Carbon buildup on Toyota pistons and rings

[cjcride]

Originally Posted By: Silk
Originally Posted By: KrisZ

Simple, it's a Toyota. Toyota can get away and routinely gets away with all sorts of shortcomings and people will still praise it.


Yep, if it was a Mitsubishi, this thread would be twice as long, and all filled with hate for Mitsubishi...but it's a Toyota, under the carpet with all their other problems.

The carpet is getting a little lumpy.

 

[supton]

Originally Posted By: SonofJoe
I suspect that even the mighty Toyota didn't understand or anticipate the problems that this engine was having, as so much of this depends of the confluence of different factors.


I'm wondering if it comes back to when Toyota & GM were playing together. I wonder how much engine tech passed back and forth. Saturn had its 1.9L oil burner, and Toyota its 1.8L oil burner. Toyota fixed the 1ZZ-FE eventually (Saturn never did); not sure what happened with the 2AZ-FE. IIRC the headbolt issue was fixed, but that engine seems to still have a rep for oil burning.

Is there some reason for not using huge drain holes in the first place? Can oil come off the cylinder walls (as scraped off by the oil control rig) too fast? I'd think the cross sectional area of piston drain holes relative to swept cylinder wall would be some well-known chart, someplace.

 

[Silk]

Oh, a lot more Toyota problems than that! World wide. Can't dirty the Toyota name whatever happens.

 

[ndfergy]

I stand corrected.

I was looking for a correlation and the oil recommendation change in 2007 was the obvious one. However, more significantly the 2az-fe engine was also upgraded for that model year. Missed that. Whether my oil choice was a mitigating factor on my Xb, who knows? Regardless, and beyond the danger zone when oil consumption problems usually occur (140,000+ Km's when sold), I may have been lucky.

 

[Mackelroy]

https://www.youtube.com/watch?v=PgdZSXOslDM

I repeatedly mention that a quality synthetic oil is a must in modern engines. The above video clearly indicates why.

That type of oil ring , is a specialty high performance oil ring , used on some racing motorcycles , its a 2 peice oil ring, with tiny holes. They clog up on motorcycles also, that see 15 hour oil change intervals.

On these racing motorcycles piston and rings are supposed to be replaced every 135 hours, so really a non issue in that case. Where you begin to see the issue is above 500 hours. Ofcourse that doesnt take long with a street car motor.

Toyota didnt change the oil ring, although they made a slight piston change, they didnt fix the issue though, even though they are warranting the oil use issue, if it happens. You cant run that type of oil ring, longer than 500 hours or so max. Other wise it will begin to clog up via tiny oil return holes.