While I was at Uni, we had access to the SAE microfiches in the library.........heaven, as you can well imagine.
There was a paper on pre-oiler, and they were reported to have significantly increased the life of all engines that they were tested on.
But when engines last many hundreds of thousands of km, will doubling the engine life allow you to drive the car for twice as many km ?
They are used in industrial applications. I see them consistently in overhung machinery, where 'jacking' oil is applied to 'float' the shaft on the bearing before motion. The 'jacking' oil is turned on usually 1 minute or so before the machine begins turning.
This is of course where several hundred pounds is overhung (cantelever) on a bearing. I believe that very large recips. use 'jacking' oil too, I haven't noticed personally but I think I remember hearing that.
How does that help???
I live in Edmonton Alberta, were we get -30C.
Most oil pumps are direct drive, so whether the engine has to turn X revolutions to bring up oil pressure does it matter if it's turning slowing(cranking) or faster (high idle).
I think the intent is to keep the bearing loads low until the oil is up and running.
But as an example, a 10:1 engine, even just cranking will have over 200 psi at TDC, when at full throttle. A 4 inch bore will give you a bit over a tonne of load on the bearing.
I've not done the sums on an engine at idle, but I doubt it would be much more than that.
Pre-lubign means there's oil at the journal when the crank starts to turn. Jacking oil actually lifts the shaft before turning takes place.
Well said, Shannow.
Now can anyone site any evidence of issues associated with pre-oilers?
BTW SHoz, I tried that and my car just reved to 4K, when cold! It said this in the manual as well but my car started right up.