Everyone with oil temp issues

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.

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.

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]

vehl · 07-17-2009, 09:33 PM

I just hit 126c while trying to get the max speed. i didnt even get to drive to the top speed when i noticed the temp and had to slow down..#($&@$.!! my car is only the 4th car in the country so there hasnt been any 'complains' yet here.. im on the fence with installing aftermarket coolers.

semtex · 07-18-2009, 07:59 AM

Quote:

Originally Posted by vehl

I just hit 126c while trying to get the max speed. i didnt even get to drive to the top speed when i noticed the temp and had to slow down..#($&@$.!! my car is only the 4th car in the country so there hasnt been any 'complains' yet here.. im on the fence with installing aftermarket coolers.

How many miles do you have on your car?

solidsilver · 07-18-2009, 03:52 PM

As is the case with a number of people, this issue has caused me to delay my decision about buying a new Z. I do remember a few pages back some posts to the effect that with some vehicles the problem seemed to be resolving itself as the car accumulated mileage. Is it too soon predict that this might be the case with most - if not all - of the cars affected with this problem?

IDZRVIT · 07-18-2009, 03:58 PM

Quote:

Originally Posted by solidsilver

As is the case with a number of people, this issue has caused me to delay my decision about buying a new Z. I do remember a few pages back some posts to the effect that with some vehicles the problem seemed to be resolving itself as the car accumulated mileage. Is it too soon predict that this might be the case with most - if not all - of the cars affected with this problem?

If you believe that there is an oil temp issue then maybe you should look at buying a Genesis Coupe or ??? I bought the 370Z and do not track it. I'm as happy as a pig in shite with it along with most owners here. But you decide.

solidsilver · 07-18-2009, 06:22 PM

Quote:

Originally Posted by IDZRVIT

If you believe that there is an oil temp issue then maybe you should look at buying a Genesis Coupe or ??? I bought the 370Z and do not track it. I'm as happy as a pig in shite with it along with most owners here. But you decide.

Thanks for your response, although it didn't answer my question. All I was trying to find out was if some of those owners who believe they had a problem are having less of one as they wrack up the miles on their cars.

Modshack · 07-18-2009, 04:10 PM

Quote:

Originally Posted by solidsilver

As is the case with a number of people, this issue has caused me to delay my decision about buying a new Z.

Your loss. Maybe you'd be lucky and be one of the 99.5%+ who do not have any issues, but Maybe not. Life can be mighty dangerous sometimes...Sounds like you're not a gambler and should probably look at something else .

frost · 07-18-2009, 06:26 PM

Quote:

Originally Posted by Modshack

Your loss. Maybe you'd be lucky and be one of the 99.5%+ who do not have any issues, but Maybe not. Life can be mighty dangerous sometimes...Sounds like you're not a gambler and should probably look at something else .

semtex · 07-18-2009, 05:32 PM

Quote:

Originally Posted by solidsilver

As is the case with a number of people, this issue has caused me to delay my decision about buying a new Z. I do remember a few pages back some posts to the effect that with some vehicles the problem seemed to be resolving itself as the car accumulated mileage. Is it too soon predict that this might be the case with most - if not all - of the cars affected with this problem?

That's why I asked vehl about his mileage. His post gives me the impression that his car is still very new. If that's true, then (a) I wonder if he's even heeding the 1200 mile break-in procedure, and (b) I was going to point out to him that the temps tend to go down as these engines get broken in.

vehl · 07-20-2009, 08:43 PM

Quote:

Originally Posted by semtex

How many miles do you have on your car?

its currently at 1800km.

semtex · 07-21-2009, 09:35 AM

Quote:

Originally Posted by vehl

its currently at 1800km.

So you haven't even completed the break-in period yet (1200 miles, which = 1920 km). What are you doing pushing your car so hard so soon? I don't think you can really complain if you ignore the proper break-in procedure. Anyway, the experience of most people, including myself, is that as the engine breaks in more, the temps go down. Hopefully that will happen for you as well. So don't panic until you have more mileage on your car.

ADmaster71690 · 07-18-2009, 06:58 PM

I hope this doesn't sound stupid, but are there any other (perhaps less effective) methods of cooling the oil that don't involve rerouting the oil?

Would adding air ducts from the front bumper to the oil pan create a cooling effect? Or what about an electric cooler positioned down there?

These would of course not be enough for track users, but may lower oil temps to normal levels for street driving. It would also be much harder for Nissan to say your warranty is shot.

Modshack · 07-18-2009, 07:55 PM

Quote:

Originally Posted by ADmaster71690

I hope this doesn't sound stupid, but are there any other (perhaps less effective) methods of cooling the oil that don't involve rerouting the oil?

Would adding air ducts from the front bumper to the oil pan create a cooling effect? Or what about an electric cooler positioned down there?

These would of course not be enough for track users, but may lower oil temps to normal levels for street driving. It would also be much harder for Nissan to say your warranty is shot.

Simple mod here:

http://www.the370z.com/diy-section-d...your-sump.html

07-17-2009, 03:08 PM	#3 (permalink)
semtex A True Z Fanatic Join Date: Jan 2009 Location: Behind enemy lines Age: 55 Posts: 5,995 Drives: People to drink Rep Power: 34	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.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
What engine temp are you normally around?	RCZ	Engine & Drivetrain	92	06-25-2016 02:58 PM
Warm Up / Oil Temp Gauge	TacoZ	Nissan 370Z General Discussions	8	12-18-2008 02:33 PM

07-17-2009, 09:33 PM	#4 (permalink)
vehl Base Member Join Date: Dec 2008 Location: asia Posts: 140 Drives: 370z PW/ GTI Rep Power: 18	I just hit 126c while trying to get the max speed. i didnt even get to drive to the top speed when i noticed the temp and had to slow down..#($&@$.!! my car is only the 4th car in the country so there hasnt been any 'complains' yet here.. im on the fence with installing aftermarket coolers.

07-18-2009, 03:52 PM	#6 (permalink)
solidsilver Base Member Join Date: Jul 2009 Location: Northern California Posts: 5 Drives: 02 Infiniti I35 Rep Power: 17	As is the case with a number of people, this issue has caused me to delay my decision about buying a new Z. I do remember a few pages back some posts to the effect that with some vehicles the problem seemed to be resolving itself as the car accumulated mileage. Is it too soon predict that this might be the case with most - if not all - of the cars affected with this problem?

07-18-2009, 06:58 PM	#14 (permalink)
ADmaster71690 Base Member Join Date: Mar 2009 Location: Detroit Posts: 79 Drives: 2003 Saab 9-3 Rep Power: 263	I hope this doesn't sound stupid, but are there any other (perhaps less effective) methods of cooling the oil that don't involve rerouting the oil? Would adding air ducts from the front bumper to the oil pan create a cooling effect? Or what about an electric cooler positioned down there? These would of course not be enough for track users, but may lower oil temps to normal levels for street driving. It would also be much harder for Nissan to say your warranty is shot.