Oil longevity article
 

I am sure this link has been around for awhile, but I hadn't ever seen it. It looks suspiciously a lot like the Amsoil one that I have seen, but who knows? Anyway, I thought it was interesting.

http://neptune.spacebears.com/cars/stories/mobil1.html

I've seen that before, it's an interesting read.

From what can be inferred from the page, figure that getting 10k between changes for your beater using synthetics would be no problem, with a filter change at 5k accounted for and top-ups as necessary.

The problem that I have with the extended period (i.e. 10k) changes is the oil filter change seems like a good idea - and my filter is on the bottom of the car next to the oil pan. I suppose I could try and see how much oil comes out if the filter is removed without draining the oil . . .

Even if it's perfectly horizontal, you'll still get oil coming out of the filter area regardless of whether you drain the pan first or not. It shouldn't matter that much, IIRC most cars have an anti-drainback valve that will prevent you from dumping all the oil out of the engine when you unscrew the filter.

I'll be the forum guinea pig anyway. :) My beater is scheduled to do just that (and the filter placement is identical to your description), so I'll tell you if I made a huge mess or not. ;)

My mistake, there is no anti-drainback mechanism in the passages from the pump to the filter, I got it mixed up. That valve is in some (most?) filters to prevent the oil from draining back out of the filter when the engine is not running. This is important because a lot of engine wear happens when starting the car, so you want as much oil as possible stored past the pump to get to the main bearings (also related to why you should fill up the new filter).

We forgive you. :)

I got teh mbr stamp of approval! :bigpimp:

The filter is normally after the pump, so only the oil in the filter or the immediate mounting area should drain out.