Re: Solid Bearings vs. Roller Bearings
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Yes, I agree Dennis, the temperature of the oil has a big effect on the amount of drag a bearing has. I have watched V8 engines on a dyno pick up 20-30 hp from the oil temperature going from 150 degs to 200 degs.
From: "destorzek@... [STMFC]"
Sent: Friday, March 24, 2017 12:02 AM
Subject: Re: [STMFC] Solid Bearings vs. Roller Bearings
---In STMFC@..., wrote :
I'm not 100% convinced that a car with roller bearings takes less effort to start moving it but I can see a good argument for it. At speed? Well, that's another story.............
It depends... If the car with plain bearings was moving, stopped briefly, and then restarted, likely not much difference. But... if the car with plain bearings sits for a while, say a day or so, the weight of the car squeezes the oil out, and the Babbitt bearing settles down on the journal. Now, you need to move the car to reestablish that film of oil between bearing and journal, and that is what causes the hard starting. The colder the ambient temperature is, the longer it takes to get the bearing floating on that wedge of oil.
I can attest, back in my railway museum days, that when we received our first roller bearing equipped passenger car, we found all sorts of places we thought the track was level, but wasn't. Places we'd set coaches while switching for years, the newcomer would silently start to drift away.