370Z oil consumption

FricFrac · 11-16-2010, 04:23 PM

Quote:

Originally Posted by WarmAndSCSI

So much misinformation in this thread. No piston rings take THOUSANDS of miles to break in, at least that should never be the case. With an OEM engine that has plateau-honed cylinder walls and pre-lapped piston rings, your rings and cylinder walls will break in within a matter of seconds. Really all you're doing in the first couple hundred miles is ensuring the peaks of the oiling cross hatch are flattened all the way (the plateau honing process gets most of this done) and that all of the valleys are cleaned out.

If you're having oil consumption past 1000 miles or so, there is likely something wrong that will rear its ugly head later. An engine has only so much "time" for a proper break-in to occur - after that window, your cylinder walls will likely be permanently glazed to some extent.

OEM-recommended break-in procedure is just CYA on their part.

That said, who knows where the root cause of the oil consumption problem on the VHR lies... Nissan will likely never admit to their fault. But I don't understand the point of a bunch of people who have probably never even touched the inside of an engine throwing around a bunch of conjecture. I'm fine if a bunch of experienced engine builders and tuners like myself want to have an intelligent, experience-based discussion proposing what the root cause might be, but what's going on in all of these oil recommendation and oil consumption threads is just asinine.

..and saying that your rings are seated within a few seconds is just as much misinformation. Sure if you are cutting limbs off a tree with a chainsaw you can go through them in a few seconds but when you are wearing in rings which are very hard against your cylinder wall that are suppose to be resistant to wear you are going to "seat" in somewhat but definately not fully. You are basically machining materials which are resistant to wear and it doesn't take seconds. Show me ONE profesional racing team that races a car after a few seconds of break in.... not qualifying but a full race.

I agree with you that there is a lot of misinformation in this thread but going to the other extreme doesn't help.... there is enough exageration going on here. There are a hand full of motors that do suffer from oil consumption - just like any other manufacture.

For the record my oil consumption has significantly reduced in 15,000Km...

TypeOne · 11-16-2010, 04:27 PM

Off topic but my car just turned 14k miles and with the 2500 miles on it since the last change, looks like it has used less than 1mm of oil off the stick.

Seems pretty good to me... *whew*

WarmAndSCSI · 11-16-2010, 04:34 PM

Quote:

Originally Posted by FricFrac

..and saying that your rings are seated within a few seconds is just as much misinformation. Sure if you are cutting limbs off a tree with a chainsaw you can go through them in a few seconds but when you are wearing in rings which are very hard against your cylinder wall that are suppose to be resistant to wear you are going to "seat" in somewhat but definately not fully. You are basically machining materials which are resistant to wear and it doesn't take seconds. Show me ONE profesional racing team that races a car after a few seconds of break in.... not qualifying but a full race.

I agree with you that there is a lot of misinformation in this thread but going to the other extreme doesn't help.... there is enough exageration going on here. There are a hand full of motors that do suffer from oil consumption - just like any other manufacture.

For the record my oil consumption has significantly reduced in 15,000Km...

Any engine with plateau honed cylinder walls and pre-lapped piston rings - all of which have been properly cleaned before assembly - is essentially broken in the second you fire it up. As soon as the engine is flushed of whatever residual loose metal that was still present, it's ready to go. I can point you in the direction of hundreds of drag racing teams that break in their engines for the first time with full-out quarter mile passes. This is even the case for multi-thousand-horsepower top fuel engines. In fact, it's quite essential that such engines get run full-out very soon after they are fired up for the first time.

The wear-in items you have to be concerned about during break-in of a properly prepared race engine do not include the piston rings and cylinder walls. (think more of camshafts, oil pumps, and other machined parts that have high-load contact with other metal components which do not use bearings but only a hydrostatic layer of oil). You explained yourself how hard both of materials in the piston ring-to-cylinder wall interface are - it should be easy to understand why a few hundred or thousand miles of break in SHOULD NOT cause any kind of measurable wear on them when they're designed to last hundreds of thousands of miles

Engine break-in is predetermined by how an engine is assembled. Speaking of a modern OEM-built engine, you'll find they are built to not need any significant break-in period. I'll do a nice analysis of the next OEM shortblock I receive for a build... should be in a few weeks. I can guarantee you that the cylinder walls will be plateau honed and very clean, along with the piston rings being pre-lapped.

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11-16-2010, 04:27 PM	#2 (permalink)
TypeOne A True Z Fanatic Join Date: Jul 2010 Location: Baton Rouge, LA Posts: 2,682 Drives: BSM 370 Rep Power: 1852	Off topic but my car just turned 14k miles and with the 2500 miles on it since the last change, looks like it has used less than 1mm of oil off the stick. Seems pretty good to me... whew