Don Terrill’s Speed-Talk

No more cold start scuffing? http://wardsauto.com/engines/supplier-u ... 63414d19b6

Or the ultimate coated bearing?

MadBill wrote: ↑Thu Oct 26, 2017 12:37 pm No more cold start scuffing? http://wardsauto.com/engines/supplier-u ... 63414d19b6

Or the ultimate coated bearing?

Pretty cool but the way I read it, they are just for hybrid stuff. I wonder would they work in say a 2HP/CID with high rpm?

Bill, i could not help but notice that in the first sentence they seemed to think (made mention of) LOW viscosity oils having a down side??

Mixed friction....another new age term I have to remember...

Krooser wrote: ↑Thu Oct 26, 2017 2:42 pm Mixed friction....another new age term I have to remember...

LOL!
Probably another way of saying junk.

Notice the pictured bearing does not have a 180 groove.

Interesting - these hybrid engines stop and start the engine at traffic lights and must see a lot of bearing scuff, especially using low viscosity oils (for efficiency.) These are hybrid bearings that have low coefficient of solid-on-solid friction when there's insufficient oil pressure to keep a proper oil film layer.

Sort of like the cam bearings, when you crank an engine with say 350/1000# of spring force...

Just a harder slippier bearing with a big "pool" instead of the groove and oil hole. Could work real good.

It's nothing more than marketing talk.

Manufacturers have to remove the lead from bearings to get it out of the environment. Same as getting it out of the fuel.
Aluminium has been used but plastics are the way of the future.
Driving a starter/ alternator off a belt is a bit silly when you can drive it off the end of the crank like Toyota do with the prius. That removes side loadings.

Their description does not say if the entire bearing is constructed of polymers or whether they are describing coatings and wear layers.

I think obviously materials technology in all types of internal combustion engines is constantly improving and coatings and bearing construction materials have already advanced significantly, even in the performance market and racing venues.

This use also is talking about obviously more direct contact between the crankshaft and rod bearing surfaces and the crankshaft journal surfaces , ie in the start/stop use in hybrids with super light weight oils.

I personally like the new performance bearings that use an aluminum-silicone bi-metal layer and oil retaining surfaces and there ability to run on good crankshaft surfaces with little or no wear and actual polishing characteristics. These are the bearing types most OEMS are now using in todays' long running engines. I personally think the old tri-metal babbit bearings have seen their best days and are on the way out.

That photo looks like a 302 Ford main bearing; 160 degree groove.

I have been using that aluminum type bearing for quite a while now; Clevite though.
All Polymer might work well in the light load upper mains.

There seems to be confusion with the term "mixed friction." It's an unfortunate marketing department choice of term with no effort to educate.

The reality is there are two types of plain bearing operation: starting from zero rpm there is contact between the bearing and journal. During start up this is the major wear period of every plain bearing system properly designed to be touch free during hydrostatic operation.

In engineering terms that startup phase and the later at speed hydrodynamic operation of a journal bearing are different, the two types of operation are entirely diverse. The first one does involve friction. The second does not if it's working properly.