great technical description of Toyota's 2ZR-FE

[friendly_jacek]

engine here (pdf): http://physics.usc.edu/Undergraduate/temporary/corolla2009/2zrfeeng.pdf

One thing caught my attention:

Quote:
The lining surface of the connecting rod bearing has been micro-grooved to realize an optimal amount of oil clearance. As a result, cold-engine cranking performance has been improved and engine vibrations have been reduced.


Quote:
The lining surface of the crankshaft bearing has been micro-grooved to realize an optimal amount of oil clearance. As a result, cold-engine cranking performance has been improved and engine vibrations have been reduced.


Can someone explain what this is all about?

IIRC, microgrooving increases oil layer thickness independently from viscosity, right?

 

[supton]

Sounds like they left a rough surface with the hopes of oil not draining off of it?

 

[friendly_jacek]

LOL: I found my answers and more in this presentation: http://www.devilsurface.com/pdf/Orientation.pdf

 

[eljefino]

I always thought when you assembled an engine you needed to put hose on the end of the con-rod studs as you dropped the pistons down so you wouldn't micro-groove your crank. Maybe Toyota discovered something accidentally?

 

[supton]

I was thinking their "micro-groove" is what everyone else calls "machine marks" -- and tries to minimize. Maybe they hope to do less work (less polishing) and charge more for it?

 

[mechanicx]

It's pretty much how most all late model engines are designed. It's about time Toyota starting using roller cam followers with hydraulic lash adjusters.

 

[friendly_jacek]

Originally Posted By: mechanicx
It's pretty much how most all late model engines are designed.


Are you talking specifically about microgrooved bearings?

If you are just talking about hydraulic lifters, I hear you. However, to give Toyota credit, I just checked clearance in 1ZZ-FE after 86,000 miles of mostly city driving and no adjustment was needed. They figured out a way to eliminate wear from their old fashioned solid lifters.

 

[mechanicx]

Switching to roller finger followers and hydraulic lash adjuster favored by domestics but most of the features- piston oil cooler jets, VVT, timing chains, offset bores, multilayer steel headgaskets etc are seen on various late model designs.

Anyway the way this engine is designed is the way I'd want an engine. I'm not sure who else is using microgrooved bearings, but it's not a new idea. People were suggesting to use a scotchbrite to rough up the bearing in the Hotrod community for decades. It wasn't a good idea to do it that way as scothbrite has abrasives that can be left behind and the bearing's outer layer could be haphazardly removed.

 

[SteveSRT8]

Mostly marketing, very little real advancement of engineering in there.

 

[friendly_jacek]

Originally Posted By: SteveSRT8
Mostly marketing, very little real advancement of engineering in there.


Look, we are not talking about cutting edge here. This engine powers a lowly corolla and has been in production for several years already.

Talking cutting edge, Toyota has a valvematic version of this engine that makes 10% more power with 10% less gas consumption.