At this point, my decision to install an oil cooler is more for peace of mind than anything else.

TheWeatherman · 07-17-2009, 03:24 PM

Quote:

Originally Posted by Robert_Nash

I don't think that's what is being implied. This is what I've gathered from all this discussion and looking into it myslef...

From sources I've read and people I've talked with (and there has been quite a variety at this point), the flashpoint of an oil is a measure of how readily the oil actually breaks down from heat...the higher the flashpoint the more heat the oil can take before it starts to breakdown (Synthetics have a higher and in some cases a much, much higher flashpoint than non-synthetics).

All oils break down and heat is a major factor in that but the higher the flashpoint, the longer the oil life and the higher the temperatures it can tollerate before it breaks down. Or another way you can look at is that flashpoint indicates how long the oil can do the job of protecting the engine before it becomes unable to do so and the higher the heat; the more frequently you should change your oil.

However, it is also true that the viscosity of the oil changes (thins) as oil increases in temperature so, all other things being equal (and they rarely ever are); the higher your engine oil temperature is, the less "protection" the oiled engine parts have because the viscosity gives a thinner and thinner layer of protection as the heat increases. This would be different from how long the oil can do its job but rather how well it can do its job at any given temperature.

What I've yet to see anybody translate is how much or how little all this actually affects the life of an engine. If the 3.7 engine oil consistently runs at 240 degrees; how much sooner, on average will the engine fail than if it was consistently running at 220 or 200 or 180?

I think we can all agree that, 180 or 200 is "better" for engine life than 240 but that doesn't tell us how much better...at the consistent 220 mark, will the engine die at 210,000 miles instead of 220,000 or will it die at 155,000 instead of 220,000?

The bearings may well break down and fail "sooner" with high temps than not but how soon and will anyone own their 370 long enough to even find out??? I don't know the answer; if anyone actually does they should speak up!!!

Ahhh, Robert. As the oil turns... I keep trying to stay out of this, and someone always has to bring it back up. I practice all the self-control I can, but just get to the point of people not reading the old posts. I made a quick recap in my post above. Someone in another post said it best. "By the time this would even be an issue, if it even is an issue, you'd be along to your 3rd vehicle already." Mine would probably need every other part replaced before any of the motor's parts would die.

Here's another statement... So you have the "eco-friendly" bearing. So why wouldn't the limp mode be at 255? Ufff.

semtex · 07-17-2009, 03:32 PM

Quote:

Originally Posted by TheWeatherman

Here's another statement... So you have the "eco-friendly" bearing. So why wouldn't the limp mode be at 255? Ufff.

Because although the bearings start to weaken at 260, they don't actually start disintegrating until 300. It's all in Kojima's article. Ufff.

When does limp-mode kick in? 280? So Nissan evidently decided put the limp mode threshold at 20 degrees before the disintegration temp, probably as a bit of a buffer.

But I don't want any weakening of the bearings at all if it can be avoided. If there was a way we could set our own limp-mode threshold temps (like how we can adjust our shift light), I'd set mine at 255.

TheWeatherman · 07-17-2009, 03:34 PM

Quote:

Originally Posted by semtex

Because although the bearings start to weaken at 260, they don't actually start disintegrating until 300. It's all in Kojima's article. Ufff.

When does limp-mode kick in? 280? So Nissan evidently decided put the limp mode threshold at 20 degrees before the disintegration temp, probably as a bit of a buffer.

But I don't want any weakening of the bearings at all if it can be avoided. If there was a way we could set our own limp-mode threshold temps (like how we can adjust our shift light), I'd set mine at 255.

Well, buy a cooler then. Uff.

semtex · 07-17-2009, 03:42 PM

Quote:

Originally Posted by TheWeatherman

Well then by a cooler then. Uff.

I already did. Uff. Look, I don't care if you don't feel one is necessary. You can do whatever you want with your car. And we can agree to disagree. But where do you get off coming on here, acting like some censorship Nazi trying to end discussion on a topic, saying that the thread needs to be locked, etc.? If you don't think it's a topic worth discussing anymore, fine, then unsubscribe from the thread and don't discuss it anymore. But just because you don't think it warrants further discussion, that doesn't somehow give you the right to silence everyone else like some self-appointed censor of the forum.

TheWeatherman · 07-17-2009, 03:50 PM

Quote:

Originally Posted by semtex

I already did. Uff.

To bed with this already, huh? Whatever. I for one am installing an oil cooler just to play it safe.

Okay. The "Nazi" will step back. The "Nazi" will say it once more. Track it, put on a cooler. That's right from the engineers at Nissan right to my phone.

You just said above you didn't have on you cooler, but are deciding to put it on. To me that's not having one on your car.

semtex · 07-17-2009, 03:59 PM

Quote:

Originally Posted by TheWeatherman

Okay. The "Nazi" will step back. The "Nazi" will say it once more. Track it, put on a cooler. That's right from the engineers at Nissan right to my phone.

Alright, I'm going to step back too. If I offended you with the 'Nazi' remark, I apologize. This isn't worth getting into a pissing contest over. But I want ask you one thing. Do you really consider Nissan engineers to be impartial in this? I mean, what else are they going to tell you? If their employer made a bad call and under-equipped a car, are they going to openly tell people 'yeah, we screwed up on this one'? I'm thinking no. Could be wrong, but my gut says no. Like I said in an earlier post, for me personally, this is really just about peace of mind at this point. I have no problem stating (and have already stated) that there is no hard evidence that 260 degrees will actually cause any long-term reliability issues. If someone asks me why I have an oil cooler, I am not going to tell them that it's necessary to prevent damage to the engine, I am going to tell them that it's just for peace of mind, can't hurt, etc. I think you and I are actually much closer to being on the same page than you might realize. Again, I apologize if you took offense at my previous post.

semtex · 07-17-2009, 04:01 PM

Quote:

Originally Posted by TheWeatherman

You just said above you didn't have on you cooler, but are deciding to put it on. To me that's not having one on your car.

I have already purchased the Stillen kit, but it is not yet installed. It is sitting in my garage until my next oil change. So when you said buy a cooler, I said I already did because, well, I already did. Sorry for the confusion.

07-17-2009, 03:08 PM	#754 (permalink)
semtex A True Z Fanatic Join Date: Jan 2009 Location: Behind enemy lines Age: 53 Posts: 5,995 Drives: People to drink Rep Power: 32	I repeat, from Mike Kojima's article on his blog: "the new environmentally friendly bearings started to loose their load bearing capacity at temperatures as low as 260 degrees." [sic] __________________ "There are no small accidents on this circuit." -- Ayrton Senna 316.8whp & 248 ft/lbs (Dyno Dynamics) \| 319whp & 256 ft/lbs (DynoJet) (04/23/10) Stillen G3 CAI, CBE, Pulley / F.I. LTH / GTSpec Ladder Brace / Setrab Oil Cooler / UpRev-tuned by Forged Perf.

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