Ed, thanks for sharing the pix & info with us. Nice work!
I do question whether having a base-plate end vs a dome-end bypass valve makes any real difference in the long run- but that's what makes horse races.
While I understand the theory behind the base-end bypass, in the real world it seems the dome end bypass is "good enough". (I suspect that's not because the dome-end bpv lets so little cooties through, as because the real-world base-end bpv lets more cooties through than we'd like to think.)
About nitrile vs silicone adbv: Mom's car is a 1994 Mercury Grand Marquis, 4.6 L V-8. I've had Motorcraft & other filters used on it, & can tell no difference on start-up noise, etc with most of them. For the past 6 months(just under 3000 miles right now) it's had Havoline 10w30 oil & a Havoline T-36 oil filter(Purolator Premium Plus clone) on it, no problems or startup noise. Will get the oil changed very soon, & use a MotorCraft FL820S filter- since I have one sitting on the shelf! But the Hav filter seems to have done so well that I'll get another while they're on sale for the following oil change.
At least with these filters, nitrile seems to be, once again, "good enough". Maybe using Lube Control in the oil helps to keep the nitrile valve supple?
I was surprised that the Motorcraft filter had so much less surface area than some of the others. Still, it seems to work well. The FL820S is certainly an excellent choice for any of the engines that spec it, and all told, I've probably used more MC's than all the other brands combined on the Mercury.
Thanks again, & please don't let the critics prevent you from posting any more pix, studies, or conclusions.
