quote:
Originally posted by BOBISTHEOILGUY:
I have a liiiiiiittle comment I'd like to make. IMO, I do not believe that most wear is coming from start up so much as it is in town driving. OK, why?, well, consider this, first, most don't let their engines sit longer than over nite then you're restarting the engine unlike a race car sits for weeks at a time. This is the primary reason for a pre luber in a race car.
When you start your car engine, you do not have a load on the engine as it is just in idle. Once oil pressure is up, which only takes a few seconds, then most will go.
Now, when does it wear most? During starts from a light. Why? well at idle, you have say about 28lbs of oil pressure at the rod bearings waiting on the light. When the light changes, you accelerate, during which time, your rod will stroke up and down at min 2-4times before the full oil pressure is back up to 40+, so during that time, UNDER A LOAD, you are SHEARING the 28lbs of hydrodynamic wedge between that bearing and crank, thus, you're scuffing those parts causing wear. This is why an engine running down the hwy has less wear as that engine maintains a heavy amount of oil pressure wedge on the rod bearings and not shearing the oil. It's only during acceleration from a complete stop where the engine has time to allow the pressure to drop. That's why grannie's car last longer as she lightly accelerates as opposed to the young boy that does constant jack rabbit starts.
This IMO is where you have most wear. This also is why I am working on the oil pressure drop accros oil filters as to I truley believe this is what is contributing to the wear due to oil flow.