Oil
So many things can go wrong with oil, and we could cover a whole book on the subject. Oil's main function is lubrication, obviously. Second to that is grabbing soot, carbon, metal bits, gum wrappers, and whatever else is floating around in your engine. The oil is then supposed to carry it over to the oil filter, where it gets removed.
Sounds good in theory, right? The problem is that any liquid solution can only pick up so much before some of that junk starts falling out. If you stuff enough midgets into the door of a Cadillac, they'll eventually start coming out the other side.
Additionally, conventional oils don't handle heat too well-heat like you might find in a mud-coated Jeep engine going up a steep incline or that you might find in a tow rig on a steep, long grade. The oil gets to the point where it turns to sludge and stops protecting the engine and adding contaminants to the remaining good oil.
The Solution
The only way to filter oil down under 20 microns is to not try to filter all the junk in one pass. Enter what is called a bypass oil filter. A bypass oil filter is typically an add-on to your current oil system, and the way it works is it takes a small percentage of the oil on each pass.
OK, let's take a step back. A regular spin on filter is called a full-pass filter. One hundred percent of the oil pumped by your oil pump passes through it. So to filter finer engine-damaging particles without starving your engine of oil, you need to skim some of that off for finer filtration yet leave enough to still lubricate the engine. This is the bypass oil.
We had been meaning to move our oil filter to a remote-style setup for quite some time when we stumbled upon the Amsoil Dual Remote Filtration System (BMK-13) and decided it was just what we needed. In one remote-mounted unit, there is a full pass and a bypass spin on filter.
Since this was going on an M-715, which is driven about once a month, we added a pre-oiling system too. Popular in quarter-mile cars that are driven about as often, the pre-oiler releases pressurized oil into the oil system when (in our case) the key is turned to the "on" position to prevent dry starts. The Amsoil AMK-01 bolts onto the BMK unit and only requires a switched positive and ground connection to function.
The only thing left was to keep the oil cool. Since this M-715 is known to run on the warm side and is slated for towing duties, we wanted to keep the oil as cool as reasonably possible so it would be better able to do its job. We turned to B&M and installed the Hi-Tek cooling system under the bed of the truck. The system includes an electric fan and a thermal switch that turns on at 176 degrees and off at 140 degrees, which is well below the temperature oil breaks down.
While Amsoil recommends oil change intervals of 15,000 miles, we are going to push that to 25,000. There are a few reasons for this: we've got 11 quarts of oil in the system now, which we think provides us some fudge factor (up from the stock eight quarts); the cooler will ensure that the oil doesn't get anywhere near the point of turning to sludge and dropping out; we put a better-quality synthetic oil in it; and, most importantly, we are going to swap the filters of the BMK-13 out religiously at the recommended intervals.
If you can figure out the diameter and thread pitch for the screw-on filter of your application as well as the diameter of the seal between the block and the filter, Amsoil can set you up with something that works for you. They don't have an extensive application guide, but many of the stock oil filters share these dimensions, and that's all you need.