Yup!
I started to run FilterMags a few years ago after looking how much got caught in the transmission pan!
I’m using a PAIR of FilterMags and more neodymium bar magnets on the empty spaces around the filter
the FilterMags doesn’t cover.
Over the years I’ve tried most major brands of oil filters, in each case the engine oil darkened just as quickly.
In vintage cars hi blow-by can allow soot to darken oil. In late model cars, blow-by is a lot less, it’s mostly wear metals.
I’m up to 8 months before then engine oil darkens instead of 2 months! The UOA come back with lower metals across the board.
I figure with 50% less iron allowed to circulate in the oil then wear to other parts including lead babbit main bearings drops to.
So far lead is at < 1PPM - meaning “trace level” only, kinda nice!
I use a drain plug mag too with a 1” long mag built in, but no accumulation on it for the last 3 years. My PPMs overall are fairly low anyway.
Since oil pan steel is .080” or thicker, magnets on outside of steel pan have little effect in the oil pan, plus you can’t clean off
the inside. The steel shell of a spin-on filter is under .020” thick so FilterMags and bar mags work well, when get rid of the filter
you get rid of the metals too!
Since oil filters are spec’d around 95% (at 20 microns) all the stuff picked up is way smaller and never gets caught in filter – just the magnets.
I tried what’s in this PDF, lots of good pics too:
FILTERMAG vs HOMEBREW
https://app.box.com/s/uxvu8dmscf5wcgftutdm0ejqwgn86tw7